超高层框架-核心筒结构竖向变形差的实测与分析

Measurement and analysis on vertical deformation difference of a super high-rise building with frame-core tube structure

以南海荣耀国际金融中心为工程背景,对塔楼的12、23、35层、主屋面(169.75 m)及塔顶(179.50 m)楼层的外框架柱与核心筒进行设点观测。基于观测结果,得到从结构施工到结构封顶258 d后外框架柱与核心筒的竖向变形差,并对观测数据进行曲线拟合分析,预测出结构封顶2年后相对观测点的竖向变形差。利用有限元程序SATWE分析外框架柱与核心筒的竖向弹性变形差。考虑混凝土收缩徐变以及竖向构件含钢率的影响,利用有限元软件MIDAS/GEN的CEB-FIP 1990模型进行施工模拟,分析从结构施工至结构封顶2年后外框架柱与核心筒的竖向变形差;通过对比实测数据与有限元模拟数据,分析由竖向构件变形引起的框架梁端的附加弯矩可调幅度。结果表明:对于超高层框架-核心筒结构,考虑了混凝土徐变和收缩的实测变形差比弹性计算变形差小约70%,即由竖向构件变形差引起的连接处框架梁端的附加弯矩值比有限元的模拟值小很多。研究认为,DBJ 15-92—2013《高层建筑混凝土结构技术规程》第5.2.4条中,对高层建筑结构中框架梁附加弯矩的调整幅度上限值可提高到40%。

With reference to the Nanhai Glory IFC Project, the measured vertical deformation difference between the frame column and core tube from the commencement of construction to 258 days after finishing of top story, was obtained through observation points at the 12th, 23th, 35th floor, roof （ 169.75 m） and the tip of tower （ 179.50 m）. By conducting curve fitting analysis on the data obtained, the vertical deformation difference of the structure two years later after finishing of top story can be predicted. The elastic deformation difference was obtained by using the finite element program SATWE. Considering the creep and shrinkage and the effects of steel ratio, the CEB-FIP 1990 model of＇ the finite element software MIDAS/GEN was used to simulate construction process and analyze the vertical elastic deformation difference of the structure at time up to two years after finishing of top story. By comparing the measured and FEA data, the adjustable range of additional moment at the frame beam end caused by the deformation of vertical members was analyzed. Results show that in the super high-rise frame-core tube building, the measured deformation difference with the concrete shrinkage and the creep taken into aceount is 70% less than the elastic deformation difference and the additional moment at the joint of the frame beam end caused by the deformation difference of vertical members is far less than the FEA results. The adjustment of the limit of additional bending moment was put forward from an economical perspective. Based on studies, the adjustable range of additional moment at the frame beam end of the high-rise building in article 5.2.4 of DBJ 15-92--2013 ＇ Technical specification for concrete structures of tall building＇ can be increased to 40%.