Question

A single unequal angle ISA 90 x 60 x 6 mm is connected to a gusset plate 12 mm thick with 5 number of 18 mm diameter bolts. The 90 mm leg is connected to the gusset plate. The net section rupture strength is ___ kN. Assume shear lag reduction factor as 0.7 and steel grade to be Fe410 and yield strength as 250 MPa.

• A. 170.22
• B. 173
• C. 186.32
• D. 182.73

Answer 1

The correct option is B 173

For 18 mm diameter bolt, diameter of bolt hole = 20 mm
Net section rupture of angle,

$T_{dn}=\frac{0.9f_u}{{\gamma }_{m_1}}{A}_{nc}+\beta \frac{f_y}{{\gamma }_{m_0}}{A}_{go}$

$\beta =0.7$

Net area of connected leg,

$A_{nc}=(l_1-\frac{t}{2}-d^{{}^{\prime }})t=(90-\frac{6}{2}-20)\times 6=402{\text{mm}}^2$

Gross area of outstanding leg,

$A_{g_0}=(l_2-\frac{t}{2})t=(60-\frac{6}{2})\times 6=342{\text{mm}}^2$

$T_{dn}=\frac{0.9\times 410}{1.25}\times 402+0.7\times \frac{250}{1.1}\times 342$

$=173079.5\text{N}=173\text{kN}$