RC双肢矩形空心墩抗震性能研究

Study on Seismic Performance of RC Double-Limb Rectangular Hollow Pier

摘要: 为探究钢筋混凝土(RC)双肢矩形空心墩的抗震性能，本文以某典型双肢矩形空心墩缩尺试件开展了恒定轴压(轴压比0.12)下的水平往复拟静力试验，分析了其破坏过程、滞回特性、刚度退化及耗能能力。结果表明：试件呈典型的“墩顶与墩底双塑性铰弯曲破坏”，伴有显著弯剪耦合效应；屈服后墩端裂缝密集，滞回环“捏拢”明显且刚度退化迅速；加载至极限位移(67.5 mm)时，塑性铰区混凝土严重剥落，加载梁端出现剪切裂缝，承载力降至峰值的85%以下。该类构件大变形下应注意局部损伤而造成的耗能受限，抗震设计中应重视薄壁截面横向约束及墩–梁–台体系的强度匹配。

Abstract: To investigate the seismic performance of reinforced concrete (RC) double-column rectangular hollow piers, a horizontal cyclic quasi-static test under constant axial compression (with an axial compression ratio of 0.12) was conducted on a typical scaled specimen of a double-column rectangular hollow pier in this paper. The failure process, hysteretic characteristics, stiffness degradation, and energy dissipation capacity were analyzed. The results show that the specimen exhibits a typical “double plastic hinge flexural failure at the pier top and bottom”, accompanied by a significant flexure-shear coupling effect. After yielding, cracks at the pier ends become dense, the hysteretic loops show obvious “pinching”, and the stiffness degrades rapidly. When loaded to the ultimate displacement (67.5 mm), the concrete in the plastic hinge region spalls severely, shear cracks appear at the end of the loading beam, and the bearing capacity drops below 85% of its peak value. For this type of component under large deformations, attention should be paid to the limited energy dissipation caused by local damage. In seismic design, emphasis should be placed on the transverse confinement of thin-walled sections and the strength matching of the pier-beam-abutment system.