尺寸效应对钢筋混凝土桥墩抗震性能影响的试验研究

摘要

To study the size effect on column flexural behavior,a 4 170 mm height reinforced concrete bridge column specimen and a 3/4 replica model were tested under quasi-static reciprocating low-cyclic loading.Their structural force-displacement curves,cross-sectional moment-curvature curves,lateral displacements due to bar slip and cyclic energy dissipations were compared based on dimensional principle.The analysis results showed that the structural lateral load and the envelope curves of cross-sectional moment-curvature relations exhibit similar relation;however,because of lateral displacement due to bar slip,the maximum lateral drift of the replica model is larger than that of the original specimen and the amount of energy absorption to drift ratio is lower for the replica model.Furthermore,the flexural component and bar slip component of the lateral deflection at the top of the columns were computed according to the simplified curvature distribution curve and reinforcement slip model.Finally,the study results were synthesized into a suggested for mula used to estimate bridge columns' displacement ductility with size effect.%通过两个符合相似关系的钢筋混凝土桥墩水平低周往复加载试验，分析尺寸效应对桥墩抗震性能影响。依据量纲原理，分别比较试件墩顶力-位移曲线、墩底塑性区截面弯矩-曲率曲线、墩顶滑移位移分量及桥墩能量耗散能力，结果表明，两试件墩顶水平抗力、截面抵抗弯矩和曲率延性基本符合相似关系，无明显尺寸效应；但由于纵筋粘结滑移的三维影响，缩尺试件墩顶水平位移包含较大滑移位移分量，同比耗能偏低，尺寸效应显著。基于此，针对弯曲主导破坏桥墩，根据简化曲率分布模型和纵筋滑移模型，分别计算墩顶弯曲位移和滑移位移分量，推导给出模型试验中桥墩位移延性的建议反演公式。