DSS-1st

Introduction

Design of Steel Structure

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STEEL STRUCTURE

Different types of structures in which steel has been used a structural material. They include

Bridges Towers Multi-storey buildings Storage tanks Industrial buildings, etc

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Why is steel such a good construction material?

What is its demerits?

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STRUCTURAL STEEL PRODUCTS

They are classified into the following:Flat hot rolled products – plates, flat bars,

sheets and stripsHot rolled sections – rolled shapes, and

hollow structural sectionsBoltsWelding electrodesCold rolled shapes

12

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STEEL SECTIONS

• Steel sections are rolled in industry in the standard shapes called rolled sections. The shapes of rolled sections are: Steel I-Sections; Channel Sections; Angle Sections; Tee Sections; Steel Bars; Steel Tubes; Steel Plates

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Steel products and steel tables• The structural sections produced in India include open

sections such as beams, channels, tees and angles. Closed (hollow) sections such as rectangular and circular tubes are available only in smaller sizes. Solid sections like bars, flats and strips are available.

• These sections are designated in a standard manner with the letters IS indicating that they satisfy the prescriptions of the Indian Standards Specifications (SP 6(1)) followed by the letter indicating the classification and type of section and a number indicating the size of the section.

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Contd..• Beam sections are classified as ISLB (light), ISJB

(junior), ISMB (medium), ISHB (heavy) and ISWB (wide-flanged) sections.

• Channel sections are designated as ISLC, ISMC etc.• Angles are designated as ISA followed by the size

of each leg and the thickness. Both equal and unequal angles are available.

• Sometimes two different sections have the same designation but their weight per unit length is slightly different.

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Structural Design

Structural design is a scientific & creative process. The structural design should satisfy

◦ Safety◦ Stability◦ Serviceability◦ DurabilityAnd result in◦ Economic (cost of construction & maintenance), ◦ Aesthetically pleasing, and ◦ Environment friendly structures.

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Iterative Design Process

ConnectionsIntroduction

Importance

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Introduction• Connections are structural elements used for joining

different members of a structural steel frame work.

• Connection elements consist of components such as cleats, gusset plates, brackets, connecting plates and connectors such as rivets, bolts, pins, and welds.

• Connections between different members of a steel frame work not only facilitate the flow of forces and moments from one member to another, but also allow the transfer of forces up to the foundation level.

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Why Connection Failure Should be Avoided?

A connection failure may be lead to a catastrophic failure of the whole structure

Normally, a connection failure is not as ductile as that of a steel member failure

For achieving an economical design, it is important that connectors develop full or a little extra strength of the members, it is joining.

Connection failure may be avoided by adopting a higher safety factor for the joints than the members.

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Classification of Connections

• Method of fastening: rivets, bolts and welding.• Connection rigidity: simple, rigid or semi-rigid.• Joint resistance: Bearing connections and friction

connections• Fabrication location: Shop or field connections.• Joint location: Beam-column, beam-to beam,

column to foundation

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Classification of Connections (cont.)

Connection geometry: Single web angle, single plate, double web angle, top and seat angles (with and without stiffeners), end plates, or header plate, welded connections using plates and angles, etc.

Type of force transferred across the structural connection: Shear connections, shear and moment connection or simply moment connection, tension or compression, tension or compression with shear.

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Classification Based on Joint Rigidity

Rigid: That develop the full moment capacity of connecting members and retain the original angle between the members under any joint rotation. Rotational movement of the joint will be very small

Simple: No moment transfer is assumed between the connected parts and hence assumed as hinged (pinned). Rotational movement of the joint will be large.

Semi-Rigid: May not have sufficient rigidity to hold the original angles between the members and develop less than the full moment capacity of the connected members. In reality all the connections will be semi-rigid only.

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rivets, bolts and welding.

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Rigid connections

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Simple connections

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Semi Rigid connections

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Examples of Rigid Connections

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Examples of Pinned Connections

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Rivets and Riveted Connections

Riveting not used now due to:

The necessity of preheating the rivets prior to driving

Labour costs associated with large riveting crews.

