Civil Engineering Reference
In-Depth Information
From Eqn 5,
f
tc
=367 psi,
f
s
=26100psi (interpolated from the Authors'
result),
a
=39.5 in (centre of support to centre of load),
b
=1.5 in,
θ
=tan
-1
44/
44.5=44.67°,
V
u
=367×39.5×1.5+26100 (2.95) 0.711
=21755+54 743=76 498 lb (340.3 kN)
Eqn 8
,
f
s
=38100 (interpolated from the Authors' result),
V
u
=38 100×2.95×0.711=79 930 lb (355.5 kN).
Subedi method (beam-panel P311)
=(134.5+155+1.9+2.6+185.2)=479.2 kN (107 700 lbs).
5.6
Design example 2: ACI Code
12 k/ft (dead load)+100 k/ft (live load);
f
c
=4000 psi,
f
y
=60 000 psi.
Assume
d
=0.9/h=0.9 (15)=13.5 ft or 162 in.
l
n
/
d
=25×12/13.5×12=1.85<2.0, hence treat as a deep beam.
beam self weight 15/12×15×0.150=2.8 k/ft
total factored load=1.4(12+2.8)+1.7 (50)=105.72 k/ft.
distance of the critical section=0.15 ln=0.15×25=3.75 ft.
Design of flexural reinforcement
Provide 12# No. 10 bars
A
=15.24 in
2
