【摘要】 为研究移动模架荷载预压试验中垮塌原因,以某桥梁工程移动模架垮塌事故为例,通过查阅移动模架设计图纸及事故现场照片,初步推断了事故原因,并采用有限元软件建立该移动模架的整体结构分析计算模型,分析在各级预压荷载下结构整体变形、受力,在此基础上对受力最不利的横梁的强度、刚度和弹性稳定性进行了复核计算。结果表明:箱梁模板缺少沿桥纵向必要的刚性支撑,在预压荷载自重的纵向水平分力作用下,整个箱梁模板体系发生纵向平移;移动模架各片横梁之间间距较大,横梁面外刚度相对较弱;移动模架施工中真实的受载集度与预压试验的荷载均匀分摊方式的差异也会产生不安全因素。计算结果基本验证了推断结论的正确性,为防止类似事故发生提出了相关建议。更多还原

【Abstract】 To analyze the causes of the collapse accident in the movable formwork preloading test,the movable formwork collapse accident of a bridge project was cited as an example.By examining the drawings of the movable formwork and the accident site,the causes of the accident were preliminarily interfered.The finite element software was used to establish the global structural analysis and calculation model of the movable formwork,to analyze the overall structural deformation and load bearing capacity in different preloading stages.Based on the calculation,the strength,stiffness and elastic stability of the cross beams that carry the most unfavorable loads were verified.The results of the verification show that the formwork of the box girder lacks stiff supports along the bridge length,so that longitudinal translation was observed on the overall box girder formwork system under the action of the horizontal components of the self weight of the preloading in the longitudinal direction.Because the spacings among cross beams of the movable formwork are big,the out-of-plane stiffness of the cross beam is relatively weak.Unsafe conditions will also appear in the movable formwork construction,relating to the real load carrying concentration degree and the uniform load allocation mode in the preloading test.The calculation basically verifies that the interference is correct,and suggestions are given for the prevention of the similar accidents.更多还原