Truss Design - Faculty Wing - EN1993
Truss Design - Faculty Wing - EN1993
Truss Design - Faculty Wing - EN1993
Figure 1 The critical section of Faculty Wing Truss (highlighted) for member design
Modelled by Jonathan Hohenkirk 26/06/2017 using STAAD Pro V8i
Figure 2 The member lengths of critical section of Faculty Wing Truss for member design
Modelled by Jonathan Hohenkirk 26/06/2017 using STAAD Pro V8i
Figure 3 The member lengths of critical section of Faculty Wing Truss for member design
Modelled by Jonathan Hohenkirk 26/06/2017 using STAAD Pro V8i
Figure 4 Showing the loadings applied to the critical section of the truss as well as deflection, compression and tension
occurrences.
*Pink lines are the resultant deflected shape which is exaggerated by a factor of 984%
Assume section of S275-Square Hollow Section (SHS) 60mm x 60mm x 5mm (hot finished)
d/t 50 2
Ned / Nb rd 1.0
Where:
So:
Nb rd = X A fy / m1
Where:
Fy 275 N/mm2
X = 1/ [ + (2 2)0.5
And
2
, =
2
Where:
= non-dimensional slenderness
= 205 /2
= 533000 4
= 777
= 1786.236
10702 275 /2
= = = 0.406
1786236
From table 6.1 & 6.2 EN.1993.1.1, = 0.21 (Buckling Curve = a for S275 Grade Steel)
= 0.61 = 0.94
There fore
Nb rd = X A fy / m1
= 276.6 KN
So: 0.84 1
Figure 5 The Steel SHS section designed for member 44 in the top chord of the truss (max compressively loaded member).
Created by Jonathan Hohenkirk using STAAD Pro V8i
Bottom chord Design
From Clause 6.2.3 of EN.1993.1.1: Tension Members, the design value of the tension force NED at each
cross section shall satisfy:
1.0
.
Where . = Design Tension Resistance (lesser of Npl,Rd and Nu.Rd)
Design Data
Using member 36 (max loading)
Design of Section
Maximum ultimate tension = 104.93 KN
Assume section of S275-Square Hollow Section (SHS) 60mm x 60mm x 5mm (hot finished)
Npl,Rd = Agross fy / m
= 294.25 KN
And the ultimate resistance:
Nu Rd = 0.9 Anet fu / m2
= 275.54 KN
The smaller value should be taken as the design tension resistance = 275.54 KN
104.93
= = 0.38 < 1
. 275.54
Therefore assumed section is adequate in tension resistance.
Figure 6 The Steel SHS section designed for member 36 in the bottom chord of the truss (member in maximum tension). Created
by Jonathan Hohenkirk using STAAD Pro V8i
Assume section of S275-Square Hollow Section (SHS) 50mm x 50mm x 3mm (hot finished)
A=5.54 cm2
The classification of the cross section
Fy = 275 N/mm2
d/t 50 2
Design of Section
From Clause 6.2.4: Compression Members, the design value of the compression force NED at each cross
section shall satisfy:
1.0
.
. =
For class 1,2 or 3 cross sections
Figure 7 The Steel SHS section designed for member 52 in the diagonal member of the truss (member in maximum compression).
Created by Jonathan Hohenkirk using STAAD Pro V8i
Purlin Member Design
Total Dead Load acting on design purlin: Steel Sheeting = 0.075 KN/m2
Figure 8 The steel C-channel section designed for member 133 (longest purlin member).
Created by Jonathan Hohenkirk using STAAD Pro V8i
Final Design Sections for critical truss