【摘要】 通过5根无箍筋和7根有箍筋矩形截面钢筋混凝土框架柱试验,研究不同加载角度时,低周往复斜向水平荷载作用下,矩形截面框架柱双向受剪的破坏机理和计算方法。结果表明,不能用单向剪切理论计算矩形截面框架柱双向受剪承载力的原因,主要是矩形截面框架柱双向受剪时,斜裂缝开展迅速,部分混凝土提前退出工作,导致轴压力对混凝土强度的提高作用有限。其次,按单向剪切理论计算矩形截面框架柱双向受剪承载力时,两个方向共用一个混凝土截面,重复考虑了混凝土的抗剪能力。据此分析无腹筋矩形截面框架柱双向受剪承载力的相关性,并用椭圆方程描述其相关关系,提出对混凝土项和轴力项共同折减的双向剪切理论,并建立低周往复水平荷载作用下矩形截面框架柱双向受剪承载力的计算公式。计算结果与试验值相比表明是偏于安全的。最后考虑承载力抗震调整系数,给出了考虑地震作用时矩形截面框架柱双向受剪承载力的建议公式。更多还原

【Abstract】 The mechanism and calculation method of bilateral shear strength of rectangular frame columns(RFC) under low-cyclic oblique horizontal loads were investigated based on an experiment including 5 rectangular frame columns without stirrup and 7 rectangular frame columns with stirrup.The results indicate unilateral shear theory can not be used to calculate bilateral shear strength of RFC.The main reason is that the diagonal crack of column develops rapidly under bilateral shear force,and the the concrete strength increased by axial force is limited.Secondly,the bilateral shear strength offered by concrete of RFC is calculated iteratively by unilateral shear theory.Based on the above analysis,the correlation property of bilateral shear strength of RFC without stirrup is analyzed.The results show the correlation relationship can be described as ellipse equation.And then an amendatory theory was put forward,Which reduced the shear strength offered by concrete and axial force together on two principal axes.The comparison between the calculation and experimental results shows the formula is feasible and safe.At last,a formula to calculate bilateral shear strength of RFC under qrthquake was presented,in which γRE is considered.更多还原