多塔斜拉桥力学特性及其关键力学参数研究

采用有限元分析理论,应用三维有限元分析软件ANSYS,建立3～6塔主跨跨径为1 400 m的多塔斜拉桥有限元分析模型,分析了典型工况下4种方案的内力和变形,研究了索塔数对多塔斜拉桥静力特性、动力特性和静力稳定性的影响特点,探讨了索塔数对多塔斜拉桥活载挠度、塔顶纵向位移等关键力学参数的影响规律.分析结果表明：索塔数由3塔增至6塔时,塔根弯矩最大增大47.1%,主梁弯矩最大增大39.9%,边塔塔顶位移增加15%,一阶弹性稳定系数最大下降8.3%,颤振稳定性指数最大增加4.3%;主梁边跨竖向挠度比中间跨大11%左右,且中间跨挠度相近;索塔数对索塔受力影响显著.

Study mechanics property and key mechanics parameters of multi-tower cable-stayed bridges

Four 3d finite element models,including three-tower,four-tower,five-tower and six-tower cablestayed bridges,were established by using ANSYS software.Inter-force and deflection of the structure are analyzed to find some valuable mechanics characteristics,including the static property,dynamic property and static stability property of multi-tower cable-stayed bridge.Furthermore,the key mechanics problems affected by tower-numbers,such as deflection of beam,top displacements of tower,were discussed.The results show that comparing study on mechanics property of 3 to 6 cable-stayed bridge,bend moment of tower root increases maximally 47.1%,bend moment of beam increases maximally 39.9%,longitudinal displacement of side tower increases 15%,First order instability factor decreases maximally 15%,flutter stability index increases maximally4.3%.Deflection of beam in middle span was similar,and their values are larger than those of side span about11%.It is remarkable that inter-force of tower is large with increase number of tower.