Cost involved in careful inspection and removal of poorly installed rivets

High level of noise associated with driving rivets 

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BOLTED CONNECTION

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Types of Bolts

• Unfinished bolts or black bolts or C Grade bolts (IS: 1363-1992)-bearing type connections

• Turned bolts - Expensive & used in Spl. jobs

• Precision (A-Grade)& Semi-precision (B-Grade) bolts (IS: 1364-1992) -They are used when no slippage is permitted

• Ribbed bolts (Rarely used in ordinary steel structures)

• High strength bolts (IS: 3757-1985 and IS:4000 - 1992)-Friction type connections

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Black or Ordinary Bolt and Nut

Source: AISC

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Hexagonal Head Black Bolt and Nut (IS 1363)

Figures in brackets are for High-strength Bolts & Nuts

Black bolts are inserted in clearance holes of about 1mm to 2mm more than the bolt diameter and then tightened through the nuts.

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Tensile Properties of Fasteners

In property class 4.6, the number 4 indicates 1/100th the nominal ultimate tensile strength in N/mm2 and the number 6 indicates the ratio of yield stress to ultimate stress, expressed as a percentage. Thus the ultimate tensile strength of class 4.6 bolt is 400 N/mm2 and yield strength is 0.6 times 400, which is 240 N/mm2

For grade 4.6 bolts, nuts of grade 4 are used and for grade 8.8, nuts of grade 8 or 10 are used.

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Dimensions of Grade 4.6- Hexagon Head Bolts (IS 1364)

Sizes in Brackets not preferred.

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High-Strength Bolts (IS 3757)

Made from bars of medium carbon steel. Bolts of property class 8.8 and 10.9 are commonly used.

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High-Strength Bolts (cont.)

The material of the bolts do not have a well defined yield point.

Instead of using yield stress, a so-called proof load is used.

The proof load is the load obtained by multiplying the tensile stress area (approximately equal to 0.8 times the shank area of bolt) by the proof stress.

In IS:800 the proof stress is taken as 0.7 times the ultimate tensile stress of the bolt.

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High-Strength Bolts (cont.)

Source:www.nichiasteel.co.jp

• They are identified by manufacturer’s identification symbol and property class identification symbol 8 S or 8.8 S or 10 S or 10.9 S which will be embossed on the heads of these bolts.

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High-Strength Friction Grip (HSFG) Bolts

• Special techniques are used for tightening the nuts to induce a specified initial tension in the bolt (called the proof-load), which causes sufficient friction between the faying faces.

• Such bolts are called High-Strength Friction Grip bolts (HSFG).

• Due to this friction, the slip in the joint is eliminated; joints with HSFG bolts are called non-slip connections or friction type connections

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Bolt Tightening Techniques

When slip resistant connections are not required, high strength bolts are tightened to a ‘snug-tight’ using an ordinary spud wrench.

When slip resistant connections are desired with HSFG bolts, three methods are used: Turn-of-the-nut tightening (part–turn method) –

Cheap, more reliable, and common method.Direct tension indicator tightening, Calibrated wrench tightening (torque control

method).

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Bolt tightening using impact wrench

Source: AISC

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Turn-of-the nut Tightening

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Behaviour of bolt-Turn-of-the-nut Method

In this method the bolt deformation is a critical factor

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Direct Tension Indicator Tightening• There are two types of proprietary load – indication devices. • The first type of device indicates the load by producing a measurable change in

gap between the nut and the gripped material.

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Direct Tension Indicator Tightening (cont)

In the second type, the bolt is tightened by turning a nut, which has a protruding nib; the tightening is continued till the nib shears off.

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Calibrated Wrench tighteningWrenches are calibrated by tightening,

in a hydraulic tension-measuring device, using a minimum of three bolts of the same diameter.

Impact wrenches are set to stall when the prescribed bolt tension is reached. A click sound can be heard and felt when the set torque is reached.

Manual torque wrenches have a torque indicating device, using which the torque required to produce the initial tension is measured.

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Advantages of Bolted connections

Bolted connections offer the following advantages over riveted or welded connections:

Use of unskilled labour and simple toolsNoiseless and quick fabricationNo special equipment/process needed for installationFast progress of workAccommodates minor discrepancies in dimensionsThe connection supports loads as soon as the bolts are tightened

(in welds and rivets, cooling period is involved).

Main drawback of black bolt is the slip of the joint when subjected to loading

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Load-Deformation Behaviour of Different Types of Fasteners

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Advantages of HSFG Bolts• HSFG bolts do not allow any slip between the elements connected,

especially in close tolerance holes, Thus they provide rigid connections.

• Because of the clamping action, load is transmitted by friction only and the bolts are not subjected to shear and bearing.

• Due to the smaller number of bolts, the gusset plate sizes are reduced.

