Compute the initial deflection of the beam at midspan under service loads with the following specifications: f'c = 4000 psi, 36-inch height, depth of rebar assumed to be 3 inches less than the height, 16-inch width, 4 #9 bars (tension), Grade 60 rebar, 30' clear spans, service loads of: DL = 0.25k/ft, LL = 1.2k/ft. The DL does NOT include self-weight of the beam or of the precast concrete deck planks that have a weight of 60 PSF. The beam picks up a tributary width of 12 feet. Also, note that this beam is continuous and is the middle beam of 5 equal spans. Check the initial deflections against the ACI deflection requirements. Then calculate the long-term deflections and check those against the ACI requirements. For both situations, assume that finish materials will be attached to the beam. Last: Instead of performing a structural analysis to determine the maximum deflection in the beam, conservatively figure that the maximum deflection will be 60% of what it would have been for a simply supported beam.
Compute the initial deflection of the beam at midspan under service loads with the following specifications: f'c = 4000 psi, 36-inch height, depth of rebar assumed to be 3 inches less than the height, 16-inch width, 4 #9 bars (tension), Grade 60 rebar, 30' clear spans, service loads of: DL = 0.25k/ft, LL = 1.2k/ft.
The DL does NOT include self-weight of the beam or of the precast concrete deck planks that have a weight of 60 PSF. The beam picks up a tributary width of 12 feet. Also, note that this beam is continuous and is the middle beam of 5 equal spans.
Check the initial deflections against the ACI deflection requirements. Then calculate the long-term deflections and check those against the ACI requirements. For both situations, assume that finish materials will be attached to the beam.
Last: Instead of performing a structural analysis to determine the maximum deflection in the beam, conservatively figure that the maximum deflection will be 60% of what it would have been for a simply supported beam.
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