Question

Calculate the tensile strength of a truss-member, L = 2.5 m if it consists of double angles 100 x 100 x 8 with tack rivetting.
Given,
(i) Area of angle 100 x 100 x 8 = $15.39c{m}^2$,
(ii) Thickness of gusset plate = 10 mm
(iii) Nominal diameter of rivets = 16 mm,
(iv) Permissible tensile stress = 150 MPa,
(v) As per IS : 800 (1984) for single angle, the net effective area =
$A_{net}=A_1+K{A}_2$
$where,K=\frac{3A_1}{(3A_1+A_2)}$

$A_1=\text{effective cross-sectional area of the connected leg,}$
$A_2=\text{the gross cross-sectional area of the unconnected leg}$

Answer 1

Nominal diameter of rivet = 16 mm
$\therefore$ Gross diameter of hole, d' = 16 + 1.5 = 17.5 mm

Double angles 100 x 100 x 8 mm with tack riverting.


$A_{net}=A_{gross}-\text{Area of hole}$

$=2\times 1539-2\times d^{\prime }\times t$
$=2\times 1539-2\times 17.5\times 8=2798m{m}^2$

$\therefore \text{tensile strength}={\sigma }_t\times A_{net}$

$=150\times 2798$
$=419700N$
$=419.7kN$