Question

A freely supported beam AB of span 4 m is subjected to a UDL of 1kN/m over the full span and a moment of 2kN-m at support A as shown in the figure. The resulting BM at mid-span C of the beam will be

• A. 1 kN-m (sagging)
• B. 1 kN-(hogging)
• C. 2kN-m (sagging)
• D. 2kN-m (hogging)

Answer 1

The correct option is A 1 kN-m (sagging)

(a)

The reaction at end A

$\Rightarrow R_A\times 4=1\times 4\times 2+2$

$\Rightarrow R_A=2.5kN$

$\therefore$ BM at mid-span C is

$M_C=2.5\times 2-1\times 2\times 1-2$

= 1 kNm (sagging)