Situation: A two-span pedestrian walk-way bridge is made up of a series of 24×36 inchrectangular section beams of 42 feet span each, as shown in the figure. The center-to-center spacing between these beams is 8 feet. A 6-inch thick slab rests on these beams. The slab is not monolithically cast with beams. Criteria: The load consists of 20 psf superimposed dead load and 100 psf live load. Use fy =60,000 (for flexure design), and f'c = 4,000 psi for all calculations.

Required: Using the load given and considering that only the dead load and live load combination will be critical,

(a) Compute the design factored load (wu) for the slab and (qu) for a typical beam.

(b) Show the bending moment and shear diagram for a typical (two-span) beam under a uniform load qu.

(c) Using the value in Part (a) and the bending diagram in Part (b), compute the maximum design negative and positive moments (Mu).

(d) Design flexural reinforcement for the entire beam. Note: steel design is needed for positive moment (midspan) and negative moment (support).

(e) Show a sketch for the reinforcements you designed.

(f) As expected, the slab is a simply supported and has a span of 8 feet. We plan to use #3 steel for the slab. Design reinforcement for the slab using the load you computed in Part (a); and show a detail for the reinforcement you designed.