粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅱ:动力响应数值分析

Anti-seismic properties of damaged concrete bridge piers with hollowcross-section strengthened with adhering steel platesⅡ: numerical analysis on seismic dynamic responses

针对具有初始弯曲损伤的粘钢加固混凝土箱型桥墩,采用柔度法和纤维模型,进行了系统的地震动力响应数值模拟计算,分析了地震作用下加固桥墩的地震剪力、墩顶位移、剩余刚度等性能指标,并在拟静力试验的基础上综合研究其抗震加固力学行为.分析结果表明,地震荷载作用下地震中桥墩仍然发生加固钢板上缘产生塑性铰的破坏模式,与拟静力试验结果一致.加固前后桥墩抗震性能的对比结果表明,经粘钢加固形成新塑性铰的加固方式可有效增强桥墩的抗震能力.初始损伤程度、加固钢板厚度和长细比等对加固桥墩抗震安全度的影响较小.大轴压情况下,安全度快速降低.

The flexibility method and the fiber model were used to numerically simulate the earth-quake dynamic response of the damaged concrete bridge piers with hollow cross-section strengthened with adhering steel plates.The performance index,such as the seismic forces at the piers bottom, pier top displacement and residual stiffness,were analyzed,and on the basis of model tests the seis-mic mechanics behaviors of the strengthened piers were comprehensively studied.The analysis re-sults show that the failure modes of the strengthened bridge piers under the earthquake actions are al-so displayed as the occurrences of plastic hinge in the superior margin of the steel plates,which coin-cides with the pier model testing results.The comparison of the seismic performances before and af-ter strengthening validates the effectiveness of the strengthening method with steel plates of making new plastic hinge.The effects of the initial damage degree,steel plate thickness and slenderness rati-os on the seismic safety degrees of the bridge piers are small.However,when the axial compression ratio is large,the seismic safety degrees decrease quickly.