摘要
为准确获取钢桁系杆拱桥主拱无应力状态下线形及节点空间位置信息,提出基于有限迭代的无应力状态计算方法。该方法以桥梁设计线形为初始无应力线形,考虑成桥过程中体系转换和荷载变化,计算其在荷载作用下的空间线形,将该空间线形与设计线形的差值反向叠加至初始无应力线形进行修正,开展多次迭代计算直至无应力线形经荷载作用后空间位置无限逼近桥梁设计线形。以长沙暮坪湘江特大桥为背景,建立钢桁拱有限元模型,考虑桥梁体系转换,进行有限迭代计算,得到钢桁拱的无应力线形,并与实际设计值进行比较分析。结果表明:柔性系杆力大小是影响桥梁结构特征及无应力线形计算的关键因素;假定系杆预张力为0时,无应力状态下主拱跨度等于系杆长度,迭代计算所得上弦杆预拱度、主墩水平位移等大于实际设计值;而考虑一定系杆预张力后迭代计算的结果则与设计值匹配,验证了方法的正确性。本文提出的有限迭代计算方法可根据系杆拱桥成桥状态精准求解其无应力线形及各节点空间位置,为同类型桥梁设计提供重要的理论指导。
This paper presents a finite iterative method to calculate the geometry and spatial locations of nodes of the steel truss tied arch bridge under stress-free state of the arch.Using the design geometry of the bridge as the initial stress-free geometry,the spatial geometry of the bridge under loading conditions is calculated,considering the systematic transformation and load variation during the construction of the bridge.The differences between the calculated spatial geometry and the design geometry are inversely superimposed into the stress-free geometry for modification.Multiple iterations are conducted till the stress-free geometry infinitely approximates the design geometry under load actions.The method has been applied to the Muping Xiangjiang River Bridge in Changsha.The engineering practice demonstrates that the stresses in the flexible ties are the key factors influencing the structural characteristics and stress-free geometry calculation.Assuming a pretension of 0 for the ties and the situation that the arch span equals to the tie length under stress-free state,the iterated upper chord precamber and horizontal main pier displacement are bigger than the actual design values.Counting the pretension of ties,the iterated values agree with the design values,justifying the presented method.The finite iterative method can accurately calculate the stress-free geometry and spatial locations of nodes of the steel truss tied arch in accordance with the geometry of the completed bridge,and provide an insight into the design of same type of bridges.
作者
常柱刚
魏标
王宁波
王冲
CHANG Zhugang;WEI Biao;WANG Ningbo;WANG Chong(Changsha Planning and Design Institute Co.,Ltd.,Changsha 410007,China;School of Civil Engineering,Central South University,Changsha 410075,China;Tianjin Municipal Engineering Design&Research Institute Co.,Ltd.,Tianjin 300392,China)
出处
《桥梁建设》
北大核心
2025年第2期139-145,共7页
Bridge Construction
基金
国家自然科学基金项目(52278233)。
关键词
钢桁拱桥
系杆拱
无应力状态
有限迭代法
结构体系转换
节点空间位置
有限元法
steel truss arch bridge
tied arch
stress-free state
finite iterative method
structural system transformation
node spatial location
finite element method
