Question

A simply supported beam AB has the bending moment diagram as shown in the following figure.

The beam is possibly under the action of following loads:

• A. Couples of M at C and 2M at D
• B. Couples of 2M at C and M at D
• C. Concetrated loads of M/L at C and 2M/L at D
• D. Concetrated loads of M/L at C and couple of 2M at D.

Answer 1

The correct option is A Couples of M at C and 2M at D

There is sudden change in bending moment at point C and D this shows couple of moment is acting at C and D

Couple acting at C = change in BM = M

Couple acting at D = change in BM = M - (-M) = 2M