Abstract: Taking Liu-Wu Bridge in Lhasa as the research project，the finite element model of the bridge was established by using the software MIDAS /Civil． The dynamic characteristics，seismic response and vice arch inclination change were analyzed， in order to study the performances of the structure． The results show that the low-order mode shapes of the bridge is mainly the transverse bending of the deck，the lateral stiffness of the deck is weaker; when the waves are inputted in one direction and three dimension，the change rules and influence degree are different in the internal forces for each control section of the lord vice arch． The enlargement of vice arch inclination angle significantly improves the lateral stiffness of structure， and decreases the bending moment of arch rib as well as the lateral displacement of the arch top． But it has little impact on the internal forces of the main arch．

Key words: leaning arch bridge, dynamic characteristics, seismic response, inclination change

摘要： 以拉萨市柳梧大桥主桥为工程背景，采用有限元软件MIDAS /Civil 建立空间有限元计算模型，分别对其动力 特性、地震响应、副拱倾角变化对结构性能的影响进行分析。计算结果表明: 该桥的低阶振型以桥面系的横弯为主， 桥面系横向刚度较弱; 地震波单向输入和三维输入时，主副拱各控制截面内力的变化规律和影响程度不同; 副拱倾 角增大可显著提高结构的横向刚度，能减小拱肋面外弯矩和拱顶横向位移，而对主拱轴力影响相对较小。

关键词: 斜靠式拱桥, 动力特性, 地震响应, 倾角变化