基于模态测试的梁桥横向联系损伤识别及传载能力评估

Damage identification and load transfer capacity evaluation for transverse connection of beam bridges based on modal tests

梁桥横向联系的优劣关系到桥梁结构的整体稳定性和承载状况。为科学准确地识别梁桥横向联系的损伤位置,评估横向联系构件的传载能力,以实际工程中16 m跨径简支空心板梁桥为研究对象,提出基于主梁跨中模态振型横桥向变化率之比以及相邻主梁模态挠度差的横向联系损伤识别方法,通过有限元仿真分析,对损伤识别指标的有效性进行验证,并定义横向传载性能折减系数ζ,用于评估横向联系的传载能力。结果表明:利用一阶模态振型横桥向变化率之比的增大位置能够进行铰缝的损伤定位;根据相邻主梁之间的模态挠度差在铰缝处的突变现象,也能够准确识别铰缝损伤位置;ζ是评判桥梁横向联系最显著的指标,ζ越大,其横向传递荷载的能力越差,因此,基于模态测试得出的横向联系传载性能折减系数ζ可作为评估铰缝横向传载能力的可靠指标。研究结果可为工程中检测、评估简支梁桥的横向联系安全状况提供有益参考。

The advantages and disadvantages of the transverse connection of beam bridges are related to the structural stability and bearing condition.To scientifically and accurately identify the damage location and evaluate the load transfer capacity of transverse connection members of beam bridges,a 16-m span simply-supported hollow slab beam bridge in the actual project was studied in this paper.A damage identification method of transverse connection based on the transverse change rate ratio of mid-span modal modes of the main beam and the modal deflection difference between adjacent main beams was proposed.Through a finite element simulation analysis,the validity of the damage identification indexes were verified,and the reduction factorζof transverse load transfer performance was defined to evaluate the load transfer capacity of transverse connection.The results show that the damage location of hinge joints can be determined using the position where the transverse change rate ratio of the first-order modal mode is increased.Based on the sudden change of the modal deflection difference between adjacent beams,the hinge joint damage location can also be accurately identified.ζis the most significant index to judge the transverse connection of bridge.The load transfer capacity of transverse connection is decreased with the increase in the value ofζ.Therefore,the reduction factorζbased on modal tests can be used as a reliable index to evaluate the transverse load transfer capacity of hinge joints.The research results can provide a useful reference for the detection and evaluation of the transverse connection safety of simply-supported beam bridges.