Question

For the overhanging beam shown in figure, the magnitude of maximum bending moment (in kNm) is

• A. 40

Answer 1

The correct option is A 40
$R_A+R_B=60kN$ $[\sum F_v=0]$

Taking moment from point B,

$[\sum M_B=0]$
$R_A\times 4-(10\times 4\times 2)+20=0$
$R_A=10kN$
$R_B=50kN$

Bending moment is maximum where shear force is zero (i.e shear force changes its sign).

Bending moment at B,

$M_B=-20\times 2$
= 40 kN (Hogging)

Bending moment at point '1 m' from the right of point A,

$M=10\times 1-(10\times 1\times \frac{1}{2})$

$=5kNm$ (Sagging)

Maximum bending moment is at point B i.e., $40kNm$.