Truss Analysis MCQ with answer and solution

Concept

Efficient analysis of selective truss members

Formula

ΣF_x = 0, ΣF_y = 0, ΣM = 0

Step-by-step solution

1. The Method of Joints requires solving sequentially joint by joint from the supports inward, which is tedious for large trusses. 2. The Method of Sections cuts through up to three unknown members and applies global equilibrium to one isolated part. 3. This allows rapid, independent determination of internal forces in specific members directly. 4. Hence, Method of Sections is the most efficient choice for analyzing a few selected members. Answer: B

Explanation

The Method of Sections is specifically suited for determining forces in a few designated members of a large truss without solving the entire structure. Passing an imaginary cutting section through the members of interest allows direct solution using three static equilibrium equations.

Why the other options are wrong

A) Method of Joints requires calculating all preceding joints, making it very slow for few members in a large truss. C) Virtual Work is primarily used for deflections rather than axial force analysis. D) Flexibility method is used for indeterminate structures.

Shortcut

Method of Sections = Cut and solve only the target members; Method of Joints = Solve every joint.

Common mistake

Choosing Method of Joints which is computationally inefficient when only isolated member forces are desired.