Structural Calculations FOR Sample Project Demonstrating MESS Light Gauge Steel Add in for Tedds

Microsoft Word - 16057 (A - V2-2 and instructions added) - Sample Design using MESS LGS add in for Tedds.docxModern Engineered Software Solutions Ltd
Suite 4
Tilcon House
Contents
BREVe .................................................................................................................................................................... 5
Floor Truss - Lattice .............................................................................................................................................. 17
Lintel ..................................................................................................................................................................... 31
Building Dimensions ...................................................................................................................................... 49
Loads applied ................................................................................................................................................. 49
Bracing Forces ............................................................................................................................................... 50
Braced bays required to resist wind load applied to face ‘L’ .......................................................................... 50
Braced bays required to resist wind load applied to face ‘W’ ......................................................................... 50
Overturning Check ......................................................................................................................................... 51
Sliding Check ................................................................................................................................................. 51
Alpha-Crit Checks .......................................................................................................................................... 52
DESIGN PHILOSOPHY
Design is purely to demonstrate some the range of designs available in the Modern Engineered Software
Solutions Ltd Add in for Tedds and Breve and to show users how to enter the required data properly. The
building is a sample 10m square, three storey building with a C section roof joist and lattice truss floor
joists. Wall studs are at 600mm c/c under load bearing and ‘façade’ or infill face.
Infill and ‘Façade’ is stud designed, detailed and installed so carry ONLY own self weight of studs and
cladding with wind load ONLY. Façade studs do NOT carry floor or roof loads OR contribute to ‘racking’
faces.
Load Bearing stud design is checking studs under floor and roof loading, as well as self weight
and wind load. Loads are entered as per metre run (taken from reactions of joists) and the calculation
separates out per stud based on ‘centres’
Racking and sliding checks are in accordance with latest industry guidance, including 4.5kN per pair of
studs at 600mm c/c, Alpha Crit checks and lack of member capacity checks in bracing as deemed to not
be required as deflection limits design.
Wind loading calculation, roof joist, wall stud design’s (load bearing and infill / façade), floor joist, lintel and
sliding, racking and overturning checks are to Euro Codes, BS EN 1993-1-3 for material and EN 1991-1-4
for wind loading. Calculations are in line with industry guidance such as SCI guide ED005. The software
also produces trimmer designs around openings, similar to the roof and floor designs to both EN 1993-1-3
and BS 5950-5, as are all the other designs.
Loads as table below noted in calculations and repeated here for clarity
Description Load in kN/m2
Roof Dead Load 0.9kN/m2
Roof Imposed Load 0.6kN/m2
Wall Dead Load 0.5kN/m2
Profile used is 150 x 1.6 and 100 x 1.2, but many more are available.
Standards and Codes of Practice
All imposed loadings are in accordance with assumed loads.
Structure is designed in accordance with SCI Guide P402 as Industry Guidance in terms of stability
ethos, etc. It is assumed that the erection, construction and generic details such as holding down
not specifically detailed in these calculations are based on this guide for the calculations’ to be
valid.
Material has been designed to BS EN 1993-1-3 and BS 5950-5
Please note that this design is a sample desk top study and not intended to be built from. In the case that it was to be built from
the erector is responsible for checking site details are as per design. Any and all queries to be directed to the engineer. Practice
do not take design responsibility for the use of the calculations without signing off any manufacturing or construction drawings to
ensure that design intent has been fully translated. The production of this report and calculations is subject to our standard terms
and conditions, available upon request and posted on the practice web site. Site inspection is categorically not allowed for and is
not the responsibility of the engineer or practice.
Drawings and 3D images kindly supplied by Vertex(UK) Ltd
MMCEngineer Ltd
Lingerfield, Knareasborough
Sample design showing output of LGS add in for Tedds
Job Ref.
Date
BREVE
Above is created using the MESS Breve Add in for Excel.
Site ID is EITHER
selected from map by
using Browse Site OR
directly entering into the
Job Ref.
WIND LOADING (EN1991)
This section is produced using the built in Tedds Wind Module from the “Engineering Library” -
WIND LOADING (EN1991-1-4)
Eaves type Sharp
Basic values
Location ST139963
Distance to shore Lshore = 34.00 km
1 0
0 0
currently NOT possible to ‘pre
load’ the figures from Breve, so
we suggest keeping Breve /
accessing the required figures
Job Ref.
