Structural Concrete - Hassoun

574 Chapter 16 Continuous Beams and Frames
3 no. 9
2 no. 10
3 no. 9
2 no. 10
2 no. 9 2 no. 9
2 no. 9
2 no. 6
3 no. 9
2 no. 10
2 no. 6
2 no. 10
2 no. 9
6 no. 9
3 no. 9 2 no. 5
2 no. 10
3 no. 7
37
28.1
45 3.75
15
Figure 16.18
Example 16.2: Reinforcement details of frame sections.
The assumed a equals approximately the calculated a. The section acts as a rectangular section;
therefore, use six no. 9 bars. Check b min (to place bars in one row):
( ( 9 3
b min = 11 + 2 + 3 = 16.13 in. >16 in.
8)
8)
Place bars in two rows, as shown in Fig. 16.18.
b. Design the critical section at joint B: M u = 336.8 K ⋅ ft, b = 16 in., and d = 21 − 2.5 = 18.5 in.
(for one row of steel bars). The slab is under tension, and reinforcement bars are placed on top
of the section.
R u = M u 336.8 × 12,000
= = 738 psi
bd2 16(18.5) 2