Trusses and frames differ in that:
Try it first: pick an option, then read the explanation.
Correct answer: D. Trusses can't bend but frames can
Asked in SSC JE 25/01/2018 (Morning)
Detailed Explanation
Both trusses and frames are made of straight members, but they are connected and loaded differently.
Why “Trusses can't bend but frames can” Is Correct
In a truss, members meet at pins and loads are applied only at the joints, so each member carries only axial tension or compression — it does not bend. In a frame, members are rigidly connected and loads may act along them, so they carry bending moments and shear — they can bend. That is option (d).
Why the Other Options Are Wrong
- A. Trusses can bend, frames can't: It is the reverse.
- B. Both can bend: Ideal truss members do not bend.
- C. Neither can bend: Frame members do bend.
Key Point
Truss: pin joints, axial force only. Frame: rigid joints, bending + shear + axial.
Key Concepts for Students
- Portal frames and multi-storey frames resist load by bending.
- Real truss joints are bolted or welded but are analysed as pinned.
- Secondary bending stresses in trusses are usually small.
Practice more: this is question 12 in Beams and Trusses MCQs – Part 1. Try the whole set and check every answer instantly.