In the bamboo portal frame figure given below, consider that the joints are rigid enough to transfer the forces and moments without any losses and the supports are as shown in the figure. This bamboo portal frame is subjected to uniformly distributed loading, W kN/m in the vertical direction. In this scenario, the bending moment at joint ‘B’ in the figure will be (A pinned at base, D on a roller)
- AWl²/12 (Hogging)
- BWl²/24
- CWl²/12 (Sagging)
- D0Correct
Solution
Concept
Pinned-roller portal frame
Step-by-step solution
1. With a pin at A and a roller at D there is no horizontal reaction. 2. The column carries no moment, so the moment at B is zero.
Explanation
The frame is statically determinate with no horizontal thrust.
Correct answer: D) 0