中文摘要：

正常运营中的桥梁结构，总会受到车辆荷载、环境因素等的影响，导致结构性能发生不同程度的退化。桥梁结构的模态参数是反映结构性能的重要指标，研究影响模态参数的各因素对结构模态的敏感程度，是评估结构性能的重要途径。本研究以一钢拱桥为例，采用有限元软件Ansys建模，对结构进行自振模态分析，并选取影响结构模态的5个材料参数进行分析计算，比较各参数对结构模态频率的敏感性。结果分析表明，5个材料参数对结构模态频率的敏感性各不相同，拱肋弹性模量敏感性最强，对结构高阶、低阶模态都有影响；吊杆弹性模量模态敏感性最弱；材料密度和弹性模量对模态频率的影响正好相反。

英文摘要：

Because of the vehicle loads and environmental factors,the behaviors of bridge structure in service is becoming deterio-ration.The modal parameters are important indexes of structure,so sensitivity analysis of natural vibration is an important way to evaluate the behavior of bridge structure.In this paper,using the finite element software Ansys,calculation model of a steel arch bridge was built,and the natural vibration modals were obtained.In order to compare the different sensitivity of material parame-ters which may affect the natural vibration modal,5 factors were chosen to perform the calculation.The results indicated that dif-ferent 5 factors had different sensitivity.The leading factor was elastic modulus of arch rib,and the elastic modulus of suspender had little effect to the sensitivity.Another argument was the opposite sensitivity effect happened between the elastic modulus and density of the material.