【摘要】 2025年3月28日，缅甸曼德勒市附近发生了7.9级地震。距离地震中心15 km左右的阿瓦大桥，在地震中出现了落梁破坏，其桥梁的支座与桥墩也有不同程度的损坏。为了探究阿瓦大桥的破坏机理，该文通过有限元分析软件OpenSees建立阿瓦大桥的全桥模型与对应的连续梁模型，选取1组内比都台站记录的地面运动加速度时程以及4组与此次地震类型相同的典型的走滑型地震的地面运动加速度时程数据，进行三向地震反应时程分析。结果表明，由于强烈的地震作用，阿瓦大桥中间桥墩的支座发生破坏，从而导致顺桥向位移过大，发生落梁。与之相对应的连续梁体系虽然支座也发生破坏，但桥梁的位移明显降低，不会出现落梁情况。文中结合分析结果与历史落梁震害的成因提出了提高简支梁桥抗震性能的对策与建议。更多还原

【Abstract】 On March 28, 2025, a magnitude 7.9 earthquake occurred near Mandalay City, Myanmar. The Ava Bridge, located about 15 kilometers from the epicenter, experienced unseating damage during the earthquake. Both its bearings and piers were damaged to different extents. To study the failure mechanism of the bridge, this research developed both a full-bridge model and a corresponding continuous girder model using the finite element software OpenSees. For seismic response analysis, one set of ground motion records from the Naypyidaw station and four sets of typical strike-slip ground motions were used. These records were chosen to represent the same type of earthquake as the 2025 Myanmar Earthquake. They were applied as input in three orthogonal directions. The results show that strong seismic shaking caused failure of the bearings at the intermediate piers of the Ava Bridge. This bearing failure led to excessive longitudinal displacement, ultimately resulted in unseating. In comparison, although bearings in the continuous girder model also failed, the overall displacement of the bridge was much smaller, preventing unseating damage. Based on the analysis and historical causes of unseating failures, this paper proposes strategies and recommendations for improving the seismic performance of simply supported girder bridges.更多还原