Structural Concrete - Hassoun

Problems 723
Figure 18.23 Problem 18.3.
18.4 Design a typical flight of stairs in a public building for the staircase arrangement shown in Fig. 18.24.
The stairs are supported by central beams, A and B. Design only one flight and the supporting beams A
and B. The runs are 1.0 ft (300 m) deep and the rises are 6.5 in. high. Use f c ′ = 3ksi (20 MPa), f y = 60 ksi
(400 MPa), and a live load equal to 80 psf (3.85 kN/m 2 ).
Figure 18.24 Problem 18.4.
Note: Design the beams for bending moments and shear, and neglect torsional moments caused by loading
one-half of the steps.
18.5 Repeat Example 18.3 if the run is 12 in. (300 mm) and the rise is 6 in. (150 mm).
18.6 Repeat Example 18.3 if the landing is 5 ft (6 × 10”), runs are 8.33 ft (10 × 10”), risers at 5.5 ft (11 × 6”),
and the live load is 120 psf.