单调水平荷载作用下钢筋混凝土柱受弯性能尺寸效应试验研究

为了研究钢筋混凝土柱的受弯性能尺寸效应，对6个钢筋混凝土柱试件进行不同轴压比下的单调水平加载试验。试件的轴压比和截面尺寸不同，剪跨比和配筋率保持一致。分析名义极限弯矩、延性、中和轴高度和塑性铰长度等受弯性能随截面尺寸的变化规律。结果表明：名义极限弯矩、峰值荷载时混凝土压应变、延性、中和轴高度和塑性铰长度都表现出明显的尺寸效应，随截面尺寸的增大而减小；轴压比越高，名义极限弯矩和峰值荷载时混凝土压应变尺寸效应越明显；轴压比较低时，位移延性系数的尺寸效应更明显。在试验基础上，提出考虑截面尺寸影响系数的钢筋混凝土柱受弯承载力计算式，使大小尺寸试件计算结果的安全储备系数趋于一致。

Experimental study on size effect of flexural behaviorfor reinforced concrete columns subjected tomonotonic horizontal loading

Six reinforced concrete columns subjected to monotonic horizontal loading under different axial compressive ratios were tested to investigate the size effect on flexural behavior of columns. Axial compressive ratio and section size of specimen were different, while the shear span ratio and reinforcement ratio remained constant. The flexural behavior of specimens was analyzed, including nominal ultimate flexural moment, ductility, location of neutral axis and length of plastic hinge, etc. The analysis results show that the size effect of nominal ultimate flexural moment, compressive strain of concrete at peak loading, ductility, location of neutral axis and length of plastic hinge is apparent, which decrease as the specimen size increases; when axial compressive ratio is big, nominal ultimate flexural moment and compressive strain of concrete at peak loading show more significant size effect; when axial compressive ratio is small, the size effect of displacement ductility coefficient is more apparent. Then on the basis of experiment, a practical calculation model of flexural strength of reinforced concrete column considering section size effect coefficient was proposed. The safety coefficient of large size specimen is consistent with results of small size specimen.