高铁斜拉桥组合梁桥面板有效宽度系数研究

Study on Effective Width Coefficient of Composite Beam Deck of High Speed Railway Cable⁃stayed Bridge

为研究斜拉桥组合梁混凝土板在拉索轴向压力和弯矩共同作用下有效宽度系数沿桥跨长度方向的分布规律,以一座高速铁路组合梁斜拉桥为实例,建立有限元模型,计算跨中及桥塔位置组合梁段混凝土有效宽度系数,并与规范推荐值进行对比验证。同时,计算压弯综合作用对混凝土正应力的影响。结果表明:拉索轴向压力作用下,混凝土有效宽度系数由跨中向桥塔逐渐增大;弯矩作用下,混凝土有效宽度系数由跨中向桥塔逐渐减小;采用有限元模型计算得到的斜拉桥组合梁混凝土有效宽度系数能够综合考虑拉索轴向压力和弯矩,比规范推荐值更安全;压弯作用下的有效宽度系数能够较好评判混凝土正应力横向分布不均匀程度。

To study the distribution law of the effective width coefficient of the composite beam concrete deck of a cable-stayed bridge under the combined action of axial tension and bending moment of the cables along the length direction of the bridge span,a finite element model was established to calculate the effective width coefficient of the concrete in the composite beam section at the mid-span and tower of a high speed railway composite beam cable-stayed bridge as an example,and compared and verified with the recommended values in the specifications.At the same time,the influence of the combined effect of compression and bending on the normal stress of concrete was calculated.The results show that under the axial pressure of the cable,the effective width coefficient of concrete gradually increases from the mid-span to the bridge tower.Under the action of bending moment,the effective width coefficient of concrete gradually decreases from the mid-span to the bridge tower.The effective width coefficient of concrete in composite beams of cable-stayed bridges calculated by finite element method can comprehensively consider the axial pressure and bending moment of the cables,which is safer than the recommended values in the specifications.The effective width coefficient under bending can effectively evaluate the degree of uneven transverse distribution of normal stress in concrete.