Blog

Determine the lightweight modification factor, λ, for a rectangular beam with b = 17 in. and d = 22 in., four uncoated No. 8 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 8 in. along the span. Assume 5,000-psi normal-weight concrete and a clear cover of 1.75 in.

Use ACI 318-14 Table 25.4.2.2 to determine the development length for the straight tension bars (no hooks) in a rectangular beam with b = 18 in. and d = 20 in., three uncoated No. 8 Grade 60 bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 10 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 1.75 in.

A rectangular beam has a cross section of b = 16 in., h = 24 in., and d = 21.5 in. It is reinforced with five No. 6 Grade 60 bars. The concrete strength is 5,500 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. Determine the strength φMn for this beam.

A rectangular beam with cross section b = 14 in., h = 28 in., and d = 25.5 in. supports a total factored uniform load of 2.70 kips/ft, including its own dead load. The beam is simply supported with a 20-ft span. It is reinforced with five No. 6 Grade 60 bars, three 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 3,300 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 five bars is φMn = 235.8 kip-ft, and the strength of the remaining two bars is φMn = 98.32 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

A pipeline with an outside diameter of 435 mm and a wall thickness of 9 mm is pressurized to 1.8 MPa. Due to thermal expansion, a compressive force of 26 kN is generated along the length of the pipes. Determine the normal stress along the length of the pipes. Ignore the bending stresses due to the weight of the pipes and the fluid that they contain.

A rectangular beam has a cross section of b = 16 in., h = 26 in., and d = 23.5 in. It is reinforced with three No. 7 Grade 60 bars. The concrete strength is 6,700 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. Determine the strength φMn for this beam.

Force P = 50 N is applied to a lever at the end of a 32-mm-diameter shaft. Force Q = 925 N is applied directly to the shaft. Determine the normal stress σy at point K. Let a = 170 mm and b = 235 mm.

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 22 in., four galvanized No. 6 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 8 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.75 in.

Force P = 45 N is applied to a lever at the end of a 30-mm-diameter shaft. Force Q = 905 N is applied directly to the shaft. Determine the normal stress σy at point K. Let a = 130 mm and b = 235 mm.

Use ACI 318-14 Table 25.4.2.2 to determine the development length for the straight tension bars (no hooks) in a rectangular beam with b = 18 in. and d = 22 in., five galvanized No. 6 Grade 60 bars placed in the top of the beam, and No. 4 Grade 60 stirrups located every 12 in. along the span. Assume 5,000-psi normal-weight concrete and a clear cover of 2 in.