基于不同桥墩的连续刚构桥受力分析

Force Analysis of Continuous Rigid Bridge Based on Different Piers

连续刚构桥是墩梁固结结构,墩梁协同受力,桥墩的选取至关重要。本文通过有限元软件对桥梁进行模拟,研究当桥梁选取不同桥墩时,桥梁在不同荷载作用下的位移、应力以及内力的变化,以此来选择最适合该项目的桥墩类型,为以后类似的桥梁设计和计算提供相应参考。研究结构表明,当桥墩的刚度较小时对主梁的弯矩有明显的削峰作用,同时会减少主梁运营阶段的应力,但刚度过小会导致桥梁产生较大的位移,不利于线形控制。当桥墩刚度较大时会增大桥梁成桥稳定性,减小桥梁位移,但刚度过大时增大墩顶位置处的弯矩,增大桥梁运营阶段应力,不利于桥梁长期发展。当低墩采用刚度较大的单肢薄壁,次高墩采用刚度较小的双肢薄壁时桥梁稳定性最差,同时会使桥梁各位置所受内力差值最大。当均采用双肢接单肢的组合墩时,其桥墩的刚度差值最小,可以顺应桥梁的变形,使桥梁各处的内力分配均匀,同时在荷载作用下各处的变形的差值最小,桥梁稳定性最好,同时各位置所受内力更均匀。

The continuous rigid frame bridge is a pier girder consolidation structure,and the pier girder is coordinated under stress,and the selection of the pier is very important.In this paper,the bridge is modulated by finite element software.It is proposed to study the changes of displacement,stress and internal force of the bridge under different loads when the bridge is selected with dif-ferent piers,so as to select the most suitable type of pier for the project and provide a corres-ponding reference for similar bridge design and calculation in the future.The study of the struc-ture shows that when the stiffness of the piers is small,it has an obvious peak shaving effect on the bending moment of the main beam,and at the same time will reduce the stress in the operation stage of the main beam,but when the rigidity is too small,it will lead to the large displacement,not conducive to linear control.When the stiffness of the pier is large,the stability of the bridge will be increased and the displacement of the bridge will be reduced,but when the stiffness is too large,increasing the bending moment at the position of the pier crest and the stress in the opera-tion stage of the bridge is not conducive to the long-term development of the bridge.When the low pier adopts a single limb with greater stiffness,the stability of the bridge is the worst when the wall and the second high pier are thin-walled with small stiffness,and the difference of internal force at each position of the bridge is the largest.When the combined pier of double limb and sin-gle limb is adopted,the stiffness difference of the pier is the smallest,which can conform to the deformation of the bridge and make the internal force distribution of the bridge everywhere equal,at the same time,the difference of deformation in various places under the action of load is the smallest,the stability of the bridge is the best,and the internal force at each position is more uni-form.