摘要:
深圳文化馆新馆建筑造型复杂、内部空间变化较多,存在超过21 m的大悬挑空间。为确保整个结构具有合理的抗侧和抗扭刚度,在建筑楼梯、电梯间设置了8个钢筋混凝土筒体,这些筒体与周边框架柱形成框架剪力墙结构。但由于建筑内外空间上的变化和功能上的特殊要求,该结构存在较多的不规则项和复杂子结构。如文化馆典型楼层开洞率达32%以上,馆内各区域功能差异较大,区域之间仅通过室内连廊连接在一起,实际楼板情况与刚性楼板假定不符,此时如何评判结构的变形指标以及楼板协调变形的能力成为设计的一个重、难点;将文化馆划分为三个区域,分别为左侧、右侧核心筒群区域以及东侧大跨度钢结构区域,选取三个区域中的典型观测点,考察地震作用下观测点的变形,进一步判断楼板是否具有协调三个区域变形差异的能力。对大悬挑区域进行了方案对比阐述,同时对与悬挑桁架上弦相连的楼盖构件进行受力分析,讨论其在结构遭受罕遇地震作用、薄弱连接位置的楼板出现损坏引起楼板刚度退化甚至是完全退出工作时,能否保证桁架与核心筒之间的传力。东侧区域建筑功能要求大柱跨及楼层通高,典型柱距8.4 m×16.8 m,且仅可在L4~L8层布置钢柱,B1~L4层之间则须要设置Y型斜柱承托上部钢柱;分析Y型斜柱传递重力时其独立承担倾覆荷载的能力,同时Y型斜柱为3~4层的跃层柱,其能否满足稳定承载力和抗连续倒塌要求均为讨论的重、难点。在考察结构刚度指标(如层间位移角)时,可根据结构受力情况采取分区统计方式,捕捉关键监测点的变形值,综合评判楼盖协调变形的能力。对于室内连桥以及楼板薄弱连接位置,通过建立分离体模型进行包络设计,同时加强楼板配筋。通过在支承大悬挑桁架的剪力墙内设置型钢梁柱和斜杆的方式形成立体筒体,并充分考虑楼板刚度退化对大悬挑桁架与筒体之间构件的受力和变形影响,分析结果表明,大悬挑整体结构可满足各项验算。Y型斜柱独立承担倾覆荷载的能力较弱,设计时加强斜柱与核心筒群之间的楼盖连系,严格控制斜柱与核心筒之间拉梁的应力比。Y型斜柱设计时,应考虑构件的初始缺陷进行非线性稳定承载力分析,明确斜柱的稳定承载力储备。采用线性静力拆除构件法,可判断斜柱结构满足抗连续倒塌要求。选取典型的大悬挑桁架与剪力墙连接节点和型钢混凝土桁架转换节点作为研究对象,提出相应的节点加强构造,通过节点有限元分析,确保节点的安全可靠。
Abstract:
The new Shenzhen Cultural Center has complex architectural shape and many internal space changes, with a large cantilevered space of more than 21 meters. In order to ensure reasonable lateral and torsional stiffness of the whole structure, 8 reinforced concrete tubes are set up in staircase and elevator of the building, which form the frame shear wall structure with the surrounding frame columns. However, due to the changes in the inner and outer space of the building and the special requirements in the function, the structure has many irregular items and complex substructures. For example, the opening rate of the typical floor of the cultural museum is more than 32% , due to the large functional difference between the various areas in the museum and the connection between the areas only through the indoor corridor, the actual situation of the floor is not consistent with the rigid floor assumption. At this time, how to evaluate the deformation index of the structure and the ability of the floor to coordinate the deformation becomes a major difficulty in the design. The cultural center is divided into three areas, namely, the core tube group area on the left side, the core tube group area on the right side and the large-span steel structure area on the east side. The typical observation points in the three areas are selected to investigate the deformation of the observation points under earthquake action, and further judge whether the floor has the ability to coordinate the deformation differences among the three areas. The scheme of the large cantilevered area is compared, and the stress analysis of the floor members connected to the upper chord of the overhang truss is carried out. The force transfer between the truss and the core tube can be ensured when the structure is subjected to rare earthquake and the floor in the weak connection position is damaged and the floor stiffness is degraded or even completely withdrawn from work. The function of the building on the east side requires large column span and floor height. Typical column distance is 8. 4 m×16. 8 m, and steel columns can only be arranged in L4-L8 floors, and Y-shaped slanted columns can be set between B1-L4 floors to support the upper steel columns. The ability of Y-shaped slanted column to independently bear overturning load is analyzed when gravity is transferred. At the same time, Y-shaped slanted column is 3-4 stories cross-layer column. Whether it can meet the requirements of stable bearing capacity and resistance to continuous collapse is a key and difficult point to discuss. When the structural stiffness index ( such as the inter-story displacement angle) is investigated, the deformation value of key measuring points can be captured by sectional statistics according to the structural stress situation, and the ability of the floor to coordinate deformation can be comprehensively evaluated. For the indoor bridge and the weak connection position of the floor, the envelope design is carried out by establishing the separating model, and the floor reinforcement is strengthened. By setting steel beams, columns and inclined rods in the shear wall supporting the large cantilevered truss, the three-dimensional tube structure is formed, and the influence of floor stiffness degradation on the force and deformation of the components between the large cantilevered truss and the tube structure is fully considered. The analysis results show that the large cantilevered truss and the tube structure can meet the checking calculation. The ability of Y-shaped slanted column to independently bear overturning load is weak. In design, the floor connection between slanted column and core tube group is strengthened, and the stress ratio of pull beam between slanted column and core tube is strictly controlled. When designing the Y-shaped slanted column, the nonlinear stability bearing capacity analysis should be carried out considering the initial defects of the component, and the stable bearing capacity reserve of the slanted column should be defined. By using linear static alternate path method, the slanted column structure can be judged to meet the requirements of continuous collapse resistance. The typical joint of the large cantilevered truss and shear wall and the transfer joint of steel reinforced concrete truss are selected as the research object, and the corresponding joint strengthening structure is proposed.