Determine the size modification factor, ψs, for a rectangula…
Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 23 in., three uncoated No. 7 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 8 in. along the span. Assume 4,000-psi normal-weight concrete and a clear cover of 1.75 in.
Read DetailsDetermine the epoxy modification factor, ψe, for a rectangul…
Determine the epoxy modification factor, ψe, for a rectangular beam with b = 18 in. and d = 20 in., four epoxy-coated No. 8 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 10 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.5 in.
Read DetailsA high-altitude spherical weather balloon expands as it rise…
A high-altitude spherical weather balloon expands as it rises, due to the drop in atmospheric pressure. Suppose that the radius r increases at the rate of 0.16 inches per second and that r = 38 inches at time t = 0. Determine the equation that models the volume V of the balloon at time t, and find the volume when t = 280 seconds. (5 points)
Read DetailsDetermine the epoxy modification factor, ψe, for a rectangul…
Determine the epoxy modification factor, ψe, for a rectangular beam with b = 16 in. and d = 22 in., five epoxy-coated No. 9 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 40 stirrups located every 6 in. along the span. Assume 7,000-psi normal-weight concrete and a clear cover of 2 in.
Read DetailsA rectangular beam with cross section b = 14 in., h = 22 in….
A rectangular beam with cross section b = 14 in., h = 22 in., and d = 19.5 in. supports a total factored uniform load of 1.70 kips/ft, including its own dead load. The beam is simply supported with a 18-ft span. It is reinforced with four No. 5 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 7,200 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 = 106.4 kip-ft, and the strength of the remaining two bars is φMn = 53.8 kip-ft. If the distance from the support to the theoretical cutoff point is 4.792 ft, determine the distance from the support to the actual cutoff point (i.e. use ACI 318-14 Section 9.7.3.3).
Read Details