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FOREWORD

The first edition ol Korean Building Code—Structural, KBCS (2005) wasthe culmination of extensive efforts to integrate various structural designcodes for buildings into a single comprehensive set of regulations byArchitectural Institute of Korea, and notified by Korean Ministry ofConstruction and Transportation as an enforcement ordinance of BuildingAct in April 6, 2005. One of the primary goals of this building code is toencourage structural design and building practices that follow up therapid developments and improvements in engineering professions a’ndaddress the international standards, As a turther step is embody thepurposes of the Korean Building Code, the need for English version otthe code has been apparently recognized by the structural engineers andcode officials,

Design Loads for Buildings and Other Structures — English Version is astandard for structural design loads based on the Korean BuildingCode—Struclural, KBCS (2005). and Korean Standard Loads for Buildings(2000). The provisions in this English version are prepared mainly for theadoption in internationalized structural engineering protession and buildingindustry, The design loads prescribed in the provisions involve deadload, live load, snow load, wind load, earthquake load, soil andhydrostatic pressure, and other loads, This standard establishes theminimum regulations for structural design of buildings and the otherstructures, And the priority in the adoption and use would be given tothe Korean Building Code—Structural, KBCS (2005) in the case ol differentengineering interpretations,

April 29, 2006

Li—Hyung Lee, PhD,, PEPresidentArchitectural Institute of Korea

Wan—Ho ‘t1, Ph.D. PEChairman, Committee for English Version of Standard Design Leads

MEMBERS OF COMMIVFEE

Design Loads for Buildings and Other Structures (English Version, 2006)Wean—Ho Yi, Ph.D., P6, Ohairman

Myeong—Han Kim, Ph.D., Secrelary

Nam—Shik Ahn, Ph.D

Young—Sang Cho, Ph.D., P2

Hee—Jung Ham, Ph,D,

Bong—Boo Jean, P6, R~

Li—Hyung Lee, Ph.D., P2

Young—Hak Lee. Ph.D.

Korean Building Code—Structural (Korean Version, 2005)

Bong—Soo Jeon, P2, PA, Chairman

Hong—Gun Park, Ph.D., P2, Vice—Chairman

Jin—Gyu Song, PhD,, Secretary

June—Sig Choe, P2

Can—Chul Choi, Ph.D.

Young—Cheol Ha, Ph.D.

Myung—Jai Heo, Ph.D., P2

Soon—Jo Hong. Ph.D.

Sung—Mok Hong, Ph.D., P2

Byung—Joo Jeong, PhD,

Duc—Jae Kim, PhD,, P6

Hyo—Jin Kim, P2

Kyu—Suk Kim, Ph.D., P2

Sang—Sik Kim, Ph,D,, P2

Won—Ki Kim, Ph,D,, P2

Dong-’Geun Lee, Ph,D,

Jun—Jae Lee, Ph.D.

Moon—Bc, Lee. PhD

Seung—Joon Lee, PhD,

Dee—Young Park, P2

Tae—Ho Son, P2

Ho—Key Yoon, P2

Standard Design Loads for Buildings (Korean Version, 2000)

Duc—Jae Kim, Ph,D,, P2, Chairman

Heon—Soo Chung, PhD,, Secrelary

Seung—Lyeol Cha, P2

Han—Wook Cho, Ph.D.

Chang—Sik Choi, Ph,D,, P2

Ki—Bong Choi, PhD,

Jae—Chul Chung. Ph.D., P6

Voung—Cheol Ha, Ph.D.

Sang—When Han, Ph.D., P2

Bong—Boo Jeon, P6

Ha—Rim Kim, Ph.D.

Hyo—Jin Kim, P2

Jong—Rak Kim, Ph.D.

Myung—Jun Kim, Ph.D., P2

Won—Ki Kim, PhD,, P2

Han—Seon Lee, Ph.D.

Li—Hyung Lee, Ph.D., P6

Bok—Man Park, Ph.D., P2

Sung—woo Shin, Ph.D.

Woon—Taek Woo, Ph.D.

Kang—Pyo Cho, Ph.D.

Young—Hwan Choi, Ph.D.

Sung—Gui Hong, Ph.D.

Jang—Ho Kim, Ph,D,

Moon—Sung Lee, PhD,

Chul—Ho Cho, PhD,, P2

Sang—Kyuu Cho, Ph,D,, P2

Hang Choi, Ph.D.

Mun—Sik Chol, PhD, P2

Si—Hyun Chung, P2

Sang—2u1 Han, Ph.D.

Sung—Gui Hong, Ph.D.

Dong—Hyeok Kim, Ph.D.

Hee—Cheul Kim, Ph.D.

Jong—Ho Kim, P6

Kyu—Suk Kim, Ph.D., RE

Sang—Sik Kim, Ph.D., P2

Dong—Geun Lee, Ph.D.

Kwang—Yerl Lee, Ph,D,

Myung—Jae Lee, Ph.D.

Hong—Gun Park, Ph,D,, P6

Yeong—Soo Shin, Ph.D., P2

Mun—Sik Choi, PhD,, P6

Jae—Chul Chung, PhD,, P2

Sang—Whan Han, Ph,D,, P2

Kap—Pyo Hong, Ph.D.

Sung—Gui Hong, Ph.D.

Sang—Sik Jang, Ph.D.

Ha—Sun Jeong, Ph,D,

Hak—Moon Kim, Ph.D., P2

Jong—Rak Kim, Ph.D.

Sang—Dee Kim, Ph,D,

Seok—Koo Kim, Ph.D., P2

Cha—Dong Lee, Ph.D., P2

Han—Sean Lee, Ph.D.

Li—Hyung Lee. Ph.D., P6

Myung—Jae Lee, PhD,

Choon—Kyong Mah, P6

Sung—woo Shin, Ph.D.

Waon—Ho Yi, Ph.D., P2

Contents

1 General1.1 Scope

1.2 Definitions

1.3 Symbols and Notation

1.4 Classification of Design Load

1.5 Combinations of Londs

2 Dead Wads

2.1 Definition

2.2 Weights of MateriaL, and Constructions

S Live Loads3.1 Genera!

3.2 Classification of Liv) Loads

3,3 Reduction in Live Loads

3.4 Similar Live Loads

4 Snow Loads

4.1 Generats

4.2 Ground Snow Loads, 5,.

4.3 Flat—Roof Snow Loads, S~

4.4 Sloped—Roof Snow _oads, S,

4.5 unbalanced Roof Snow Loads

4.6 Drifts on Lower Roe’s (Aerodynamic Shade)

4•7 Rain—on—Snow Surc~arge Load

4.8 The Rest Snow Loan

5 Wind Loads5.1 General

5.2 Design Wind Loads on Structural Fromes

2828

28

29

31

33

36

39

40

itt

41

42

5.3 Design Wind Loads on Root Frames

5.4 Design Wind Loads on Building Components and Cladding

445,5 Dynamic Response Due to Wind Actions 46

5.6 Velocity Pressure 46

5.7 Gust Effect Factor for Structural Framas and Roof Frames 53

5,8 Pressure and Force Coetticients for Structural and Root Frames

57

5.9 External and Internal Pressure Coefficients for Loads on Building

Components and Cladding 63

6 Earthquake Loads6,1 General

6.2 Load Combinations

6.3 Site Ground Motion

6.4 Earthquake Loads—Criteria Selection

6.5 Equivalent Lateral Force Procedure icr Seismic Design

6.6 Seismic—Force—Resisting Systems

6,7 Dynamic Analysis Procedure

6,8 Structural Component Design Requirements

6,9 Architectural, Mechanical And Electrical Comoonents

6,10 Seismic Design Requirements for Nonbuilding Structures

7 Soil and Hydrostatic Pressure and Other Loads7.1 General

7.2 Soil and Hydrostatic Prossure

7.3 Thermal Stress

7.4 Fluid Pressure

7,5 Contents Load in Storage Tank

7.6 Transportation Equipment and its Component Loads

99

9

15

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19

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103

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118118

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119

119

120

1 General1.1 Scope

This standai-d provides the requirements for the calculation of loads,which is applied to buildings and other structures. For the calculation ofdesign loads and external forces based on the specL.l studies andresearches, and if it is approved to be equal or more than therequirements presented in this standard, however. some of the provisionsin this standard need not be applied.

1.2 DefinitionsAcross—wind Vibration Irregular vibration in across—wind directiondue to buffeting, vortex—shedding, and wakes.

Active Fault: A fault determined to be active by the authority having

jurisdiction from properly substantiated datn

Aeroelastic Instability Vibration Vibration occurred when themodification of wind pattern around a structure 1w aeroelasticitv is surhthat it increases rather than decreases vibration.

Attachments : Means by which components and their supports aresecured or connected to the seismic—force—resisting system of thestructure. Such attachments include anchor bolts, welded connections,and mechanical fasteners.

Base : The level at which the horizontal seismic ground motions areconsidered to be imparted to the building.

Base Shear : Total design lateral force or shear at the base.

Basic Wind Speed : 10—minute mean wind speed over a flat and openterrain at an elevation of 1Dm with a return period of 100 years.

I I General 9

l3earing Vail System -A structural system without a completevertical load--earning 5~iCO frame. Bearing walls or bracaig elements

provide support Cur suhstanlial vertical loads. Seismic lateral force

resistance is provided oy -hear “ails or braced frames.

Boundary Element In ight—frame construction, diaphragms and shear

tvall boundary members o which sheathing transfer forces, Boundai

elements include choids nd drag struts at diaphragm and shear wall

perimeter, interior opening -. discontinuities and reentrant corners,

Braced Frame As~ essentially vertical truss, or its equivalent, of the

concentric or eccentric ty’)e that is provided in a bearing wall, building

frame, or dual system to resist seismic forces.

Building Frame System A structural system with an essentially

complete space frame pro cling support for vcrtical load. Seismic lateral

force resistance is provided by shear walls or braced frames.

Design Earthquake Tl:-,’ earthtit,ake effects that are the corresponding

maximum considered uartnquake effects.

Design Spectral Respu’ Sc Acceleration Design spectral response

acceleration at short perio 5. S1~ and at I - secood period, S~1.

Design Wind Speed \Vind speed for use in design considering basic

wind speeds, terrain condions. topographic conditions, and importance of

a building.

Bauble Frame System A structural system with an essentially

complete space framc prcvding support for vertical loads, Seismic force

resistance is’ provrded lx shear walls or braced frames. The momeat

frame shall be capable ‘ resistrng at least 25 percent of the design

seismic forces,

Enclosed Structure building that has a roof and full perimeterwalls fi-ort, floor to roof l - el

Exposure Category An exposure category thaI adequately reflects thecharacteristics of ground surface irregularities for the site at which thebuilding or structai-e is to be constructed.

Exposure Con sI ant The height rove ground in -a hich change of

vertical wind speed prol5les with height by the infiuence of surfaceroughness starts.

External Pressure Factors Producl of the external pressure coeflicient

and gust effect factor to be used in determination of wint loads for

building components and cladding

Flexible Diaphragm A diaphragm is flexible for the purpose of

distribution of story shear and torsional moment when l:he maximum

in—plane deflection of the diaphragm itself under lateral load is more than

two times the average dnfi. of adjoining vertical—resisting elements under

equivalent tributru-v lateral load.

Flexible Structures Dynamically sensitive structures due to additional

load generated by interaction between wind and a structure.

Gust Effect Factor It is defined as the ratio of expected maximum tomean structural response that represents the dynamic response phenomenapi-oduced by the action of wind gustiness of longitudinal component.

Importance Factor A factor that accouats for the degree of hazard tohuman life and damage to property. The importance factor is used toadjust the level of structural reliability of a building or other structure tobe consistent with the building classifications.

Influence Area The total summation of influence area fran the upperstories. The influence area is four times the tributary area for an interiorcolumn and an interiut foundation, two times the tributary area for agirder or a continuous beam,

Intermediate Moment Frame A moment frame in which members

‘10 Design Leads tor BuSd’nr~s and Other Struacres — --15 I General 11

and joints are capable of resisting forces by flexure as well as along projected on a plane normal to the wind direction.the axis or the members.

Reduction Factor A factor that accounts for the reduced design live

Internal Pressure Coefficient Product of internal pressure coefficient load due to the area supported by the member.and gust effect factor to be used in deterniiimtiuri of wind loads forbuilding components and cladding Return Period The basic probability of high winds needed for

structural design is the exceedence probability that a given wind speed

Leeward Face Thc side sheltered from the wind, will be exceeded within a one—year pedod. The reciprocal of exceedanceprobability is called the return period.

Mechanical and Electrical Components Components permanentlyattached to structures, including supporting structures and attachments. Rigid Structui’es A building or other structure ‘vhicb can neglect an

additional load generated by interaction between wind and a structure.

Moment Frame System A structural system with an essentiallycomplete space frame pr-rwiding support for vertical loads. Seismic Seismic Forces The assumed forces prescribed herein? related to the

lateral force resistance is .‘‘ovided by moment frames, response of the building to earthquake motions, to be used in the designof the building and its components.

Monnslope Free Roof Planar roof with no enclosing walls underneath.

Seismic Force Resisting System The part of the structural system

Nominal Height of the Atmospheric Boundary Layer Wind speed that has been considered in the design to provide the required resistance

is zero at the surface, and it increases with height above the ground in to the seismic forces prescdbed herein.

an atmospl~eric boundanr layer. Above this height of layer exists gradient

wind which does not vafl with height. This height is defined as such. Seismic Response Coefficient A coefficient decided 1w Eq. (6.5.2)’—

The height above ground ~~hich is not to be affected by ground surface Eq. (6.5.4) C.roughness. Wind speed is not to he changed in this height.

Seismic Use Group Seismic use groups and occupancy importance

Nonbuitding Structures Nonbuilding structures include all factors in accordance with <Table 6.4.1>.

self—supporting structures that cmxv gravity loads and that may be

required to resist the effects of earthquake. Seismic Zone A zone classified by the expected seismic activities and

seismic intensities.Nonstructural Member The constructional element of the buildingexcluded for structure analysis. Shear Wall A wall, beadng or nonbearing, designed to resist seismic

forces acting in the lane of the wall,Normal Moment Frame A moment frame in which members andjoints are capable of resisting forces by flexure as well along the tLXis Site Class A classification assigned to a site based on the types ofof the members. soils present and their engineering properties as defined in <Table

6.3.2>

Projected Area Area building either normal to wind direction or

1 2 uesign Loads for Bucrdings and OIlier slruclures — Art I General . 1 3

Strong Diaphragm A diaphragm is rigid for the purpose of force resisting structui-al system of roof.distribution of story and orsional moment when the lateral deformationof the diaphragm is less than or equal to two times the average story Wind Load on Structural Frames Wind loads for the desgn of maindrift, wind—force resisting structural system of buildings

Story Drift The horizontal deflection at top of the story relative to Wind Pressure Coefficient A coefficients that are normalized by thethe bottom of the story. velocity pressure at the reference height.

Story Drift Ratio The qory drift divided by the story height. Wind Speed Profile Factor Factor accounting for the rhange in windspeed with height and surface roughness.

Story Shear The summation of design lateral seismic forces at levelsabove the story under cot;eideration. Windward Face The side from which the wind is blowing.

Topographic Factor Topographic factor, which reflects the change of 1.3 Symbols and Notationthe mean wind speed that occurs when wind passes at right angles to A influence area j1≥40in2)escarpments or ridge—shaped topography. A Projected area or effective wind area,

A site coefficientTorsion Vibration Torsional vibration is caused by asymmetric wind . . -A shear sectton area of shear wall parallel to the direction of thepressure distribution on the windward face, side faces and leeward face. seismic load at 1st level, mThis is due to both wind turbulence and the vortex in the building’s

A,, tnbatary areawake.

B donension of a building or a structure not-mal to wind direction. m

Tributary Area Area o~ floor is supported by the vertical members. B1 background excitation factor (factor representing frequencycomponent except for natural frequency of the huildingi

Velocity Pressure Design wind pressure to be used in the C reduction factor of live loadsdetermination of wind loads for buildings. C, base roof snow load factor

exposure factorVottex—induced Vibrati,.in Vibration due to periodic lateral force C1 wind force coefficients for the design of structural and roofcreated by vortex shedding, frames

C, roof slope factorWind Force Coefficient A coefficients that are norma]ized by the

C thermal factorwind load operating on the wall of structure at the reference height.

external pressure coefficientF Wind Lond on Claddint. Wind lo id fos the design of ci idding os othe C, , e”ternal pressuie coefficient on the wind~nid face

elements of huildings C, external pressure coefficient on the lee;x ard f ice

C5 mtemal precsurc coefficient fot enclosed buildings a suxicturcs

Wind Load on Roof Fr acs Wind loads for the Oesign ot miii uind— D length of s’sc a wall at 1st lerel iii

I 4 005100 Loads for Soitd,ngs and Other sirucicres — “OK I General 1 5

F wind force spectrum factorF, portion of the seismic base shear included at level

F, equivalent static force for the seismic design of nonstructural

component

F, lateral seismic force at level x

Cf gust effect factor for structural and roof frames

C, I gust effect factor ~or internal pressure

CC,, external pressure oefficient for building components antI cladding

internal pressure coefficient for building components and cladding

H height of hill or escarpment mimportance factor

4 turbulence intensit-c at the reference heightimportance factor for wind load

importance factor for sno’v load

K exposure factor

topographic factor

L honzontal dimension of a building measured parallel to the winddirection, m

turbulence length scale at the reference height, in

horizontal distance upwind from the crest to where the difference

in ground elevation is half the height of hill or escarpment, m

I? response modification coefficient

i?, resonance factor

SI

s1snow load on flat roofs, kN/m2

size reduction fact or (factor representing reduction of turbulence

effect due to scale of a building)

ground snow load, tN/rn2

sloped roof snow load, kN/m 2

fundamental period of the structure, secbase shear force

V0 basic wind speed, rn/s

it,, design wind speed at the mean roof height h above ground level,

ni/s

seismic design shear in story x

design wind speed at height a above ground level, rn/s

W total weight of structure

wind load on cladding, N/rn

wind load on structural frames, N/rn 2

weight of structure in story f.~

total weight of the non—structural element

wind load on roof frames, N/rn2

distance to center of pressure from windward edge of roof, in

height above ground level, mexposure constant, m

nominal height of the atmospheric boundary layei-. in

diameter of circular cross—sections and least horimntal dimensionof square, hexagonal, or octagonal cross—section at elevationunder consideration, mdepth of protruding elements such as ribs and spoilers, in

height from springline to roof top, m

g gravitational accelerationpeak factor

mean roof height of a building, m

height of obstruction above the surface of the roof, in

height of balanced snow load, m

clear height from top of balance snow load to

adjacent upper roof, (2) top of parapet, or (3)on the roof, mheight of chimney, tank, and similar su’ucture, in

height of sno’v drift, in

the height from the base to level or x. m

height of the structure above the base to the roof level, in

h, height from bottom of dome to springline, in

h, height of sign board, m

diameter of domed roof, m

4 1 length of the roof upwind of the projection or parapet wall, in

(1) closest point on

top of a projection

16 Dadgn toads for nuifeings and Olser Siruclures — “is I General 17

larger dimension o sign board, in

smaller dimension of sign board, in

1st mode frequency of building, t-t

5. Etu-lhquake load C E1

1. Soil and hydrostatic pressuit C if)

g. lemperature load ( T)

h. Flood load (F)

i. Machinery and moving load C U)

j, Other loads

1.5 Combinations of Loads

15.1 Load Combinations for the Design of Concrete Swucturcs

U= 0.75(1.4D+ IlL-I- 1.7 TV)U= 0.9D+ L3 TV

U=0.75(l.4D-I-L7L) ±1 OF

U=O.9D+ 1.OF

U= 1.4/3+ 1.7L + 1.811U=09D+ (.811

U 1.1/3+ l.7L-I- I 5FU=O.SD±l.5F

U=0.75C1.JD+1.7L+ LST)U~1.4D+1.5T

(1.5.2)

(1.5.3)(1.5.4)C1.5.5

(1.5.6)(1.5.7)

(1.5.8)(1,5.9)

1.5.10)

(1.5.11)

p design wind pressr’e on cladding, N/tn2

p, design wind force on structural frames, N/rn2

design wind force on roof frames, N/o~

velocity pressure at mean roof height h above ground level, N/rn2

velocity pressure at height Z above ground level, N/rn2

I r,se-’to--span ratio of domed roof

turbulence factor

separation distanc between the roof and adjacent structure, in

iv width of the additi :nal snow drift, in

power law exponent of mean wind speed

a. deflection of level tat the center of the mass at and above level x

a~. deflection of level,- at the center of the mass at and above level xdetermined by an elastic analysisdamping ratio of I ~t mode

o angle of plane of roof from horizontal in degrees,von Karman constant( ~s0.4)level crossing frerj~ency, fi.

ratio of solid area~ to gross area

O ratio of solid area to gross area of one tower face for thesegment under consideration

O upwind slope C ~= rI/2L,)the average downwind slope, measured from the crest of a hill,

ridge, or escarpment to the ground level at a distance of SI-I

1.4 Classification of Design LoadLoads for the structural design of structures are as follows and detailsare based on from Chapte 2 to Chapter 7.a. Dead load CD)

lj. Live load C L1

c. Snow load (3)

ul, Wind load C iv1

1 8 Oesioo Loads lou Oujtdungs and Other Structures — 15

1.5.1.1 Strcutures, components, and foundations shall be designed so thattheir design strength equals or exceeds the effects of the factored loads

on the following combinations.

