先简支后连续结构体系桥梁施工过程监测及其仿真分析

The Construction Survey and FEM Simulation of Prototype Bridges of Simply Supported-Continuous System

以浙江某高速公路跨江大桥引桥的原型桥为例,运用虚拟层合有限单元法,对先简支后连续结构体系的施工过程进行空间仿真分析,系统研究该类结构体系施工过程中的力学特性。认为:首期预应力张拉给预制构件的顶、底板提供了充足的应力储备,保障了连续预应力张拉及后期恒、活载作用下构件的安全;体系转换对构件的应力重分布具有重要的影响;不同的连续端混凝土浇筑和后连续预应力张拉顺序会导致永久支座负弯矩区的压应力储备不同。

Take the prototype approach bridge of a expressway river-crossing mega-bridge in Zhejiang province as an example, Virtual Laminated Finite Elements Method (VLFEM) is applied to carry out the space simulation analysis for the construction process of a simply supported-continuous structure system and study the mechanical properties of such system during construction. It is concluded that the tensioning, caused by the first batch of prestress, makes the roof and base plate of the prestressed unit have ample stress reservation thus ensure the safety for structural member under continuous prestress tension as well as under the dead and live load in later stage. The transition of structure system affects significantly the re-distribution of the stress of structural member. The cast of concrete at different end and the post-tensioning of continuous prestress make the negative bending moment section of the permanent support have different compressive stress reservation.