Page 8 - Mechanics of Structures – Chapter 1
P. 8
Mechanics of Civil Engineering Structures – Chapter 5
Solution
. .
Shear Stress Equation, τ =
.
Where,
20 (4)
1. S = Shear force = = = 40,000 N
2 2
2. To determine from base and Ixx = ∑ = (90 10)(85) +(80 10)(40) = 63.82 mm from base
⃐
∑ (90 10)+(80 10)
3. To determine Ixx = Second moment of area = Ixx1 + Ixx2
3 3
2
2
= ( + A1d1 ) + ( + A2d2 )
12 12
90 (10) 3 2 10 (80) 3
= ( + (900)(85-63.82) ) + ( +
12 12
2
(800)(63.82-40) )
6
6
= (0.41 x 10 ) + (0.87 x 10 ) mm 4
6
4
= 1.28 x 10 mm
Consider section as shown in sketch
90 mm
τ 1
10 mm
τ 2
τ 3
τ 4 80 mm
τ 5
10 mm
Section 1 – τ 1 : at top most fibre of section
Section 2 – τ 2 : at connection of flange and web passing through flange
Section 3 – τ 3 : at connection of flange and web passing through web
Section 4 – τ 4 : passing through N.A
Section 5 – τ 5 : bottom most fibre of section
NHO JKA PSAS Page 8