• Deformation is minimized.• Holes larger than usual can be provided to ease erection and take

care of lack-of-fit. However note that the type of hole will govern the strength of the connection.

• Noiseless fabrication, since the bolts are tightened with wrenches.

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Advantages of HSFG Bolts• The possibility of failure at the net section under the working loads

is eliminated.• Since the loads causing fatigue will be within proof load, the nuts

are prevented from loosening and the fatigue strength of the joint will be greater than in welded/connections.

• Since the load is transferred by friction, there is no stress concentration in the holes.

• Unlike riveted joints, few persons are required for making the connections.

• No heating is required and no danger of tossing of bolt. Thus safety of the workers is enhanced.

• Alterations, if any (e.g. replacement of defective bolt) is done easily than in welded connections.

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Drawbacks of HSFG Bolts

Bolting usually involves a significant fabrication effort to produce the bolt holes and associated plates or cleats.

Special procedures are required to ensure that the clamping actions required for preloaded friction-grip joints are achieved.

The connections with HSFG bolts may not be as rigid as a welded connection.

HSFG bolts are about 50% higher than black bolts The percentage elongation at failure is 12% only.

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Bolt HolesBolt holes are usually drilled.IS: 800 allows punched holes only in materials whose

yield stress (fy) does not exceed 360 MPa and where thickness does not exceed (5600/fy) mm.

Bolt holes are made larger than the bolt diameter to facilitate erection.

Oversize holes should not exceed 1.25d or (d+8) mm in diameter, where d is the nominal bolt diameter in mm.

Slotted hole [provided to accommodate movements) should not exceed 1.33d in length (for short slotted hole) and 2.5 d in length (for long slotted hole).

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Pitch, Staggered holes & Gauge

A minimum spacing of 2.5 times the nominal diameter of the fastener is specified in the code to ensure that there is sufficient space to tighten the bolts, to prevent overlapping of the washers and to provide adequate resistance to tear-out of the bolts.

The edge distance should be sufficient for bearing capacity and to provide space for bolt head, washer and nut.

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Bolt Dia, Pitch & Edge Distances as per IS 800

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Gauge Distances for bolts as per SP-1

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Note on IS Rolled Sections

Bolting is often poorly executed:• Shank gets bent due to tapered flange• To avoid it useTapered washers (IS 5372/IS 5374)

BEHAVIOUR AND DESIGN OF BOLTED CONNECTIONS

Typical Bolted Connections

Behaviour of Bolted JointsAs soon as the load is applied, there is a very small friction at

the interface; slip occurs and the force is transferred from bolts to other elements through bearing of bolts.

Once the bolts are in bearing, the connection will behave linearly, until yielding takes place at the following: 1. At the net section of the plate(s) under combined tension and

flexure. 2. On the bolt shear plane(s) 3. In bearing between the bolt and the side of the hole.

The response of the connection becomes non-linear after yielding and failure takes place at one of the critical section/locations listed above.

Behaviour of Multi-Bolt Connection (cont.)

In multi-bolt connection, the behaviour is similar except that the more highly loaded bolt starts to yield first, and the connection will become less stiff.

At a later stage, due to redistribution of forces, each bolt is loaded to its maximum capacity.

In a long bolted connection the bolts at the end of a joint resist the highest amount of shear force.

Behaviour of HSFG Bolted Connection

• In HSFG bolts, the slip will occur when load overcomes the frictional resistance provided by the preload of the bolt.

• After slip occurs, the behaviour is similar to the normal bolts.

• In this case also, it is commonly assumed that equal size bolts share the loads equally in transferring the external force.

Force Transmission Through Bolts

Possible Failure Modes

Possible Failure Modes

Thus any joint may fail in any one of the following modes:Shear failure of boltShear failure of plateBearing failure of boltBearing failure of plateTensile failure of boltsBending of boltsTensile failure of plate

Bearing Failure of Bolt

Photo by P.S. Green (Copyright© AISC)

Tension Failure of Bolts

Photo by J.A. Swanson and R. Leon of Georgia Institute of Technology © AISC

Bearing Failure of Plates

Photo by J.A. Swanson and R. Leon of Georgia Institute of Technology© AISC

Design Strength Of Black Bolts• The nominal capacity, Vnsb, of a bolt in shear is

given in the code asV (f / 3 )(n A n A )nsb u n nb s sb lj lg pk

where nn = number of shear planes with threads intercepting the shear plane,

ns = number of shear planes without threads intercepting the shear plane,

βlj = reduction factor which allows for the overloading of end bolts that occur in long connections

βlg = reduction factor that allows for the effect of large grip length,βpk = reduction factor to account for packing plates in excess of

6mm.

