预应力混凝土矮塔斜拉桥0号块钢束布置方案研究

Research on the Layout Plan of Steel Tendons for Block 0 of Prestressed Concrete Low Tower Cable-stayed Bridge

成达万高速铁路渠江特大桥主桥为(139+278+139) m预应力混凝土矮塔斜拉桥,0号块为墩塔梁固结,固结区域构造及预应力钢束布置均较为复杂。为了探究该墩塔梁固结区域的应力分布,验证该区域预应力钢束布置的合理性及合规性,基于静力等效原理,首先提取出全桥整体计算模型的单元内力,并采用有限元软件建立0号块局部计算模型;其次将全桥整体计算模型单元内力转换至整体坐标系下并施加于有限元模型;最后对0号块在主力及主力+附加力等多种工况进行精细化计算分析,并对有无塔柱范围内竖向预应力钢束两种钢束布置方案分别进行计算分析和对比。计算结果表明,塔柱范围内布置竖向预应力钢束后,塔柱根部主拉应力由2.41 MPa降低至0.76 MPa,塔柱的应力分布状态也得到了明显的改善,同时也验证0号块纵向及横向预应力钢束设置的合理性,为该桥0号块位置纵横向及竖向预应力钢束布置提供了理论依据。

The main bridge of Qujiang super major bridge on Chengdu-Dazhou-Wanzhou High-Speed Railway is a(139+278+139)m prestressed concrete low pylon cable-stayed bridge.Block 0 is the consolidation of pier,tower and beam.The structure of consolidation area,layout of prestressed tendons and stress state are very complex.In order to explore the stress level and state of the consolidation area of the pier,tower and beam,and verify the rationality and compliance of the layout of prestressed tendons in this area,based on the static Equivalence principle,the element internal force of the overall calculation model of the whole bridge is first extracted,and the local calculation model of block 0 is established by using the finite element analysis software,and then the element internal force of the overall calculation model of the whole bridge is converted to the overall coordinate system and applied to the finite element model,Finally,refined calculation and analysis were conducted on the main force and main force+additional force of block 0 under various working conditions,and two steel tendon arrangement schemes,including vertical prestressed steel tendons within the range of tower columns,were calculated,analyzed,and compared.The calculation results show that after arranging vertical prestressed steel tendons within the range of the tower column,the main tensile stress at the root of the tower column is reduced from 2.41 MPa to 0.76 MPa,and the stress distribution of the tower column is also significantly improved.The working stress is more reasonable,and it also verifies the rationality of the longitudinal and transverse prestressed steel tendon settings of block 0.This provides a theoretical basis for the longitudinal,transverse,and vertical prestressed steel tendon layout of block 0 of the bridge.