摘要
下承式系杆拱桥受力及构造复杂,如何使得结构受力合理,是系杆拱桥设计和施工中的关键问题之一。文中以某快速路下承式系杆拱桥为工程案例,采用有限元软件midas FEA,选取中拱肋处拱脚关键分叉部位作为实体单元,建立拱脚局部空间有限元实体模型,分析其应力分布规律。结果表明,拱脚节点应力分布较为均匀,拱脚局部大部分区域主拉应力和主压应力分别小于1.86 MPa和-19.4 MPa,均处于限值范围内,拱座绝大部分区域正应力、主拉应力及主压应力均处于限值范围内,拱座受力较为合理;对于局部应力超标,均属于拱座底支座垫板应力失真区域,该区域影响可忽略;中拱肋处拱脚支座反力与边拱肋相差较大,中拱肋应力远大于边拱肋,进行主梁纵横梁相关构件尺寸设计、支座选型时应注意加以区分;分叉拱肋之间通过是否设置连接桁架进行计算分析对比,表明增设连接桁架可有效降低拱座拱肋最大主压应力,提高拱肋结构安全度。
Due to the complexity of stress and structure of through tied arch bridge,how to make the structure stress reasonable is one of the key problems in the design and construction of tied arch bridge.A tied arch bridge on an expressway is taken as the engineering case,the key bifurcation part of the arch foot at the middle arch rib is selected as the analysis object,and the finite element software Midas/FEA is used to establish the local space finite element solid model and study the stress distribution law.The results of internal force analysis show that the stress distribution of arch foot joints is relatively uniform.The main tensile stress and main compressive stress in most areas of arch foot are less than 1.86 MPa and-19.4 MPa,respectively,which are within the limit value range.The normal stress,main tensile stress and main compressive stress in most areas of arch seat are within the limit value range,and the stress of arch seat is reasonable.For the local stress exceeding the standard,it belongs to the stress distortion area of the bearing plate at the bottom of the arch seat,and the influence of this area can be ignored.The reaction force of the arch foot support at the middle arch rib is quite different from that of the side arch rib,and the stress of the middle arch rib is much larger than that of the side arch rib.Therefore,the size design of the relevant components of the longitudinal and transverse beams of the main beam and the selection of the support should be distinguished.The calculation analysis and comparison of the structures with or without the connecting truss between the bifurcated arch ribs show that adding the connecting truss can effectively reduce the maximum principal compressive stress of the arch rib and improve the safety of the arch rib structure.
作者
刘学强
LIU Xueqiang(Fuzhou Planning Design and Research Institute Group Co.,Ltd.,Fuzhou 350108,China)
出处
《交通科技》
2023年第3期75-79,共5页
Transportation Science & Technology
关键词
拱脚
实体单元
有限元
应力分析
arch foot
solid element
finite elements
stress analysis