The factored shear force Vsb should satisfyVsb ≤ Vnsb / γmb (γmb = 1.25)

Shear Planes With and Without Threads

Threads Excluded from the Shear Plane

Threads included in the Shear Plane

Design Strength of Black Bolts (cont.)Asb = Nominal shank area

Anb = Net tensile stress area through the threads

Anb = pi / 4 (d - 0.9382p)2 ≈ 0.78 Asb

p= pitch of thread, mm

Reduction Factor for Long Joints: βlj = 1.075 – lj (200 d) with 0.75 ≤ βlj ≤ 1.0

• Reduction Factor for Large Grip Length:

βlg = 8d / (3d + lg); lg ≤ 8d; βlg ≤ βlj

• Reduction Factor for Packing plate:

βpk = (1-0.0125 tpk ); tpk is the thickness of the thicker packing plate in mm

Bolts in Tension• The nominal capacity of a bolt in tension is:

Tnb = 0.90 fub Anb < fyb Asb (γm1 / γm0 ) where Asb = Shank area of bolt

Anb = Net Tensile Stress area of bolt fyb = Yield stress of the bolt γm1 = 1.25; γm0 = 1.10

• The factored tension force Tb shall satisfy Tb ≤ Tnb / γmb ; γmb = 1.25

If any of the connecting plates is flexible, then additional prying forces must be considered.

Bolts in BearingThe nominal bearing strength of the bolt is :

Vnpb = 2.5 kbd t fu

fu = Ultimate tensile stress of the plate in MPa

d = nominal diameter of the bolt in mm t = summation of the thicknesses of the connected plates experiencing

bearing stress in the same direction (If the bolts are countersunk, the thickness of the plate minus one half of the depth of counter sinking)

kb is smaller of e/(3do), p/(3do)-0.25, fub/ fu and 1.0,

where fub is the ultimate tensile stress of the bolt, e is the edge distance, p is the pitch of the fastener along bearing direction, and do is the diameter of the bolt hole.

Vnpb should be multiplied by a factor 0.7 for over size or short slotted holes and by 0.5 for long slotted holes.

Bolts in Bearing (cont.)• The factor kb takes into account inadequate edge distance

or pitch and also prevents bearing failure of bolts. • If we adopt a minimum edge distance of 1.5 x bolt hole

diameter and a minimum pitch of 2.5 x diameter of bolt, kb may be approximately taken as 0.50.

• The bolt bearing on any plate subjected to a factored shear force Vsb, shall satisfy

Vsb ≤ Vnpb / γmb ; γmb = 1.25

Capacity Of Ordinary Bolts (Grade 4.6) Based on Net Tensile Area

Prying Forces in Beam-Column Connection

Failure Modes Due to Prying Forces

Photo by J.A. Swanson and R. Leon of Georgia Institute of Technology© AISC

External Force Vs Bolt Force In a T-stub Connection

Additional Force in Bolt due to Prying

The additional force Q in the bolt due to prying action:

• γ = 1.5

β= 2 for non-tensioned bolt and 1 for pre-tensioned boltbe = Effective width of flange per pair of bolts, mm fo = Proof stress (kN or kN/mm2)

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Bolts With Shear and Tension• A circular interaction curve, as per code:

0.122

nd

e

sd T

T

V

V

V = Applied factored shear Vsd = Design shear strengthTe = Externally applied factored tensionTnd = Design tension strength

Tension Capacity of Plate

Tension Capacity of plate:Tdn = 0.9 fuAn /γm1; γm1 = 1.25

Tension failure Limit state

Photo by J.A. Swanson and R. Leon of Georgia Institute of Technology© AISC

Tension Capacity of Plate-Staggered Holes

• Tdn = 0.9 fuAn /γm1A [b nd p / 4g ]tn h i

2

i 1

m

i

Design Strength of HSFG BoltsThe design slip resistance or nominal shear capacity of a bolt:

Vnsf = μf ne Kh Fo

μ = Coefficient of friction (called as slip factor) ≤0.55.ne = Number of effective interfacesKh = 1.0 for fasteners in clearance holes = 0.85 for fasteners in oversized and short slotted holes = 0.7 for fasteners in long slotted holes loaded parallel to the slotFo = Minimum bolt tension (proof load) ≈ 0.8 Asb fo

Asb = Nominal shank area of bolt fo = Proof stress ≈ 0.7 fub

fub = Ultimate tensile stress of bolt

Design Strength of HSFG Bolts (cont.)

