Week 10 Challenge
Step 1:-In the grid put 0
then go to translational repeat
type on spacing 50
link steps
ok
Then copy both the nodes
go to translational repeat
click on Y axis
type 12 in spacing
then join both the nodes
click on beam and right click
then go to insert node
add mid point
copy the mid point
and creat a node 2.5m up
then join the nodes both side
then copy the end node
in 1.2m distance
creat nodes
then mirror it with pick point other side
Step 2:-
No. of Horizontal member at Roof Level along single roof = (Length of Rafter / Spacing) + 1
Length of Rafter = √[(Half of Span)2 + (Height of Rafter)2]
=√(252 + 2.52)
Length of Rafter = 25.1247 m
No. of Horizontal members at roof level = (25.1247 / 1.2) + 1 = 20.94 + 1 = 21.94
Says = 22 Nos
In 22 Nos,
Top most one is Ridge and Last one is Eave Strut.
Therefore Remaining Members are Purlin.
No. of Purlin for entire span = 2 x 20 = 40 Nos.
Step 3:-
No. of Girts = Height of column / Spacing
Height of Column = 12 m
Brick wall height = 2 m
Hence girts arranged in remaining 10 m
No. of Girts on one side = 10 / 1.5 = 6.67
Says 7 Nos
Total number of Girts on both side = 2 x 7 = 14 Nos.
Result:-
- Number of Purlins on Entire span = 40 Nos
- Number of Girts on both Side = 14 Nos
- Number of Ridge = 1 No
- Number of Eave Struts = 2 Nos
- 2) Run the analysis
- go to post processing mode
- done
- go to result
- layout
- utilization
- then double click on beam
- go to beam result
- then go to steel design
- utilization ratio= FX/FCY
- Ned/N1 rd >1
- 3) Given data:-
Dimension of Building = 10 m x 5 m
Height = 6m
Bay spacing = 2.5 m
Wall opening = 15%
Building is situated in Chennai
Assume:-
1) Terrain Category 3
2) Design life of the structure 50 years
3) Topography: Plane with upwind slope Ɵ < 3°
4) Roof Angle = 5°
Aim:-
To calculate the wind pressure on the wall of building with the given inputs.
Procedure:-
Step 1:-
Basic wind speed Vb = 50 m/s ( For Chennai as per IS 475 part-3 Fig. 1)
Design wind speed Vz = Vb x K1 x K2 x K3 x K4
Where K1 is Probability factor (risk coefficient) taken from Table 1
Considering general building and structure and Vb =50 m/s
K1 = 1.0 for design life of structure 50 years & and for given Basic wind speed of 50 m/s
K2 is Terrain roughness & height factor taken from Table 2
K2 = 0.91
K3 = Topography factor for Upwind slope < 3° from Clause 6.3.3
K3 = 1.0
K4 = Importance factor for cyclonic region for Industrial Structure from Clause 6.3.4
K4 = 1.15
Therefore Vz = 1.0 x 0.91 x 1.0 x 1.15 x 50 = 52.325 m/s
Step 2:-
Wind pressure Pz = 0.6 (Vz)2
Where,
Pz = wind pressure at height z in N/m2
Vz = design wind pressure at height z in m/s
Therefore
Pz = 0.6 x (52.325)2 = 1.643 kN/m2
Step 3:-
Design wind pressure Pd = Kd x Ka x Kc x Pz
Where,
Kd = wind directionality factor 1.0 for cyclone affected region
Ka = Area averaging factor 0.9 for tributary area < 25 m2
