未来地震的强度具有不确定性，在超设防地震下，斜拉桥的桥塔横桥向有可能进入非线性状态． 基于某大跨度斜拉桥，文中建立了空间有限元模型，分析了强震下横桥向的地震反应，引入能力与需求之比来判断横梁是否进入屈服状态．同时，采用纤维梁单元模型模拟横梁的非弹性行为，重点研究了横梁屈服对斜拉桥横桥向整体抗震性能的影响．结果表明:斜拉桥横梁的能力与需求之比较小，将其按延性抗震设计比较合理;横梁的地震轴力变化较大，对横梁的屈服弯矩有较大的影响;横梁屈服后对斜拉桥的横向地震反应有较大的影响，可能会增大塔底弯矩，设计中需要考虑．

The intensity of future earthquake is unpredictable.The tower in transverse direction of cable- stayedbridge may act in a nonlinear way in ultra- fortified earthquakes.In this paper,by taking a long- span cable- stayedbridge as the research object,a finite element model is established to analyze the transverse seismic response of ca-ble- stayed bridge under the action of strong earthquake.Then,the seismic capacity- to- demand ratio is introduced tojudge whether the crossbeam is yielding.Moreover,a fiber section beam element is employed to simulate the ine-lastic behavior of crossbeam,and the influence of crossbeam yielding on the transverse seismic response of cable-stayed bridge is finally investigated in detail.The results show that (1) as the seismic capacity- to- demand ratio ofcable- stayed bridge crossbeam is relatively small,a ductility design for crossbeam may be more reasonable; (2) theseismic axial force of crossbeam changes significantly,which may greatly affect the yielding moment; and (3) asthe yielded crossbeam greatly affects the transverse seismic response of cable- stayed bridge,the increasing bendingmoment of tower base should be considered in the design process.