Which one of the following is the condition for maximum shear in a cantilever ?
- AIt occurs when a series of concentrated loads are not placed at the farthest point away from the fixed support
- BIt occurs when a series of distributed loads are placed at the farthest point away from the fixed support
- CIt occurs when a series of concentrated loads are placed at the nearest point away from the fixed support
- DIt occurs when a series of concentrated loads are placed at the farthest point away from the fixed supportCorrect
Solution
Concept
Position of moving loads for maximum shear
Step-by-step solution
1. The shear at a section of a cantilever is the sum of the loads on the portion beyond the section (towards the free end). 2. Moving loads must therefore be placed so that as many loads as possible lie on the span, which means they extend to the farthest point from the fixed support.
Explanation
Maximum shear at the fixed end is obtained when the loads cover the whole span, up to the free end.
Why the other options are wrong
(a) negates the condition. (b) deals with distributed loads. (c) places the loads near the support, which does not load the full span.
Shortcut
Maximum shear: load the whole span.
Correct answer: D) It occurs when a series of concentrated loads are placed at the farthest point away from the fixed support