【摘要】 贵黔高速鸭池河特大桥为(72+72+76+800+76+72+72)m的钢桁-混凝土梁混合梁斜拉桥,采用主跨800m、设计承重能力350t的缆索吊机进行中跨钢桁梁的悬臂拼装施工。该缆索吊机未设置临时索塔,将索鞍直接安装在桥塔横梁外伸的悬臂梁上。为了验证缆索吊机的使用性能,及吊机加载对桥梁变形的影响,在投入使用前对缆索吊机进行了静、动载试验。静载试验荷载分4级在起吊点逐级加载;动载试验荷载分3级,起重跑车承载着试验荷载从起吊点起吊,以一定速度逐步向跨中方向移动,当荷载移动到1/4跨和1/2跨位置时,静置45min。荷载试验测量了主缆轴力和位移、桥塔和锚碇位移、索鞍下方悬臂梁的应力和变形等。荷载试验结果表明:缆索吊机结构安全,机具设备运行良好,满足设计和施工要求;缆索吊机加载时对桥塔偏位影响较大,边跨增加背索以平衡缆索吊机对该桥变形的影响;荷载试验的现场实测值与理论计算值吻合较好,证明采用的通过测量应变推算主缆轴力的方法可行。更多还原

【Abstract】 The Yachi River Bridge on Guiyang-Qianxi Expressway is a steel truss-concrete hybrid girder cable-stayed bridge with span arrangement of(72+72+76+800+76+72+72)m.During the cantilever assembly construction of the steel truss girder in the central span,the cable crane with spanning capacity of 800 mand design carrying capacity of 350 twas used.No temporary towers were installed for the cable crane,the saddles were directly installed on the cantilevers extended from the bridge pylon cross beam.To verify the working performance of the cable crane and the influence of the load application of the cable crane on the deformation of the bridge,static and dynamic load tests were done to the cable crane in advance.In the static load test,the loads were applied in four stages at the lifting location.The loads in the dynamic test were applied in three stages,the lifting trolley carrying the testing load started to lift from the starter lifting point,and then move toward the midspan gradually with a certain speed.When the load was moved to the locations of 1/4 and 1/2 span length,a static duration of 45 min was held,then,the main cable axle force and displacement,pylon and anchor block displacement,and the stress and strain of the cantilever beam under the saddle were measured by the load test.The results of the load tests demonstrate that the structure of the cable crane is safe,and the components work well,which can meet the design and construction requirements.The process of load application of the cable crane has great influence on the pylon offset.Back stays should be added to the side spans to counteract the bridge deformation induced by the cable crane.The data from the load tests and the calculated data were in good agreement,proving that the method of measuring strain to predict the main cable axle force is feasible.更多还原