拱肋损伤肋拱桥动力响应试验研究

Experimental study of dynamic response of ribbed arch bridge with damaged ribs

针对某服役40余年的钢筋混凝士旧拱桥制作了有机玻璃缩尺模型，结合实际工程结构中拱肋的损伤情况，利用切口在模型中拱肋截面的不同位置来模拟损伤，对拱肋截面不同位置发生不同程度损伤情况下的拱桥模型进行了动力模型试验研究。得到了各种损伤情况下结构频率、振型、拱肋上点的动应变；基于ANSYS有限元分析软件对各种损伤状态下结构的动力特性进行了数值模拟；探讨了动力损伤指纹（频率、振型、动应变）对拱肋损伤的灵敏性和变化规律．研究结果表明．结构的一阶水平自振频率对拱肋截面损伤灵敏度较高，1／8～1／4跨度拱肋范围．内拱肋截面的损伤对结构自振频率影响较其他位置略微显著；结构振型曲线对拱肋跨中截面的损伤灵敏度较高；竖直方向的振型曲线较水平方向振型曲线对损伤的敏感性高；拱肋动应变对拱肋截面的损伤较为敏感．

Based on an old reinforced concrete arch bridge, which has been in-service for about 40 years, a scaled one-span bridge model was fabricated by organic-glasses. Notches fabricated by saw cutting were introduced into the arch ribs to simulate the damage. Dynamic experiments were executed on the undamaged and damaged model. Dynamic responses （structural frequency, mode shape, dynamic strain） of different damaged models were achieved. Numerical simulation was performed by ANSYS software. Sensitivity analyses of the dynamic signature to the damage location were investigated. Relation between structural dynamic signature and the damage was discussed. It is shown that the 1st-order horizontal frequency, vertical mode shape and the dynamic strain are sensitive to the damage on the arch rib, and the structural frequency is more sensitive to the damage on 1/8-1/4 of the arch rib span than the damage on other locations, and the structural mode shape is more sensitive to the mid-span damage.