现浇混凝土护栏对空心板边铰缝受力性能的影响研究

Research on Influence of Cast-in-Place Concrete Parapets on Mechanical Performance of Edge Hinge Joints of Hollow Core Beams

为在空心板梁桥设计中合理地考虑空心板边铰缝的受力性能,以杨司高架桥20 m单幅预制空心板梁为背景,考虑现浇混凝土护栏对其空心板边铰缝受力性能的影响并开展参数影响研究。采用Abaqus软件建立空心板梁有限元模型,对比考虑护栏前、后空心板边铰缝的受力性能,并分析护栏高度、护栏分缝深度及预应力等参数对空心板边铰缝受力性能的影响。结果表明:考虑现浇混凝土护栏参与受力后,边铰缝跨中剪力增大最大,增大82.6%,不满足欧洲规范要求,在空心板设计中应考虑混凝土护栏的影响;随着护栏高度增大,空心板边铰缝跨中剪力呈线性增大;随着护栏跨中分缝深度增大,空心板边铰缝跨中剪力先减小后反号增大,总剪力变化较小,剪力纵向分布规律显著改变;随着施加预应力的增大,空心板边铰缝跨中剪力和总剪力呈线性减小,剪力纵向分布规律变化较小。

The Yangsi Viaduct,which contains a 20 m-long span consisting of precast hollow core beams,is used as a case to study the mechanical property of and way to properly take the advantage of the mechanical property of the edge hinge joints in the design of the hollow core beam bridge.The influence of cast-in-place concrete parapets on the mechanical property of the edge hinge joints of the hollow core beams is analyzed and the parameter effects are studied.A finite element model of the hollow core beam bridge was developed by Abaqus,to compare the variation of the mechanical property of edge hinge joints before and after the casting of parapets,and the influence of parameters of the parapets on the mechanical property of edge hinge joints was analyzed,including the parapet height,depth of slits in the parapets and prestress.It is shown that when the weights of the cast-in-place concrete parapets are considered,the shear forces in the midpsan edge hinge joints will get maximum increase,reaching 82.6%and failing to meet the requirements of Eurcodes,thus it is necessary to consider the influence of the concrete parapets on the hollow core beams in design.As the parapet height increases,the shear forces in the edge hinge joints at midspan rise linearly.But with the increase of slit depths in the parapets,the shear forces in the edge hinge joints at midspan reduce first and then reversely increase,the fluctuation of overall shear forces is minimal and the longitudinal distribution rule of the shear forces is remarkably changed.Along with the rise of the prestress applied,the shear forces in the edge hinge joints at midspan and the overall shear forces decrease linearly,and the longitudinal distribution rule of the shear forces shows minor change.