Question

Four angles of ISA 90 x 90 x 10 mm are used for a built up column as shown in the fig. The column is subjected to a compressive force of 1200 kN. If a flat of 80 x 10 mm size is used as lacing bar for the single lacing system and inclination of the lacing bar is 45${}^{\circ }$ with vertical, then the each lacing bar is designed for an axial force of _________.

• A. Zero
• B. 10.6 kN
• C. 21.2 kN
• D. 5.2 kN

Answer 1

The correct option is C 21.2 kN

$V=2.5\%$ of axial load

$\frac{2.5}{100}\times 1200=30kN$

$F=\frac{V}{2.sin\theta }=\frac{30}{2.sin45}=21.2kN$