When tension is applied to a smooth reinforcing bar, its diameter is decreased. Due to the decrease in diameter, the adhesion and friction bonds that originally held it in place are quickly lost.

If the depth of the beam varies, the compressive and tensile forces due to flexure will be parallel.

Determine the epoxy modification factor, ψe, for a rectangular beam with b = 16 in. and d = 24 in., three uncoated No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 40 stirrups located every 8 in. along the span. Assume 5,000-psi lightweight concrete and a clear cover of 1.75 in.

In a lapped splice, the force in one bar is transferred directly to the adjacent bar.

Assuming Vs does not exceed 4sqrt(f’c)bwd, the maximum spacing for vertical stirrups in the following beam is _____. Let b = 14 in. and d = 41 in. There are four No. 7 longitudinal tension bars and No. 4 stirrups at 11 in. o.c.

At a point subjected to plane stress, the stresses are σx = 10 ksi, σy = 25 ksi, and τxy = –20 ksi. Determine the angle θp corresponding to the orientation of the principal planes at the point.

Compression-development lengths are longer than tension-development lengths, because some force is transferred to the concrete by the bearing at the end of the bar and there are no cracks in such an anchorage region.

Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 18 in. and No. 4 stirrups. This beam has three No. 7 bars as longitudinal reinforcement. The clear cover is 2 in.

Actual bond stresses vary from point to point between cracks.

Which symbol represents the bar-spacing factor?