Altitude factor calt = Aalt 0.001m-1 + 1 = 1.2
Fundamental basic wind velocity vb,0 = vb,map calt = 26.7 m/s
Direction factor cdir = 1.00
Season factor cseason = 1.00
Exponent n n = 0.5
Probability factor cprob = [(1 - K ln(-ln(1-p)))/(1 - K ln(-ln(0.98)))]n = 1.00
Basic wind velocity (Exp. 4.1) vb = cdir cseason vb,0 cprob = 26.7 m/s
Reference mean velocity pressure qb = 0.5 vb 2 = 0.436 kN/m2
Orography
Terrain category Country
Displacement height (sheltering effect excluded) hdis = 0mm
The velocity pressure for the windward face of the building with a 0 degree wind is to be considered as 1 part as
the height h is less than b (cl.7.2.2)
The velocity pressure for the windward face of the building with a 90 degree wind is to be considered as 1 part as
the height h is less than b (cl.7.2.2)
Peak velocity pressure - windward wall - Wind 0 deg and roof
Reference height (at which q is sought) z = 8550mm
Displacement height (sheltering effects excluded) hdis = 0 mm
Exposure factor (Figure NA.7) ce = 2.30
Peak velocity pressure qp = ce qb = 1.00 kN/m2
Structural factor
Peak velocity pressure - windward wall - Wind 90 deg and roof
Reference height (at which q is sought) z = 8550mm
Displacement height (sheltering effects excluded) hdis = 0 mm
Exposure factor (Figure NA.7) ce = 2.30
Peak velocity pressure qp = ce qb = 1.00 kN/m2
Structural factor
Peak velocity pressure – internal (as roof press.) qp,i = 1.00 kN/m2
Pressures and forces
Net force Fw = pw Aref
MMCEngineer Ltd
Job Ref.
Zone Ext pressure
Walls load case 1 - Wind 0, cpi 0.20, -cpe
Zone Ext pressure
Overall loading
Equiv leeward net force for overall section Fl = Fw,wE = -55.3 kN
Net windward force for overall section Fw = Fw,wD = 47.4 kN
Lack of correlation (cl.7.2.2(3) – Note) fcorr = 0.85 as h/W is 0.855
Overall loading overall section Fw,D = fcorr (Fw - Fl + Fw,h) = 87.3 kN
Roof load case 2 - Wind 0, cpi -0.3, +cpe
Zone Ext pressure
Walls load case 2 - Wind 0, cpi -0.3, +cpe
Zone Ext pressure
Overall loading
MMCEngineer Ltd
Job Ref.
Date
Lack of correlation (cl.7.2.2(3) – Note) fcorr = 0.85 as h/W is 0.855
Roof load case 3 - Wind 90, cpi 0.20, -cpe
Zone Ext pressure
Walls load case 3 - Wind 90, cpi 0.20, -cpe
Zone Ext pressure
Overall loading
Lack of correlation (cl.7.2.2(3) – Note) fcorr = 0.85 as h/L is 0.855
Roof load case 4 - Wind 90, cpi -0.3, +cpe
Zone Ext pressure
Walls load case 4 - Wind 90, cpi -0.3, +cpe
Zone Ext pressure
MMCEngineer Ltd
Job Ref.
Overall loading
Lack of correlation (cl.7.2.2(3) – Note) fcorr = 0.85 as h/L is 0.855
MMCEngineer Ltd
Job Ref.
Job Ref.
Member as Roof OR
Floor (Roof defaults to
Distance between
Job Ref.
MMCEngineer Ltd
Job Ref.
BoardType = "Flat Roof"
Load factors
Permanent G = 1.35
Variable Q = 1.5
Section dimensions and material properties for a joist to EN 1993-1-3
The floor joist is a lipped C section from Generic 150x45x1.6, manufactured from 390 N/mm2 steel with a Z275 coating to
BS EN 10346.
Corner radius r = 2.4mm
Core thickness tn = t – 0.04mm = 1.6mm
Basic yield strength fyb = 390.0 N/mm2
Modulus of elasticity E = ESEC3 = 210.0 kN/mm2
Shear modulus G = 80769 N/mm2
Partial factor M0 = 1.0
Second moment of area about y axis Iy = 129.1 cm4
Effective Section Properties
Second moment of area about y axis Iy.eff = 121.5 cm4
Elastic section modulus for bending about y axis Weff.y = 15.8 cm3
Serviceability Deflections
For cross-section stiffness properties the influence of rounded corners should always be taken into account. For this
example it is assumed that the maximum stress at serviceability is the design yield strength divided by 1.5. BS EN 1993-1-
3, 5.1(3)
Iy = 129.1cm4
Iy.eff = 121.5cm4
BS EN 1993-1-3, 7.1(3)
Job Ref.
Date
The influence of rounded corners has been taken account in the calculation of the Igr and Ieff values used to calculate Ific.
