大跨度RC天桥施工全过程的力学分析

利用有限单元法，研究澳门某学校建筑的大跨度行人天桥在混凝土施工过程中，出现的不正常挠度，导致天桥底模板支撑发生失稳压弯破坏严重事故，事件的发生并非直接由外来荷载的扰动所引起，而是由于天桥结构内部不同浇灌龄期混凝土强度，刚度的发展，引致桥体发生内力重分布，这种内力重分布使天桥墙体底部某些模板支撑的反力增大，导致原来已因设置数量不足而接近失稳临界状态的天桥底模支撑，发生了屈曲破坏，文中对这种施工暂态结构的力学特性进行了探讨。

Mechanical Analysis of a Long Span RC Overpass during the Whole Course of Its Construction

In a long span overpass of a school building in Macao, there appear abnormal during the course of its construction. The damage of unstability and bent of form braces at the base of overpass was ensued and was studied by finite element mcthod during its whole course. This event was found to be caused by redistribution of internal force of overpass body instead of directly by the perturbation of external load. During different ages of concrete pour, the development in strength and stiffness of concrete within the structure of overpass resulted in redistrlbution of internal force of overpass body. This redistribution of internal force enhanced the counter force, namely,reaction stress, of some form braces at the base of overpass which approached critical state of unstability due to inadequate installation in number and then buckling occurred. An inquiry is made into mechanical property of this transient structure during construction.