移动模架是一种用于混凝土桥梁现浇成桥的大型施工设备,针对混凝土浇筑过程中流动混凝土对外模板的侧向面压力进行了分析,研究其对移动模架整体结构强度、刚度和稳定性的影响.利用有限元分析软件 ANSYS 分别建立了移动模架外模板系统和主梁支撑系统的空间有限元模型,采用施加面压力方式模拟流动混凝土对外模板的作用力,分析得出主梁和横梁承受外模板的载荷值,将其作为主梁支撑系统有限元模型的载荷边界条件,分析了模板侧压力对主梁强度、刚度和稳定性的影响.结果表明:流态混凝土会对单侧主梁产生5 103 kN 的总侧向附加载荷,由于端模板约束作用,荷载峰值出现在主梁跨中区段;侧向附加载荷会使主梁箱体内部横隔板局部应力增大,最大线弹性应力增幅达到257 MPa;侧向附加荷载在主梁横截面内产生扭矩,改变了腹板区剪应力状态和屈曲失稳位置,降低了主梁外侧腹板的屈曲稳定性.%The Movable Scaffolding System(MSS)is a large-scale construction equipment for the concrete bridge.In this paper,the lateral surface pressure resulted from concrete flow in the pouring process was analyzed to study its influence on the strength,stiffness and stability of the main girders.The 3D finite element model(FEM)of the formworks and the main girder support system were established by using the software ANSYS.To obtain the load of formworks acting on the main girders and crossbeams,the surface pressure load was applied on the side formworks to simulate the pressure generated by the concrete flow.The results show that the concrete flow produced a total lateral load of 5 103 kN for the sin-gle－side main girder.Due to the constraint effect of end formworks,the peak of additional lateral load appears in the mid－span of the main girder.The increase of local stress in diaphragm plate of main gird-ers is significant,i.e.,the maximum linear elastic stress increase quantity is 257 MPa.The bucking stability of outside web of main girder was reduced because of the additional lateral load.The reason can be contributed to the additional torque in cross section of the main girder caused by additional lateral load,which changes the shear stress state and buckling instability position in the web region.
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