The factored design force Vsf, should satisfy:

Vsf ≤ Vnsf / γmf γmf = 1.10 if slip resistance is designed at service load

γmf = 1.25 if slip resistance is designed at ultimate load.

Long Joints:The design slip resistance is reduced byβlj = 1.075-lj / (200 d) but 0.75<βlj ≤ 1.0

• The fomulae for bearing & tension resistance, and Combined Shear and Tension are similar to those of Black bolts.

Coefficient of Friction

Block Shear StrengthIt is taken as the smaller of :

Avg, Avn = minimum gross and net area in shear along a line of transmitted force(along Lv)

Atg,Atn = minimum gross and net area in tension from the hole to the toe of the angle or next last row of bolt ingusset plates (along Lt)

fu,fy = ultimate and yield stress of

the material respectivelym0 = 1.10; m1 = 1.25

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Typical Block Shear Failure

Photo by J.A. Swanson and R. Leon of Georgia Institute of Technology© AISC

Capacities of HSFG Bolts

Connection with HSFC Bolts

Case Study: Kemper Arena collapse

source: http://en.wikipedia.org/wiki/Kemper_Arena

The secondary steel plane trusses were supported by the space frame by pipe hangers at 42 different panel points. Each of these hangers carried 622 kN in tension. the roof was designed to hold water as a temporary reservoir. 

On June 4, 1979 severe wind (110 km/h) and rain storm (108 mm) caused a portion (61 by 66 m )of Kemper Arena's roof to collapse

Details of the Kemper Arena Hanger Assembly

The important lesson to be learnt by this failure is that high-strength bolts, which are relatively brittle, should not be used in joints subjected to fatigue loads.

HSFG bolts, with pre-tensioning, are suitable for such connections. 

Pin Connections

Pin Connection (cont.)

Design of Pins• Shear capacity(a) if rotation is not required and the pin is not intended to be removed:

0.6 fyp A.

(b) if rotation is required or if the pin is intended to be removed : 0.5 fyp A

• Bearing capacity(a) if rotation is not required and the pin is not intended to be removed:

1.5 fy dt

(b) if rotation is required or if the pin is intended to be removed : 0.8 fy dt

fyp is the design strength of the pin, fy is the lower of the design strength of the pin and the connected part, t is the thickness of the connected part,

Design of Pin (cont.)Bending(a) if rotation is not required and pin is not

intended to be removed: 1.5 fyp Z(b) if rotation is required or if the pin is

intended to be removed: 1.0 fyp Z

where, A is the cross-sectional area of the pin, d is the diameter of the pin, Z is the section modulus of the pin

Simple Connections

Connections may be classified as:• Lap and butt joints• Truss joint connections • Connections at beam-column junctions

Seat angle connectionWeb angle connectionStiffened seat angle connectionHeader plate connection

• Tension and flange splices

Lap Joints

Butt Joints

Typical Truss ConnectionsBlock shear model may be used to predict the ultimate capacity of gusset plate connections in tension.Local buckling may be prevented , by restricting the unsupported edge of a gusset plate to 42ε times the thickness, where ε= (250 / fy)0.5.

Case Study: I-35W Mississippi River Bridge

Source: http://en.wikipedia.org/wiki/I-35W_Mississippi_River_bridge

On August 1, 2007,the bridge collapsed into the river, killing 35 people and injuring 100.The National Transportation Safety Board (NTSB), concluded that the gusset plates contributed to the failure of the bridge, as their thickness was 50% less than the required. NTSB found 16 fractured gusset plates from the bridge's center span.

Clip and Seating Angle Connections

Also called seat-angle connection.

Minimum length of bearing at edge of root radius= Reaction / (web thickness x design strength of web)  

Design of Unstiffened Seating Angle Connection

The design consist of the following steps:Select a seat angle having a length equal to the width of

the beam.Keep the length of seat more than the bearing length

given by b = [R / t w (fyw / γmo )]

where R = reaction from beam A dispersion of 450 is taken from the bearing on the cleat

to the root line. Length of bearing on cleat, b1 = b- (Tf + rb)

rb ,Tf = root radius and thickness of beam flange

Design of Unstiffened Seating Angle Connection (cont.)

