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整体大节段提升施工工艺在大型桥梁施工中运用逐渐趋于成熟,但提升系统设计因不同桥型结构、不同施工环境等情况而异,重点要结合现场条件、结构安装空间要求以及用于整体提升的支撑结构的安全及稳定性等方面的要求进行全面的、系统的设计;在保障提升系统及被提升结构安全、可靠的同时,尽可能地使提升系统结构受力明确、操作简单,最大限度地满足桥梁结构的线型设计要求及结构受力安全,并使施工工序转换步骤少,提高施工效率,节约工期,同时减小高空作业风险,以取得良好的经济效益和社会效益。 相似文献
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Dynamic modeling and active control of a strap-on launch vehicle are studied in this paper. In the dynamic modeling, the double-compatible free-interface modal synthesis method is used to establish dynamic model of the system, and its model precision is compared with those of finite element method(FEM), fixedinterface modal synthesis method and free-interface modal synthesis method. In the active control, the swing angle of rocket motor is used as design variable, and the control law design based on the model of mass center motion is adopted to validate the system. Simulation results indicate that the double-compatible model synthesis method can properly approximate the FEM which is used as the benchmark solution, and the model precision of the double-compatible modal synthesis method is obviously higher than those of the fixed-interface and freeinterface modal synthesis methods. Based on the control law design, the deflection of mass center of the launch vehicle is very small. 相似文献
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边坡的破坏与失稳是一个循序渐进的过程,在外部荷载和环境的作用下,随着应力的升高,坡体内某些部分达到屈服,滑动面逐渐形成,直至完全贯通,随着塑性应变持续增强,边坡最终发生整体破坏。文中根据岩土性质和坡体构造对边坡进行了分类,分析降雨对边坡安全系数的影响,对目前边坡工程中常用的一些稳定性分析方法进行了系统的总结,可以得到降雨对边坡的影响程度。从而直观地揭示了边坡的破坏机理,为实际工程的边坡稳定性计算提供了指导意义,为边坡的防治提供有效依据。 相似文献
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