U= 1.4/3+ IlL (1.5,1)

1.5.1.2 For the structnres in which the majority of loads zcc dead load.

such as underground structures, 1. 1D instead of f) in the term of

1 .4D shall be applied in the above combinations.

1.5.1.3 The load combinations of Eq. C L5.2), t5,4} and 11,5.5) shall

include both full and zero value of L to detemune the more severecondition.

1.5.1.4 Detailed provisions for the load combinations in the tlesign of

1 General 19

r

concrete structures are ivcn in Section 0503 32 of Korean Buihdng

Gode—Structuial KBGS (2~K)5)

2 Dead Loads1 32 Load Combinations f0r the Design of Steel Structures

2 1 Definition1 5 2 1 Sttcuturcs, compor~nts and foundation, shall be designcd so that Dead leads consist of the weight of all matenals and fi\ed equipmentstheir design stiength eciuals 0’ e’<ceeds the effects of the factoied leads incorporated into a building or othei structureon the following combinations —

U1 a (1 o12) 2 2 Weights of Materials and ConstnictionsU 1 2D~ 1 6L+0 i(L r ci S ) (1 1) In deteimining dead loads foi design puipose the actual ~cights of

U= 1 2D+ 1 6(L o, S)+ (f~ o, 0 SW) (1 ti14) materials and construttions shall he calculated based on dc isities unit

U= 1 213+1 6W+I L+0 5(L r o~ 5) (1 nib) weights, and combineu weights of mateiials

U~lZD+l0E+fiL+ S (1,16)U=0 9D+(1 OE o; 16W) (1517)

1522 The load factoi ni L f1 in the Eq (1514) (1515) and (1316)

shall lie tnken as 10 foi paiking gaiages arens occupied as places ofpublic assemhl~ and ccc ipancies in which live load is greatm than or

equal to 48 kN/ni2 The I ad factot is pci nttted to equal 05 foi all othei

live loads

I 5 2 3 The load factor on ~ f, shall he taken as 07 foi the ioof

configutation that do not hcd snow off the structure such as saw tooth

and 02 for other ioof con iguiation

1 5 2 4 Where thc effec of flood load F or soil and hythostatic

piessure, H is considereo the factored load of 1.3F ci 1 611 shall he

a pphcd

1.5.5.5 Detailed piovisions for the load combinations in the design ofsteel structures are gi en in Set tion 07017 of Korean BuilidngCode—Situctural, I(BCS 12Th)

2 Oead coeds 2120 I Design coadi for Buildings and Oiher Siruciures — 115

3 Live Loads3.2.2.1 Live loads expected by the intended usage or occupancy shall benot less than minimum live loads i-equired by <Table 3.2.1>.

3.1.1 Application 3.2.2.2 Concentrated loads shall he located so as to produce we maximumload effect in the structural members.

31.1,1 This section shall be applied in determining the minimum liveloads produced by the usage and occupancy of buildings and otherstructures. 3.2.2.3 Contact area in <Table 3.2.2> shall be used in checking two—way

shear.

3.2.2.4 Roofs of a building for manufacturing or storage shall be designedfor dead loads and additional concentrated load of minimum 10 IcN whichis assumed as dead load to be applied at main structural components orthe bottom chord of a roof truss. Roofs of other use shall be designed foradditional concentrated live load of minimum 1 kN which is considered asdead load.

3.2.1 Uniformly Distributed Live Loads

3.2.1.1 Live loads expecten by the intended usage or occupancy shail nothe less than the minimum live loads required by <Table 3.2.1>.

3.21.2 If live loads in <Table 3.2.1> are inappropriate for theconsideration of vibration ad impact forces, live loads shall be increasedaccording to actual contlitiens.

3.2.1.3 In office building~ or other buildings where partitions will beei’ected or rearranged, nunimum partition weight of 1 kN/n~ at least shallbe added to minimum unifermly distributed live loads, unless the specified

r

3,1 General

lIve load exceeds 4 lcN/m~.

3.2.2 Concentrated Live Loads

3.1.1.2 In case this sectio ~ is not applied, the estimated live loads shallhe specified by their source.

3.2 Classification of Live LoadsLive loads are divided into uniformly distributed live load and

concentrated live load, and the load which produces the greater load

effect shall he applied.

22 Destgn Loads br SuildEn5s and Oiher Siruciures — U’ie Loads 23

(Table 3.2.1) Minimum Uniformly Olalrlbuted Live Load (kN/m’)

r

Occupancy use

II Ikiign loud for nook wriglirjsg zaire thrir, lii tim! visit] Is, slcirmdard iii caisidcroitiroz of retail In,,

uvo Load

Occupancy use Live Load

S Living rooms common areas and corridors for 20

I Residential dwe’,’ngb, Eolccniea of aparimeni houses 3.0

a, Private rooms and their corridors 2,0

2 HospItals ‘~Operahng rooms, common areas end llieir 30

corr Hors

a, P’ivale rooms and heir corridors 2.03 Accomm000liOn —

b. Public areas and Iheir corridors 5,0

a. 0 Ices and corridors 2.5

b, a Lobbies 4.04 Office buildings

c, a Offices or special use and their corridors 5,0

d, Cocumeni slack 5.0

a. Classrooms and their corridors 3.0

b. Lobbies 4.0S Schools

c, General taboralories 3.0

d. Laboralorles br heavy materials 5.0

a. Ralalla and deparimenla (lirst floor) 5,0

6 Stores b. Retails and deparimenls above llrsl 110cr 4.0

c. ‘/Tho]esale 6.0

a. Lobbies and corridors 50

b. Siege Iloora 7.0

c. Realauranla 5.0

Assembly areas and d. Cock rooms (for business) 7 0recraallonal areas

e, Booed seals 4,0

I, Movable seals 5,o

0. Dance halls and ballrooms 5,0

a, Gymnasium floors, sporis ground 5,0

a Sports lscil,liea b, Fixed stands 4,0

c, Movable stands 5.oa, Reading rooms and corridors 3,0

9 LIbrariesb, Slack rooms 7.5

a, Passenger car I 4.0

Indoor b. Lighlwalghl reck and emply bus 5.0

c. Truck and heavyweighl truck0 less than total 12 0weight lalont

a, Passenger car [ s.cto Parking Indoor Driveway b, Lightweight Iruck and amply bus 10,0

and ramp Ic, Truck and Ileavymeighi truck less than total 16‘veighl IS ionl

a. passenger car, 11gb bwei ghl Irucic and emply bus 12,0Ouldoor b, Truck and heavyweight Iruck” less lhsn lolel

melohi lB tonI

a, Lighl 5.0it Storage a:arehouses

b. Heavy 12,0

a. Light 6,012 Manulacluring

b, Heavy 12.0

~ a, Roof dillicull to access 1,013 Roots

b. Roof with Ilitle loading 2,0

J c, a, Roof gardens or assembly ourposes 5,r

d, Heliport 5,0

4 MachIne rooms Air conditioning rooms. eleclrical/mochanlcal rooms 5,0

15 Yards and sQuares Open yards or squares 2,0

24 Design Loads for Buildings and Other Slruclures — AIK i Live Loads 25 I

(Table 3.2.2) Minimum Ccncentraied Live Loads 3.3.2 LimitationsContact Area forI Concentrated

Occupancy or Cue [ Two—way Shear~ Load (kNI

Cm’)

1 Classrooms and tibrartas 5.0 0.5

2 Offices, hospital rooms, and tignt manufacturing 10.0 0.5

~ Portono ~~r~er car 10.0 o.otsVasi mum wheel~ Truck nct bus 0013toad

.1 Root difllcutt to access 1.5 0.5

5 Stair steps Cappty to tIle mtddti-r 01 steps) .35 0,0025

Maxtaum allowable take—off~ load less than 20 Ml 28 [ 0,04

6 Hetiport ~~lm attowabte lake—ott

I ] load sos than 60 kM 0,09

3.3 Reduction in Live Loads

3.3.1 Reduction Based on Influence Area

3.3.1.1 For columns, founuations, girders and continuous beams for which

influence area is 40 mu o’ greater, the design live loads are permitted to

he reduced to a unreduced live loads times reduction factor. C

c=

where, C reducti n factor of live loads.

A Influenre area with A ~ 10m°.

(3.3.1)

3.3.1,2 The influence arc~ , /1, for a column or a foundation is the total

summation of influence area from the upper stories. The influence area,

A, is four times due triburary area for an interior column and an interior

foundation, two times du tributary area for a girder or a continuous

beam.

3.3.2.1 For a column or foundation, reduction factur, (4 shall be

determined using Eq. (3.3.1), ~vliere Use value uf the reduction factor. (4

is not less than 0.5 for members with a tributary area from just one

floor, nor less than 0.4 for other members.

3.3.2.2 For a girder or continuous beams, the reduction factot, (4 shall be

deten’nined using Eq. (3.3.11, hut not less than 0.7.

3.3,2,3 A simply supported beam or slab is not permitted to he designed

with live load reduction.

3.3.2.4 Reduction of live loads is not permitted in item (6) to item (12),

item (14) and item f 15) of <Table 3.2.1> except when a column anti a

foundation are permitted to be designed with the reduction factor, C, nut.

less than 0.8

3.4 Similar Live Loads

3.4.1 Applications c.tf Similar Live Loads

3.4.1.1 Hanclrails, guards, and grab bars of a parapet, a balcony or stairs

shall he to resist at least a horizontal load 0.4 RN/rn foraresilence, and

0.8 kN/no for others.

3.4.1.2 An inner ;vail with height clearance greater than or eoual ta 1.8

m shall be designed to withstand a uniformly distributed load, 0.25

RN/n?, acting perpendicularly to the partition face except for partition or

similar wall components whose locations are subject to change.

26 Oesign Loads for Buildinls and OtIter Structures — ‘yR SluveLaads 27,

r

4 Snow Loads4.1 Generals

4.1.1 Scope

4.1.1.1 When the effect of snow toads acting on a roof is huger than theminimum roof live loads determined from r32 and r34 the snow loadsin this section shall be applied.

4.1,1.2 The effect of snow loads shall be considered on the wall surfaceexpected to act.

4.2.1.1 Ground snow loads to be used in the determination of designsnow loads for roofs shall he as set forth in <Table 4.2.2>. When<Table 4.2.2> is used it should be considered that local variation can bebrought due to regional climate and topography. Even though it is thesame area <Table 4.2.2> cannot he used for specific regions such as a

hilly areas or mountainous regions.

4.2.1.2 Grotuxl snow loads for sl~c,flc region can be calcilated consideringthe snowfall average outs and average snow weight through actualinvestigation and study.

4.2.1.3 Minimum ground snow loads shall be 0.5 lcN/mt.

4,2.2 Basic Value of Ground Snow Loads

The basic value of regional ground snow loads ( s~, IQO—vear mean

recun’ence interval) shalt he in <Table 4.2.2>,

(Table 4.2.2) Basic Value of Ground Snow Loads( S5)

Region

seoul. Suwon, chuncheon Seosen, chungju, Ocejeonchupungreyong, Pohang. Gunsan, Taegu, cheonfu, ulsan, Gwang~u,

Pusan, cl,ungmu, klokpo, Veosu Chelu, Seogwipo, Jin1u, Wullin,

IC Ii so n

4.1.2 Guideline of Snow Loads

4.1.2.1 The design roof 5mw loads shall be calculated based on groundsnow loads considering basic values of roof snow loads factor, exposurefactors, thermal factors, imoortance factors, shape factors of roof and loaddisb’ibution condition.

4.1.2.2 The basic value of ground snow loads are based on the maximumsnowfall average outs (IOU—year mean recurrence interval) shown in<Table 4.2.2>. If the mean recurrence interval is not applied as 100years, compensated values of ground snow loads in accordance to themean recurrence interval shall be used.

4.2 Ground Snow Loads, s~

4.2.1 Calculation of Ground Snow Loads

Ground snow Loads

I kN/ni~)

0,5

lnchaon 0 8

Soacho 2,0

Gangneung 3.0

Uileungdo, Daegwan[yeong 7,0

4.3 Flat—Roof Snow Loads, s1The snow loads, 5~ , on a flat—roof shall be calculated using Eq. (4.3.1)

S~ C,’ C~ C, J~ Sg (kN/m2) (4.3.1)

28 Design Loads for Buildings and Olher slruclures — A’S4 snow Loads 29

4.3.1 Basic Roof Snow Load Factor (C~)

The basic roof snow load lactor defined in Eq. (431) is generally 0.7.

4.3.2 Exposure Factor cc

The \ralue for C~ defined in Eq. (4.3.1) shall be determined from <Table

4.3.2>.

Terrain Category”

A. Above tire recline in windswept arruntatnous areca 0,8

0. FbI. unobstructed areas exposed ‘r wind flowing over open water 0,9

C. Open tarrat n with scattered cbs truc~’ ons having heights generetly teas than 9,1 in. 1.0

0. Urban and suburban aroas, wood-.d areas, or other terrain with numbarous closely

spaced obstructions having the sir. at single—family dwellings Or larger.

5, Large city centers a4th at least 5051 of the buildings having a height excess 01 213w, 1.2

Thermal Condition C,

Healsd structuros(snow loads under control) 1.0

Unheated structures

(snow loads without control) 1.2

• Facillttes with greater than 5000 m’ total hoer area (‘asbity whorepeople congregate in one ores, sports Iscililtos. transoorlalionfacilities . eahtbihton facilIties and maritabing becilitiest

• Greater than 5—story acceminodetiona, ofticetet. dormitory and apartment

- Greater than 3—story school

itt [ Alt buildings except those listed In Categories I, II, and IV

IV ] -Agricultural facilities, temporary facilities, and ‘Ilinor storage tecitilies 0.8

4.3.5 Minimum Allowable Values of s. for Low—Slcpe Roofs

4.3.5.1 Minimum allowable values of S~ shall apply to monoslope, I-ia. antI

gable roofs with slopes less than 15” and curved roofs where thi, verticalangle from the eaves to the crown is less than 10”.

4.3,5.2 For locations where the ground stiow load, S~,. is I kN;m2 or less.

the flat—roof snow load, S1 , shall be not Jess than the grrrvnd snow load

multiplied by the impootance factor.

4.3.5.3 In locations where the ground snow load, s.. exceeds 1 kN/nn~,

the flat—roof snow load, s~ , shall be not less than 1 leN/rn1 multiplied bythe importance facton’.

r<Table 434) Importance Factor ( I,)

(Table 4,3,2) Exposure Factor (

category Nature of Occupancyi tmporlance

-- - Factor ( /,)- Fsctlttisa wtlh greater tItan 1000 m’ total floor area storage o~

Irealment lad lily nt dan~prntta articres, hospitals and crop’

health—care tacililies, communication centers and other pc es 2required for emergency reaponse. power generating stations and ‘re

and rescus stations pubtic utility lacititlasi- Greater than 15—story apartment and otticetet

I ‘ti,’ ynnait car star. ‘Jolt lv i’~a1.i.n’’. ‘ic. tin’ ;a,ticrtsit,.tl t’,ixtti’ni< dw,ae tSr Ito’ tirIt ltw,el< “laln,’rl,,ia<,in. riley.- du’.-r,t’.’jr trw’s liril crc tattler, iii turitlir. C <trill hr claiw-teet lii

4.3.3 Thermal Factor (C,

The value for C, defined ~ti Eq. (4.3.1) shall be determined from <Tnblo

4.3.3>.

(Table 4,3.3) Thermal Factor ( C,i

4.3.4 Importance Factor ~‘j

The value for j, defined ti Eq. (4,3.1) shall he detensiined from <Table4.3.4>.

4.3.5,4 The live load reductions shall not be applied to snow toads.

4.4 Sloped—Roof Snow Loads, s,The sloped—roof stiow load, S., defined in Eq. (4,3f shall be obtained by

30 Destgn toads for Suildings and Other Structures — /4 i snow Loeda 31 -

multiplying the flat—roof snow load, s~. , by the roof slope factor, c;

S,= C, S, (kN/n:°) (4.4.1)

Values of C, for warm roofs, cold roofs, curved roofs, and multiple roofs

aie determined from r441 to r444

4.4.1 Warm—Roof Slope Factor, C,

4.4.1.1 For wann roofs vitli an unobstnicted slippery surface that willallow snow to slide off the eaves, the roof slope factor C, shall be

determined using the dashed line in [Fig. 4.4(a)].

4.4.1.2 For warm roofs that do not meet the aforementioned conditions,the solid line in [Fig. 4.4 (a)] shall be used to determine the roof slopefactor C,-

4.4.2 Cold Roof Slope Factor

4.4.2,1 For cold roofs with an unobstructed slippery surface that willallow snow to slide off ‘he eaves, the roof slope factor C, shall be

determined using the dashed line in [Fig. 4.4th)].

4.4.2.2 For cold roofs that do not meet die aforementioned conditions, thesolid line in [Fig. 4.4(b)] shall be used to determine the roof slope factor

C,

4.4.3.1 Portions of curved roofs having a sloped exceeding 70’ shall lieconsidered ft-ce of snow load (i.e., C, 0).

4.4.3.2 Root slope factor for curved roofs shall be determined the

appropriale curve in [Fig. 4.41. The roof slope means an angle belween

a horizontal line and a tangent line slope from eaves to Ihe top.

4.4.4 Roof Slope Factor for Multiple Folded Plate, Sawtooth, and

Barrel Vault Roofs

Multiple folded plate, sawtooth, or barrel vault roofs shall have a C,

1.0. with TiO reduction In snow load because of slope (i.e.. S =

4.5 Unbalanced Roof Snow Loads

Balanced and unbalanced loads shall he analyzed separatelY. Winds from

all directions shall he accountad for when establishing unbalanced loads.

i.o

0.8

0.6

0,4

0.2

Cs

1.0

0.8

0.6

c,

0.4

0.2

20’ 60’ 90’Roof slope(a) Warm Roots. c. ‘-‘ 8.0

IFig. 4.41 Roof 5lope Factor ( C’,)

0 30’ ‘3 90’Roof Slooc

(b) cold Roofs, c. 1.0

4.4.3 Roof Slope Factor for Curved Roofs

I 32 Design Loads for Buildings and Olher Slruclures — - 4 ‘ Snow Loads 33

4.5.1 Unbalanced Snow Loads for Hip and Gable Roofs

4.5.1.1 For hip and gable roofs with a slope less than 15° or exceeding70°, unbalanced snow loads are not required to be applied.

~H~HH~

~

4.5.2.3 If the slope of a straight line from the eaves (or the 70° point, ifpresent) to the crown is less than 10° or greater than 60°, unbalanced

snow loads shall not be taken into account.

4.5,2.4 Unbalanced loadsdiagrams in [Fig. 4.5.2].considered free of snow.

(a) Roof Slope < 30’

0a A aCave Crown 30’ po,nt Cave

,Wind

0.55, .2~3rr’rT]11l~ ~ 25 ‘C,

A a a a acrown 30’ point 70’ pont Cove

‘Alternate distribution it another roof abuts

Ic) Root slope > 70’

1Ff0. 4.5.2] Balanced and Unbalanced Loads for Curved Roots

Wind .,,.,,.~.

Balanced0

Load

Unbalanced

Load

* t’l,t’vvt*irc’t ,e,ts.t;,,,crd ,.-,,o,v tends for a Xnt*, loin lion IS’exrc’ding 70’

[Ftg. 4,5.1) Balanced and Unbalanced Loads for Curved Roots

shall be determined according to the loadingIn all cases the windward side shall be

IS.

