三塔悬索桥静动力特性与中塔选型  

Static and dynamic properties of three-tower suspension bridge and structural type selection of mid-tower

作　　者：梁鹏[1] 吴向男[1] 李万恒[2] 徐岳[1] 

机构地区：[1]长安大学陕西省公路桥梁与隧道重点实验室,陕西西安710064 [2]交通运输部公路科学研究院,北京100088

出　　处：《交通运输工程学报》2011年第4期29-35,共7页Journal of Traffic and Transportation Engineering

基　　金：国家自然科学基金项目(50808019);"十一五"国家科技支撑计划项目(2009BAG15B01);中央高校基本科研业务费专项资金项目(CHD2009JC024)

摘　　要：为探讨三塔悬索桥与两塔悬索桥静动力特性差异与中塔选型,以泰州长江大桥为原型,基于有限位移理论建立相应的两塔、三塔(混凝土中塔与钢中塔)悬索桥的空间有限元模型,分析了各种结构参数下的静力和地震效应。研究结果表明:与两塔悬索桥相比,由于中塔顶缺乏边缆的有效纵向约束,三塔悬索桥整体刚度较小,变形较大,自振频率低;汽车作用下主缆抗滑、桥塔受力、主梁挠跨比等在常规两塔悬索桥中很容易满足要求的指标,但对三塔悬索桥却成为控制指标。三塔悬索桥的3个指标都与中塔抗推刚度密切相关,但其对中塔抗推刚度的需求是矛盾的。"人"字形钢中塔三塔悬索桥的主缆抗滑安全系数为2.17,汽车作用下桥塔最大应力为182 MPa,最大挠跨比为1/210,全部满足要求。可见,"人"字形钢中塔较好地兼顾了3个控制指标的需要,做到了构件刚度和缆索体系刚度的优化,是合理的中塔形式。In order to discuss the static and dynamic properties differences between three-tower and two-tower suspension bridges,and select the rational structure type of mid-tower,based on the Taizhou Yangtze River Bridge,the 3D space finite element models of two-tower suspension bridge and three-tower suspension bridges with concrete mid-tower and steel mid-tower were set up by finite displacement theory and the static and seismal effects were analyzed under various structural parameters.Analysis result shows that compared with two-tower suspension bridge,because the mid-tower is lack of effective restraints from side cables,three-tower suspension bridge has lower total stiffness,lower natural frequency and larger deflection-to-span ratio of main girder.Under vehicle loads,the anti-slipping safety factor between main cable and saddle,the forces of mid-tower and the deflection-to-span ratio of main girder are not important for two-tower suspension bridge,but become controlling indices for three-tower suspension bridge.The indices are related to the anti-pushing rigidity of mid-tower,but have incompatible demands for the rigidity.Under vehicle loads,when the steel mid-tower with upside-down Y shape is selected,the anti-slipping safety factor between main cable and saddle of mid-tower is 2.17,the maximum stress of mid-tower is 182 MPa,the deflection-to-span ratio of main girder is 1/210,and they meet correlative demands.Obviously,due to the application of steel mid-tower,the indices are rationally considered,the stiffness optimization of components and cable system is achieved,so,it is an appropriate structure for mid-tower.9 tabs,7 figs,13 refs.

关 键 词：桥梁工程 三塔悬索桥 静动力特性 中塔选型 有限元分析 主缆抗滑安全系数 主梁挠跨比 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]