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Identify, from the following, the correct value of the bending moment MA (in kNm) units) at the fixed end A in the statically determinate beam shown below (with internal hinges at B and D), when a uniformly distributed load of 10 kN/m is placed on all spans.
(Hint: Sketching the influence line for MA or applying the Principle of Virtual Displacements makes the solution easy).
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- –80
- – 40
- 0
- + 40
Correct Option: C
(Influence line Diagram, ILD for MA)
Ordinate at B, 2/y = 1
⇒ y = 2
Ordinate at D = 2
BM at A = loading intensity X area under load
| = 10. |  | × 4 × 2 |  | + 10 | | - | × 4 × 2 | | = 0 | 2 | 2 |
