塑性铰区碳纤维约束空心薄壁墩抗震性能分析

Analysis on seismic behavior of hollow rectangular thin-walled pier confined by CFRP

对5根长细比为8的碳纤维约束墩及2根未约束的对比墩进行了拟静力试验,考察了碳纤维包裹量、配箍率2个参数对碳纤维布约束空心薄壁墩破坏机理及抗震性能的影响规律.试验结果表明:所有墩的破坏形态均表现为弯曲破坏模式;空心薄壁墩在塑性铰区域采用碳纤维约束后的承载能力和延性得到较大提高;对于配箍率为0.85%的约束墩,其抗震性能提高较明显;碳纤维具有与箍筋相似的力学性能,可以有效地改善空心薄壁墩的抗震性能,提高延性和耗能能力;结构抗震加固设计时须考虑碳纤维布最佳包裹量.

Five hollow thin-walled piers confined with CFRP（carbon fiber reinforced polymer） and two normal piers were designed and tested under axial toad and cyclic lateral force. The length-diameter ratio of all piers is 8. The influence of two parameters, including axial compression ratio and pattern of CFRP wrapping, on the ductile and ability of energy dissipation of piers are taken into account. The main failure patterns as well as performance of piers are analyzed. Test results indicate that flexural failures are the main patterns of all piers. Wrapping CFRP at plastic hinge zone of piers can observably improve its ductility, energy dissipation and seismic performance. With the increase of layers of CFRP, ductility improved. CFRP, which have the same mechanical properties as stirrups, can effectively improve the seismic performance of hollow thin-walled pier except ultimate bearing capacity, included ductility and energy dissipation capacity. The optimal reinforcement rate of CFRP relates to structural design parameters. Thereby these test properties above will provide qualitative understanding for researching seismic performance evaluation and retrofit of hollow thin-walled piers.