Question 1
A continuous concrete beam with an effective depth of 400mm is reinforced with 6-20M bottom bars through the positive moment inflection point. Mr at the point indicated in the figure is 211kN.m while Vf at the inflection point is 400kN. Regular, uncoated bars have been used. f’c= 35MPa (normal density concrete) and fy=400MPa.
Determine if the bar size at the inflection point is adequate according to CSA A23.3 Cl.12.11.3.
Question 2
The simply supported beam below subjected to specified dead and live load (uniformly distributed) in the figure below has been designed to meet the maximum moment requirement with 10-30M bars arranged as shown below. The effective depth of the beam is 790mm. There is 40mm side cover to the reinforcement at the supports. The bars are uncoated and there is at least minimum shear steel throughout the beam.
Determine cutoff points for three of the top bars (3 out of the 5-30M bars). Detail the beam and ensure that CSA A23.3 requirements for bond are met. Use the centre-centre distance (10m) as the span to distribute moment. Use the support edge-support edge as the span to distribute the shear.
A continuous concrete beam with an effective depth of 400mm is reinforced with 6-20M bottom bars through the positive moment inflection point. Mr at the point indicated in the figure is 211kN.m while Vf at the inflection point is 400kN.
Use Canada CSA building code.