Steel Design – Net effective area in angle tension members In the design of a single-angle tension member, the net effective cross-sectional area used for strength checks explicitly accounts for which factor(s)?

Introduction / Context:
For tension members composed of angles, especially when only one leg is connected, the stress distribution is nonuniform near the connection. This leads to the phenomenon of shear lag, which reduces the effectiveness of the outstanding leg. Codes therefore distinguish between net area and net effective area when computing tensile capacity.

Given Data / Assumptions:

• Member type: single-angle or unequal leg angle connected through one leg.
• Connection uses bolts or welds at the end (gusset).
• Strength check performed in limit state of tension yielding or rupture.

Concept / Approach:

The net area An is obtained by deducting holes from the connected cross-section along the critical path. However, due to shear lag, not all of An is effective in transmitting axial force at the critical section. The net effective area Ae is computed by multiplying An (or gross area of outstanding leg, as applicable) by a reduction factor that accounts for connection geometry (e.g., distance from the connected leg to centroid). Thus, Ae reflects both hole deductions and the end-connection effectiveness in force transfer, ensuring that rupture capacity is not overestimated.

Step-by-Step Solution:

Verification / Alternative check:

Design standards (e.g., IS 800 LRFD/WSD analogues) explicitly include shear lag reduction for angle members; examples show Ae < An when only one leg is connected, validating the need to include connection effectiveness.

Why Other Options Are Wrong:

(a) Ignores shear lag; (b) mentions eccentricity but the relevant codal concept is shear lag effectiveness, not adding direct bending; (c) tack welds/bolts along the length are not relied upon for net effective area; (e) gross area overestimates strength.

Common Pitfalls:

Using An instead of Ae for rupture checks, neglecting stagger effects in hole deduction, or assuming full effectiveness of the outstanding leg without verifying connection details.

Final Answer:

Effectiveness of the end connection (shear lag) in addition to bolt-hole deductions