某佛塔巨型通天柱底层拔柱改造工程设计与施工研究

Design and construction research on renovation engineering of removing bottom layer columns of direct-to-sky mega columns in one pagoda building

既有建筑托梁拔柱改造能够在建筑外立面不变、结构内部改动量最小的情况下有效地增大建筑内部使用空间,是一项有着重要实用价值的技术。但由于设计难度大、施工复杂,施工过程中安全风险较高,因此还未形成系统完整的设计理论和施工技术。结合某高层佛塔底层1 200mm直径通天柱拔柱改造工程,探讨托梁拔柱改造过程中结构的受力特点、防倒塌设计与施工技术要点。充分利用拟拔除混凝土柱截面尺寸大的特点,将其切割成600mm×600mm的素混凝土方柱,作为托换过程中的临时支撑,将拔柱托换过程中结构体系动态的变化过程转变为静态的平衡受力过程,显著地降低了托换施工过程中的风险。

Supporting beam and removing column methods used in renovation of existing buildings can effectively enlarge the inner usage space of buildings with the unchanged external facade and minimum renovation work, which is a technology of great practical importance. However, due to the high difficulty of design, complex construction, and high safety risk during the construction process, systematic and complete design theory and construction technology for supporting beam and removing column methods has not been developed yet. Based on a practical renovation engineering of removing bottom layer columns of 1 200 mm diameter of direct-to-sky mega columns in one pagoda building, the key points of load bearing mechanism, progressive collapse design and construction techniques were discussed in the renovated process of the structure using supporting beam and removing column methods. This project took full advantage of the large cross-section of the concrete column designed to be removed, which was cut into plain concrete square columns with the cross-section of 600 mm×600 mm and used as temporary supports during the transfer construction process. The dynamic change process of the structural system in the process of supporting beam and removing column was transformed into the static balance process, which significantly reduced the risk in the process of transfer construction.