Therefore, the second moment of area for serviceability is given by
Ific = 124cm4
RA,ULSgk = (G gk Sjoists L ) / 2 = 1.8kN
Reaction under qkV ultimate loads is,
RA,ULSqk = (Q qk Sjoists L ) / 2 = 1.4kN
Reaction under qkW ultimate loads is,
RA,ULSqkW = (Q qkW Sjoists L ) / 2 = 2.0kN
Reaction under ultimate loads is,
RA,ULS = Max((RA,ULSgk + RA,ULSqk), (RA,ULSgk - RA,ULSqkW)) = 3.2kN
Reaction under gk un factored loads is,
RA,SLSgk = (gk L ) / 2 = 2.3kN/m
Reaction under qk un factored loads is,
Variable, RA,SLSqk = (qk L ) / 2 = 1.5kN/m
Wind, RA,SLSqkW = (qkW L ) / 2 = 2.3kN/m
Reaction under un factored loads is,
RA,SLS = Max ((RA,SLSgk + RA,SLSqk) , (RA,SLSgk - RA,SLSqkW)) = 3.8kN/m
Design Moment
Applied design moment is given by,
BM = Max((((G gk + Q × qk) Sjoists L2 ) / 8), (((G gk - Q × qkW) Sjoists L2 ) / 8)) = 4.0kNm
Resistance of Cross-Section
Bending Moment – BS EN 1993-1-3, 6.1.4
Design moment resistance for bending about y axis is given by, Mcy,Rd = (Weff.y fyb ) / M0 = 6.1kNm
Ratio 0.65
Lateral Torsional Buckling
The member is assumed to be restrained along the length of the inner and outer faces by the connection to the diagonals
and boarding. Therefore, the member is not required to be checked for lateral torsional buckling.
Roof Deflection Check
For light weight steel roofs assuming fall to roof to prevent ponding there is only one serviceability criteria that should be
checked to ensure acceptable performance of the roof in service.
Imposed load deflection less than span/360.
Total load is, W = Max(L Sjoists qk, L Sjoists (qkW – gk)) = 1.8 kN
Deflection due to load is given by = (5/384) (W L3)/ (E Ific)) = 11.2mm
Reactions used in
Job Ref.
Deflection Criteria - PASS
Roof Deflection Check
For light weight steel roofs assuming fall to roof to prevent ponding there is only one serviceability criteria that should be
checked to ensure acceptable performance of the roof in service.
Imposed load deflection less than span/360.
Total load is, W = Max(L Sjoists qk, L Sjoists (qkW – gk)) = 1.9 kN
Deflection limit is
Job Ref.
offers differing ‘Board types’
selected when changing
NOT applicable to British Standards so
removed when standard selected
Job Ref.
Date
When it comes to selecting the floor type don’t forget to look at the Notes!
SCI Guide P402 discusses various floor types in Table 2.7 but as an Engineer doesn’t tell us weights OR floor types for the four
deflection checks. Working with the SCI we have ‘enhanced’ the tables and included them in the Notes – sample below:
Output Screen
Moment Checks
Deflection Checks
MMCEngineer Ltd
Job Ref.
Job Ref.
BoardType = "Flat Roof"
Number of effective joists carrying 1kN point load Neff = 2.75
Load factors
Permanent G = 1.35
Variable Q = 1.5
For a lattice joist, using C section’s from Generic 150x45x1.6, manufactured from 390 N/mm2 steel with a Z275 coating to:
Effective cross sectional area of section Aeff = 2.3 cm2
Gross cross sectional area of section Agr = 4.0cm2
Depth of C section b = 45.0mm
Depth of lattice truss D = 245.0mm
Position of cenroid in relation to the web yc,eff =b / 2 = 22.5mm
Diameter of screw d = 4.2mm
Gross Second moment of area of section Iz = 9.8cm4
Effective Second moment of area of section Iz.eff = 8.2cm4
Effective Second moment of area of section IficC = Iz – (1/1.5) (Iz – Iz.eff) = 8.70cm4
Gross Second moment of area of section Iy = 129.1cm4
Effective Second moment of area of section Iy.eff = 121.5cm4
Effective Second moment of area of section Ificy = Iy – (1/1.5) (Iy – Iy.eff) = 124.06cm4
Material gauge t = 1.6mm
Yield strength of section fyb = 390N/mm2
Ultimate Yield strength of section fu = 440N/mm2
Average yield strength fya= MIN((fyb + (fu - fyb) ((7 4 tcor 2) / Agr)), ((fu +fyb) /2)) = 399N/mm2
Modulus of elasticity E = ESEC3 = 210 kN/mm2
Effective depth of lattice deff = D – (2 yc,eff) = 20cm
Second moment of area of lattice Ific = 2(IficC +( Aeff (deff/2)2)) = 479cm4
Maximum member length for lattice Lm = deff /cos(45) = 28cm
Compressive resistance Nc,Rd = (Aeff fyb / M0 = 90.1kN
Tensile resistance Nt,Rd = (Agr fya / M0 = 157.5kN
Members restrained at either end by 2No. 5.5 diameter screws:
Member as Roof OR Floor (Floor
offers differing ‘Board types’
Job Ref.
