摘要:
某医院新建住院楼结构总高79.6 m,地上18层,两栋住院楼对称布置,住院楼之间分别位于9F~10F、12F~13F以及15F~16F处间隔设置了3个空中连廊,连廊跨度25.2 m。主体塔楼采用钢框架屈曲约束支撑结构体系,三个钢连廊楼面主梁作为弦杆,上下层之间设置中心支撑,形成平面桁架。连廊相比于主体塔楼结构宽度收窄,由24.3 m减小至7.8 m。整体结构体型复杂,连廊对抗震性能要求较高,且胎架拆除的施工顺序不仅对结构会产生附加效应而且会影响现场施工效率。为此分析了宽度收窄式多层间隔高位连体结构设计、施工过程中的关键技术问题及解决方案。通过比较分析连体结构与主体塔楼分别采用强、弱连接方式对主体塔楼的振型模态、抗侧与抗扭刚度以及节点构造形式的差异,确定了连体结构的强连接方案。基于抗震性能化设计目标,对高位连体结构进行了设防地震不屈服验算。结果表明,杆件和楼板承载力满足既定的抗震性能目标。根据胎架拆除的施工阶段不同,对比分析了两种施工方案对连体结构产生的附加内力和附加变形,结合现场施工效率,确定采用每层连廊安装完毕即拆除相应胎架的施工方案。分析结果表明:两侧主体塔楼对称的高位连廊宜采用强连体形式,为保证强连体刚度可协调两侧塔楼,应保证连体结构平面内抗剪承载力大于设防地震下楼板最大剪力标准值,施工阶段可以连接体桁架作为上部连接体胎架支座,附加应力与附加挠度可通过合理施工步释放,且附加挠度可通过施工模拟分析对胎架高度进行补偿。
Abstract:
A newly built hospital has a total height of 79. 6 meters and 18 floors above ground. Two symmetrical inpatient buildings are arranged, and three aerial corridors are set at intervals between the 9th and 10th floors, 12th and 13th floors, and 15th and 16th floors respectively. The span of each corridor is 25. 2 meters. The main tower adopts a steel frame braced structure system, and the frame beams of the three steel corridors act as chord members, with center supports between upper and lower levels to form a plane truss. The width of the corridors narrows from 24. 3 meters to 7. 8 meters compared to the main tower structure. The structure is complex, and the corridors have high seismic performance requirements. Additionally, the order of dismantling the scaffolding not only causes additional effects on the structure but also affects on-site construction efficiency. Therefore, key technical issues and solutions in the design and construction process of multi-layered high-rise connected structures with narrowing widths have been summarized. By comparing and analyzing the differences in modal vibration modes, lateral and torsional stiffness, and joint construction forms between the connected structure and the main tower using strong and weak connections, a strong connection scheme for the connected structure was established. Based on seismic performance-oriented design objectives, a seismic non-yielding verification was performed on the highrise connected structure, and the results showed that the load-bearing capacity of the members and floors met the established seismic performance targets. Depending on the stage of scaffolding removal, two construction schemes were analyzed for additional internal forces and deformations caused to the connected structure. Considering on-site construction efficiency, it was determined to adopt a construction plan that involves removing the corresponding scaffolding immediately after each floor’ s corridor installation is completed. The analysis results indicated that the high-rise corridors symmetrically located on both sides of the main towers should adopt a strong connected structure form. To ensure the stiffness of the strong connected structure and coordinate the two side towers, the shear bearing capacity within the plane of the connected structure should be larger than the standard value of the maximum shear force of the floor under fortify against earthquake. During the construction phase, the connecting truss can be used as a support for the upper connection scaffolding, and additional stresses and deflections can be released through reasonable construction steps. Additional deflections can be compensated for by adjusting the height of the scaffolding based on construction simulation analysis.
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