Week 10 Challenge

1) AIM : To find out number of purlins and girts for the given building.

PROCEDURE :

Height of column = 12m.

Height of brick wall = 2m.

No of girts on one side = (12-2)/1.5 = 6.

Total no of girts on both sides = 2*6 = 12.

Rafter span = 50m.

Rafter span upto ridge = 25m.

Roof slope = 1 in 10 => Ridge height = 2.5m.

Length of rafter upto ridge = `sqrt(25^2+2.5^2)`= 25.125m.

Spacing of purlins = 1.2m .

No. of purlins on one side = 25.125/1.2 = 21.

Total no of purlins = 2*21 = 42.

RESULTS :

Total no of girts = 12.

Total no of purlins = 42.

2) AIM : To optimize the given frame.

PROCEDURE :

The below is the image showing properties assigned to the frame

The properties of the members are given below.

Design ratios are shown in the image below

3) AIM : To determine the wind load on the wall of a given indistrial building.

PROCEDURE : The given building is

Basic wind speed of Chennai Vb = 50m/s

Probability factor k1 = 1.0 (From Table 1 of IS875 part 3)

Assuming the structure category '2'

Terrain roughness & height factor k2 = 1.0 (Upto 10m height), (From Table 2 of IS875 part 3)

Topographioc factor k3 = 1.0 ( Assuming slope of ground is less than 3 degrees ), (From clause 6.3.3 of IS 875 part 3)

Importance factor for cyclonic region k4 = 1.15 (For Industrial buildings)

Design wind speed Vz = Vb*k1*k2*k3*k4 = 50*1.0*1.0*1.0*1.15 = 57.5 m/s.

Wind pressure upto height 10m Pz = 0.6*Vz^2 = 0.6*57.5^2 = 1.98 KN/m2

0.7 * Pz = 1.39 KN/m2

Wind directionality factor Kd = 0.9

Tributary area = min(10*6, 5*6) = 30m2

Wind averaging factor Ka = 0.8

Combination factor Kc = 0.9 for clad buildings

Design wind pressure Pd = Ka*Kd*Kc*Pz = 0.8*0.9*0.9*1.98 = 1.28 KN/m2 < 1.39KN/m2 (0.7*Pz)

Therefore Pd = 1.39 KN/m2

4) AIM : Static Check problem

Procedure :

Load Case 1) Dead Load (DL)

Self Weight factor – 1.1

Roof Sheet loading = 0.5 kN/m²

Purlin load = 6 kN/m²

^{Load Case 2) Live Load (LL)}

Live Load on Roof = 1.5 kN/m2

^{Load Case 3) Wind Load (WL)}

Wind Load on rafter (Pressure) = 2 kN/m²

^{The above loads are applied to monoslope roof structure and static check was done in STAAD.}

^{The loads and reactions are given below.}

L/C		Fx kN	Fy kN	Fz kN	Mx kN-m	My kN-m	Mz kN-m
1	Loads	0	-2207.057	0	33105.858	0	-11089.493
	Reactions	0	2207.057	0	-33105.858	0	11089.493
	Difference	0	0	0	0	0	0
2	Loads	0	-478.885	0	7183.271	0	-2394.424
	Reactions	0	478.885	0	-7183.271	0	2394.424
	Difference	0	0	0	0	0	0
5	Loads	0	-638.513	0	9577.693	0	-3192.564
	Reactions	0	638.513	0	-9577.693	0	3192.564
	Difference	0	0	0	0	0	0