内置型钢增强开圆孔RC梁受剪承载力计算方法

Calculation method of shear capacity of RC beams with circular web openings reinforced with encased section steel

为提高腹部开圆孔RC梁的受剪承载力,提出了内置型钢增强方法。该方法采用角钢焊接而成的六边形型钢部件布置在圆孔周围。针对孔侧剪切破坏、弦杆剪切破坏两种模式,研究了内置型钢增强开圆孔RC梁受剪承载力计算方法。以受剪承载力等强为原则,对照1根实腹RC简支梁,采用提出的受剪承载力计算公式设计了4根开圆洞RC简支梁所需内置型钢件以及箍筋的截面积。有限元与试验结果表明:内置型钢增强开圆孔RC梁可以实现与RC实腹梁受剪承载力等强;受剪承载力公式计算值与有限元模拟值最大误差为6.2%,与试验值最大误差为14.3%,三者吻合较好,受剪承载力计算公式具有较好精度。

In order to improve the shear bearing capacity of RC beams with circular web openings,a reinforcement method of encased section steel part was proposed.In this method,a hexagonal steel section welded by angle steel was arranged around the circular openings.Aiming at the two shear failure modes beside the openings and at the chords,the calculation methods of shear capacity of RC beams with circular web openings reinforced with encased section steel were respectively studied.Based on the principle of equal strength in shear capacity,compared with one simply-supported RC beam with a solid web,the cross-sectional areas of encased section steel parts and stirrups required for four simply-supported RC beams with circular web openings were designed by using the proposed calculation formula of shear bearing capacity.The finite element analysis and test results show that the designed encased section steel reinforced RC beams with circular web openings can achieve the same shear bearing capacity as RC beams with a solid web.The maximum error between the results of the formula and the finite element simulation is 6.2%,and that between the formula and the test is 14.3%,which are in good agreement.Therefore,the proposed shear bearing capacity calculation formula has good accuracy.