复合受力作用下混凝土构件的剪压比试验研究

Experimental study of effects of shear-compression ratio on the composite bearing capacity of reinforced concrete member

统计不同文献的压弯剪试验数据,剪力对复合受力构件的承载力存在削弱作用,而我国设计规范目前采用"柱端弯矩增大系数"、"强节点系数"等调整弯矩、剪力设计值,没有相应压弯剪复合受力的计算方法,也无法量化考虑剪力对复合受力构件承载力的影响。本次课题进行了6个固定剪压比钢筋混凝土Z型柱试件和5个不同预加偏压作用下钢筋混凝土柱的复合受力试验研究,着重研究了复合受力作用中"剪力"的影响机理,通过压剪相关曲线与弯剪相关曲线相比可知,剪应力对压弯剪复合作用的影响尤为显著。因此,在课题研究成果基础上提出剪压比概念,即剪力作用与轴压作用之比值,由此作为混凝土构件复合受力破坏状态的重要判断依据,当剪压比超过0.1时,复合作用中剪力上升为构件破坏的直接因素。

According to the data statistics of RC members＇ capacity under axial compression-bending-shear loading states,the shearing force weakens the capacity of reinforced concrete（ RC） member. And current design codes adopt some coefficients to adjust design values of bending moment or shear force,there is no corresponding method to consider the influence of shearing force. The experiments of 6 Z-shaped concrete column specimens with same shear-compression ratio,and 5 concrete column specimens with different preload compressive stress are carried out,and the impacts of shear force on inclined section bearing capacity of the reinforced concrete members are studied.Through comparison between M-V interactive curves and N-V interactive curves,the shearing strength has a significant influence on composite bearing capacity. The concept of shear-compression ratio is suggested,which is the key to define the critical failure state of concrete members under combing load. When the shear-compression ratio exceeds 0. 1,the shearing force becames the direct factor of member ＇s damage, and this should be considered.