悬挂式曲线轨道梁纵向预应力受扭分析

Analysis of Longitudinal Prestressing of Suspended Curved Track Beams Subjected to Torsion

悬挂式曲线轨道梁在自重及外荷载作用下受力复杂,纵向预应力作用下的结构受扭对体系预应力筋布置参数影响很大。为进一步研究预应力筋参数设置对曲线轨道梁扭矩作用的影响,通过截面尺寸500 mm×1000 mm,曲线半径R=100 m的3×30 m悬挂式连续体系轨道梁为例,建立了PC轨道梁Ansys有限元模型,分别对不同设置方案下轨道梁各控制截面扭矩值、竖向弯矩和横向弯矩进行了分析,同时探讨了预应力筋布置位置参数的调整对轨道梁成桥状态下的扭矩影响规律。研究表明:纵向预应力筋布置参数对曲线轨道梁扭矩影响很大,通过轨道梁曲线内外侧纵向预应力筋梁端锚固点和弯起点位置的调整,可使轨道梁扭矩减小20%左右,同时对轨道梁横向弯矩的影响幅值最大能达到400 kN·m;在竖向弯矩方面会有小幅影响,但整体在规范容许范围内。本研究可为悬挂式轨道梁预应力筋的布置参数,尤其是在进行曲线轨道梁受扭设计时提供参考。

Suspended curved track beams are subjected to complex forces under the action of their weight and external loads.The torsion of the structure under the action of longitudinal prestress has a great influence on the arrangement parameters of the prestressed tendons of the system.To further study the effect of prestressing tendon parameters on the torque effect of curved track beams,by taking the 3×30 m suspended continuous system track beam with the section size of 500 mm×1000 mm and the curve radius of R=100 m as an example,we established the Ansys finite element model of the PC track beam.The torque value,vertical bending moment,and transverse bending moment of each control section of the track beam under different setting schemes were analyzed respectively.At the same time,the paper discussed the influence law of the adjustment of the prestressed tendon position parameters on the torque of the track girder in the bridge state.The research shows that the arrangement parameters of longitudinal prestressing tendons have a great influence on the torque of curved track beams.By adjusting the anchor point of the beam end of the longitudinal prestressed tendons inside and outside the curve of the track beam and the position of the bending starting point,the torque of the track beam can be reduced by about 20%.At the same time,the maximum influence amplitude on the transverse bending moment of the track beam can reach 400 kN􀅰m;there will be a small impact on the vertical bending moment,but the overall is within the allowable range of the specification.The research in this paper can provide a reference for the arrangement parameters of the prestressed tendons of the suspended track beam,especially in the torsion design of the curved track beam.