Page 181 - Handbook of Civil Engineering Calculations, Second Edition

1.164 STRUCTURAL STEEL ENGINEERING AND DESIGN

FIGURE 50

Corresponding to the applicable limit states are Eqs. (K1-3) and (K1-5), each of which
has N, the length of bearing, as a parameter.
Solving for N, we obtain

R u R n (2.5k + N)F t t w
100 kips 1.0(2.5 1 /8 in. + N) 36 kips/sq.in. 0.40 in. (1.01 cm) (K1-3)
3
N 3.5 in. (8.89 cm)

1.5
N
t w
R u R n 68t w 1 + 3 (K1-5)
2
F y t f
d
t f
t w
N 8.6 in. (21.8 cm)
The minimum length of bearing is N 8.6 in. (21.8 cm). Rounding up to the next full
inch, let N 9 in. (22.9 cm)
2. Compute the area of the bearing plate
The area of the bearing plate is determined by the bearing strength of the concrete sup-
port. Using the following equation, the design bearing strength is

A 2
c P p c 0.85f c
A 1
A 1

where A 2 /A 1 2.
Substituting in Eq. [11.6], we obtain
kips
100 kips 0.60 0.85 3 A 1 2
sq.in.
2
The area of the bearing plate A 1 32.7 sq.in. (210.9 cm ).
Because the bearing plate dimensions are
A 1 32.7 sq.in.
BN A 1 : B 3.6 in. (9.14 cm)
N 9 in.