T

I1.55/C,-r 0

Cave

~V2

4.5.1.2 For slopes between 15° and 70°, the structure shallresist an unbalanced unifcian snow load on the leeward

1.SS,/C,. In the unbalanced situation, the windwardconsidered free of snow.

25,/C

- a/aC

aCrown Cave

be designed toside equal to

side shall he

W,nd

‘Alternate distribution it another roof abula

(b) 30’ < Roof Slope < 70’

4.5.2 Unbalanced Snow loads for Curved Roofs

4.5.2.1 Portions of curved roofs having a slope exceeding 70° shall beconsidered free of snow load.

4.5.2.2 If the slope of a straight line from the eaves (or the 70° point, ifpresent) to the crown is greater than 70° unbalanced snow loads shall bedetermined using [Fig. 4.4].

Cave

452,5 If the ground or another roof abuts [Figs. 4.5.2(b) and ‘c.’i curvedroof at or within 0.9 in of its eaves, the snow load shall not be decreasedbetween the 30e point and the eaves but shall remain constant ( 2 S,/ c,)at the 30° point value. This distuSbution is shown as a dashed line in

i 34 Daatgn Loads or Buildtnga and other Structures — AIX I 4 snow Loads 35

[Fig. 4.5.2],

4.5.3 Unbalanced Snow Loads for Multiple Folded Plate, Sawtooth,

and Ban-el Vault Roofs

4531 Unbalanced sno~ loads for multiple folded plate, sawtooth, and

barrel vault roofs shall increase from 0.5 Sf at ridge or CrOWn to

at the valley as shown ic [Fig. 4.5.31.

4,5.3,2 Snow depths abo’c the valley shall he determined by dividing thesnow load by the densty of that snow from Eq. (4.5.1). Thereforeunbalanced snow loads alove the valley shall be substituted by the value

less than 3S,JC~

0.43 S~t 0.0023 ≤ 6.6 ( kN/in°) (4,5.11

$1 EJ_LILE ~4~4E

4.5.4 Partial Loading

Any adverse effect of removing half the balanced snow load over anyone portion of the loaded ca shall he considered.

4.6 Drifts on Lower Roofs Aerodynamic Shade)For adjacent higher struct cc or a hump drift and sliding of snow shallhe considered to calculate cealized loads

36 oc’srgn Loads for Oui!drngs and OThsi Slrucrrsres —

4.6.1 Lower RoofsRoofs shall he designed to sustain localized loads from snow drifts thatform in the wind shadow of (1) higher Potions of the same structure; and(2) adjacent structures and terrain features.

4.6.1.1 Regions with Light Snow Loads

rn areas where the ground snow load is less than 0.5 kN/m2, drift loadsare not required to he applied.

4.6.1,2 Lower Roof of a StructureSurcharge load due to snow drifting at a lower roof shall be as shown in

[Fig. 4.6.1], the drift loads shall be superimposed on the balanced snow

load. ff hr/kb is less than 0.2, drift loads are not required to be applied.

The drift height.~,, shall he determined directly from [Fig. 1.6.2] and it is

not required to be greater than hr~ The drift width. Ic. shall equal 4 lid and

if it exceeds the width of the lower roof, the drift shall be truncated at

the far edge of the roof, not reduced to zero there. The maximumintensity of the drift surcharge load equals ‘~d multiplied by Eq. (4.5.1).

4.6.1.3 Adjacent Structures mid Terrain Features

The requirements in Sections 4.6.1.1 and 4.6.1.2 shadl also be used to

determine drift loads caused byu higher structure or terrain feature within 6

m of a roof. The separation distance, s. between the roof and adjacent

structure or ten’ain feature shall reduce applied drift loads on the lower roof

by the factor (6— s)/6. If the height of structures exceeds 6 m drift loads is

r

S,ijaecrsLea:

U,,tara~aLes’s

+ 1

~rLris. c,/

L0,,JS.c Os somewhat teas; see searron 453

151g. 4.5.3] Salanc 4 and Unbalanced Snow Loads for a Sawtooth Root

belong

[Fig. 4.6.1] configuration of Snow Drifts on tower Roots

snow Loath 37

nut required to be applied.

4.6.2 Roof Projections

4.6.2.1 The method in 4.6.1 shall he used to calculate drift loads on all

sides of roof projections if the prqjection length exceeds 4.5 m.

4.6.2.2 The height of suc drifts shall be taken as half the drift height

from [Fig. 4.6.11 (i.e.. 0.5 1. i. /, equals tO the length of tire i-oof upwind

of the projection or p~u-ape. ~vall and its value is less than 15 m.

ho,

DriftHeight(ml

a

2

S. r;o,n,ss..orLoad( kNfm(F~. 4.6.21 Drill Height ~‘~d1

onto the lower roof. The solid lines in [Fig. 4.4] shall he used to

determine the total extra load available from the upper roof, regardless of

the surface of the upper roof.

4.6.3.2 The sliding snow lend shall not he reduced unless a oruon of

the snow on the upper roof is blocked from sliding onto th’’ lower roof

by snow already on the lower roof or is expected to shde c]ear of the

lower roof.

4.6.3.3 Sliding loads shall he supenmpused on the balanced snow load, if

lower roof and higher roof are separated as j;, or 6 m. the sliding snow

load is not required to he applied.

4.6.4 Overhanging EavesThe roofs that drain water over their eaves shall he capable if sustaininga uniformly distributed load of 2.05, on all overhanging port ens there.

4.7 Rain-on-Snow Surcharge Load

4.7,1 Rain Stu’charge LoadFor lorations where it rains on the roof with snow the rain—on—snowsurcharge load shall be determined in <Table 4.7.1>.

<Table 4.7,1) Rain—on—Snow Surcharge Load

4.6,2.3 The d]ift

bigger value.

loads at the junction of two projections shall he used a Roof Slope Rain—on—Snow Surcharge Loed

< 1124 0.25 kN/m

~1/24

4.6.3 Sliding Snow

4.6.3.1 The extra load ca.secl by snow sliding off a sloped roof onto alower roof shall be derenmned assuming that all the snow that

aectimulates on the upper :oof under the balanced loading condition slides

4.7.2 Ponding Instability

Roofs shall be designed to preclude uonding instability. Roof deflections

caused by full snow loads shall he investigated when determining thelikelihood of ponding instability froni rain—on—snow or .‘Oili snow

5

38 DesIgn Loads or Buildings and Other Siruclures — ‘IL 4 Snow Leeds 39

ineltwater.

4.8 The Rest Snow Load 5 Wind toadsThe effect shall be required to be applied if the iest snow load affects on

the structural safety as follow: 5.1 General

5.1.1 Scope4.8.1 The lateral pressure due to snow on the exterior wall ofstructures

5,1,1.1 Design wind loads specified in this section are applied to the

estimation of minimum wind loads on buildings which are presupposed to4.8.2 Sedimentation load of snow elastically behave during strong wind.

4.8.3 For snow blows to a veranda, the snow load 5,1,1.2 Design wind load applications on wind force—resi~ong systems

shall be classified into wind loads on so’uctural frames and wind loads on

roof frames respectively.

5.1.1.3 Design wind loads on components and cladding shall be applied tothe design of cladding, finishing materials of building surface, and their

base structural components (just called “cladding” hereafter).

5.1.2 Fundamentals

5.1,2.1 Design wind loads are divided into design wind loads onstructural frames, design wind loads on roof frsunes. and design windloads on cladding. Their respective design wind loads are calculated by

multiplying design wind force or design wind pressure by projected area

or effective wind area.

5,1.2,2 Velocity pressure is die product of air density and square of

design wind speed as shown in Section 5.6.1.

5,1.2,3 Design wind force is calculated by multiplying velocity pressure,gust effect factor, and wind force coefficient together. For the design

wind pressure, wind pressure coefficient is used instead of wind force

40 Design Loads for Buildings and Oilier Siruclures — All’ 5 Wind Loads 41

coefficient. However, design wind pressure on cladding is calculated by

multiplying external pressurt coefficient. internal pressure coefficient, and

velocity pressure together, weere external pressure coefficient and internal

pressure coefficient include gist effect factor.

512.4 Wind—tunnel tests or other appropriate analytical procedures

covering wind—tunnel tests should be conducted in cases that in ~vind

load calculations for struci oral fi-anie design, roof frame design and

cladding design, buildings or structures are subjected to have across—wind

vibration, torsional vibration, vortex--induced vibration. and aeroelastic

instability or to he so light in weight and vein,’ low in stiffness such us

long span suspension roofs~.~ staved cable ronfs, and long span membrane

ioofs that aeroelastic instal Hi ty in roof frames can occur or to have

vibration of inappropriate c adding doe to the extent and construction

method.

where, q~ velocity pressure at mean roof heighti N/rn2)

velocity pressure at height Z abet c ground level

C N/rn2) (described in 5.6)

gust effect factor for structural frames and roof

frames (described in 5.7)

external pressure coefficients on the windward face

(described in 5.8.2)

external pressure coefficients on the leeward face

described in 5.8.2)

5.2.2.3 Design wind pressure ( p1) for structural frames of open buildings

and other structures shall be calculated tising the following equation.

(3,2.31

5.2 Design Wind Loads on Ssuetural Frames

where, C]. velocity ressure at height Z above ground level

I N/m)

5.2.1 Scope

This section prescribes desi~.n wind loads on enclosed building structures.

open btiilding structures. asic other structtwes,

5.2.2 Calculation of Design Wind Loads on Structural Frames

5.2.2.1 Design wind load I t•gi for souetural frames shall be calculated

using the following equation

ll~ A (5,2,1)

a, gust effect factor for structural fran,cs and roof

frames (described in 5.7)

c, force coefficients described in 5.8.5, SAd, 5.8.7, 5.8.S,

and in 5.8.9)

5.3 Design Wind Loads on Roof Frames

5.3.1 Scope

This section prescribes calculation of design wind loads on roof frames of

enclosed buildings and partially open buildings and on roof frames of

monoslope free roofs.

where, p~ design ttsnd pressure for structural frames N/in2)

A projected ,reat m11

5.2.2.2 Design wind pressure p~) fur structural fi’ames of enclosed

buildings shall lie calculated using the following equation.

fr0,’ (q~ C,~— (5.2.2’

5.3.2 Calculation of Design Wind Loads on Roof Franirs

5.3.2.1 Design wind loads C on roof frames shall be calculated by the

following equatton.

= p A ,53.il

42 Design Loads for Ouildings and Other Siructures — ALE 5 Wind Loads 43

where, p~ design wmd force on roof fra’nes( N/rn2) 5.4.2 Calculation of Design Wind Loads on Building Components

A effective wind area( m21 and Cladding

5.3.2.2 Design wind pressure ( p,) on roof frames of enclosed buildings 5.4.2.1 Design wind loads on building components and cladding shall beI calculated using the following equation.and partially oi~n buildings shall be calculated in accordance with the

following equation. jy p~’ A (6.4.1)

Pr Qh (Gf C~— C, C5) (5.3.2) where, p design wind pressure on cladding~ N/rn1), provided

where, ~ velocity pressure at mean roof height h( N/mi) that it should not he less then SOON/rn2.

gust effect factor for structural frames and roof ~. A effective wind area(rn2)

frames described in 5.7)

gust effct factor for internal pressure (described in 5.4.2.2 Design wind pressures on building components and cladding shall

Section 3,3.2) he calculated using the following respective provisions.

ç. external pressure coefficients (described in Section (1) For external walls subjected to positive pressure on buildings with

5.8.2) mean roof height greater than 20m,internal pressure coefficients (described in Section p~ = q~(GC, — GC~,) t5.4,2)

5.8.3) (2) For external walls and roofs subjected to negative pressure onbuildings with mean roof height not less than 2Dm.

5.3.2.3 Design wind force p. on roof frames of nionoslope free roofsPc = QIJCCr. 0Cc’)

shall be calculated using the following equation. ‘‘

— (.3) For external walls and roofs of buildings with mean roof L’~ght less= Qh c1 than 2Dm, (where velocity pressure, q~,. shall be applied based on

where, ~ velocity pressure at mean roof height h( N/rn2) Exposure Category C)

gust e~’fect factor for structural frames and roofP= q~(CC~ — CC5) (5.1.4)

frames cescnbed In 5.7)

Cf force coefficients (described in 5.8.6) where, q1 velocity pressure at mean roof height h1 N/rn2)velocity pressure at height Z above ground level

5.4 Design Wind Loads on Building Components and Cladding I~ C N/rn2)

5.4.1 Scope CC,~. external pressure coefficients for building

This section prescribes desgn wind loads on building components and components and cladding(described in 5,9)

cladding. CC5, internal pressure coefficients for buildingcomponents and cladding(described in 5.9)

44 Oesign toa~ for Buildinos and Other Sirucluan — AIK 5 Wind Loadi 45

5.5 Dynamic Response Due to Wind Actions 5.6.2.2 Design wind speed V. J7,, shall be calculated using Eq. (5.62)

considering basic wind speed, exposure factor, topographic factor, and

5.5.1 Scope iportance factor.

This section prescnbes desieii policy for across—wind vibration, torsional (56~)

vibraoon, vortex—induced vibration, and aeroelastic instabibty which may

he responsible for turbulence md wakes. where ~ basic wind speed ( mjs) (described in 5.6.3)

Ic. exposui-e factor (described in 5.6.4)

5.5.2 Design Policy ‘C: topegi’apluc factor (described in 5.6.5)

Wind—tunnel tests or approriate analyses should he performed “lien L, importance factor of a building (described i;: 5.5,5)

buildings or other structures are expected to have across—wind vibration,

torsional vibration, vortex—induced vibration, and ae,’oelastic instability.5.6.3 Basic Wind Speed

5.5 Velocity Pressure Basic wind sl~ed V.1 shall he as given in <Table 5.6.3: and [Fig. 5.6.3]by the construction site. However, if there are effective measured data,

the” can be replaced.5.6.1 Scope

This section prescribes a ba:’ic wind speed being used in design velocity

pressure, exposure factor, top~.graphic factor, and importance factni’.

5.6.2 Calculation of Velocit,’ Pressure

5,6.21 Velocity pressure ~. evaluated at height Z above ground shall be

calculated using Eq. (5.6.la) ,:nd velocity pressure ~ at mean roof height

using Eq. (5.6th).

rh~P V,2 (5.6.1

~— .L~ V.° (5.61 hi

where, ~, air densit (assumed to be 1.25 N s2 /rnt)

design ~tind speed at mean roof height J~ above

ground .evel(ni/s)

V. design ‘.vind speed at height Z above ground level

(ni/si

46 Dos:gn toads or Suiidings and Other Structures — : 5 Wind Loads 47

The nominal hebbl Dl atmoaphen: boundary layer 1w)

— a Paum, roe exponoer Cl a nrrmdn peru

o.6.4 Exposure Factor

5,64,1 Exposure factor K.0 shall be provided in <Table 5.641> 5.6.4.2 Exposure constant Z4 and power law exponent of mean wind

according to the exposure of construction site, exposure constant, and the speed a with exposure categories shall be given in <Table 5.6.4.2.>nominal height of atmospheric boundary layer.

(Table 5.6.3) Basic Wind Speed by the construction She V0 ‘1

t.ocalicn V5(abed

~ Seoul, lnchecrr, Gimpo, Sucheon, curl, 05cc, Songtsn, Pyeonglaek, Siheung, 30Seoul. Geauheur’, kiym’g, Suwon, Mean, Gunpo, Uiwang, Anseor’g, canghwa

Incheonnrelropolilan city. Yangpyeong, Seongrurm, Hanam, yongin. Uijoorrgbu, Oongducheon.

Gyeonggi—do Pocheon, Paiu, Gwualgiu, Olheung, Migum, Veoju, Icheon, Shingel, 26Jengh omen

Sokcho. oangneung, Kongyang. Jumun(in 40

Geclin. Ganeung, Oon”bae, Samcheok, Wcrrdeolc 35Gang no n—h a

chuncheon, Hwachecn, Yanggu, cheorwon. Kimbus. Inie. Yeongwol,.leongsoon. Teebaek. Wonju, Pyeongchang. Hongcheon

Janghang 40

oaeiecn Tosses. Seceun, che~nglu. Omecheon, Seocheon, Anmyando, Jcclliwon,merropohilan city, cheonan, tdongseong. <wsngcheon. arson

chungchecng Oae(eon, Danigjin, Har’cluk, Sunghwan, ,Jincheon, ,leungpyeong, Onyang 30nanrbuk—do

Eumseong. Cheongyo’ig. Geumsan, Ycongdong, Garigp. Nonsan, Jecheon. 25chungju, Buyeo, Soc5 ‘r, Oanyang, Goesan. ckcheon —

Pohang, ulleungdo. G.jrycngpo, Ocheon, Honglise. Kempo 45

Susan, Guano, Jangar, yconil, Oedong, Gadeckdo 40

Susan ulsan, Tongyeong, G;die. cocoons, Jinhee, cimhae, Mason, changwon.metropolitan oily, Vangsan, Jinycong, Ulyn, Pyconghae, Mgang. Gyeonguu. Namhae. 35

oaegu Samcheonpo -

meiropolilan ally. Ge oncheon. Soya, So iranglin, N’eongdeck. Sschecn 30Gyeongsang Desgu, Veongiu, S ml, G’n,cheon, Veongcheon, Andong. Songhwa,nambuk—do pungg’. Yecheon, Cneongsong, veongyang, Hayang, Gyeongean,

cheongdo. Namji, u ryeonlg, chupungryeong, Sanglu, Seoneen. Gunwi, 25uuscong. klungyeong. Jeomchon, Flamcheng, Jrniu, csocrrang, Hamyang,Sancheong, Goryeany curangnyeong, Hapcheon, Mllyanlg

Gunean. Misung - - 40

)hokpo, Veosu. Wandc. Jindo. Okgu, Hohwa. Ikean, Geumil. Heenem, Saansan.

Gmangiu, Oaeduck. Doyang, Grlreung.w,elrcpoullan ally, Gwsngju Naju r’lwa;un, yeongsm, mo, Sanglin, Janigheung, Soseong,Jeollanambuk—do Beolgyo, Suncheon, cl.’rangyeng, tdueri, Hampyeong, Yeonggeang c

Jeonju, Hamyol. Jinani, Nuts, Samnye, Damyong. Sum,, ‘lawmen, Sunchang,Gurye. Gochang, Jury u, Jangeu, Seungiu, mmii, Teem

Je1u—do The whole area 40

iron

1Pm0. 5.6.31 BasIc Wind Speed V.

(Table 5.6.4.1> Exposure Factor J<’, based on Exposure

Height Z Above Ground Level Exposure category -

(ml A B c

25 0.58 0,61 1.0 1,13

4~ 254 0,2221 0.45r 0,717~ 0.972’

Hal rITZ, erector ecenslent ll,lI

48 Design Loade for autldlngs and Other Structures — ASK 5 Wind Loads i

Ri Eva saarb celotsi itt 11wNeonunat lrsi5ri at tIE OlnXlsbtlOrts Soup Ktry layer (ml

as Pe-saei law esporteet ci aeon misc-at

Topographic Factor ( KUpwind Slopel (6)

Escarpments ( 6,S 0.05) Hills and Ridges çl~ ≥ 0.1)

005 1.05

0.1 1.09 21

0,2 1,18 141

≥D.3 1.27 1.01

Notes:For hilts and riders a,llt do’wneund dose Opo< <5,1. tuscan interpolation btiitsecrt lila Se values tar rcars’aan’.a.

title oil’s tones dIsh be altered

oshane.g’ upvt.nd a-cool ut = JL1

e t’~rnra ~nd downwind stopa lisa lila Cl*dt a I eacarltnettts - bits and 115000 is starcrtcw Cl 1w at gloriedla’,cl

(Table 5.6.5(2)) Application Scope of Topographic Factor K .~ (m)

Topographic ScooaHeight and Distance t—

Category upwind

Vertical hnignt• Greater of /, and t Itt

Hills arid (above ground level)

Ptdgea Horizontal distanceI Greater ot Is!, and 2.~/f

(From crest)

Verttcal height[ Greaten of a. and I-tB(above ground oval)

Eocanpmorita~ Horizontal distance Greater at I .SL andI Greate’~’ ,tL , and PH~ Front cneal) 35JJ

—Uppur vent onourdac p15w

“-a, / ILhnddrecton czzr~

Hortyantat boundary a 900 — 4 ~ / — Honiroalat boon nan

~GZOtlSH~eaterol~i~2Lor059d0 ~ia a a 5 Ii

and asg and 25j

H’ eat ot bent c-It aot,nlary wand strait he 05cc ad as grarnn roar o

(Table 5.6.4,2) Exposure Constant ~ ~, Nominal Height of the Almospheric Boundary

Layer Z0, and Power Law.Exponer of Mean Wind Speed a

Exposure Category A B C

z. (ml 2Dm 15m tOm 5Dm

Z (ml 50Dm F 400m 30Dm 250m

a 0.33 0,22 0,15 0~I0

(Table 5.6.5(1)) Topographic Faclor K-.

