中文摘要：

分别建立了三塔缆索承重桥3种桥型的有限元计算模型,通过对比研究,给出了3种桥型的一些力学特性.进行主跨为1 400m的3种桥型方案试设计,论证了3种桥型的可行性,给出了三塔缆索承重桥的一些经济特性.对比了3种桥型的施工方法,论述了施工期间力学性能较佳的桥型.研究结果表明：协作桥的中塔主缆抗滑移稳定性较难满足设计要求;3种桥型索塔的轴力相近,而斜拉桥主梁的轴力很大,稳定性相对较差;斜拉桥扭弯频率比最大,比悬索桥大37%左右,比协作桥大8%左右;协作桥经济性能较佳,其单位面积造价比斜拉桥和悬索桥分别少29%和15%;悬索桥的施工工艺较为成熟,施工期间具有更好的稳定性.

英文摘要：

Three finite element models are established for super-long span cable-stayed supported bridges with three towers.Then,some mechanical properties are revealed by a comparative study.A trial design of three types of bridges is accomplished.Then some economic properties are compared and construction method of three types of bridges is discussed.The investigation results show that the factors of restrict cable slide of cable-stayed suspension bridge can not meet the requirment of the code.The axis force of town of three types of bridges is close,but the axis force of the cable-stayed bridge beams is the largest and its static stability is not good.The ratio of the natural frequencies of the flexural and torsional vibrations of cable-stayed bridge is larger than that of suspension’s by 37% and it is larger than that of cable-stayed suspension’s by 8%.The investment cost can be saved from the cable-stayed suspension bridge compared with others two.The unit area cost of the cable-stayed suspension bridge is lower than that of the cable-stayed bridges by 29% and that of the suspensions by 15%.The construction method of the suspension bridge is easier to carry out and its stability during the process of construction is better than the other two methods.