(Tributary area = 6 x 2.5 = 15 m2)
Kc = combination factor 0.9
Therefore
Pd = 1.0 x 0.9 x 0.9 x 1.643 = 1.331 kN/m2
Step 4:-
Wind load acting in a direction normal to the individual structural element or cladding unit
F = (Cpe – Cpi) x A x Pd
Where,
Cpi = internal pressure coefficient
Cpi = +0.5 and -0.5 for opening of 15% of wall area i.e. medium permeability (Clause 7.3.2.2 of IS :475, part 3)
External pressure coefficient:
L = 10 m; w = 5 m; h = 6 m
h/w = 6 / 5 = 1.2
l/w = 10 / 5 = 2
Thus as per table 5 of clause 7.3.3.1 of IS:475, Part 3
For 1/2 < h/w < 3/2 and 3/2 ≤ l/w < 4
Wind angle Ɵ
Cpe
Wall A
Wall B
Wall C
Wall D
0°
+0.7
-0.3
-0.7
-0.7
90°
-0.5
-0.5
+0.7
-0.1
Case-I Ɵ = 0°
Cpnet = Cpe - Cpi
For Wall A
Cpnet = +0.7 – (+0.5) = +0.2 (Pressure)
Cpnet = +0.7 – (-0.5) = +1.2 (Pressure)
Design Wind Force for Wall A
F = Cpnet x A x Pd
FA = +0.2 x 6 x 2.5 x 1.331 = +3.993 kN (Pressure)
FA = +1.2 x 6 x 2.5 x 1.331 = +23.958 kN (Pressure)
For Wall B
Cpnet = -0.3 – (+0.5) = -0.8 (Suction)
Cpnet = -0.3 – (-0.5) = +0.2 (Pressure)
Design Wind Force for Wall B
F = Cpnet x A x Pd
FB = -0.8 x 6 x 2.5 x 1.331 = -15.972 kN (Suction)
FB = +0.2 x 6 x 2.5 x 1.331 = +3.993 kN (Pressure)
For Wall C & D
Cpnet = -0.7 – (+0.5) = -1.2 (Suction)
Cpnet = -0.7 – (-0.5) = -0.2 (Suction)
Design Wind Force for Wall C & D
F = Cpnet x A x Pd
FC&D = -1.2 x 6 x 5 x 1.331 = -47.916 kN (Suction)
FC&D = -0.2 x 6 x 5 x 1.331 = -7.986 kN (Suction)
Case-II Ɵ = 90°
Cpnet = Cpe - Cpi
For Wall A & B
Cpnet = -0.5 – (+0.5) = -1.0 (Suction)
Cpnet = -0.5 – (-0.5) = 0.0
Design Wind Force for Wall A & B
F = Cpnet x A x Pd
FA&B = -1.0 x 6 x 2.5 x 1.331 = -19.965 kN (Pressure)
FA&B = 0.0 x 6 x 2.5 x 1.331 = 0.000 kN
For Wall C
Cpnet = +0.7 – (+0.5) = +0.2 (Pressure)
Cpnet = +0.7 – (-0.5) = +1.2 (Pressure)
Design Wind Force for Wall C
F = Cpnet x A x Pd
FC = +0.2 x 6 x 5 x 1.331 = +7.986 kN (Pressure)
FC = +1.2 x 6 x 5 x 1.331 = +47.916 kN (Pressure)
For Wall D
Cpnet = -0.1 – (+0.5) = -0.6 (Suction)
Cpnet = -0.1 – (-0.5) = +0.4 (Pressure)
Design Wind Force for Wall D
F = Cpnet x A x Pd
FD = -0.6 x 6 x 5 x 1.331 = -23.958 kN (Suction)
FD = +0.4 x 6 x 5 x 1.331 = +15.972 kN (Pressure)
Result:-
Maximum design Pressure on the Wall = 47.916 kN
- 4) Given data:-
Self Weight factor – 1.1
Roof Sheet loading = 0.5 kN/m2
Purlin load = 6 kN/m2
Live Load on Roof = 1.5 kN/m2
Wind Load on rafter (Pressure) = 2 kN/m2
Assume Frame height as 5m
Support as Fixed.
Total Dead Load = 0.5 + 6 = 6.5 kN/m2
Dead Load on Main frame = 6.5 x 6 = 39 kN/m2
Dead Load on Gable frame = 6.5 x 6 / 2 = 19.5 kN/m2
Live Load on Main frame = 1.5 x 6 = 9 kN/m2
Live Load on Gable frame = 1.5 x 6 / 2 = 4.5 kN/m2
Wind Load on Main frame = 2 x 6 = 12 kN/m2
Wind Load on Gable frame = 2 x 6 / 2 = 6 kN/m2
Aim:-
To apply Dead load, Live Load & Wind Load on the structure and find the support reaction.