5,6,4,3 Exposure category hall be provided in <Table 5.6.4.3> by the

surface condition of construclian site.

(Table 5.6.4.3) Exposure Category

EnpasareSurface R sghnann Condition of Ihe Sarroundiag Ground

Category l

.4 Large city centers mar closely spaced tall buildlaga higher than tO—story

B F Urban and suburban o~-aas with closely spaced nnaidenliol or other builDings with~ height at 3.5w or so or acaltered mediutn—riae buildings

C Opon ternai n with acr1ito red ohatrucltons with the height at 1.5—tOm on so orscattered low—rise butto-ngs

~ Pat, unobstructed arora or scattered abstractions less than tErn such go coastalarea, groabland, airport wlc,

5.6.5 Topographic Factor

5,6,5.1 TopographiC factor shall be basically 1.0 where there ate no

effects of escarpllsents, hills, and ridges on wind speed.

5,6,5,2 Topographic factor j’,, necessary for speed—up aver escarpments,

hills, and ndges shall be I ted in <Table 5.6,5(11> and its scope of

applications shall be in <Ta); e 5,6,5(2)>.

rictus,nun n,:ia ass rages cr111 dnartcrr.d dope () O5-<b5~<t) I. !wgar tntetpctalgn Darw.’cti rho K,, maca Ice

0000rnmenia. tails, and edges shall be biloarar

50 Design Loade for Buildings and Other Structures — Alit,S Wind Loads SI

Upper vertical boundary plane (Table 5.6.6) Importance Factor I

// /‘////Q~?~Horirontal boundary l,/~ ‘ / / / z

W~drrecton~~ — boundary mane

sIc 0.03

~reator~l Greater of 3 L,

and 25ff andsH

Height or verlical boundary pa .erstt be selected aa greater value Dl L, and 7ff

where ~ upwind slooe, calculated from ~ =

the average downwind slope, measured from the crest

of a hi]1, ridge, or escarpment to the ground level ata distance of SE

II : height of•’•~.sca~jments, hills, and ridges Cm)La: horizontal distance upwind from the crest to the point

where the ground elevation is a half of the height ofhill or esi::arpment (in)

5.6.6 Importance Factor

Importance factor j~ shall he defined in <Table 5.6.6> in accordance

with the design return period which considers use, sociality, economicalefficiency, and importance of buildings.

tn’ponlance FactorImportance Nature ot Occupancy and Scale ci Buildinga

~ ttarardnus substance storage or treatment facilities, hospitals and

othet hearth care Iacitrlies, broadcasting stations, communicalion and• operation canters, pnaer generating stations, lire stations, public

Special service lacilities. arid facilities tor the old and the weak i’yith a total .10

ttonr areas greater than 1000 a’

~ Apartments and ottice—Frotels higher than 15—storyViewing and assembly tacilities, eports lacititiea, transportatio’rfacilities, exhibition lacilirea, and sales laci inca with a total ho:,

1 area greater than 5,000 aa• Lodging tactliiies, otlice—hotels, dormilortoa, and apartments higher

than 5—story‘ Schools htgher ihan 3—story

2 ‘ Buildings and other structures escept those listed in category ISpecial, (1). and (31 [

3 ‘ Temporary facilities, agricultural lacitities, and light storage lacilittes [“S’ 0,8t

5.7 Gust Effect Factor for Structural Frames and Roof Frames

5.7.1 ScopeThis section prescribes gust effect factors for the calculation of designwind loads on structural frames and roof frames.

5.7.2 Gust Effect Factor

5.7.2.1 Gust effect factors, calculated for structural frames and roofframes in case that, building structures are assumed to be rigid orresonance effect due to wind actions can be neglected, are listed in<Table 5,7,2,1>, However, the gust effect factors can be calculated by thefollowing Eq. (5.7.1).

52 Design Loads for Buildings and Other Structures — AtK5 WindLoads 53

(Table 57.2.1) Gust Effect Factor (or Structural Frames and Roof Frames

C ~)

Exposure Cttcgory Gust CIted Factor

A 2.5 —

3 2.2

C 1.9

0 1.8

C1= 1 ± 47j I~

where, ~f turhulencv factor

/ 3’l-3a \ -

~ 2+a

turbulence intensity at reference height

‘b 0.1

B7 : background excitation factor(factor

(5.7,1)

representtng

fieqtjency component except for natural frcquency

of a 1 iilding)

B,= 1— [T~ 5.1CLSWITB)t](Bf/t)9t1j

1.33 Jr~ B

k = —0.33: heR

mee roof height of ii building, ni

B : builcing width measm-ed normal to wind direction(ml

loigitudinal turbulence scale at reference height

01 a building (nil

cower law exoenent of mean wind speed (described in

5.6.31

nominal eight of the atmospheric houndruv layer (nil

(describori in 5.6,31

5.7.2.2 Gust effect factors (or flexible structurEs, structures greater than

lOOm in height, and buildirns of which resonance effects due to wind

actions can not be neglected shall he calculated using Eq. (5,7,21.

However, the rigid buildings and die flexible buildings shall be

determined by [Fig. 5.7.2.2] ~tnd vertically slender structures such as

chimneys with height—to—width ratio less than 7 are assumed to be rigid

structures.

G7= 1 + ~‘-‘ V B,-t- R,

where. c, gust effect factor

turbulence factor

-~ 2±a

turbttlence intensity at reference height

4= 0.l(-~— )~“~

(5,721i

B. : backgrountl excitation factor(factoi’ representing

fretiuencv component other than the natural

frequency of a building)

Bf= 1— [ (1+ 5.1(LJ~~Wi(Bih)tJj

Ar

0.33 : ]~ ≥ B

—0.33 Are B

it mean roof height of a building Ira I

B ooilding witith measured normal to wind direction (ml

longitudinal turbulence scale at reference height of a

builditig (tn)

L,,=

power law exponetit of neat] ‘vincI speed (described tn

5.6.31

z. : the nominal height of the atmospheric boundary layer

Cm) (described in 5.6.3)

peak factor

g,= V 2ln(600v,)+ 1.2

level crossing frectuencv C Hz)

54 Oestgn Leeds for Buildings and Other Structures — AtS 5 Wind Loads 55

~j flo~ ‘~fl~

natural frequency for the first translational mode in

the windward direction (it can be obtained by thedynamic ~.nalysis)

resonance factor (factor representing natural frequency

component of fluctuating displacement of a building)

0,’01 0.2 06 I 2 6

I,

-~o ~ •.czE:Jo

Plan

Concrete structures

Steel structures

E l.7~

[Fig. 5.7.2.2] classification oF Rigid 51 ruclurca and Ficicibic Structures

Rf=-fr S1F

damping ratio for the first mode in windward direction

(It can be obtained by the dynamic analysis)

F wind force spectrum factor (factor representing powerof fluctuating wind for the first mode in windwarddirection

.S’ISf= { 1 + 2.11 nob! v~ 1111 -~ 2. l(n0Bf V~)l

5.8.1 ScopeIn Section 5.8, the design pressure and force coefficients for structuraland roof frames and internal pressure coefficients and gust effect factorfor internal pressure for roof frames are defined.

5.8.2 External Pressure Coefficients, c~, on Structural and Roof

Frames for Enclosed or Partially Enclosed Buildings

External pressure coefficients, C~. for enclosed buildinqs shall he as

given in <Table 5.8.2>. External wall pressure coefficients, C~ are

specified in a) of <Table 5.8.2>. For windward wall, velocity pressure,

,~., calculated at height .r shall be used. For leeward and side walls, thevelocity pressure, q ,, evaluated at mean roof height, h, shall be used. For

roof, external pressure coefficients in h) of <Table 5.8.2> shall he applicrlfor windward and leeward faces with considerations of roof elope angle

0.

5.8 Pressure and Fnrce Coefficients for Structural and Roof Frames

Elevation

FlaxiblobuidIngs

o Rigid buildingLogarithmic decrement

~ (Damping ratio)

4(arL,,! F,,

<Table 5.8.2> External Pressure Coefficients, C,~. for Enclosed Buildings

Wind

— ‘3]

a) Wall Pressure Coefficients,

{l + 7l(n~L6! V,,)9~’°size redu-tion factor (factor representing reduction of

turbulence effect due to the scale of a building)

PLAN ELEVATION

56 Design Loads for Buildings and older structures — Alit 5 Wind Loads 57

Applicable VelocitySurface LII; ci Pressure

Wndward Wall Al] valv~a 0.5 in

0’’] —0,5

Leeward We]] 2 —0,2

≥~ —0.2

Side Walls Al] va]v’s —07

NaiveI. Naiaiiafl:

C Mcafl,oa’ iieiiliii, in meTe,;.

a Neigh] here ~,evwa, in

q eli Ve]aoie Dressier in mInions pee vies to fedora ri/nil. doriuiiiOd ii ilIpeci ice nei11lit.

bI Hoof Pressure Cieefliciunts. C.,

WindwardWind Angle 0 (degreos) Leeward

Direction ‘“ I, —~“T—0 iO-1S 20 30 i 40 50 ≥60

≤0,3 —07 02• 02 0.3 04 05 0010

!_____i____’____Marina] —0.7 ‘09 —0.2 0.3 I o.s 0,0W —07

10 ridge ~—t’1 0 —0,7 ] —09 —075 —0,2 0.3 0.5 0010

≥1,5 —07 —o~fl__—0.9] —0,9 —0.35 0.2 cow

Paral] a] ~ or /i/LS2.5 —0]

0 ridge hi B Or k/L>2.5 0.S 0.8

Ii ]~-ie.,lri,’ eiitel tiis,’ieiii\’ 1.1 ..vi,... •,liie]d ii.’o,rrvii~.

\O~i iiS~

rv’,i; iii. eK

Ji:lt,,ri~i.eiiiii,hri—, ‘,,‘.iiia’.i ]xiiliiii;,iiiii,,iiev:ii.,i.,ierietii.i,iinilieiiiiiiili]iiieiiiei,

ii, ,,e’evr .ircvi:eirrinl psiridlie] iii ifi,elilivritiw

iii

Ii i Slaici ii,’. lids],]. iii

cc. 4, ‘‘iiic’i’.e ifl’ecin’. iii ir’ivrieir. en., ‘iii ii. iiei,rI i>lin i, ev.iloeieii iii rc.eicxriw’

0 ll,iI ‘he. eire~he. iii iIcisifl.~

5.8.3 Internal Pressure Coefficients, c ,., and Gust Effect Factor for

Internal Pressure, or, for the of Roof Frames of Enclosed Buildings

For enclosed buildings, internal pressure coefficients, or,,, and gust effect

factors, C, shall he complied as given in (Table 5.8.3>.

<Table 5.8.3> Internal Pressure Coefficients C ,~, end Gust Effect Fader

tar Internal Pressure, C ,. for Enclosed Buildings

c, [ C.

0 or — 04 1.3

5.8.4 External Pressure Coefficients, c,. for Arched Roofs

For arched tools, external pressure coefficients, c,~, shall hr complied as

given in <Table 5.8.4>. The values of external pt’essure coefficients,

C ~., are dependent upon the heighL above ground to the edge of the

eaves of the arched roof and the location along the external surface of

the arch, either windward quarter, center half, or leeward quarter.

<Table 5,8,4> Exlernal Pressure Coefficients, C~.. for Arched Roots

Rise to Open [Condition Ret]o.

~ .~ ~ Windward Quarter Central ‘tell l Leeward duerler

] O<,<O.2 —0.9 —0.7—, 0,5t,,;(i O.2≤y’(O.3’ 1Sy—O,Z 0.7—, —0.5

~ O.3≤y≤06 2.75y—O,7 —07—n. . —0.5

h.~ti Q≤y<o.5 1.47 L —0.7—, i —0.5

Shiv,, tier d’eriii—eire,i iafi, ii O’i 557103 ,i]ionui,i’r,elliv-e’,,i’. run Ii, or—:] mist,, h,’eeenl(i liv’

iiiirivniu,axielirrieiae,i e,i l.Sr—1L3

l. en.eii;eliw,;

5. = f/I

f lldalui ]ueiir.ieiiialiiies,rieiiri,iiej: Simm 0 rae, ~,f eec,,, sun]

Ii~ fta,dii Inc mmmiii] level

58 . ossion Loads Icr dulloings end otter Slruclures — AIK 5 Wind Loads . 59

ccrz C,

C”

H

58.5 Force Coefficients, C,, for Chimneys, Tanks, and Similar

Structures

For chimneys, tanks, and simlar stsuctures, force coefficients, C,,, shall be

complied as given in <Table 53.5>. The values of force coefficients, C~ are

dependent upon the cross—sectienal type and surface condition, and the ratio ofheight of structure to least horizontal dimension of cross—section, 4 ,Id.

<Table 5.8.5> Force Coefficients c’, for Chimneys, Tanks, and Similar Structures

C,Cross—Section Suriince Condition

/s, Id =1 I,, H aT 1, Id x25

Square wind normal to taco) - All 1,3 1,4 2,0

Souare wind along diagonal) All .0 1.1 15

Hexagonal or octagonal All 1.0 1.2 1.4

Moderately smooth 0.5 0.6 0.7

Round Id z1q. 5,3) Rough (did 0.02) 0.7 [ 0,8 0,9

Very rocgh (did ~a (1.08) 0.8 1,0 1.2

Round (dh17 5.53) All 0,7 0,8 1.2

050755;Notation;

d Disnels, el circular cross—sections aeu lead horizontal dimercion 01 Square, heragonal, or ectagoralcrozs—sscllenalsioua lion under con, Carailon It, eaters;

d’ Depth 01 olotrecing nemesis ouch as rL’z area zosilero, in molars

/t, HaishI of Slmcloro. I neater, and

Ca velocity pressure eeaiualed at arbitrary height z steno ground, in nea.lons per squat eeetete (H/m°l,

5.8.6 Force Coefficients, C,a for Monoslope Roofs over Open

Buildingsporce coefficients, C1, shall be complied as given in

(Table 5.8.6) for monoslope roofs. The values of force

coefficients, C1, are dependent upon the roof slope angle 0 and

the ratio of dimension of roof measured normal to wind direction to

dimension of roof measured parallel to wind dtrection, LID.

Location of central pressure, X,. shall be determined as the

distance to a center of pressure from windward edge of roof.

<Table 5.8.6> Force coefficients. C ,.. icr Monoalope Roots over Open BuildIngs

Root Angle — C, for LI/I Values of:

Degrees 5 3 2 1 1)2 1/3 1)5

10 0,2 025 0,3 0.45 0,55 F o,r 0,75

IS v.35 i 0.45 0.5 0.7 0,85 0,9 0.8520 0.5 0.6 0,75 0.9 1.0 0.95 i 0.9

25 0,7 0.8 0,95 1,15 1.1 105 I 0.9530 0.9 1,0 1.2 1,3 1.2 0,1 I

I Location of central Pressure, :1 ILRoof Angle

~ tar LID Values of: -,

Degraeo LID = 2’4 LI/I = 1 LID 1)5’~l)2

10—20 0,35 0.3 0.3

25 0.35 0,35 0,4

30 0.35 0.4 0.65

Nones:I. Nuns i o’ccs act noreei to the

lund sloe directed outinete

2. nIna eMail Os .,stanred to deemed by to depsees roe heirontal

a Notation:

L : Dtaznsion ci rest enca: urea nertnai to naiad direction in incurs:

B: Orannsion ft real enamored parallel to wind demise, in 501Cc;

K1 Distance I 0 center ci p,css are tent vIlla saurd edge ci root In moons. 5.10

& : Root stops angie In dagiees~

5.8.7 Force Coefficients, C , for Solid Signs

turrace Two cases slut beconudenuot’ II ‘ste a loran dime’—,. music: usa 2)

Force coefficients, C7 shall be complied as given in <Table 5,8.7> for

solid signs. The values of force coefficients, C,. are dependent upon the

ratio of height to width. Iz j fl and the ratio of larger dimension to

smaller dimension, zn / ~, for at ground level and above ground levelsigns, respectively.

Cole i

f

0.6-J

60 Design Loads icr Buildings and Olter structures — AOl 5 i Wind Loads 61

<Table 5.8.7> Force Coellicienls, (‘ br Solid Signs

At Ground Level -~ Above Ground Level

Ralio of height 0 width - Ratio of larger dimension to I

( 11, 5) smaller dimention C,15 / II

≤3 12 ≤6 .25 13 10 1.3

5 14 16 1.4

0 15 20 520 1:5 40 175

~0 1 5 60 1.85≥ 40 2 C’ ≥ 80 2.0

\Cyrlis~5l1,5- LVIII, L’l)1flitIL,’ XIIIIOIVIISS l—o-- OLILL 0< IV. l4V’~O’fl.I ‘I’~d[ Is. vIes, I

2. slur, liv wisslr do ,I,,I;wrv In,,, liv g,r-r,rsI I Is Trill as’r IsIl~< II,,,, Il_a, Ifle ‘Iv 005111 ,lilVOVLrrlI

‘Is’S ls,er,isslrrwrl 5, Iv iv <“awl k’<-I

ii ,,,sl ‘~irl’’ws-’V’’~1 ,l,r,cI,,s,’ ~h.1l I .‘sr-trxI

o “~~tmi iii

/ :ll,r,ql,t ‘.1

‘it Ians’r ,l’r,’_aia,rii ‘‘1 <si,. I,,

~iilIVIlIll5~iO’~lilI —irLiLlllIilcs,lr.

5.8.8 Force Coefficients, c for Open Signs and Lattice Frameworks

Force coefficients, C ,~ slial’ be complied as given in <Table 5.8.8> for

open signs and lattice frame corks. The values of force coefficients. C,.

are dependent upon the ratio of solid area to gross area. ç.

<Table 5.8.8> Force Coefficients, C,. for Open Signs and Lattice Frameworks

C’

4’ Flat—Sideo Rounded MembersMembers 0 5.3 ,/V’~ .~ 53

( 0,1 2.0 1,2 0.80.l”0,29 I.e 1,3 090.3”0.7 , 1.6 ‘.5 1,1

NOTeS.

‘swIll opo~.rwiV sss,pr,smn 30% 0~ ma, <‘II,, <‘Olin we:,a’e class,lrecI all Cecil 4I052

2 Nolairow 5. Sal’s 0’ seP. dive a ‘0 WO5<

Oa,,,ler ala lyr.~crs! ,s,.rsa’V’ -roe, I, m<iV’VZ v.1:1

V’Sar.rIs aresCu,o veolsoled 0’, ,s,ghl a abase ground ,n,penloos oar <qva’e slivers, N,rr

5.8.9 Force Coefficients. C for Trussed Towers

Force coefficients, C,, shall be complied as given in <Table 5.8.9> for

trussed towers. The values of force coefficients, C,, are dependent upon

the cross sectional type of a tower.

<Table 5.8.9> Force Coelficienis, C,. for Trussed Towers

Tower cross SecI,on C-,

square it,F~ 5.5/ 4.11

L_~__~ZEZEEZJ~7Z,s’lrrlC<I. I_ar <I I’’r,r,l sb,rcliisir dc’csl. II,,, w,s,c,,,.,...I, ~ir’’’.r,I, II Ii~ .:lx-,.,fl,_I (,,sa’’’s’f,icicr’ l’r,ili s’ Ow’s,!

TI,,’ lrI,wlrvlIr,e 1,0, 1,_allIs l,r’.,aI CI,osrIIIIfl-rss,nr,’I~-r.Tj-—r,

urrisnl;, it<15,I ,nerlrr~.:5 l’,rr,’vn-n’r c’r’lI;ir’’i,e,- r,,,,I, liv l,srrnIlx~rs. llI’:-L!s’ctrlLlOiIletosrlliiIlIz Ill,’ I.I5’’,Ir< li5r,i’r’ r,rcfii,rirr,1-. I’ 1.,.. <-II~

i,r;I,0 ‘rIo, ,klsa,sriir,,’ ‘,virid firer.,. on -.,r,l,

11.51 -1’ 0.57 <.1.1)I. I’,,r ,s’.rrr, ss,,Tli .ilr~.r,s’ ,-er’,,—<,,-Ii. vr-’ci ,.rI I v ‘<uP] I ,‘IT,,II, diLl .1.115’ 1,115. srirr,’ Ir,’l~.’’ 55 s44~ lIirsrLr,l

LI] ill’

I ~-O,75$≤1.2SO’s! l,rl,rr ‘‘I ta’Vsti’I lns,,wa’-.rv<, ,o lr~~kt”s. osslails, ]irOil’. r’lrsal’ sir, ,:4u4 Iv c- ,],:oi j --I’l’Ispl!nilni~Ip’

1,,L’eavidrfl,r,,’r I1,riill.,r(, ,din,s,r.

