高速铁路节段预制全胶拼连续梁施工线形分析

Alignment Analysis of High-speed Railway Segmental Precast Full-glued Continuous beams under Construction

为保证节段预制全胶拼三跨预应力混凝土连续梁的设计成桥线形,通过长线和短线台座结合预制节段,再逐跨拼装节段成桥,采用初始切线位移法模拟计算逐跨拼装施工过程,新拼装单元沿着相邻的已经拼装完成单元的切向位移方向安装,计入刚体转动引起的竖向位移,保证制造线形、拼装线形计算与实际施工相符。参数敏感性分析表明,钢筋混凝土容重、混凝土弹性模量、钢束与管道壁摩擦系数分别增大10%时,梁体向上的竖向变形分别减小约30%、5%、1%;钢筋混凝土容重变化对线形影响很大,建议实测控制素混凝土容重波动在2%以内;采用实测的混凝土容重、弹性模量、有效预应力等参数计算和监控制造线形、拼装线形,预应力张拉前、后,计算与实测变形误差由6.6 mm降低到2.9 mm,最终梁面实测高程与设计高程最大误差6.4 mm,实现成桥线形高精度计算和施工。

In order to realize the design of bridge alignment of segment prefabricated full-glued assembled three-span prestressed concrete continuous beams,the prefabricated segments were fabricated by long-line and short-line pedestals,and the segments were assembled into bridges one by one.Initial tangential displacement method was used to simulate the span-by-span assembly construction process.The new assembly unit was installed along the tangential displacement direction of the adjacent assembled unit,and the vertical displacement caused by the rotation of the rigid body was taken into account to ensure that the calculation results of manufacturing alignment and assembly alignment were consistent with the actual construction.The parameter sensitivity analysis shows that the bulk density of reinforced concrete,the elastic modulus of concrete and the friction coefficient between tendons and pipe wall all increase by 10%,and the upward vertical deformation of beam decreases by about 30%,5%and 1%respectively.The change of bulk density of reinforced concrete has a great influence on the alignment.It is suggested that the measured bulk density of plain concrete should be controlled within 2%.The measured concrete bulk density,elastic modulus,effective prestress and other parameters are used to calculate and monitor the manufacturing alignment and assembly alignment,which can reduce the calculation error from 6.6 mm to 2.9 mm compared to before and after pressing,and the finished deck elevation error is 6.4 mm which help realize high precision calculation and construction of the completion bridge alignment.