Blog

Simply supported beams loaded with only gravity loads develop negative bending moments throughout the span.

A beam has dimensions of b = 18 in., h = 26 in., and d = 23.5 in. and is reinforced with 3 No. 8 bars. The concrete strength is 4,300 psi, and the yield strength of the reinforcement is 60,000 psi. Determine the strength Mn for this beam.

Simply supported beams loaded with only gravity loads develop tension cracks along the bottom of the beam.

The textbook author recommends using As’ ≤ 0.5As in doubly reinforced beam sections.

The thickness of concrete cover should be decreased for highly corrosive environments.

A beam has dimensions of b = 14 in., h = 28 in., and d = 25.5 in. and is reinforced with 2 No. 6 bars. The concrete strength is 3,700 psi, and the yield strength of the reinforcement is 60,000 psi. Assuming the reinforcement has yielded, determine the tensile force T in the reinforcement.

If a beam is supported by a girder of essentially the same depth, the compression fans that form in the supporting girder tend to tie the beam and girder together.

If a designer wants to reduce the size and weight of a beam, he/she could use additional tension reinforcement and add compression reinforcement to keep the section tension-controlled.

A continuous beam’s flexural reinforcement must extend at least _____ from the point where it is no longer needed to resist tension. Assume f’c = 4,000 psi, fyt = 40,000 psi, d = 23 in., w = 13.5 in., and t = 6 in. There are five No. 7 longitudinal tension bars and No. 5 stirrups at 6 in. o.c.

The use of compression reinforcement permits the use of more tension reinforcement to increase the strength of a given beam section while keeping the section tension-controlled.