Ii 2’~ iiali,,rI

‘,,rrll-’ls’l’,s’s, ISiS’ l’’,rr’’-’’’~,’,,s,, ii,st~rr,,,u- I

5.9 External and Internal Pressure Coefficients for Loads on Building

Components and Cladding

5.9.1 Scope

In Section 5.9, the design external pressore coefficients. CC,,, and the

design internal pressure coefficients. CC ri for building comtxtnents and

cladding are defined.

5.9.2 External Pressure Coefficients , cc <~. on Loads on Building

Components and Cladding ‘with Mean Roof Height Greater than or

Equal to 20 m

- 62 Design Loads for Ouildings and Other Struclures — AIR Wind Loads r 63 1

External pressure coefficients Cc shall he complied as given in

<Table 592> for wind loads on building components and cladding withmean roof height greater than or equal to 20 m. External pressures actingon the edge of the wall and roof are higher than other areas, thereforethe wail and roof surfaces are divided into different zones for the purposeof specifying the design pressure coefficients.External pressures on the roof of the building are negative and shall bedetermined for each roof pressure zone. External pressures on the ~~‘all ofthe building are both positive and negative and shall be detennincd foreach wall pressure zone,

J~sitive Prescore ] — —

~ [IZZTI CZL~ ~

.10’

~:I NegaUve l~essure tF

I Pocin~e Pressue—r Hi1 ~rr.-ll

4~®-4JPLi4-H-~

fl~[J III—i—i

- ~ZZL ~F‘ —~ H JNegative Pressure

59.3 External Pressure Coefficients , cc,~, for Building Walls with

Gable Roofs and Roof Surfaces on Low—Rise Buildings with Mean

Roof Height Less than 20 m

External ~val] pressure coefficients, CC . shall be complied as given in

<Table 59.3(1)> for gable roofs on low—rise building with mean roofheight less than 20 in. The values of external wall pressure coefficients,

Cc ~, can be reduced by 1096 if roof slopo o is less than or equal to

10°. It is noted that the vertical ordinate denotes extei-nal wall pressurecoefficients, GC,~, to be used with the velocity pressure, q~, evauated at

mean roof height I, based on Exposure C. Each wall shall be designed forpositive and negative pressures. It is also noted that a caution shall be

taken in the region of notation a which indicates the edge of a wall.

oc~. (walls)

‘.4

13

0

H23

—3—3.2-4

—s—o

—l—I.e

—3

—4

-6

(Table 5.9.2> External Pressure Coefficients CC,.. on Loads on Building Componentsand Cladding with Mear Roof Height Greater than or Equal to 20 m

2345 Ii

Bliacliva Wnd AreaSquare Oelers (ii,’)

to

345 10 50oc~ moo

—2—25

3.2—4

—s—5 I

I l..lf~nrv.m,l ~,r.Sfl_41,ic ,r,d1 ‘cnn,l .kft’.~ aur’.iI ul ,, c•.Inn,s.r4 ,.e~lxfrlj,a

In,ikli4tr

.LCa.-tIiucnI!casr 1,crcx,kw,,l,rs’l,,O 6111’ lflw’,,b:rn,4a,lea ‘IO~,a’~ Gc,., •-,.ij.- flce,locrc’ ci

.:T,,I4e 555l1~~ ,,,xl ‘,tlnts,l ,‘ bred ret l5cp~cuc’ C.

1. Itch tc:,ll ,I,,,ll he irsigecel Icr ,‘cxicr.un, rsc,Inc u,d ,breI,vc,,rr~c,,,e—,

cci,, ken t,crtys,t-,,l iS,,,cer,cII. but car Ice 2:,tj 15,.\la,,,,,ni IlIxhI. II aacr,: ted

I Ir~~l,t :,hw,’ ,imi,n,I

a—l‘1.3—2

2.6—3

—4

—t

I 2345 IiEllacliva Wind Area

Square Nialars (a’)

64 Daacgn Loads for Buildings and Other Sliuctures — AIK 5 Wind Loads 65

<Table 59.3(2)> represents the external pressure coefficients for the joof

surfaces of gable roofs, art) those can be classified into 3 types for

application.

Type 1: Wind angle a ≤ :ts shown in figure a).

Type 2: Wind angle 10 K Or. 39as shown in figure hI.

Type 3: Wind angle 30 K Or 45 as shown in figure c).

As external pressures on th building of roof slope angle less than 3~

are negative, external press to coefficients shall be determined based on

the coiresponding roof presr-ul’e zone. As extet-nal pressures on the ‘oaf

of the building for 30 K 6 K 45 are both positive and negative, roof

structures shall he designed 3 a safe manner for both cases.

! ~_______ CL

‘i-s-2

‘2‘2.2—1

-5‘i-i-6

(Table 5,9,3(1)) External Wall Pressure Coefficients , GC~.. for Gable Roots on Low—Rise

Buildings with Mean Root Height Less than 20 m

cci.

Walls

-s

—l

—4

‘S

‘0

P-icr Pt

— fl’’’7’~ F Ii FI i]F F F F

— FT] IF INegative 1:. -

4 isElteclive Wind ASquare Macor- In’)

solEs:I. tilija. iii Stint] -5-ill I a- Rnionn t St Ill - riot 0 50

a Cii It i’ssnx.iooil tort rttttlilsr 0-tilt ti’,lcigiixrt l-:r lr:lsiiisliii isi.:iiitt ttilroni:,vo inL—nsrc.

:iiti,itl&i.~ (X’ hi is ti-al nh Si h.isttn sit tr1.i ‘sri. U

4. 02.tiiiii,,:

lOt iii I .ini hi-.ittsitil chhiix—s-inh Ii- ii.lhi_ 5th it—rn—is ninik,. h-i into.. ilojiottoor i-:. ii ISi ot—to ix

Is 2 trait rail lath:. lit airier.

(Table 5.9.3(2)> External Root Pressure Coelfictents . GC~. for Gable Roots on Low—Rise

Buildings with Mean Roof Height Less than 20 so

a)

‘i.(;c.

RootPlan

J_,jPositivo PressureFi. F F

-2

-4

-5

‘O

— ~FFt FIi

—i — rNe~ciur-c Pressure2345 Ii 54

Elleclive Wind AreaSquare Meters ri’)

0 Wi

66 - Design Loads los Outlrhincis and Other Slruclures — AlE 5 Wind Loads 67

a. act CL

n m nci

$1___ a

5.9.4 External Pressure Coefficients , cc,~ for Monoslope Roofs on

Low-Rise Buildings with Mean Roof 1-leight Less than 20 n0

External roof pressure coefficients, Gc_. shall be complied as given in

<Table 5.9.4> for monoslope roofs 00 low-rise building :tth mean r~f

height less than 20 m.The values of external roof pressure coefficients, cc.. are specified in

figures a) and b) for two types of the roof slope angle 0 . Eachcomponent and cladding shall be designed for maximum positive andnegative pressures. The external roof pressures are not dependent upon

the effective wind area if effective wind area is greater than or equal to

10 m2. The values of positive pressures shall be determined with the roof

slope angle B and are same for all the pressure zones. It is noted that

the notation a in <Table 5.9.4> represents the width of pressure

coefficient zone, in meters.

0% of least horisoolol dimension o- 0_40. eihichoee’r is osolles.

dimension Or t~o ‘n.

js:Mean root mighT in nn€I,,s

be’ 501 less lion cuTter 4% ci local hoi,snnlal

b)

GCk

-I.,-2

.3-2.6.4

.5

-6

— -~ ~‘n_1jtiyg Pressure

-~t—O)-~ -

—~ - -

I H_-4~ —

j_—~•Eff®UF~~ —E ItTNegative Pressure

—I-1-4-2-26.3

.4

.5

-6

PoolPlan

so’ < a ≤ 30’

cl

I 5345 50

Elimailve Wind Ares

Square Melers (ri)

50

cc,

cc Ga cc

.J~JrPosiUveThuI—,

-i-s

-22—3-4

—S

-0

~~th-0

0

~::The lade Pressure

I_S

—l.05—Is

—4

—s

-6

SSOTESNotation:

so’ <0 •i- 45’

2306 0

Ellective Wind .ssea

Squnre Motors (nil

68 tOesigri Loads (or Buildings and Oilier Structures — Aik 5 - Wind Loads i 69

I Owl, any emory art nirr000lyn th.’rII twkir,rrle 012I\IflrrIfl,

3 rnitiraf rryrhir’,rte&,rrryro CC,, In ~ q Ieoalerr l;sor’uw C’

.2 Iron Ireyldixyso rylef my Cloy Ewionsv B. rolculootre. ‘roe yule slidt In IymtIltJtrsnI lyo 03.

I, NOe;,lireI’

yr lI)’r 000 I._rL~t hlin000teJ thlIle0sOI’,’a 001’ 0 ci: mtijdis.vtc’ yr —mollor. Ixyt yr. los—o yloyry moIre’ 1’. —1 moO tzwoer,00I

IJIINIOIOreI err 1.0 IlL

A iOlr’.rrryyyel

a)

(Table 5.9.4) Exlernal Roof Pressure Coefficients . Gc,0, for Monosfops Roofs onLow—Rise Buifdingo with Mean Roof flaighf Less than to 20 m

r ___

1~t 2 345 15 50

• j ~Positive po’esrt’;~~

~:it ~i— fl’— - — I~~0 - -

Tt~.Em:’a’i

Os

C—2

0.2“1.7—3

‘4‘4,4—5

—5

2

0.20

‘S

4z_zz iLL JJLJ~t—~ Negative_lkessure

a -. io•B)

2 345 10

Etteclive Wind Area

Square meters (a’)

50

/i.

5.9.5 External Roof Pressure Coefficients ~ç, for Multispan Gable

Roofs on Low—Rise Buildings with Mean Roof Height Less than 20

In

External roof pressure coefficients. GC ,~, slityll he complied ass given in

<Table 5.9.5> for multispan gable roofs on low—use building with mean

roof height less than 20 rn.The values of external roof pressure coefficients, CC , are sp.::’ned in

figures a) and b) for two types of the roof slope angle 6 . The values ofexternal roof pressure coefficients shall be determined by a’ of <Table5.9.3(2)> if the roof slope angle 6 is less than or equal to 100.

In this table, the notation ~ represents the width of precsure coefficientzone, in meters, and is based on a single span module, \Terdcal ordinatedenotes the external roof pressure coefficients. CC,, . basetl on Exposure

C. The component and cladding shall be designed for maximum positiveand negative pressures.

0.70

‘2,2—2.7—3

—5

C

217 2a

U4aç

-11 ~‘

‘3.0 r~I

01

to’ < a ≤ so’

0,5

—t—I.e

—3.34—4

—5

—s

54 It’ll_S.

a a 45 tO

Effecttve Wind AreaSquare meters Is’)

70 Oeslgn Loads for Buildings end Other Struofures — .415 5 WInd Loads 71

0

—I

—2—3—3--,—4‘.4 2—4-,—5

a)

(Table 5.9.5) Exlernal Roof Pressure Coefficients GC,. for Mullispan Gable Roofs onLow—Rise Buildings with Mean Roof Height Less than 20 in

I

a-

a

cc,.

—I

‘.5

—3

—4

—5

—a

a act a

2

0.70

—2—2.4-3

—4

—5

‘.0

10 -< 0 ≤ 3W

Ii,Iin.itn.,,,caavl.-t,shr.,v: ln,[I’ss,ha-,,ain,llarI ~,4ai,vi-

4 tail li-icy -‘liii 0nnn’-~- ci yr 0-hi ‘clir,:ll.-vLca~ ,,iaill.-n_ bitt,,, S las:— - -‘thai—s li-siditncni-,xt’-r ID in.

bl.ni,inn.t Iisc~n,

5.9.6 External Roof Pressure Coefficients, QC,. for Sawtooth Roofs

on Low—Rise Buildings with Mean Roof Height Less tErm 20 m

External roof pressure coefficients, ~C shall be cornpli~-ct as given in

<Table 5.9.6> for sawtooth roofs on low—nse building with mean roof

height less than 20 in The values of external roof pressure coefficients.

CC,,., shall be determined by a) of <Table ft9,5(21> if the roof slopeangle 0 is less than or equal to 10’. If the roof slope angle 6 is greaterthan or equal to 10’ and less than 30, roof zone ti’ for negative pressure

calculation is divided into different spans, a, 5. c. and ci, and tie valuesof external roof pressure coefficients shall be determined for -tch span.The component and cladding shall be designed for maximum - -~ sitivo andnegative Pressures.

2 345 10Etlective Wind AreaSquare meters (ml

hI

ss

Ka act a

a

a

~~:~E::::E~Cz

Negative Phtaautw

I—il

0

— I

—2

—3

—4

—5

-e

30’ <9 45’

I 2345 10Effective Wind AreaSquare maters (ml

50

50410’

I. Eisa ~- liT. utlires em cc,, hum at sO <tait - 2lOlh2l> sliadi is used.

2. \aia-st enithuate ukuato CC.,, to ha toad ‘dii- based iii Eiqxaun, c.

3. IS,- tauluti,gs $cd suttan Ln1xnsjre It. adaulatyci mania shalt hi naithidird boa 1.9

72 oestan Loads for Buildings and Other Structures — AIR 5 WInd Loads 73

(Table 5,9.6> External Roof Pressure CoeFficients, CC1~., For Sawtooth Roots onLow—Rise Buildings v1th Mean Roof Height Less than 20 in

6 Earthauake Loads

N0TtS~

~+E—EJ~~;~~

~ a [ Negative Thessesee

1:1)1 - lit. va[ucs of CC’, uitni 1N ‘‘‘ib.il be used.

Z I. 1111011 01:1010 it-cocci is be 11001011, 50,104 00 lto,uaun: 0.

1 :5. bsekbuus u,tcd silisri ltx~uy—a,o, 0. c:4c,itj uS n—oure 1i.1l Is nu’lt,ol:al In 451I. It’d, ciannewc dull 11, duasied for lucolilt, .1 tOOStIOS cool 102111w

5 Nceiion:

a lin.,of]c,u lc,duuueS cii’s, :so~,w 0. ,,, wliid,evcr ii. casIo,: baa m’t boo tic::, ,,aI,er1c,ot

am or 1.0 SI.

Olnaa nsf sight. in macro

6.1.2 Change of Occupancy

5.9.7 Internal Pressure Coefficients, a’ for Buildings

For enclosed buildings, the xulues of internal pressure coefficients. CC,,shall be 0 or —0.52 for components and cladding.

When a change of occupancy results in a structure being reclassified to ahigher seismic use group, the structure shall conform to the seismicrequirement for a new structure.

6.1.3 AlternationsExisting structures being altered need riot comply with Chapter 6,provided that the following conditions rn-c met.(1) The alternation do not create a structural irregul~uitv as defined iii

I 2315 tO

F F FFFFesiti~’eftessure

CC

l.a1.4.2

-3.6—4

ma-s5A

.4

.2

t0

—2,7—3-0.2—3-s‘-4

—3

—6—-/

cc go

to, < I ≤ 30’

1 2345 13 50

Elleclive Wind ‘seaSquare meters (at)

6.1 GeneralEvery structure, and portion thereof, shall as a minimum. be- designed andconslructed to resist the effects of earthquake motions as prescribed bySection 6.

6.1,1 Additions to Existing BuildingsAn addition that is structurally independent from an existing structure shallbe designed and constructed as required for a new structure in accordancewith the seismic requirements for new structures. An addition thai is notstructurally independent from an existing structure shall lx- designed andconstructed such that the entire structure conforms to the seismic—forceresisting requirements for new structures unless the following conditions aresatisfied.(1) The addition conforms with the requirement for new structures.(2) The addition does not increase the seismic forces in any structural

element of the existing structure by more than 5 percent, unless thecapacity of the element subject to the increased forces is still in

compliance with these provisions.

(3) The addition, which is limited to the extension of 1/10 ‘ii total floor

areas or of 1 story in height, or remodelling of the enisti’ig buildings

that have been used for nnore than five years since the

aclmowledgements for use of buildings were issued.

74 oesign Loads For Buildings and Olher Slruclures — AlE 6 I Earthquake Loads 75

Section 6,4.4 or make an existi p structural irregularity nioie severe.

(2) The alternation does not increase the seismic forces in any structural

element of the existing structure by more than 5 pet-cent, unless the

capacity of the elenient subject to the increased forces is still in

compliance with Chapicr ii

(31 The alternation does nt decrease the seismic resistance of any

structural element of the existing structure to less than that required

for a new structure.

(4) The alternations do not rt-’ult in the creation of an unsafe condition.

load combination, design strengths are pcrniitted to be deiemiined using

an allowable stress increase of 1.7 and a resistance factor, ~, of 1.0.

This increase shall not be combined with increases in allowable stressesor load combination reduction.

6.3 Site Ground Motion

6.3.1 Seismic Zone and Site CoefficientSeismic zones and corresponding site coefficients are

6.3.1>set for’ ii ‘ii <Table

6.2 Load Combinations

6.2.1 Ultimate Strength DesignWhere Ultimate strength descn or limit state design is used, the factorfor seismic load incorporated with each design methodalogy shall he 1.0.

6.2.2 Allowable Stress Design

\\Oiet-e allowable stress design working stress design) is used, the factor for

seismic load in the load cornNnation involving seismic load shall be 0.7. In

this case, increases in allowable stresses are penmttcd by this code or the

nlatenal reference standard.

6.2.3 Special Seismic Load

Where the design of the memaers like a piloti structure causing instability

of entire structure, or members inducing a significant change of seismic

loads, special seismic load (F.,) shall be used as seismic load combination

involving seismic loads in lie’’ uf using seismic load (El.

E,,,”s25E±0,2S05D i6.3.t)

where, s~ A redundancy coefficient obtained in accordance with

<Table Ii 6.1>.

The terra need not exceed the maximum force that can be

transfen’ed to the e:lement by the other elements of the

lateral— force—resisting system.

Where allowable stress design methodologies cue used with the special

<Table 6.3,1.> Seismic Zone nd Sire Coctitciont I A

‘ Seinmic NumericalSeismic Zone Areas in korca -creificient (A)

1 All areas fbi included in zone 2 [ oil

2 NorThern area of Kangwon—do, Souihwesl em area of 0,07JeoilaNam—do, Jeju—do —

Na,iitiai era, ‘>1 l’e,,anra,i’ai’cSia,ia. c,’1. Tharci,er,. cl’irwa,s,. Itii[i’ iflvr. i’~vmscl,iaiii. ‘!iiiiOiiL ‘(1,1

rl,eid,,et Oi’.. Sekrh,(,ir‘e,il,,rraic-ni,,,me,.~ j,,itiNan—iii, Ole,a,. Sire. hi,’,xie, ‘,eieeaa,eer i,,rf,. I [maim V’.vieg,en. Ci.!il in. i a

i;inriiyor~rec \u’tia, Oir

6.3.2 Site Class DefinitionsThe site shall he classified as one of tile site classes in <Table 6.3.2>

considering the effects of soil properties, geological conditions, surface or

underground topography on the ground motion.

<Table 6.3.2) Site Class Definitions

Averaga Properiies in Top 30m

Standard PenairationSlim soil Shear Wave Soil tenironed SheerSoil Profile Name Realsiance, —_

class volocily. — Si’e”al’l. £Ar the number or

C nile) ~lt) NImm1)blocs_/30’Jmm

5A Hard rock e)1500 — —

S5 Rock 760< a ,t 1500

Very dense soil and-h~ 360(r,,≤760 11>50 >100soil rock

5,, Stat soil proliie 180< a, ii 350 IS ≤ 50 50 ≤ s, ≤ 100

5’, Soft soil prolile 080 11< 15 < so

76 Design Loads for Buildings and Oilier Siruclures — MN 6 i Earthquake Loads I 77

6.3.3 Design Spectral Response Acceleration S OS

= 0.2S,,1/50,

T4~ 5,’i/~,c

The design spectral response accelerations for shont period, S,~, and the

design spectral response accelerations for 1—second period, s,,,, shall be

determined based on <Table 6.3.3> and on <Table 6.3.4>, respectively.

