Civil Engineering Reference
In-Depth Information
stirrup reinforcement under the upgraded loads. Otherwise, indicate the need for
shear strengthening.
Problem 2.7
For the beam given in Problem 2.6, check extreme fiber stresses and steel stress
under (a) dead load only and (b) dead load + 20% live load at the time of strengthen-
ing. Determine ε
bi
at mid span in both cases.
Problem 2.8
For the circular column section in Example 2.6, determine the increase in column
core capacity relative to the loss of concrete cover using the Mander et al. (1988)
model. Take the #3 spiral transverse reinforcement at
(a)
S
= 1.75 in. as obtained based on the ACI 318 equation
(b)
S
= 1 in. to invoke higher confinement effect
Problem 2.9
Repeat the third part of Example 2.7 by deriving
I
cr
and determining the stresses
based upon it. Compare the answers to what you got in Example 2.7. What do
you conclude?
APPENDIX A
TABLE A-1
Rebar is Sized Nominally by “Eigths of an Inch” of the Bar's Diameter. A #3
Bar is 3/8" in Diameter. A #6 Bar is 3/4" in Diameter. 3/4 is the Same as
6/8. Every Bar Can be Measured in Eights of an Inch. A #10 Bar is About
10/8˝ in Diameter. This is the Same as 1.27"
Diameter
Area(in
2
)
Lbs/Inft
Diameter (Metric)
Metric Bar Size
No. 2
0.250"
0.05
0.167 lbs
6.35 mm
No. 6
No. 3
0.375"
0.11
0.376 lbs
9.52 mm
No. 10
No. 4
0.500"
0.20
0.668 lbs
12.7 mm
No. 13
No. 5
0.625"
0.31
1.043 lbs
15.8 mm
No. 16
No. 6
0.750"
0.44
1.502 lbs
19.05 mm
No. 19
No. 7
0.875"
0.60
2.044 lbs
22.225 mm
No. 22
No. 8
1.000"
0.79
2.670 lbs
25.4 mm
No. 25
No. 9
1.128"
1.00
3.400 lbs
28.65 mm
No. 29
No. 10
1.270"
1.27
4.303 lbs
32.25 mm
No. 32
No. 11
1.410"
1.56
5.313 lbs
35.81 mm
No. 36
No. 14
1.693"
2.25
7.650 lbs
43.0 mm
No. 43
No. 18
2.257"
4.00
13.60 lbs
57.33 mm
No. 57
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