地锚式万向铰独斜塔斜拉桥温度效应分析

地锚式万向铰独斜塔斜拉桥结构体系新颖,为分析温度荷载作用下该类桥梁成桥状态的结构响应,以三亚海棠湾河心岛景观桥(主跨99.8 m钢斜塔双边工字钢梁独塔斜拉桥)为工程背景,建立桥梁结构有限元模型,分析体系温差、日照温差、索梁(塔)温差对桥塔偏位、主梁线形以及索力的影响。结果表明:体系温差下桥塔以纵向弯曲和纵向偏转为主,体系降温将引起全桥主梁下挠,体系升温效应相反,最大背索索力变化为成桥索力的6.1%;日照温差下桥塔以横向弯曲为主,纵向偏位较小,对主梁线形、斜拉索索力影响较小;索梁(塔)负温差下有索区主梁发生向上位移、背索索力增大,正温差下相反,对桥塔偏位基本不影响。

Analysis of Temperature Effect of Earth-Anchored Single Inclined Pylon Cable-Stayed Bridge with a Universal Hinge

The earth-anchored single inclined pylon,cable-stayed bridge with a universal-hinge is a novel structural system.To analyze the structural response of the bridge of such type in the completed state under thermal loads,the aesthetically-appealing bridge located in the island that is in the Haitang Bay,Sanya,is taken as a case for the study.The bridge is a cable-stayed bridge with a main span of 99.8 m,with a steel inclined pylon and superstructure comprising two lateral I steel beams.The finite element model of the bridge was built up to analyze the effects of system temperature difference,solar temperature difference and temperature difference between stay cables and girder(pylon)on the displacement of the pylon,main girder geometry and stay cable forces.The results show that longitudinal bending and rotation are the dominant vibration modes of the pylon under system temperature difference.Decrease of system temperature can result in the downwarping of the main girders of the whole bridge,but the increase of system temperature gives rise to the opposite effect,with the variation of maximum back stay force reaching 6.1%of the force in the completed bridge state.Under the solar temperature difference,the pylon is mainly subjected to transverse bending,with small longitudinal displacement,which exerts minimal influence on the geometry of the main girder and the stay cable forces.Under negative temperature differences between cables and girders(pylon),the main girder in the cable-stayed region shows sign of upwarping,the forces of the back stays increase,but the positive temperature difference will bring opposite effect,which is considered negligible to the pylon displacement.