Difficulty: Easy
Correct Answer: 180
Explanation:
Introduction / Context:
Slenderness ratio limits control buckling susceptibility of compression members. IS 800 specifies maximum KL/r values depending on the nature of loading and whether the member is part of a bracing system, a member under wind/seismic forces only, or a member carrying sustained loads.
Given Data / Assumptions:
Concept / Approach:
Under sustained gravity loads, lower slenderness is mandated to limit buckling and service deflections. The code stipulates KL/r ≤ 180 for such compression members, with higher limits reserved for members under transient wind/earthquake loads or tension-only bracing components when un-stressed under normal loading.
Step-by-Step Solution:
Verification / Alternative check:
Cross-reference with summarized tables in steel design handbooks reproducing IS 800:1984 limits: 180 (sustained compression), 250–300 for wind/seismic-only conditions in certain cases.
Why Other Options Are Wrong:
Common Pitfalls:
Applying relaxed limits meant for wind/seismic-only members to gravity-carrying columns or struts.
Final Answer:
180
Discussion & Comments