(Table 6.3.3) Design Spectral Response Acceleration Mr Short Periods.

S,,,

(3) For periods greater than T5. the design spectral response

acceleration, 5~, shall he given by Eq. (6.3.3).

SC=0.6-~T’r0.1Sj), (632)

(6,3.31

where, T = Fundamental periodtin second) of tl’=srrocture.Seismic Zonesite class

~ 1 2

5.t L. 2.0 M1’ .4 i.e MA

5 , 2,5 AlA ~5 MA

.s, ....~..........L 3.0 hA 3,0 .14,4

5,, - 3.6 MA 4,0 MA

5,, 50 11.4 6.0 IrA —

33 (In I II’S Case, he ess, en 0. ~4r,I ‘en p0~00 sccnlerallsn Is lot u’l,mOIa level eOs[vsIsnl

a Iwo 115155 Cl ISO CalIhqsske, tim re0.lrsnso sme CI 2400 yea’s.

<Table 6,3,4) Design Spectra! Response Acceleration for I Second Period,

Sb!

~ Seismic ZoneSilo class

I 1 2

0,8.11,4 0,7.1111

Sn - 1,0 sItu ID AlA

Si .6 MA .6 ,If.1

5,, -- 2,3 JJ,4 2.3 MA

, SI, 64 31,5 3.4 .11.4 —

H. C o_LoT — 8.33 -

f r.3,,,

// N/

iT

7~, T~ 1.0

6.3.4 General Procedure Response Spectrum

The general design response spectrum curve shall he developed asindicated in [Fig. 6.3.11.

(1) For periods less than o~ equal to T11. the design spectral response

acceleration, 5 ,. shall be determined from Eq. (6.3.2).

(2) For periods greater that” or equal to T1, and less than or equal to

T ~, the design spectral l’esl.’ilnse accelei’atioi~, 5,, shall he taken equal to

[Fig, 6,3,11 Design Resoonse Spectrum.

6.4 Earthquake Loads—Criteria Selection

6.4.1 General

Each structure shall be assigned to a seismic design category in

accordance with Section 6.4.3. Seismic design categol’ies are used to

determine permissible structurai systems, limitations on height and

irregularity, those components of the structure that must be designerl for

seismic resistance and the types of lateral force analysis that must be

performed,

6.4.2 Seismic Use Groups and Occupancy Importance Far Irs

Each structure shall he assigned a seismic tise grotip and corresponding

occupancy importance factor as indicated in <Table 6.’l.l>,

78 Design Loads for Buildtngs end Other Structures — Alt 6 EarthQuake Losde 79

Where a structure is occupied for two or more occupancies not included (Table 6.4.1) Seismic Use Groups and Occupancy Importance Factors

6.4.3 Determination of Seismic Design CategoryAll structure shall be assigned to a seismic design category based ontheir seismic use group and the design spectral response accelerationcoefficients, S,w and S05, dc’tenuined in accordance with Section 6.4.2

and 6.3.3. Each building and structure shall be assigned to the mostsevere seismic design catego.v. if seismic design categories determinedbased on <Table 6.4.2> and Table GAS> are discrepant.

Occupancy IriportariceFooted /et

I city PlanningPogions Besides

Wuilding or structure containing asic orexplosive substances “nih total tloor area

Buildings and other mare or equal to ‘000 rn, hosottals, tire -stations, power generation stations,

structures that oroasni

essential tacitilies or buildings and at hor at’ ucture S having

hasardous tacilities critical national dofense tunctions. toreigntherein housing or diplomatic estebtishmants, lacilitiso for 1,5 1,2

children, wotlare tacittlies or the agedsupporting toxic or

public welfare facititios end labor wettareexplosiva chemical andsubstances, lscilttiea

. Aparlmsnt or attica building higher than or

equal to Is stories.

. ‘ Facilities for public psrlormance, —~_________________

gathering, inspection, exhibition, business

Buildings and other or commercial pu’suii larger than orstructures that equal to 5000m5 at the total tioor are

a

represent a oubstanliet

hazard to human tile in Building or structure for accomodations, 1,2 1.0attica buildings, dormitories or apartments

the event ot failurehigher than or eoaet to 5 stortes, F

. School higher than or equal to S stories.

Buildings and other

structures except those ‘ buildings except those tided in categorieslisted in Categortes 5 (5) and i, 1,0 0.8and I,

6.4.4 Building ConfigurationBuildings shall be classified as t’egular or irregular ones based on thecriteria in this section. Such classification shall be based on the plan andvertical configuration.

6.4.4,1 Plan In’egulanty

Buildings having one or more of the features listed in <Table 5.4.4> shallhe designed as having a plan structural irregularity, and shall complywith the requirements in the sections refei’red in <Table 6.4.4>.

in the same seismic use goup, the structure shall he assigned tileclassification of the highest seismic use group corresponding to thevarious occupancies. Where structures have two or more portions that arestructurally separated in accordance with Section 6.8 each portion shall besepas’atelv classified. Where a structurally separated portion of a structureprovides required access to, oequired egress from or shares life safetycomponents ~vitil another portion having a higher seismic use group, bothportions shall be assigned the higher seismic use group.

Seismic Use Group nature at Occupancy

6,4.4.2 Vertical frregttlarity

I 80 Design Loads tar Buildings and Other Structures — AtK S Eerthauake Loads I 81

Buildings having one or more of the features listed in <Table 6,4.5> shallhe designed as having vertical irregularity, and shall comply with the

requirements in the section relorred in <Table 6.4.5>.

Exceptions:

(1) Shuctural irregularity of Type 1 or Type 2 in <Table 6.4.5> do not

apply where no story drift ratio under design lateral load is greater

than 130 percent of the store drift iatio of the next story above.

Torsional effects need not he considered in the calculation of story

drifts for the purpose of his determination. The story drift ratios for

top two stories of the building are not required to be evaluated.

(2) Irregularities of Types 1 and 2 of <Table 6.4.5> are not reqtnred to

he considered for buildings with less or equal to two stories in any

seismic design category.

(Table 64.2) Seismic Design Category Based on Short—period Response Accelerations

Seismic use GroupValue of 5,,, -

S I II

O.50g ≤$,. 0 D 0

o.33g ≤ S,,. < O,50g 0 C C

O,rYg ≤5,,, < 0.339 C B B

s,,,<0.17g A A A

(Table 6.4.3) Seismic Design Calegor; Based on 1 Second Period Response Acceleration

Seismic use GroupValue of S,~ —

5 I II

Il.alcr≤S,, o 0 0

hugs S,~ ll,uOg C C

Il.oigcusa:..o.14g C B B

s,~: hl.07g A A A

6.4.5 Analysis Procedures

A structural analysis shall be made for all structures ill accordance with

the requirements of this section.

6.4.5.1 Analysis for Structtires Assigned to Seismic Design Category A,

or B

Structural analysis of structures assigned to Seismic Design Category A.

or B is permitted to carry out through equivalent lateral farce i nalysis ii•i

Section 6.5.

6,4.5.2 Analysis for Structures Assigned to Seismic Design Category C

Structures assigned to Seismic Design Category C may be designed

based on equivalent lateral force analyses in Section 6.5.

Exceptions:

(1) Structures assigned as having regular configuration uvutli more or

equal to 7Gm in height or 21 story;

(2) Irregular structures with more or equal to 2Gm in height or 6 story:

shall be designed based on dynamic analysis.

6.4.5.3 Analysis for Structures Assigned to Seisitrie Design Categurv t)

The analysis prucedures identified in <Table 5.1.6> shall be 4 for

structures assigned to Seismic Design Category B. or 5110cc ngoroos

analysis shall he made. If the structures are categorized as having plan

in’egolaritv of ‘lype 1 or 4 b’ <Table 6.4.4>, or as having vertical

irregularity of Type 1, 4, or 5 by <Table 6.4.5>, those may be divided

into having regularity.

82 Design Loads br Buildings end OIlier Struclures — AIlS S Earlirguake Loads 83

<Table 6.4,4) Plan Structural Irregularities

Seismic

. Reference DesignNo. Type Description

Section Category

ApplicationTo do cone dared when diaphra gms are not

6,5.6.4 C. PItexibie,

(Tebte• Torsional irregulartut,’ shsil be considered lo exist 6.4.6) D

iorsionat- when the maximum story drifts, computed

Irregularityincluding acciderito~ torsion, at one end at thestructure lransverso to an axis is more than l.a 6.5,7.1 C, Plines the average of the story drills at tho two

dens ci the structurePlan configuration or a structure and Itstateret—torce—reatstng system contain re—entrant

2 Re—entrant corners where both projections at Ihe structure — —Cornsrs beyond a re—entroul corners are greater than IS

percent of Ihe plan dimension Cl the structure In

the given directionDiaphragms with abrupt discontinutties orvariations in xtift’ess, including those having

Diaphragm cutout or open areas greeter than 50 percent of — —oiscontinuity the gross enclosed diaphragm area. Or changes

in etloctive diaphrigm stillness of more than 50percent tram one riory to the nextolsoontlnultlet in r- tateral—lorce—reslatance path,

act—of—Plane such as oul—ot—u’ene ottsets of the vertical 6,a,3 ~, C, 0Of Is els

elements.The vertical tatetsi —torce—resisting elements are 6842 0

Nonpareltet not pereltet to p symmetric about the major‘ Sysiews orthogonal axes c- the lateret —lorce—resisting 6 8 4 0

system.

<Table 6.4.5> Vertical Sthscturnt liTegulasitics

SeismIc. . Reference assignNo. Type Description

~ Section Category

Application

A sott story is one in which the interal attttnessSilt tn ass

, is less than 70 percent of that In the story slobleI lrregulx*rity—sott 0

above or teas than 80 percent at the average 6.4.6)story

stiftnnss of the three stories above,

Mass irregutarily shalt be considered to exist- where the ettectivo tttxss Of any story Is ttrcro

Weight ‘ i,Tobto2 . than 150 percent ot the eltective mass at an ,, 0

trreguiarity . 0.4.6)adjacent story. A roof that is ttghler thsn thettoor betow need not be constdered,Verttoai geometric irregularity shaft be

Vertical considered to exist where the hortsontal. ‘ . . (Table3 Geometric dimension of the lateral—force—resisting systew 6 6)

Irregularity in any story ts more than 130 percent of that

in an adjacent story.tn—plane

Discontinuity to An in—ptane ottsel of the tateret—torce—rasislingVertical elements greater than the length of those

4 . . 6.8.3 8,0,0Lalerat—Force— elements or a reduction in stitfness of the

Resisting resisting eletnsnt in the story ottiowale men is

A weak story Is one tn which the story tatorst

. . strength is less than 80 percent of than in theDiscontinuity instory above, The story slrength is the total

5 Cspacity—Westc - - - &.s.t a, 0, 0~ strength ot seismic—resisting elements sharingory the story sheer br the direction tinder

[ —- j consideration,

<Tabte 6.4.6) Anatyttoal Procedures for Setsmto Design Category 0

Strecturat Description Analysis Proceduro tor Seismic Design

I, Seismic use Group II buildings at ltght—tramad Equivalent lateral iorce procedure orconstruction nat eecseding 3 storIes In height Oyaawic analysis

2. Other structures not exceeding 7Cm in height in Equivetent lelerel force procedure oraddition to those ittustreled in item t above, aynemic enstysrs

3 Structures having vetlical Irregularity Df Type I, aor 3 in (Table 6,4.5); regular structure oxooodtng70m in height: arsiruc lure exceeding S stories or Dynnmto ana ye’2Cm in height with having irregularity of Type I in

(Tabte 6,4,4)

4, Other struotere having plea or vertical Irregularity, Dynamic anaiysix

- 84 Design Loads or Buildings and Other Strrtclurea — AtK 8 Earthquake loads 85

with Eq. (6.5.2).6.4.6 Deflection and Drift L:miLs

The design story drifts, .g, as determined in Section 6.5.7, shall not

exceed the allowable story dri~t, ~,, as obtained from <Table 6.4.7>.

Seismic Use Group

;Allowable Story Drill 4, (I .01 ., 0.01 Sir 0.0200

6.5.1 Seismic Base Shear

The seismic base shear, V, In a given direction shall be detennined in

accordance with the following equation.

V= C ,W 16,5.1)

where, C, the sLu~nic response coefficient determined in

accordance with Section 6.5.2

Wthe effecti e seismic weight including the total dead

load imd other loads listed below:

1) In area used for storanc, a minimum of 25 percent of the reduced

floor live load (floor live load in public garages and open parking

structures need not be included).

(2) Where an allowance for partitions is included in the floor load

design, the actual paration weight or a minimum weight of 0.5

lcN/m~ of floor area, wiichever is greater.

(3) Totol operation weight of permanent equipment.

Twenty percent of the flat roof snow load where a flat snow load

exceeds 1.5 kN/m’.

6.6.2 Seismic Response Coe?ficient

‘The seismic response coeffirient, Cu shall he determined in accordance

C ,‘~‘0.044S,.~I~ (6,54)

wl’oet’e

F: the occupancy importance ft ctor cictenru net) it~

accordance with <Table 6.1.).>

1? the response modification factor from <Table 6.0.1>

S ~< thc design spectral response acceleratlo’’ ttt short

period as determined from Section 6.3.3

s , the design spectral response acceleration at 1—second

period as determined from Section 6.1.3

7’ the fundamental penod of the holding (seconds)detem,ined in Section (‘15.3

6.5.3 Period Determination

The fundamental period of the structure, ‘I’

consideration shall he estaolished using thu

deformational chaa’acteristics of the resisting

substantiated analysis, or shall he taken as the

penod, T,. determined in accordance with the

in the direction under

structural propel’) us and

elements in it properly

approxima It’ fundamental

requirements of Section

6.3.4. The calculated fundamental period determined lv a properly

substantiated analysis shall not exceed the product of 12 itt* approximate

building period. y,.

(Tabe 6.4.7) Allowable Story drift, ci.

iv, ‘,t~ri Icier, kOr’,’ Lv,

6.5 Equivalent Lateral Force Procedure for Seismic Design

c SflI (6.5.2)

[7-frThe value of C, computed in accordance with En. (6,5,2) need not e,xceed

the following:

s/wi —n

R 16..,.,,)14

C, shall not less than

86 Design l.oads br Buitdings and Other Structures - 4(5 Eertltquake Loads 87

6.5.4 Approximate Fundamental Period

The approx’unate fundamental period C Ta), in s, shall he determined from

the fol]owing equation.

‘J’a=Crh~ (6.5.5)

where, C,. = 0.085 moment—resisting frame systems of steel

= 0.073 - moment—resisting frame systems of

reinforced concrete, and eccentrically

braced steel frames

= 0.049 ‘ill other building systems

the height in m above the base to the highest level

of the building Cm)Alternatively, the del emiination of the approximate fundamental

period , T,, in secones. from the following equation for concrete

and steel—moment reststing frame buildings not exceeding 12stories in height and having a minimum story height of 3 iii ispermitted.

= 0.IN

where, N = number of stories

(6.5.6)

The approximate fundamental period, T in s for concrete shear wall

structure is permitted to be d.serrnined by Eq. (6.5.5) or from Eq. (6.5.7).

T,=0.0743(h ) iM/\/~

A ~=EA J0.2+(D~/h ,j2j

Djh≤ 0.9

(115.7)

where. A shear see don area in in’ of shear wall parallel to the

direction of the seismic load at 1st level

7) length in in of shear wall at 1st level.

6.5.5 Vertical Distribution of Seismic Forces

The lateral force, F ~, included at any level shall be determined from the

following equations:

v.74

to

(6.5.8)

(6.5,9)

where, C vertical distribution factor.

k a distribution exponent related to the building period asfollows:

k= 1 : for buildings having a period of 0.5 sr-:ond or less.

k= 2 : for buildings having a period of 2.5 conds or less.For buildings having a period between 0.5 and 2.5 seconds,

/, shall be determined by linear interpolation between 1 and2.

5, Ic : the height from the base to level j or x

V : total design lateral force or shear at the base of thebuilding.

w ,, • : the portion of the total gravity toad of the

building, w located or assigned to level or xnumber of stories.

6.5.6 J’Iorizontal Shear Distribution

The seismic design story shear in any story, ~‘a’ shall be determined

from the following equation:

V~= ~F, (6.5.10)

where, F, : the portion of the seismic base shear induced at level

6.5.6.1 Rigid Diaphragms

For rigid diaphragms, the seismic design story shear, V, shall be tlistributed

to the various vertical element of the seismic force-resisting system in thestory under consideration based on the relative lateral stiffness of the verticalresisting elements and the diaphragm.

88 Oes,gn Loads for BuildIngs and Other Structures — At< S Earthquake Loads 89

Level ~-, ~w shall be determined from the following equation:

level j

6.5.6.2 Flexible Diaphragms

For flexible diaphragms, the design story shear shall be distributed to

various vertical elements based on the tributary area of the diaphragm toeach line of i’esistance.

6.5.6.3 Tomion

Where diaphragms are not flexible, design shall include the torsional

moment, which is the sum o~ the torsional moment, iW resulting from

the diffet-ence in locations a the center of mass and the center of

stiffness and accidental torsonal moments, 41,.,, where ~w, shall he

computed as the story shear multiplied by the eccentricity and 44 shall

he equal to the story shear caused by an assumed displacement of the

center of mass each way from its actual location by a distance equal to 5

percent of the dimension of the building perpendicular to the direction of

the applied forces.

5.5.6.4 Dynamic Amplification if Torsion

For structures assigned to Seismic Design Category C or D having plan

irregularity Types 1 of <Tabl 6.1.4>. the effects of torsional irregularity

shall be accounted for by multiplying the sum of ~, plus 5w at each

level by a torsional amplil cation factor. A ,, determined from the

following equotion:

A ~={ ~] (6.&lll

where, ~ : the (rut:. ‘mum displacement at Level x

the avt -rage of the displacements at the extreme

points ,‘ the structure at Level .r

‘l’he torsional amplification factor. A ~. is not reqtured to exceed

3.0. The more severe -ading for each element shall be considered

for design.

6.5.6.5 Overturning

The building shall be designed to resist overturning effects caused by the

seismic forces determined in Section 6.5. The overturning moment at

M~ r~F.(h —h,) (&äl2)

where, F. = the portion of the seismic base shear induced at

h ~. : the height from the base to Level 7 or ~. tnt

the overturning moment reduction factor. determined

as follows:

(1) 1.0 for the toP 10 stories

12) 0.8 for the 20th story from the top and below

(3) value between 1.0 and 0.8 determined by a straight

line interpolation for stories between the 20th and10th stories below the top

6.5.7 Drift Determination and p—~ Effects

Frames and columns shall he designed to resist both brittle fracture and

overturning instability during the maximum lateral excursion of each

story. while supporting full dead and live load.

6,5.7,1 Story Drift Determination

The design story dri 0 . ~. shall be computed as the difference of the

doflections at the center of mass at the top and bottom of the story under

consideration. Where the allowable stress design method is used, 4 shall

be computed osing earthquake forces without dividing by 1,1, For

structures assigned to Seismic Design Category C or D having plan

irregularity Types I of <Table 6.4.4>, the design story drift, 4. shall be

computed as the largest difference of the dellections along ar\ of the

edges of the structure at the top and hottom of the r-’orv under

consideration.

The deflections of Level ~, a ,. shall be determined in accordance with

following equation

C,,4 16.5.13)

where, C ,~ : the deflection amplification factor in ~Table 6.6.1>

90 Oesign Loads (or Bui]dings and Other Structures — AIt< 6 Earthquake Loads 91

the deflec’ions determined by an elastic analysis of

the seismic—force--resisting systemthe occupancY importance factor determined from

For determining comp]iance with the story drift limitation of <Table6.4.7>, the deflections of Level x, 8 ~., shall he calculated as required in

this section. For purposes of this drift analysis only, the upper boundlimitation specified in Section d.5.4 on the computed fundamental period,T, in seconds, of the building, shall not apply.

The design ston’ drift, 4, shall be increased by the incremental factor

relating to the j’— ~ effects, ag 1.0/Cl— 0). where 0 is the stability

coefficient as determined in Section 6.5.7.2.