Distance of end bearing on cleat to root angleb2 = b1 + g – (ta + ra)

Select an angle with connect leg > 100mm. The bending moment, Mu = R (b2 / b1) x (b2 / 2)

Equate it against the moment capacityMd = 1.2 Z (fy / γmo)

When Md < Mu , revise the section.The shear capacity of the outstanding leg of cleat is calculated as

Vdp = w t fy / (3 γmo); should be >R Calculate no. of bolts; Also choose a nominal top cleat angle

Stiffened Seat Angle

Design of Stiffened Seat Connection

• Assume the size of seat angle on the basis of bearing length similar to unstiffened seat connection.

• The outstanding leg must not exceed 14ε times the thickness, where ε = (250 / fy)0.5 to avoid local buckling). The required bearing area is calculated as Abr = R / (fy / γmo)

• Choose the thickness of the stiffener angle >thickness of the web of the beam.

Design of Stiffened Seat Connection (cont.)

Assume that the reaction from the beam acts at the middle of the outstanding leg of angle.

Compute the eccentricity, B.M., and tension acting in critical bolts, similar to the bracket connection.

Check the critical bolt using the interaction formula.

Provide nominal angle at the top of the beam & connect with two nominal size bolts on each leg of the cleat angle.

Web Angle ConnectionDouble web cleat connection is preferred over single sided web cleat connection.The beam reaction is transferred by shear and bearing from the web of the beam to the web bolts and to the angle cleats. These are then transferred by the cleat angle to the bolts at the junction of supporting member.Then to the supporting member mainly by shear and also by tension and compression. The beam is designed as a simply supported beam

Flexible End Plate ConnectionThis connection behaviour is similar to the legs of web angles connected to the column flange.Limit the thickness of the plate and position the bolts not too close to the web and flange of the beam. Keep the length ‘a’ < 30t Design the beam for zero end moment. Design the column for the eccentric beam reaction.

The reaction is transferredBy weld shear to the end plate, by shear and bearing to the bolts, by shear and bearing to the supporting member.

Web Side Plate Connection

Consists of a fin plate that is fillet welded to the supporting member, and bolted to the beam web.

Use only ordinary bolts. Design the bolts to fail by bearing of the connected plies and not by shear of the bolt. Keep Edge distances > two times bolt diameter. Make resistance of the welds attaching the fin plate to the support > the moment applied by the bolts. Select minimum size of weld, relative to the web thickness, to achieve ductility

Moment Resistant Connections

• Used in framed structures, where the joints are considered rigid.

• Classified as– Eccentrically loaded connections

• Type I (Ecc. Load causing Twisting)• Type II (Ecc. Load causing BM)

– Tee stub connections and – Flange angle connections.

Eccentric Shear in Connections

Ecc. Shear Causing Twisting

Elastic (Vector) Analysis- assumptionsDeformation of the connected parts may be ignored.The relative movement of the connected parts are

considered as the relative rigid body rotation of the two parts about some centre of rotation.

There is friction between the ‘rigid’ plates and the elastic fasteners.

The deformation induces reactive bolt forces- tangential to the centre of rotation.

This elastic method yields conservative results.

Elastic Vector Analysis

Rotation Effect Direct Shear

Based on shaft torsion analogy

RM d

di

i2

n

PRv

Elastic Vector Analysis (cont.)

• In General, we have:

)( 22 yx

MyRx

)( 22 yx

MxRy

n

PRv

Resultant force in Bolt:

R (R R ) Ry v2

x2

x and y are Horizontal and vertical distance of ‘d’n= number of bolts

The above formula can be extended to a case having vertical and horizontal loads.

Strength (Plastic) Analysis

An iterative method to locate the Instantaneous centre of rotation.

The Elastic (vector) analysis method yields more conservative results.

Bracket-Type II Connection

The bolts are subjected to direct shear along with tension due to the moment.

Bracket-Type II Connection (cont.)

DirectShear

Tensile force in extreme critical boltAssume NA below the last bolt

n

PV 0.1

22

nd

e

nd T

T

V

V

Check:

2

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i

ne y

yMT

M* = Pe

End-Plate connections

End- plate connection

Extended end-plate connection

Rigid Beam-to-Column Connections

Flange-Angle Connection

T-Stub Connection

Beam-to- Beam Connections

Beam-to-Beam Connections

Moment Resistant Beam-to-Beam Connections

Types of Beam-Splices

Bolted Beam-Splice

Bolted Column Splice

Bolted Column Splice

Column Splices Using End-Plates