The simply supported beam shown is on a clear span of 30 ft. The beam carries uniformly distributed service loads of 1.9 kips/ft live load and 0.7 kip/ft dead load (excluding the weight of the beam). Additionally, the beam carries two concentrated service loads of 8 kips dead load each, one load being placed 5 ft in from the face of each support. The beam is reinforced with No. 3 single-loop stirrups placed in the following pattern, starting at the face of the support (symmetry about mid span): one space at 2 in., five spaces at 8 in., four spaces at 10 in., and eight spaces at 12 in. Beam width b = 15 in., h = 28 in., and d = 25.4 in. Use f′ c = 4000 psi and fy = 60,000 psi.
a. Draw an elevation view of the beam showing the stirrup layout.
b. Draw the Vu diagram.
c. Calculate ∅(Vc + Vs) for each spacing group (omit the 2-in. spacing).
d. Superimpose the results from part (c) on the Vu diagram and comment on the results.