6.5.7.2 p—i) EffectsP—delta effects on story shears and moments, the resulting member forcesand moments, and the story drifts induced by these effects are notrequired to be considered when the stability coefficient, 0, as determinedby the following equation is eqaal to or less than 1.0:

PA (6.5J4)Viz ~C ~

where, p : the total unlactored vertical design load at and above

Level ~; when calculating the vertical design load for

purposes of determining p—4, the individual loadfactors need not exceed 1.0

4 : the design story drift occurring simultaneously with

V. the seismic shear force acting between Level x and

x— 1It : the story height below Level x

C4 the deflection amplification factor in <Table 6.6.1>

The stability coefficient, p from Eq. (6.5.14) shall not exceed 0

determined as follows:

:6.5.15)

where, p : the ratio of shear demand to shear capacity for the

story between Level x and x— 1. Where the ratio, p. is

not calculated, a value of fl~ l shall he used.V/hen the stability coefficient, 0’ is greater than 0.1 but loss than

or equal to p ,,,~, interstory drifts and element forces shall be

computed including p—~ effects. Where a is greater than athe structure is pntentiallv unstable and shall be redesigned.

6.6 Seismic—Force—Resisting Systems

The appropriate response modification coefficient. R. system overstrengthfactor, ~, and deflection amplification factor, c4~ indicated in <Table

6.6.1> shall be used in determining the base shear, element design forcesand design story drift.Seismic—force—resisting systems listed as “other strucwres” Or hotindicated in <Table 6.6.1> are permitted if analytical and test data coy

submitted that establish the dynamic characteristics tind demonstrate the

lateral force resistance and energy dissipation capacity to he equivalent tothe structural systems indicated in <Table 6.6.1> for equivalent responsemodification coefficient, R. system overstrcngth coefficient. 12 ~. and

deflection amplification factor, c ~‘, values.

6.6.1 Dual SystemsTotal seismic force resistance is to he provided by the combination of themoment frame and the shear walls or braced frames in proportion to theirstiffness. The moment frame shall be capable of resisting at least 25

percent of the design forces.

6.6.2 Combination along the Same AxisFor other than dual systems and shear wall—frame interactive systems,

where a combination of different stmctural systems is utilized to resist

lateral forces in the same direction, the value, p. used for design in thatdirection shall not be greater than the least value for any of the systems

utilized in that same direction.

<Table 6.1,1>

vs

92 Design Loads Ion Buildings and Other Structures — .41K 6 Earlhqual<e Loads 93

6.6.3 Combinations of Framing SystemsWhere different seismic—force resisting systems are used along the twoorthogonal axes of the structure, the appropnate response modification

coefficient, I?, system o’erstrength factor, s20, and deflection

amphfication factor, c ,, indic:rted in <Table 6.6.1> for each system shalt

he used.

6.6.3.1 Combination Framing F’r’ctor

The response modification coefficient, I?, in the direction under

consideration at any story shall not exceed the lowest response

modification coefficient, R. fr~ the seismic—force—resisting system in the

same direction considered oh ‘ye that story, excluding penthouses. Thesystem overstrength factor. Q,,. in the direction under consideration at

any story shall not he less than the largest value of this factor for the

seismic—force resisting systerra in the same direction considered above

that story.

Exceptions:,

(1) Detached one— and two—family dwellings constructed of light framing.

(2) The response modificatic-r coefficient, R, and system overstrength

tactor, s2~, for supported structural systems with a weight equal to

or less than 10 percent ct the weight of the structure are permitted

to be detennined independent of the values of these parameters for

the structure as a whole.

(3)The following two—stags static analysis procedure ((~f and ~f:l is

permitted to he used rrovided the structure complies with the

followings:

çY~ The lower portion shall have a stiffness at least it) times [lie upper

pnrtion.

~‘i’he period of the entire sn’uctur-e shall not be greater than 1.1

times the period of tIre upper portion considered as a separate

structure fixed at the lnrse,

The flexible upper port: ‘n shall he designed as a separate structure

using the appropriate vr’iues of I?.

-:4; The rigid lower portion shall he designed as a separate structure

using the appropriate - alues of K The reactions from the upper

portion shall be those determined from the analysis of the upper

portion amplified by the ratio of /? of the upper portion to I? of

the lower portion. This ratio shall not he less than 1.0.

6.6,3.2 Combination Framing Detidling Requiremenr.sFor strucwral components common to systems having <.liffer’o:t response

modification coefficients, detailing requirements corresponding to higher

response modification coefficient, I?, shall he tised,

6.6.4 System limitations for Seismic Design Categories D

Structures assigned to Seisnt Design Categories 1) shall lie subject to

the followings.

6.6.4.1 lntenrction Effects

Moment—resisting frames that are adjoined by stiffer eicmcnts not

consider-ed to be part of the seismic—force--r-esisting svst,-:c sImlI he

designed so that the action or failure of those elements will riot impair

the vertical load and seismic—force—resisting capability of the frame. The

design shall consider and provide for the effect of these rigid elements on

the structural system at deformations corresponding to the design story

drift, 4, as determined iii Section 6.5.7.1. in addition, the effects of these

elements shall he considered when determining whether ii structure has

one or more of the irregularities defined in Section 6.4.4.

6.6.4.2 Deformational compatibility

Even’ structural component not included in the seismic-- force resisting

system in the direction under consideration shall be designed to he

adequate for vertical load—car’n’ing capacity and the induced moments and

shears restrlting from the design story drift, 4, as determined in

accordance with Sections 6.5,7.1. Where the allowable stress design is

used, 4 shall be computed withotrt dividing the earthquake force hr 1.4.

The moments and shears induced in components that are not included in

the seisniic--force—r’esisting system in the direction under consrderation

shall he calculated including the stiffening effects of adjoining rigid

structural and nnnstr’ucttrr’rrl elements.

94 easign Loads for Buildings and Ciher Structures — AIR Carrlrnoake Loads 95

(Table 6.6.1) Design Coefficients and Faclors for Basic Seismic—Force—Resisting Systems Design Coetlicienis and Factors

Design Coefficients 2nd Factors

ResponseBasic seismic—Force—Resisting S’intem” Modification System Delusion

• Overslrenglh Nnpttltcat’onC oe If ic’s nt

Factor. ~ Factor. C,I?

I, Bearing Walt Systeas

1—a, Ordinary reinforced consrele shear walls 4.5 2.5 4

1—b, Ordinary reinforced masonry shear waits 2.5 2.5 1.5

1—c. Ordinary pisin masonry shear maui; 1.5 2.5 1,5

2. BuIlding Frame Systems

2—a. Sleet eccentrically braced francs, momont—Iresisfing. connections at colur.lns away Irom 8 2 ‘Ilinks

2—b. Sleet eccentrically braced lrar’es. moment—

resisting, connections ci cotun.’m away Ironi 7 2 4links

2—c, Ordinary sleet concentrically brared frames 5 2 4,5

2—d, Stool plate sheer wails 6.5 2,5 5,5

2—e, Ordinary rainlorced concrete shea- wails 5 2,5 4,5

2—I, Relntorced masonry sneer walls” 3 2.5 2

2—g, Ordinary plain masonry shear wails’ 1,5 j 2,5 1.5

3. Moment—resisting Frame Systems

3—a. Ordinary steel moment lramss 3 3.5

3—b Intermediate reinlorced concrete rrst,enl Irames 5 3 45

3—c, Ordinary reinforced concrete moment frames 3 3 2,5

4, Duei Systems with inlermedisle Moment Frames

4—a, Ordinary steel concentrically bracrd trarnes 5 2,5 4,5

4—b. Ordinary reinforced concrels shew walls 5,5 2.5 4.5

4—c. Steel plate sheer walls 6.5 2,5 5

4—d raintorced masonry shear wallsh -, 3 3 2.5

Response System Oellection

Moditicafion Ovarstrenglh Amplification

Coefficient ado’ ,~ feclor C,

RI6, Inverted Pendulum Systems

5—a, Canlilevered column syslems 2,5 [ 2 2,5

5—b, fleet moment frames 125 2 2,5

6. other structures

6—a, other structures 3 2 2.5

6.7 Dynamic Analysis Procedure

6.7.1 Analysis Procedure SelectionOne of the following dynamic analysis procedures perfot’med inaccordance with the requirements of this section may be used in lieu ofequivalent lateral force procedure.(1) Modal Response Spectra Analysis(2) Linear Time—history Analysis(3) Nonlinear Time—history Analysis

6.7.2 ModelingA mathematical model which represents the spatial distribution of massand stiffness throughout the structure shall be constructed. For regularbuildings with independent orthogonal seismic—force resisting systems,independent two—dimensional models may he constructed to reps’esenteach system. For irregular buildings without independent orthogonuisystems, a three—dimensional model incos’pnrating a minimum of three

dynamic degrees of freedom consisting of translation in two orthogonalplan directions and torsional rotation about the vc rlscal axis shall beincluded at each level of the building. Where the diaphragms are not rigidcompared to the vertical elements of the lateral—force—resisting system,the model shall include representation of the diaphragm’s flexibility andsuch additional dynamic degrees of freedom as are required to account for

Basic Seismic—Force—Resisting System”

Tee setrdlrs seismic teice—rr:’s’”ia are’ em shell tie desirleed a a’s ‘awaited in accedrirre ‘nih I lie sp~i’e

rencriem, etc per malerirt spacilir cosmic design slaedsiss re eape’laaalai ar analysis h’: it’s pailonr,d by rambleresearch iasrlslca

SI r.tssoary sasar wails at, rst ecr’nilte a br rlrsustarsa css’gasd a Saisrsic Design csrlecorv C ar 0,

i 96 Design Loads for Buildings and Older Siru-clures — Alit i 6 i Earthouake Loads 97

(07.3)

the participation of the diaphragm in the stmcture s dynamic response. In

addition, the model shall inciude the effects of cracked sections for

concrete and masonry e]emt as and the contribution of panel zone

deformations to overall story (ift for steel moment frame systems.

6.7.3 Modal Properties

The period of each mode, the modal shape vector, the mass participation

factor, and the modal mass of the buikling shall be calculated by

established methods of structural analysis for the fixed base condition

using the masses and elasce stiffness of the seismic—force—resisting

system. The analysis shall include a sufficient number of modes to

obtain a combined modal mass participation of at least 90 percent of the

actual building mass in each o ‘ two orthogonal directions.

6.7.4 Modal Base Shear

The portion of the base shea: contributed by the ,,, IE~ mode, v ,,,, shall

be determined from the following equations:

C .,. w,. (6.7.1)

l’/ = (6.7.21

2~1

\vllel’e, ~ ,,,~ the inoda! seismic response coefficient determined in

Eq. (6.7.:).

the effecüve modal gravity load.

the p00 on of the total gravity load, IV. of the

building ut Level ~, where g’ = the total dead load

and other loads listed below:

~J) In areas tised for storage, a minimum of 25 percent of

the retluced floor live load (flour live load in public

garages and open parking structures need not he

included)

“2~ Where an all ~\vance for partition load is included in the

floor load design, the actual partition weight or a

minimum we -4ht of 0.5 kN/rn of floor area, whichever

is greater

Ii Total operating weight of permanent equipment

20 percent of flat roof snow load where t-he flat roof

snow load exceeds 1.5 kN/in

The displacement amplitude at the f’ level of the

building when vibrating in its ,,i~ mode

The modal seismic response coefficient, C ,,,, shall be determined hr the

following equation:

SIR

where, j, - the occupancy importance factor oe(ermined in

accordance with Section 6.4.2

the modal design spectral respon ~c acceleration at

period 7’,, determined from either the general

design response spectrum or a site—snecific

response spectrum

I? the response modification factor determined from

Cable 6.6.1>

Execi tion: For hi ii ding c on Si to Class Sn. or S~, the ni odal sei Sn tic

design coefficient. C ,,. for motles other than the fundamental

mode that have periods less than 0.3 second :~ permitted to be

determined by the following equation:

~ (1.0+5.0 T)

2.5H)

where, I the importance factor determined in aceor i: ace with

Section 6.4.2

I? : the response modification factor determined from<Table 6.6.1>

5 : the design spectnd response act’elc ml ion at short

periods determined fi’om <Table 6.3.3>

T the morlal period of vibration of the a,” mode ci the

98 Oesi~rs toads br Bu’(din~s and Giber Siroclomes — AIK Eamlhquake Loads 99

o .. =1~~~V T)VFW1.5 \.l~~Jl w.~

building

6.7.5 Modal Forces, Deflections and Drifts

The modal force, F fl,,, at each level shall be determined by the following

equations:

F~=C,.,,,, Vm (6.7.5)

C ,~,, = (6.7.6)Lv 10

where, c the vertical distribution factor in the ‘ad mode

v ,~, the total design lateral force or shear at the base in

the ,,~t node as determined from Eq. (6.7.1)

~ LU S the portion of the total gravity load of the

building. 14’ located or assigned to Level or x

the displacement amplitude at the j°’ level of the

building ‘vhen vibrating in its rn~ node

• the dispacement amplitude at the x~’ level of thebuilding when vibrating in its ,,/h mode

The modal deflection at each level, ~ shall be determined by the

following equation:

8,, = ~ (6.7.7)

where, c, : the deflrction amplification factor determined from

<Table 6.6..t>the importance factor determined in accordance with

Section 6.4.2

o ~ the deflection of Level x in the m° mode at the

center of the mass at Leve] x determined by anelastic analysis

The elastic modal deflection, a54~,, shall be determined by the following

equation

where F ~ : the portion of the seismic hise shear in he’ in

mode, induced at Level x

the acceleration due to gravity

T : the modal period of vibration, in seconds, of the in1

mode of the building

effective weight of level x

The modal drift in a story, 4 ,,, shall be computed as the difference of

the deflectioni., _,,,, at the top and bottom of the story under

consideration,

6.7.6 Modal Story Shears and MomentsThe story shears, story’ overturning nioments, and the shear forces and

overturning moments in vertical elements due to the ~eismic forcesdetermined from Section 6,7.5 shall he computed for each mode by linearstatic methods.

6.7.7 Design Values

6,7,7,1 The design value for the modal base shear. V each ol lIe story

shear, moment and drift qtiantities: and the deflection at eac1 level shallbe determined by combining their modal values. The combirci tion shall hecarried out by taking the square root of the sum of the squares (SRSS)

of each of the motlal values or by the complete quad’ .“ie combination

(CQC) technique.

6,7,7,2 The hose shear, V, using the equivalent lateral force pro< ‘educeshall be calculated using a fundamental period of the building of 1.5 times

the approximate fundamental penod of the building calcu1ated in

accordance with Section 6.5.4 for regular structures and L2 limes the

approximate fundamental period of the building for irregular structures.

I 00 I Design Loads or Buildings end Olher structures — Alit 6 Earthouake Loads 101

Where the calculated base shear, V is greater than the modal baseshear; V, the design values in accordance with Section 6.7.7.1 shall be

multiplied by C,,, the modification factor:

VC,, V (6.7.9)

6.7.7.3 The modal base shear, v,, need not exceed the base shear

calculated from the equivalent lateral force procedure in Section 6.5.

6.7.8 Horizontal Shear Distribution

The distribution of horizontal shear shall be in accordance with therequirements of Section 6.5.6 except that amplification of torsion perSection 6.5.6.4 is not required For that portion of the torsion included inthe modal analysis model.

6.7.9 p— ~ Effects

The p—jJ effects shall he determined in accordance with Section 6.5.7.The story drifts and story shear-s shall he determined in accordance withSection 6.5.7.1.

6.7.10 Time~History Analysis

6.7.10.1 Time HistoriesTime—history analysis shall he performed with pairs of appropriatehorizontal ground motion time—history components that shall he selectedand scaled from not less than hree recorded events. If three time—historyanalyses are performed, then Ute maximum response of the parameter ofinterest shall be used for design. If seven or more Lime history analysesare performed, then the average value of the response parameter ofinterest may he used for design. Where appropriate recordedground—motion time history pars are not available, appropriate simulatedground—motion time—histoi-y pairs shall be used to make up the totalnumber required. For each par of horizontal ground—motion components,the square root of the sum of the squares (SRSS) of the 5 percent

damped site—specific spectrum of the scaled horizontal components shallhe constructed. The motions shall be scaled such that the average valueof the SRSS spectra is not less than 1.4 times the 5 percent dampedspectrum of the design earthquake (or maximum considered earthquake)fur periuds from 0.2 T second to 1.5 T seconds.

6.7.10.2 Linear Time—History AnalysisDesign parameters such as story shears, story overturning moments, ormember forces, which are obtained by the linear time—history analysis.shall be multiplied by the importance factor and the inverse of responsemodification factor. The design parameters determined may he modified inaccordance with the requirements of Section 6.7.7.

6.7.10.3 Nonlinear Time—History AnalysisCapacities and characteristics of nonlinear elements shall he modeledconsistent with test data or substantiated analysis, considering theimportance factor. The inelastic responses may not be reduced by thequantity RI! ,. The maximum inelastic response displacement shall

comply with Section 6.4.6.

6.8 Structural Component Design RequirementsThe design and detailing of the components of the seismic—force—resistingsystem, except those of the stmctures assigned to Setsmic DesignCategory A, shall comply with the requirements of this section.

6.8.1 Discontinuities in Vertical SystemStructures with a discontinuity in lateral capacity, vertical irregularityType 5, as defined in <Table 6.4.5>, shall not be over two stories or 9meters a height where the weak story has a calculated strength of lessthan 65 percent of the story above. Where the weak story is capable of

resisting a total seismic force equal to the design force multiplied by the75 percent of deflection amplification factor C ,,, the height limitation does

not apply.

1 02 L Oesrgn Loads for Buildings and Other structures — Alk 6 I Earthouake Loads 103

6.8.2 Inverted Pendulum—Type Structures Category D shall be designed for one of the following combinations of

Supporting columns or piers of inverted pendulum—type structures shallbe designed for the bending moment calculated at the base detenuinedusing the procedures given in Section 6.5 and varying uniformly to amoment at the top equal to ene—half the calculated bending moment at

the base.

6.8.3 Elements Supporting Dtscontinuous Walls or FramesDiscontinuous walls. columns -,r other elements of structures having plan

irregularity Type 4 of <Table 6.4.4> or vertical irregularity Type 4 of<Table 6.4.5> shall have the design strength to resist special seismicload combinations of Section 62.

6.8.4 Direction of Seismic Load

6.8.4.1 Seismic Design Cntegor~ BThe direction of application of seismic forces used in design shall be thatwhich will produce the most critical load effect in each component. Therequirement will be deemed satisfied if the design seismic forces areapplied separately and indep .ndentlv in each of the two orthogonal

directions.

6.8.4.2 Seismic Design Categor’ C

The structures assigned to Seismic Design Category C shall conform to

the requirements of Section 6.8.4.1. For structures that have plan

structural irregularity ~ype 5 in <Table 6.4.4>. their components and

foundations shall he designed for one of the following combinations of

prescnbed loads.

(1 One hundred percent of tb- forces for one direction pit’s 30 percent of

the forces far the perpencicular direction. The combination requiring

the maximum component s rength shall he used.

(2) The effects of the two orthogonal directions are permitted to be

combined on a square root of the sum of the squares (SI1SS) basis.

6.8.4.3 Seismic Design Categor PThe components and foundatio ‘s of structures assigned to Seismic Design

prescribed loads.

1) One hundred percent of the forces for one direction plus 30 percent of

the forces for the perpendicular direction. The combination requiring

the maximum component strength shall be used.

(2) The effects of the two orthogonal directions are permitted to becombined on a square root of the sum of the squares (SRSSl basis.

6.8.5 Vertical Seismic ForcesIn addition to the applicable load combinations, horizontal cantilever andhorizontal prestressed components of the structures assigned to SeismicDesign Category P shall he designed to resist a minimum net upwardforce of 0.2 times the dead load.

6.8.6 Building Separations

All structures assigned to Seismic Design Category D shall be separatedfrom adjoining structures. Adjacent buildings on the same proerty shallbe separated by at least a ~ where

°MT~ (àu,) 1+(a~) 2 (6.8.t)

and 3 ,,, and a ~.. are the displacements as determined in Section 6.5.7 or

6.7.4 of the adjacent buildings.When a structures adjoins a property line not conunon to a public way,that structure shall also be set back from the property line by at least

the displacement, a of that structure.

6.9 Architectural, Mechanical And Electrical Components

6,9.1 GeneralArchitectural, mechanical, electrical, and other nonstructural components inbuildings shall be designed and constructed to resist the equivalent staticforces and displacements detemuned in accordance with Section 6.9.\-Vhere the combined weight of the supported components and nonbuildingstructures exceeds 25 percent of the weight of the structures, structuresshall be designed in accordance with Section 6.10.

