Structural Concrete - Hassoun

288 Chapter 7 Development Length of Reinforcing Bars
7.7 Calculate the lap-splice length for no. 9 tension bottom bars with clear spacing of 2.0 in. and clear cover
of 2.0 in. for the following cases:
a. When 50% of the reinforcement is spliced and (A s provided)/(A s required) = 2.
b. When 75% of the reinforcement is spliced and (A s provided)/(A s required) = 1.5.
c. When all bars are spliced at one location and (A s provided)/(A s required) = 2.
d. When all bars are spliced at one location and (A s provided)/(A s required) = 1.3. Use f c ′ = 4ksi and
f y = 60 ksi.
7.8 Repeat Problem 7.7 using f c ′ = 3ksi and f y = 60 ksi.
7.9 Calculate the lap splice length for no. 9 bars in compression when f c ′ = 5ksi and f y = 60 ksi.
7.10 Repeat Problem 7.9 when no. 11 bars are used.
7.11 Repeat Problem 7.9 when f y = 80 ksi.
7.12 Repeat Problem 7.9 when f ′ c = 4ksi and f y = 60 ksi.
7.13 A continuous beam has the typical steel reinforcement details shown in Fig. 7.16. The sections at midspan
and at the face of the support of a typical interior span are also shown. Check the development lengths
of the reinforcing bars at all critical sections. Use f c ′ = 4ksi and f y = 60 ksi.
8 no. 8
2 no. 8
6 no. 8
Figure 7.16 Problem 7.13.
7.14 Design the beam shown in Fig. 7.17 using ρ max . Draw the moment–resistance diagram and indicate where
the reinforcing bars can be terminated. The beam carries a uniform dead load, including self-weight of
1.5 K/ft, and a live load of 2.2 K/ft. Use f c ′ = 4ksi, f y = 60 ksi, and b = 12 in.