Question

If the pitch of the roof truss is 0.5 then the value of live load on purlin is ______.

Answer 1

Live load on purlin
$=[750-(\theta -10)\times 20]N/m^2$

Given,
$\text{pitch}=0.5$
$h=0.5L=L/2$

$\tan \theta =\frac{h}{\left(L/2\right)}=\frac{2\times h}{L}$

$=\frac{2\times 0.5\times L}{L}$

$\Rightarrow \tan \theta =1$

$\Rightarrow \theta ={45}^o$

$\therefore \text{Live Load}=750-(45-10)\times 20$
$=50N/m^2$
$\therefore \text{Minimum}400N/m^2\text{is considered}$