Structural Concrete - Hassoun

254 Chapter 6 Deflection and Control of Cracking
20. P. H. Kaar and A. H. Mattock. “High-Strength Bars as Concrete Reinforcement (Control of Cracking),
Part 4.” PCA Journal 5 (January 1963).
21. B. B. Broms. “Crack Width and Crack Spacing in Reinforced Concrete Members.” ACI Journal 62 (October
1965).
22. G. D. Base, J. B. Reed, and H. P. Taylor. “Discussion on ‘Crack and Crack Spacing in Reinforced Concrete
Members.’” ACI Journal 63 (June 1966).
23. P. Gergely and L. A. Lutz. “Maximum Crack Width in Reinforced Concrete Flexural Members.” In
Causes, Mechanism and Control of Cracking in Concrete. ACI Publication SP-20. American Concrete
Institute, Dearborn, MI, 1968.
24. ACI Committee 224. “Control of Cracking in Concrete Structures.” ACI 224R-01 (approved 2008). Manual
of Concrete Practice Part 1, American Concrete Institute, Dearborn, MI, 2010.
25. ACI Committee 224. “Causes, Evaluation, and Repair of Cracks in Concrete Structures.” ACI 224.1R-07.
Manual of Concrete Practice, Part 1, American Concrete Institute, Dearborn, MI, 2010.
26. M. N. Hassoun and K. Sahebjum. Cracking of Partially Prestressed Concrete Beams. ACI Special Publications
SP-113. American Concrete Institute, Dearborn, MI, 1989.
PROBLEMS
6.1 Determine the instantaneous and long-time deflection of a 20-ft-span simply supported beam for each of
the following load conditions. Assume that 10% of the live loads are sustained and the dead loads include
the self-weight of the beams. Use f ′ c = 4ksi,f y = 60 ksi, d′ = 2.5 in., and a time limit of 5 years. Refer
to Fig. 6.12.
No.
b
(in.)
d
(in.)
h
(in.)
A s
(in. 2 )
A ′ s
(in. 2 )
W D
(K/ft)
W L
(K/ft)
a 14 17.5 20 5 no. 9 — 2.2 1.8 — —
b 20 27.5 30 6 no. 10 — 7.0 3.6 — —
c 12 19.5 23 6 no. 8 — 3.0 1.5 — —
d 18 20.5 24 6 no. 10 2 no. 9 6.0 2.0 — —
e 16 22.5 26 6 no. 11 2 no. 10 5.0 3.2 12 10
f 14 20.5 24 8 no. 9 2 no. 9 3.8 2.8 8 6
Note: h–d = 2.5 in. indicates one row of bars, whereas h–d = 3.5 in. indicates two rows of bars. Concentrated
loads are placed at midspan.
P D
(K)
P L
(K)
6.2 Determine the instantaneous and long-term deflection of the free end of a 12-ft-span cantilever beam for
each of the following load conditions. Assume that only dead loads are sustained, and the dead loads
Figure 6.12 Problem 6.1.