基于简化模型的铁路桥墩健康状态快速评估方法及应用研究

Study on rapid evaluation method for health condition of railway piers based on simplified model and its engineering application

针对存在墩梁耦合效应的重载铁路多跨简支梁桥桥墩健康状态评估问题,以重载铁路多跨简支梁桥为研究对象,推导了梁体等效集中质量的计算公式,提出了多跨简支梁桥桥墩简化模型,进而建立了一套基于简化模型的铁路多跨简支梁桥桥墩健康状态的评估方法.并以南排河特大桥为试验对象,探究了该方法在实际工程中的应用情况.结果表明:锤击激励和环境激励下梁体振型等效集中质量系数计算值差异很小,其计算方法不受外部激励的影响;提出的单墩简化分析模型可以较好地等效局部墩梁体系的振动;基于模态频率和振型构建的模型修正方法可以实现桥墩墩身刚度与基础约束的定量评估;整体和局部健康评估结果均表明南排河特大桥4号和5号墩服役状态良好,该快速评估方法能够准确反映桥梁健康状态,具有良好的实用价值.

In order to evaluate the health condition of multi-span simply-supported bridge pier with pier-beam coupling effects in heavy-haul railway,this paper takes a heavy-haul railway multi-span simply-supported beam bridge as the research object.The calculation equation of equivalent concentrated beam mass is deduced,and the simplified model of pier for multi-span simply-supported beam bridge is proposed,based on which a complete rapid evaluation method is established.The Nanpai River bridge is used as the test object to study the application of this method in actual engineering.The results show that there is little difference between the calculated values of the equivalent concentrated mass coefficient of the beam under hammer excitation and that under environmental excitation,and its calculation method is not affected by the external excitation;the proposed simplified analysis model of single pier can well equate the vibration of local pier-beam system.The model modification method based on modal frequency and vibration pattern can realize the quantitative evaluation of pier stiffness and foundation constraints.The overall and local health evaluation results show that the piers No.4 and No.5 of Nanpai River bridge are in good service.This rapid evaluation method can reflect the health condition of the bridge accurately and has good practical value.