Determine the amount of steel required for a highway consisting of two 12' driving lanes with 10' shoulders on each side. Assume a 10" concrete slab resting on a gravel base and a 60-ksi yield stress for the rebar.
49
Tie Bar Spacing
c avgbar
sbar s
L f hAAs f
bar bar sbar
s c avg
A A fsA L f h
50
Standard Rebar Sizes
BarSize
Weight(lb/ft)
NominalDiameter
(in)
NominalArea(in²)
#3 0.376 3/8 0.11
#4 0.668 1/2 0.20
#5 1.043 5/8 0.31
#6 1.502 3/4 0.44
#7 2.044 7/8 0.60
#8 2.670 1.000 0.79
#9 3.400 1.128 1.00
#10 4.303 1.270 1.27
#11 5.313 1.410 1.56
#14 7.650 1.693 2.25
#18 13.60 2.257 4.00
51
Tie Bar Spacing
Source: FHWA Technical Advisory T 5040.30 52
Tie Bar Length
22 s
bond steelstrength strength
r f r
allowable bond stress (assume 350 psi)embedment length (half the bar length)allowable bar stressbar radius (half the bar diameter)
sfr
54
Tie Bar Length
allowable bond stress (assume 350 psi)embedment length (half the bar length)allowable bar stressbar radius (half the bar diameter)