(Answered): 5-4 The rectangular beam shown in Fig. P5-4 carries its own dead load (you must guess values for b ...

5-4 The rectangular beam shown in Fig. P5-4 carries its own dead load (you must guess values for b and h) plus an additional uniform, service dead load of 0.5 kip/ft and a uniform, service live load of 1.5 kip/ft. The dead load acts on the entire beam, of course, but the live load can act on parts of the span. Three possible loading cases are shown in Fig. P5-4. Use load and strength reduction factors from ACI Code Sections 9.2 and 9.3 (a) Draw factored bending-moment diagrams for the three loading cases shown and superimpose them to draw a bending-moment envelope (b) Design a rectangular beam section for the maxi- mum positive bending moment between the sup- ports, selecting b, d, h, and the reinforcing bars. Use the procedure in Section 5-3 for the design of beam sections when the dimensions are un- known. Use fe flexural reinforcement for the maximum nega tive moment over the roller support. 5000 psi and fy 60 ksi (c) Using the beam section from part (b), design Service live load1.5 kips/ft Additional service dead load 0.50 kip/ft 24 ft 9 ft Live load Dead load Live load Dead load Fig. P5-4