The straight line theory is a plastic calculation that gives a good estimate of the concrete and steel stresses at ultimate loads. It is used to calculate the stiffness, EI, at ultimate loads, for deflection calculations, and steel stresses, for use in crack-width or fatigue calculations.

Cracks due to shear are able to cross into the compression zone of the member.

Which is generally shorter?

Concrete cover may be increased to decrease a member’s fire resistance.

Cracks that lead to splitting along the reinforcement are known as _______ cracks.

A rectangular beam has a cross section of b = 14 in., h = 26 in., and d = 23.5 in. It is reinforced with four No. 5 Grade 60 bars. The concrete strength is 7,300 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.

A rectangular beam has a cross section of b = 16 in., h = 28 in., and d = 25.5 in. It is reinforced with four No. 6 Grade 60 bars. The concrete strength is 6,700 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the transformed cross-sectional area of the bars, Ast.

A rectangular beam has a cross section of b = 16 in., h = 28 in., and d = 25.5 in. It is reinforced with two No. 5 Grade 60 bars. The concrete strength is 6,100 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the modulus of rupture of the concrete, fr.

The fatigue strength of longitudinal bars is less than that of stirrups.

During serviceability calculations, it is common to ignore the presence of compression reinforcement.