从影响线角度研究3塔悬索桥力学行为  

Study on Mechanical Behaviour of Three-tower Suspension Bridge Based on Influence Line

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：《公路交通科技》2011年第4期53-59,78,共8页Journal of Highway and Transportation Research and Development

基　　金：国家科技支撑计划项目(2009BAG15B01);国家自然科学基金青年项目(50808019);中央高校基本科研业务费专项资金项目(CHD2009JC024);长安大学基础研究支持计划专项基金项目

摘　　要：以泰州长江大桥为原型,建立相应2塔、3塔漂浮和3塔约束悬索桥空间有限元模型,研究各关键效应的影响线特征及汽车效应包络,得到如下结论:主缆抗滑、中塔受力、主梁挠跨比、梁端水平位移等在2塔悬索桥中不会引起很多关注的因素,对3塔悬索桥却成为控制指标,且由汽车作用控制;缺乏边缆的有效约束引起中塔顶水平位移增大,是导致其他效应大幅增加的原因;当一个主跨全部或部分加载,另一个主跨空载时,4个控制因素最不利,但发生的概率极低;抓住规范限制挠跨比的本质和3塔2跨悬索桥变形特点,可将其挠跨比限制放宽至1/220,行车平顺仍有充足保障;汽车与恒载应力叠加后,绝大多数运营状况下,中塔都处于受压应力状态,疲劳问题不突出。Based on the Taizhou Yangtze River Bridge,3D space finite element models of two-tower,three-tower with floating system and three-tower with elastic cable between mid-tower and girder were constructed.Through analysis of influence lines＇ characteristics of various key effects and effect envelop due to vehicular load,the conclusions were got as follows：（1） Some factors such as anti-slipping safety factor between the main cable and saddle of the mid-tower,force in the mid-tower,deflection-span ratio of girder,and horizontal displacement at the end of girder,which are not important in two-tower design,become controlling ones in three-tower suspension bridges and the effects by vehicular load is most important.（2） Due to lack of effective restraint from side cable,three-tower suspension bridge has larger horizontal displacement at the top of mid-tower,which gives rise to other effect increasing.（3） When loading on all or part of a main span,and the other main span unloading,the four control factors reach the worst case,but the probability is very low.（4） By using the essence of code restriction on deflection-span ratio of girder and the deformation characteristics of three-tower two-span suspension bridge,code restriction can be flexible to relax restriction to 1/220,and comfortable driving can be guaranteed.（5） Stresses of mid-tower by vehicular load superimposed dead load are in a state of compressive stress under the vast majority of operating conditions and fatigue problem is not obvious.

关 键 词：桥梁工程 3塔悬索桥 空间有限元 影响线 抗滑安全系数 挠跨比 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]