墩梁半刚性连接的钢-混组合梁整体桥设计

湖州北刘屋桥为墩梁半刚性连接的钢-混组合梁整体桥,桥长38.2m,桥宽12.14m,跨径布置为(0.5+12+0.6+12+0.6+12+0.5)m。该桥主梁采用耐候工字钢和现浇混凝土桥面板组成的钢-混组合梁;在主梁与盖梁之间设置橡胶衬垫以适应主梁的弯曲变形;在盖梁中设置外包橡胶套的钢棒,并与端横梁现浇成整体,形成墩梁半刚接并取消墩上支座;采用整体式桥台去除伸缩缝,实现全桥无伸缩缝和支座。采用MIDAS Civil软件建立该桥有限元模型,分析其受力性能,结果表明:恒载作用下,采用整体式桥台,能更有效地发挥混凝土桥面板和钢梁各自的材料性能;桥墩位置无论采用墩梁铰接还是墩梁半刚接,均不影响整体桥主梁应力分布;温度荷载作用下,墩梁半刚接整体桥与墩梁铰接整体桥在墩顶位置处的应力分布有所不同。

Design of Integral Bridge with Steel-Concrete Composite Girder Connected by Semi-Rigid Joint

Beiliuwu Bridge in Huzhou is a steel-concrete composite integral bridge with semi-rigid connection between pier and girder.The bridge length is 38.2 m,the width is 12.14 m,and the span arrangement is(0.5+12+0.6+12+0.6+12+0.5)m.The main girder of the bridge is made of weather-resistant I-steel and cast-in-place concrete bridge deck.A rubber gasket is set at the joint of main girder and bent cap for adapting to the bending deformation of the main girder,and steel rods covered by rubber sleeve are utilized in the bent cap and cast integrally with the end crossbeam,forming a semi-rigid connection and eliminating the bearings on pier.The integral abutment is used to remove the expansion joints,thus it can be realized that the full bridge has no expansion joints and bearings.Meanwhile,a finite element model of the bridge is established by MIDAS Civil software to analyze its mechanical performance.The results show that,under the dead load,the adoption of integral abutment can make full use of the properties of materials of concrete deck and steel girder,respectively.The stress distribution of main girder will not be impaired whether hinge connection or semi-rigid connection is adopted on the top of pier.Under the temperature load,the stress distribution of the girder on the top of pier is different when the hinge connection or semi-rigid connection is adopted.