The suspension cradle is usually used in the main girder construction of cable-stayed bridge,and the bottom-slab of the girder receives strong vertical reaction force from the walking wheel of the cradle,which may crack or damage concrete floor and ribs.Safety checking is therefore necessary for the concrete structure bearing the force.The contact region between the walking wheel and the bottom-slab is unknown,yet it determines the stress and deformation.The elastic contact Hertz theory is adopted to determine the contact region and stress distribution,and the results indicates that safety checking of the floor and ribs can be carried out on this basis.%混凝土斜拉桥采用挂篮施工主梁时,挂篮底部行走轮对主梁底板产生巨大的竖向反力.混凝土底板、肋板可能在此反力作用下发生局部承压开裂破坏,需进行安全验算.行走轮与底板的接触区域是未知的,混凝土的受力变形均由接触区域决定.为寻求简单适用的计算方法,采用弹性接触Hertz理论,求解行走轮与混凝土板接触区域大小及应力分布,在此基础上应用规范推荐公式进行底板及肋板的抗裂安全验算.算例表明,该方法是可行的,可以简便地进行主梁底板的局部承压安全验算.
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