Question

A simply supported beam of 8 m span is to support a uniformly distributed load of 60 kN/m (inclusive of self weight). The built beam making use of ISLB 500 section having section modulus
$1810\times {10}^{3}m{m}^3$.
The permissible bending stress is 165 MPa and,
Required section modulus to resist bending moment is
$2910\times {10}^{3}m{m}^3.$

The sectional area of each cover plate of a built up beam is _________ mm${}^2$.

Answer 1

$UDL=60kN/m$
$Z_a=\text{available section modulus}$
$=1810\times {10}^{3}m{m}^3$

${\sigma }_{bc}=165MPa$
$Z_r=\text{required section modulus}$
$=2910\times {10}^{3}m{m}^3$

H = 500 mm

$\therefore$ area of each cover plate

$A_P=\frac{(Z_r-Z_a)}{h}$

$\frac{(2910-1810)\times {10}^3}{500}$

$=2200m{m}^2$