一种新型混合形式的混合连续梁桥结合段局部应力分析

Analysis on Local Stress of One New Beam Linked Part of Mixed Continuous Bridge

本文以重庆长江大桥复线桥为背景,拟定了组合—混凝土混合连续梁桥结构形式.新拟定的混合结构形式中,钢混结合段采用填充混凝土后承压板连接方式,结合段内力的传递主要由承压板、预应力钢筋和PBL剪力板来完成.运用大型通用有限元软件ANSYS建立组合—混凝土结合段三维有限元模型.根据运营过程中各种最不利荷载工况,计算分析了结合段种工况下的应力状态,检验拟定结构的安全性和合理性.结果表明:结构中钢梁绝大部分应力值都在-200 MPa^200 MPa之间,混凝土大部分应力值都在-20 MPa^3 MPa之间.组合梁钢梁在折角和过渡处存在少部分应力集中现象,混凝土极少部分面积区域内力超过规范允许值,但总体满足规范设计要求,可以通过改善预应力钢筋和承压板、混凝土的连接,在钢梁折角处适当增设加劲肋和使用纤维混凝土作为加强措施.

According to the Chong Qing Chang Jiang Bridge, a steel - concrete hybrid bridge structure form is defined. This new hybrid form uses after - setting concrete connection, and the force transmiss mainly rely on the bear- ing plate, the prestressed stell bar and the PBL shear plate. The finite element space model of steel - concrete beam linked part is built and calculated by ANSYS according to four load cases. From the comparion between the result of the old and new model, we found that： stress of the stell is - 200 MPa - 200 MPa. stress of the concrete is - 20 MPa ~ 3 MPa. Jonit of stell and concrete interface there is few stress concentration. But overall meet the specification re- quirements. We Can by improving the prestressed reinforcing steel bar and bearing plate, concrete connections, ap- propriately increased thickness of steel plate and the use of fiber reinforced concrete for strengthening measures.