1 04 Onion Loads for Sutldrngs and Other Stnxturts — AlIt 6 Earthquake Loads I 1 05

6.9.1.1 Applicability to Com~xinents

Components shall he considere:i to have the same seismic design category

as that of the structure that ‘hey occupy or to which they are attached,as desci-ihed in Section 6.4. The ful]owiog nonstructural components are

exempt from the requirements of Section 6.9.

(1) Components in Seismic Deign Category A.

(2) Other than parapets supported by heating walls or shear walls,

architectural components q Seismic Design Category 13 when the

component importance facti ‘:. I,. is equal to 1.0,

(3) Mechanical and electrical c ‘ruponents in Seismic Design Category B.

(4) Mechanical and electrical remponents in Seismic Design Category C.

provided that the cnnlponei t importance factor. j,, is equal to 1.0.

(3) Mechanical and electrical components in all Seismic Design Categories

that are linked with ductwork or piping hr flexible connections.

mounted at 1.2 meters or less above a floor level, and weigh 1800 Nor less, provided that the snmponent importance factor, i~. is equal

to 1.0.

(6) Mechanical and electrical ompunents in Seismic Design Category U

that are linked with ductwork or piping hr flexible connections and

weigh 100 N or less, pros ded that the component importance factor.

is equal to 1.0.

6.9.1.2 Equivalent Seismic Forces

Equivalent seismic forces, F . shall he determined in accordance with

Eq. (6.9.11. The force F, sl all he applied independently longitudinally

and laterally in combination with service loads associated with the

component. When positive antI negative wind loads exceed F,, for

nonhearing exterior wall, these wind loads shall govern the design.

F, = 0.4a ~ (i 2t) (6.SlI

(j)

F , is not required to he taken as greater than

F, 1.6S &,w, 6.9.2)

and F, shall not he taken as less than

F, = 0.33 ~~IJ1’, 6.93)

where, a compnnent amplification factor that varies from 1 to 2.5

(select appropriate value from <Table 6.tJ> or <Table

6.9.2>)

seismic design force cenlererl applied at tb, component’s

center of gravity and distributed relative to component’s

mass distnbution

component importance (actor that is either 1.0 or 1.5. as

determined in Section 6.9.1.4

averaged roof height of structure waS relative to the base

elevation

1? ,: component response modification factor that ~‘ai5es from 1.0 to

5.0 (select appropnate value from <Table 6.9.10ev <Table

6.9,2>)

S ~ design spectral I~~~;p3i1m acceleration at e’oct rHod

determined in Section 6.3.3

component operating weight

z height in structure of point of atuichment of component.

z = 0 for items at or below the base

ii fur items at or above the roof

6.9.1 .3 Seismic Relative Displacements

Seismic relative displacements, D,. shall he determined in accordance

with the equations in this Section. For two connection points on the same

Structure A or the same structural system. one at a level x and the

other at a level y. D ,. shall be determined as

a~ ((5.9.4)

D is not .reqti i red to be taken as greater than

B, = (K— (tk9.3l

For two cunnection points on separate Structure A and 13 or separate

structural system. me at a level x and the other at a level v. jj shall

T

106 Design Loads or Buildings and Oilier Slruclures — Age Esrlhoaske Loads 107

be determined as (I) The force in the connected part shall be determined based on the

= I a + a,,,j 1aa6 prescribed forces for the component specified in Section 6.9.1.2. Wherethe component anchorage is provided by shallow expansion anchors.

is not required to be taker as greater than shallow chemical anchors, or shallow (low duct:litl cast—in—place

Xii ~ anchor, a value of x ~= 1.5 shall he used in Section 6.9.1.2 to(6.9,7)B + ~-~- dete~ne the forces on the connected part.

where, B, relative se ;mic displacement that the component must (2) Anchors embedded in concrete or masonry shall be propoitioned to

be designed to accomodate carry the lesser of the following:~ the design strength of connected part

story height used in the definition of the allowable© 1.3 times the force in the connected part as given by F R

drift in <‘Fable 6.4.7>.© The maximum force that can be transferred to the connected parta ~. a ~. a,.11 deflection at building level x or y of

by the component structural systcmStructure A or B, determined by an elastic

(3) Determination of forces in aochors shall include the expectedanalysis as defined in Sections from 6.5.3

conditions of installation including eccentricities and prying effects.to 6.5.7

x height of upper support attachment at level x ~IS

measured rom the base 6.9.2 Architectural Component Designy height of lower support attachment at level x ~ Architectural systems, components or elements listed in <Table 6.9.1>

measured fom the base and their attachments shall meet the requirements of section 6.9.1afr,wable story drift for Structure A or B as

defined in <Table 6.4.7> 6.9.3 Mechanical and Electrical Component DesignAttachments and equipment supports for the mechanical and elcctrical

6.9.1.4 ~mponent Importance Factor systems, components or elements shall meet the requiren~cnts of SectionThe component importance factor, j ,., for other components shall be 6.9.1.

taken as 1.0, but the factor shall he taken as 1.5 if any of the followingconditions apply:(1) Life—safety component is required to function after an earthquake.(2) Component contains hazartous or flammable materials.(3) Storage tacks in occupancies open to the general public (eg.

warehouse retail stores)

(4) Component is in or attached to an Occupancy Category S structure in<Table 6.4.1> and it is needed for continued operation of the facilityor it is its failure could imnair the continued operation of the facility.

6,9,1,5 Component AnchorageComponents shall be anchored in accordance with the following:

108 DesIgn Loads For Butidings and Other Structures — AIR - Earthquake Loads 109

(Table 6.91) Architectural Cornoonenis Coetttcimnla (Table 69.2) Mechanical and Electrical Components Coellicients

Architectural comportnl or Element ii j

t. intenor Nonstructural Watts and Parlttton:

a Plan (unreintorcod) masonry walls

C All other nuans and partittcna

2, cantilever Elements (Embraced or brace-I to structural rams below its carter of masst

a. Parapets and cantitavor intsrtcr nonctucturat walls 2.5 ] 2.5

h, Chimneys and stacks when Iaterall~ eraced or supportad by structural 25 25rattle

3, Cantilever Ci scents (Braced I ostrucluri, Irarne above its center Di easel

a, Parapets --______________ 1 0 2.5

5. ChImneys and Slacks 1.0 2,5

c. Extenor Nonstruelural Walls t~O 2.5

4 Exterior Nanstruclurat Wall Elements anti Connections

a. Wall Element 10 2.5

.....2: early at watt panel connections t~0 2.5c. Pasleners cI the connecting system 1.25 1.0

5. Veneer

a. LimIted dalcrmabitily elements and siinchmsnls 1.0 2.5

bLow detorsabthly elements and altar 5ments 1,0 1.25

6, Penthouse (except when Iramed by an uttenston of the buttding trace) 2.5 3.5

7. Ceilings t,0 2.5

8. Cohtr.els

a. Storage cabinets and laboratory peel n~inenl 1,0 2.5

9, Access Floors

a. Special access Iloors ~ 2.5

5. Att other -____________________ tO 1.25

1O.Agoendagas end ornamentations 2.5 2.5

li~ Signs and etllboards 2.5 2.5

12. Other Rigid Components

a, Higla deiormabihty elements and ettelinenis 1.0 3,5

0. Limited detormsbtlity elements and a’nchmanls 1,0 2,5

c, Low determabllley elements and ailsc’tln ants .0 1.25

13. Other Flexible components

a. High detormability elements and alteshments 1.0 3.5

0. Limited deformabsity elements and eliachmenls 2,5 2,5 -.

c, Lam detormebility elements and altar’ mania i 2.5 1.25

It peeve i-Jail lies by seated dream’s a nslys:s. ‘ices’ v~ VS ‘5’ a 1 ltsimtied. Cur alms sat 55 isas I

redasedvaisool vi, shah be L’elaeeett 2.5, iv ilnsa it ticeibie a, liesbis iitlarttsa e5av5rnsel.’iina 5. ixisi nasa to

ill’s 0’ esioirattacttadesuio’ecne

—.-________

Mechanical end Electrical Component or Element - is A’,

I. Senerat Mechaniszti

a. Boilers and tutnaces 1.0 ~, 2,5

S Pressure vessels on skirts and iree—slandine 2.5 2,5

c, Stacks 2.5 2,5

d. Cantitevered chimneys 2.5 - 2 5

e, Other 1.0 - 2.5-C,-,..’_

2, Menutocturing end Process Machinery

a. General to 2.5

5. Conveyore Inonoersonnet) 25 2.5

3. Ptptng Systems

a, High—detormabitity elements and etlachments I 0 3.5

5. Llmiled—defermabilily elements and attachments ‘,O 25

c. Low—dolcraebiltly elements end attachments .0 , 1.25

4. HVAC System Equipment

a, Vibtehlon isolated 2.5 2.5

b. Noneibral,on isolated 10 25

c. Mounted in—line vnth ductwork 1,0 2.5

d. Other 1,0 2.5

5, Elevator Componenis 1,0 2,5

e. escalator Coaoononts 1.0 2 5

7 Trussed Tomers (Iree—alanding or auyaol 2.5 2.5

8. General Electrical

o Distributed Systems (Bus Ducts, Conduit, Cable Tray) 10 , 3.5

5. Equipments ‘.o 2.5

9. Lighting Pistures , ‘.0 1.25

ii 0 Design Loads toe Euitdtnt~e slid Dicer Structures — Aik 6 Earlltquake Loads ‘Ill

6.10 Seismic Design Requirements for Nonbuilding Structures 6.10,2 Structural Design Requirements

ii::

6.10.1 General

6.10.1.1 Nonbuilding StructuresThe requirements of this section apply to self—supporting structures thatcarry gravity loads that are not defined as buildings, vehicular or railroadbridges, nuclear power generation plants, offshore platforms, or dams.

6.10.1.2 Nonbuilding Structures Supported by Other Structures(1) If a nonbuilding structure is supported above the base by another

structure and the weigh of the nonbuilding structure is less than 25percent of the combined weight of the nonhuilding structure and the

supporting structure, the design seismic forces of the supportednonbuilding structure shall be determined in accordance with the

requirements of Scction 6.9.(2) If the weight of n nonhuilding structure is 25 percent or more of the

combined weight of the nonbuilding structure and the supporting

structure, the design seismic forces of the nonhuilding structure shall

be determined based on the combined nonbuilding structure andsupporting structural system

(3) Response modification factors shall he determined in accordance withfollowing:

(1) For supported nonbuilding structures that have component dynamic

characteristics that are not rigid, the combined system R factor

shall be a maximum of 3.

(2) For supported nonbuilding structures that have rigid component

dynamic characteristics, the combined system R factor shall be the

value of the supporting structural system.

6.10.1.3 Architectural, Mechanical . and Electrical Components

Architectural, mechanical, and electrical components supported bynonbuilding structures shall be designed in accordance with Section 6.9.

112 Oesign Loads for Buildings and Other Structures — AIK

Design of nonbuilding structures to resist seismic loads shall conform to

this section.

6.10.2.1 Weight

For purpose of calculating design seismic force in nonbuilding structures.

the weight shall include dead load and normal operating contcnts for

items such as tanks, vessels, bins, and contents of piping. The weightshall include snow and ice loads when these loads constitute 25 percent

or more of the seismic effective weight.

6.10.2.2 Fundamental Period

The fundamental perioo of nonbuilding structure shall be determined by

method as described in Section 6.5.3, or by using other rati nI methods.

6.10.2.3 Drift LimitsThe drift limitation of Section 6.4.6 need not apply to nonhuildirtgstructures if a rational analysis indicates they can be exceeded without

adversely affecting structural stability.

6.10.2.4 Seismic Design ForcesNonbuilding strictures shall be deisgned to resist miniorunt seismiclateral forces not less than thc requirements of Section 6.5.1 and

following:

(1) The response modification coefficients shall be the lesser of thevalues given in <Table 6.10.1> or the values in <Table 6.6.1>.

(2) For nonbuilding systems with response modification coefficients

provided in <Table 6.10.1>, the minimum value specified in Eq. (6.5.4)

shall be replaced by the following:

C~=0.l4 S~5J~ (6.10.11

(3) The importance factor shall be given in <Table 6.10.2>.

The vertical distribution of lateral seismic forces in nonhuilding

structures covered by this section shall be determined in accordance with

Section 6.5.5.

5 Earthquake Loeos ii 3

6.10.2.5 Rigid Nonbuilding Structures(Table 6,1O,1~ Seismic Coefficients for Nonbuliding Structures

Nonbuilding structures that have a fundamental period, 7’, less than 0.06second, including their anchorages, shall be designed for the latera] force

obtained from the following:

where,

v= 0.3S,,5Wl~ (610,2)

j~. the importance factor as defined in <Table 6.10.2>

s ‘~ the site design response acceleration as detesmined fromSection 6.3.3

V : the total design lateral seismic base shear forceapplied to a nonhuilding stricture

iv : oonbuildisng structure operating weight as defined inSection 6.10.2,1

The force shall he distributed with height in accordance with Section6.5.5.

NonbLtitding Struclure Type £4

I, Nonbuilding Irawe systems:

a, Concentric braced frames of steel 5 2 4,5

2. Moment—resisting frame systems:

a, Mosisns Irames of steel 4 3 3,5

b. Intermediate moment frames Cl concrete 5 3 ~C. ordinary moment frames 01 concrete 3 3 2.5

3, steel storage racks 4 2 3.5

4, Elevated tanks, vessels, bins, or hoppers’1 5 2 2 5

a, On braced legs 2

b. On unbracod tags 2 2.5

c, single pedestal or skirt supported 2

d. Welded steel 2 2 2a. concrete

5. Horizontal, saddle supported aelded steal vessels 3 2 2,5

6, Tanks or vessels supported on structural towers similar to buildings 3 2 2

7. Flat bottom, ground—supported tanks, or vessels:a, Mechanically anchored (welded or bolted steel) 3 ] 2 2.5b. sell—anchored (welded or bolted steel) 2.~ I 2 2

B, Reinforced or prestressed concrete 2e. Tenks milh rotntorcad nonsliding base 2

b. Tanks with anchored flexible base 2 2

9, Tsnke wIth unanchored or unconstrained tanks

a. Flexible base 1.5 1.5 1.5

b. Other meleriet 1.5 1,5 1,5

10. cast—in—place concrete silos, etscks, end chimneys having watts 3 175continuous to the foundation

11. Other reinforced masonry rtruclures not similar to buildings5 3 2 2.6

12. Other nonrainlorcsd moscnry structures not similar to buIldings5 1.25 2 1,5

3, Oher steel and reintorced concrete distributed mass cantilever structuresnot covered herein Including stacks, chimneys, silos, and skirt—supported 3 2 2,5

vertical vessels shel are not sImIlar to buildings

14, Trussed tower (irsestsndirtg or guyed), guyed stacks and chImneys 3 2 2.5

IS, Cooling lomars

a. concrete or sieel 35 155 3

b. Wood trame 35 3 3

II 4 Design Loads for Buildings and Other Structures — AltO Earthquake Loads I 115

It Tourer with Irregularity es detiard in Seclion 5,1.4

St Consort tsr ligitling Soot ilgtillrg. etc.

3) tbsoirry structures nisatloet be eltovoed a Seismic design curing cries C arid 0

Importance Factor f,qi~ 1.0 fyar IS

SeIsmic use Group Iias uettned In (Table 64))

Hazard H—i <—2

Function F—I

H—leTttosts~~ product is bioIcgicaey Or onriroementally benign: tour lire or tow physLeal

H—a Trio clams product is toted hi3h or rederale erpansion hazard. high lire hasaul, Cr ru pr shooter F 1dec10 en

determined by hr setrisnity having trriseiotcen,

F—I Nonbu,Idingslludute500tciassllied as F—aF—S = seiemc ues Creep S nonbuildieg structures Or OeSigliaied osbitary 000bslllOirla structures (COOS 55:

~am~~celien loners, lee siorago ranks, cociin3 towers, or etrelriral ssbslwiicn slnictsrresl requited Err

operation ol Seismir Use Group Suhuiclurest

Nonbuilding Structure ‘~ype 1? Th~

IS, TelecommunIcation towersa. Truss : Steel 3 1,5 3b, Pole : Steel 1,5 1,5 1,5

Wood 1,5 ‘.5 1.5Concrete 1.5 1.5 .5

c, Frgmc Stoot 3 1.5 1.5Wood 2,5 1,5 1,5

Concrete 2 15 1,5

17, Amusemcnt structures and monuments 2 2 2

18. Inverted pendulum lype structures (not ole’ ‘red tanks)i 2 2 2

‘9, Signs and billboards 3.5 1.75 3

20, Other sell—supporting structures, tank, or ur:ssetr not covered above 1.25 2 2.5

<Table 6.10.2> Srnportance FerLcrr C J~t mid Seismic Use Group Clrtssrihcrdon

for Nunhuilding Sbticture

j

11 6 Design Loads or Buildings and Other Slructures — AIK Si Earthguake Loads i ‘117

change shal] be considered.

- 7.4 Fluid Pressure7 Soil and Hydrostatic Pressure and Other Loads7.1 General 7.4.1 Above— and at—grade storage tanks contalithig thud such as water

or oil for example shall be considered as fluid pressure acting structures.

7.1.1 Application

7.4.2 In the design of storage tanks, horizontal pressure applier’ to walls

7.1.1.1 This section shall he applied in detennining the soil and and vertical oressure to bottom horizontal structures shall be considered.hydrostatic pressure and the othtr loads. Also, in the case of air pressure acting on the fluid surface, both

additional horizontal and verLical forces shall he considered.

7.1.1.2 Other live loads include thermal load, content pressure load in 7.5 Contents Load in Storage Tankstorage tank, and transportation quipment and its components loads.

7.2 Soil and Hydrostatic Pressure 7.5.1 Liq~d PressureProvisons of Section 7.4 shall be used in calculating the liquid pi-essurecaused by liquid contents in storage tank.

7.2.1 Pressure on Basement Walls

7.5.2 Pressure of Powdered and Grain Contents7.2.1.1 Basement walls shall bc designed to resist lateral presstire ofadjscenr soil, and possible snrrlwrge fmm fixed or moving loads.

7.5.2.1 Stored contcnt pressures shall be calculated considering thevariations of pressure due to loading, unloading, sudden break off of

7.2,1.2 When a portion or the “hole of the adjacent soil is below a arch—shaped stacking, air pressure, and eccentric exhaust as well as staticfree—water surface, computations shall be based on the weight of the soil contents pressure. For clustered storage tanks, cunihination of vruiousdiminished by buoyancy, plus full hydrostatic pressure, cases ranging from full loaded case to empty case in a tank snail be

considered.

7,2.2 Uplift on Floors and FoundationsIn the design of basement floors and similar horizontal structural elements 7522 Static pressure acting on the storage tank by the contents

below grade, the upward pressure of water, where applicable, shall be consists of unit vertical sonic pressure, horizontal static pressure, and

taken as the full hydrostatic pressure applied over the entire area, vertical friction force shall he considered.

7.3 Thermal Stress 7.5.2.3 ~sign Pressure of the Contents

In the design of building, the lemial load effect due to teniperamreDesign pressure shall he calculated by multiplymg either adequate luad

118 Design Loads for Buildings and Older Structures — AlK 7 Soil and Hydrostatic Pressure and Other Loads 11 9

factor or impact factor.

75.2.4 Design Pressure of Air Pressure Vessel

Design pressure of air pressure vessel shall be largest value among

following:

(I) Design pressure ignoring air pressure.

(2) Design pressure that has less air density than static state Considering

air pressure, since floating particles are not contacting each other.

(vertical friction force per unit length of wail shall be assumed to be

equal to the case with no air pressure.)

7.5.2.5 Increase or Decrease of Pressure due to Eccentric Exhaust of the

Contents

In design of vessel, flexural moments in circumference direction due to

variation of the pressure arou nd the vessel shall be reflected as

considering effect of eccentric exhaust of the contents at outlet.

7.6 Transportation Equipment and its Component Loads

7.6.1 Transportation Equiprnen~ and its Component Loads

7.6.1.1 Loads caused by transporrition system and equipment

7.6.1.2 In case of structure supporting shaft— or motor—driven machinery,

the weight and moving loads due to vibration or impact

7.6.1.3 Loads of HVAC of lnilding, ductwork, piping system and

accompanying attachments

7.6.1.4 Large stress causing transportation equipments and device loadswhen concerned with occurrence of large stress in structure

120 Design Loads for Buildings and DO,er struotures — AIK