Double-angle tension members connected on one side of a gusset plate For double angles placed back-to-back and connected to one side of a gusset plate, the allowable working stress corresponding to a given slenderness ratio is reduced to what percentage of the tabulated value?
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A80%
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B60%
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C70%
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D50%
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E40%
Answer
Correct Answer: 80%
Explanation
Introduction / Context:When double angles are connected to a gusset by only one leg (i.e., both angles connected on the same side), shear lag and eccentricity effects reduce the effective capacity. Classic specifications apply a reduction factor to the allowable stress.
Given Data / Assumptions:
- Double-angle member, back-to-back configuration.
- Connected by one leg only to one side of a gusset.
- Working-stress design context.
Concept / Approach:The reduction accounts for uneven stress distribution and shear lag in outstanding legs. A commonly adopted allowance is to reduce the allowable stress to about 80% of the value applicable to fully balanced connections.
Step-by-Step Solution:Identify connection eccentricity/shear lag → stress reduction needed.Apply standard reduction → about 80% of the tabulated allowable stress.
Verification / Alternative check:Design handbooks show factors (≈0.8) for single-sided connections of double angles to reflect reduced effectiveness of outstanding legs.
Why Other Options Are Wrong:
- 60–70%: overly severe for standard double-angle details.
- 50% or 40%: excessively conservative and not typical of code guidance.
Common Pitfalls:Neglecting reduction for single-sided connections can unconservatively overestimate tension capacity.
Final Answer:80%