摘要
随着悬索桥跨径的增大,主缆恒载索力所占的比重也随之增大,而安全系数又逐渐减小,因此,有必要对悬索桥的施工过程进行更为精确的分析。为此,首先完善了基于悬索精确解析解的索单元,提出了能自动满足主缆与鞍座相切且主缆无应力长度保持不变这两个重要条件的、能方便模拟各种鞍座及其顶推的鞍座-索单元,并根据悬索桥施工计算的特点,提出了在一个荷载步内将不平衡力分级施加的非线性方程求解新算法,最后将数值解析法与有限元法有机地结合起来进行悬索桥理想恒载状态的求解。计算表明,该方法是精确而有效的,可用于采用各种方法施工的悬索桥施工过程的精确分析和施工方案的优化,也为悬索桥的施工控制奠定了良好的基础。
With the increasing span lengths of suspension bridges, the ratio of main cable tension caused by dead loads to its bearing capacity is increasing while its safty factor is decreasing. Therefore, it is necessary to more accurately perform construction process analysis. The cable element based on exact analytical expressions for elastic catenary is perfected. A new element, named as saddle-cable element, which can be employed to model all kinds of saddles and to convenientily simulate saddle jacking, is also proposed. This dement contains two important conditions about the relationship between saddle and cable, namely that the cable is always tangent to saddle and the total unstressed length of cable remains constant. According to the construction analysis characteristics of suspension bridges, a new method, which divides the unblanced force vector into prescribed parts and makes them act gradually in one loading step, is proposed to solve the nonlinear equations. The numerical-analytical method and FEM are combined to determine the ideal state of suspension bridges under dead loads. The proposed method, whose efficiency and accuracy are demonstrated by numerical examples, can be employed to exactly analyze the construction process, to optimize the construction scheme and to control the construction of suspension bridges.
出处
《土木工程学报》
EI
CSCD
北大核心
2005年第10期76-80,共5页
China Civil Engineering Journal
关键词
悬索桥
施工过程
索单元
鞍座.索单元
几何非线性分析
suspension bridge
construction process
cable element
saddle-cable element
geometric non-linear analysis