Support Reaction’s
Reaction under gk ultimate loads is, RA,ULSgk = (G gk Sjoists L ) / 2 = 1.0kN
Reaction under qk ultimate loads is, RA,ULSqk = (Q qk Sjoists L ) / 2 = 5.0kN
Reaction under ultimate loads is, RA,ULS = RA,ULSgk + RA,ULSqk = 6.0kN
Reaction under gk un factored loads is, RA,SLSgk = (gk L ) / 2 = 1.3kN/m
Reaction under qk un factored loads is, RA,SLSqk = (qk L ) / 2 = 5.5kN/m
Reaction under un factored loads is, RA,SLS = RA,SLSgk + RA,SLSqk = 6.8kN/m
Design Moment
Applied design moment is given by, BM = ((G gk + Q × qk) Sjoists L2 ) / 8 = 7.5kNm
Strength:
Tensile capacity of member Nt,Rd = 157.5kN
Ratio 0.24
Maximum compressive load in member Pc = (Fv Lm) / deff = 8.4kN
Nc,Rd =90.1kN
Ratio 0.09
Shear Check - PASS
Fixings required, based up on applied load and fixing capacity, No. = ceiling(MAX((Pc / Fb,Rd),2),1) = 2 fixings per end.
Buckling Resistance of Member
Lateral Torsional Buckling
The member is assumed to be restrained along the length of the inner and outer faces by the connection to the diagonals
and boarding. Therefore, the member is not required to be checked for lateral torsional buckling.
Criteria 1
Dead load plus imposed load deflection less than span/350 or 15 mm whichever is smaller.
Total load is, W = L Sjoists (gk + qk) = 8.1 kN
Deflection due to load is given by = (5/384)W L3)/ (E Ific)) = 13.1mm
Deflection limit is limit1 = MIN((L / 350),15mm) = 14.3mm
Ratio 0.92
Note Number of
Job Ref.
Total load is, W = L Sjoists qk = 6.6 kN
Deflection limit is limit2 = L / 450 = 11.1mm
Ratio 0.96
Natural frequency of the floor not less than 8 Hz.
Total load for this criteria is, W = L Sjoists (gk + 0.2 qk) = 2.8 kN
Deflection limit for 8 Hz is limit3 = 5mm
Ratio 0.91
Criteria 4
Deflection of floor system less than critical value subject to 1 kN point load.
Total load for this criteria is, W = 1.0 kN
Deflection due to load is given by = (1/48) (W L3)/ (E Ific Neff)) = 0.94mm
The deflection limit for this criteria is dependent on the span of the joist.
limit4 = 1mm 3.7554 (L/1m)-0.627 = 1.37 mm
Ratio 0.69
Job Ref.
Select Standard to be used
– Note: Section to be re
selected when changing
Number of floors (Don’t include Ground Floor)
Wall self weight (0.5kN/m2 x Storey height =
1.4kN/m)
Element load to be used.
Note Loads entered as per metre run
Select section from list
Number of noggins
Job Ref.
Date
When it comes to wall self-weight don’t forget to look at the Notes!
SCI Guide P402 discusses various floor types in Table 2.5 but as an Engineer doesn’t tell us weights. We have ‘enhanced’ the
tables, with SCI’s knowledge, and included them in the Notes – sample below:
Output Screen
Capacity Checks
EC shown, BS hidden
Job Ref.
Job Ref.
Number of noggins N = 3.0
Number of floors NFloor = 3.0
Section dimensions and material properties
The wall stud is a C section’s from Generic 100 x 50 x 1.6, manufactured from 390 N/mm2 steel with a Z275 coating to BS
EN 10346.
Basic yield strength fyb = 390.0N/mm2
Modulus of elasticity ESEC3 =210000.0N/mm2
Shear modulus G = 80769 N/mm2
Partial factor M0 =1.0
Section Properties
The calculation of section properties is not included in this calculation.
Gross Properties
Radius of gyration about y axis iy = 40.2mm
Radius of gyration about z axis iz = 18.4mm
Position of y axis from flange yflange = 49.2mm
Position of z axis from web zweb = 15.9mm
Position of shear centre with respect to the z axis yo = 39.3mm
Position of shear centre…

Structural Calculations FOR Sample Project Demonstrating MESS Light Gauge Steel Add in for Tedds

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