A rectangular beam has a cross section of b = 18 in., h = 30 in., and d = 27.5 in. It is reinforced with five No. 5 Grade 60 bars. The concrete strength is 8,800 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the modulus of rupture of the concrete, fr.

A rectangular beam with cross section b = 16 in., h = 28 in., and d = 25.5 in. supports a total factored uniform load of 3.10 kips/ft, including its own dead load. The beam is simply supported with a 23-ft span. It is reinforced with four No. 8 Grade 60 bars, two of which are cutoff between midspan and the support and two of which extend 10 in. past the centers of the supports. The concrete strength is 5,100 psi (normal weight). The beam has Grade 60 No. 3 stirrups satisfying ACI 318-14 Sections 9.7.6.2.2 and 9.6.3.3. The strength of the four bars is φMn = 343.2 kip-ft, and the strength of the remaining two bars is φMn = 176.4 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

Compression-development lengths are shorter 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.

When may it be advantageous to use headed bars instead of hooked bars?

Determine the casting-position modification factor, ψt, for a rectangular beam with b = 16 in. and d = 20 in., three epoxy-coated No. 7 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 60 stirrups located every 12 in. along the span. Assume 7,000-psi normal-weight concrete and a clear cover of 1.5 in.

Usas este recipiente para tomar sopa. El hondo.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 17 in. and d = 24 in., five galvanized No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 60 stirrups located every 12 in. along the span. Assume 6,000-psi lightweight concrete and a clear cover of 1.5 in.

Universally accepted crack widths are specified in ACI 318.

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 22 in., four epoxy-coated No. 6 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 40 stirrups located every 12 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.75 in.

Bricks expand with time due to an increase in _______ above their kiln-dried condition.