DISCUSSION ON THE DESIGN ASSUMPTION OF DOUBLE REINFORCED RECTANGLE SECTION RC BEAM ACCORDING TO THE NEW CODE FOR DESIGN OF CONCRETE STRUCTURE

The new and old codes for design of concrete structure were compared in this paper,the results showed that the accounting assumption x 2a'swas not available for the new HRB500 bar in the design of double reinforcement rectangle section RC beam,the compressive reinforcement can not reach design value,so a fixed assumption was raised to fit for HRB500 bar. Meanwhile,b was supplemented under correlative formulas and terms of assumption of plane section. When the aboved assumption and b were applied in the design of double reinforcement rectangle section RC beam,the results and analysis proved that the fixed assumption was more adaptive and created less total steel consumption.