高铁大跨度混合梁斜拉桥钢-混结合段受力特性分析

为研究高速铁路大跨度混合梁斜拉桥钢-混结合段受力与传力特性,以主跨672 m的安九铁路鳊鱼洲长江大桥为背景,采用ANSYS软件建立主梁钢-混结合段有限元模型,分析其在最不利工况下的受力特点及变形特性,以及钢-混结合段长度对其受力性能的影响规律。结果表明:在最不利负弯矩工况作用下,边箱顶板与承压板焊接处存在应力集中及一定的局部拉应力;钢-混结合段混凝土在预应力作用下基本处于全截面受压状态;钢-混结合段内剪力钉和PBL剪力键受力并不均匀;钢-混结合段承压板直接向混凝土梁体传递约47.3%的轴力,是钢-混结合段传力的主要构件;钢-混结合段竖向位移及转角变化平缓,无明显的突变现象;钢-混结合段长度在1.50~3.50 m范围内时受力、传力差异并不显著。

Mechanical Property Analysis of Steel-Concrete Joint Section of Long-Span High-Speed Railway Hybrid Girder Cable-Stayed Bridge

To investigate the mechanical property and load transfer mechanism of steel-concrete joint section of the long-span hybrid girder cable-stayed bridge accommodating high speed rails,the finite element model of the steel-concrete joint section was built by ANSYS based on the case of Bianyuzhou Changjiang River Bridge on Anqing-Jiujiang High-speed Railway that has a main span of 672 m.The mechanical property and deformation characteristics of the steel-concrete joint section under the most unfavorable loading cases were analyzed,and the relationship between length and mechanical performance of the steel-concrete joint section was examined.The results show that under the most unfavorable negative bending moment,stress concentration occurred in the welds between the top plates of the edge boxes and bearing plates,with a degree of local tensile stress.The steel-concrete joint section is basically compressed under the prestressed action.Shear studs and PBL connectors in the steel-concrete joint section do not bear uniform loads.Bearing plates can directly transfer 47.3%of axial force to the concrete beams,which are the main load transfer components in the steel-concrete joint section.The variation curves of vertical displacement and rotation angles of the steel-concrete joint section are smooth,with no obvious spikes.When the length is set at 1.50-3.50 m,the load transfer capacity of the steel-concrete joint section displays negligible difference.