高速铁路混凝土连续梁预应力筋优化布置研究

Research on Optimal Layout of Prestressed Steel Bars in Concrete Continuous Beams of High-Speed Railway

以成都市东山大道1#大桥为研究对象,对混凝土连续梁预应力筋布置进行优化研究。以竖向预应力筋张拉控制应力对布置间距的敏感性分析表明,竖向预应力筋对主梁腹板主拉应力影响较大,张拉控制应力的主拉应力要低于不考虑竖向预应力钢筋的主拉应力,在设置竖向预应力后,主拉应力减小0.67 MPa,降低幅度较大。采用有限元软件计算得到箱梁腹板中部的主拉应力方向,据此进行竖向预应力筋优化布置,通过调整预应力钢筋的倾斜角度来改善腹板受力状态以提高主拉应力方向上的压应力储备。优化后,主拉应力平均值为-0.58 MPa,优化前的主拉应力平均值为-0.27 MPa,方差分别为9.04E-03、7.65E-02;与优化前相比,优化后主拉应力全部转化为压应力,平均值下降0.29 MPa,主梁纵向受力更合理,应力分布更均匀。

This article takes the 1#Dongshan Avenue Bridge in Chengdu as the research object to study the optimization of the layout of prestressed steel bars in concrete continuous beams.The sensitivity analysis of the tension control stress of vertical prestressed steel bars on the layout spacing shows that the vertical prestressed steel bars have a significant impact on the main tensile stress of the main beam web.The main tensile stress of the tension control stress is lower than the main tensile stress without considering the vertical prestressed steel bars.After setting vertical prestressing,the main tensile stress decreased by 0.67 MPa,with a significant decrease.The direction of the main tensile stress in the middle of the box girder web is calculated using finite element software,and based on this,the inclined arrangement of the vertical prestressed reinforcement is carried out.By adjusting the inclination angle of prestressed steel bars,the stress state of the web can be improved to increase the compressive stress reserve in the direction of the main tensile stress.After optimization,the average value of main tensile stress was-0.58 MPa,while the average value of main tensile stress before optimization was-0.27 MPa,with variances of 9.04E03 and 7.65E-02,respectively.Compared with the state before optimization,the main tensile stress after optimization has been fully converted into compressive stress,with an average decrease of 0.29 MPa.The longitudinal force of the main beam is more reasonable and the stress is more uniform.