Structural Design In Extension Project Of Xiamen NanHu Pearl

Xiamen South Lake Pearl is a integrated high-rise building with commerce, entertainment, office and residence. In order to meet the functional requirements of the construction, shear wall structure of small space is layed in the upper of the building, and frame-corewall structure of large space is layed in the lower part of the buliding. The structure plan is clearly irregular, asymmetric, which belongs to transfinite complex high-rise structure. In this thesis, design methods of this type of structure are studied:①in order to make the upper and lower layer's stiffness of the transfer story uniform and not sudden change, the layout of the upper shear walls are processed carefully , which makes the vertical somatotype of the high-rise building regular and uniform, and lateral stiffness is greater on the lower structure and smaller on the upper structure, changes gradually and uniformly. The layout of the structure should make the centre of mass and centre of stiffness coincided as far as possible, which can reduce the torsional effect under horizontal load.②After the general calculation of structure, the calculation results are analysed, the important parameters such as natural vibration period,Structural Displacement and structural stiffness are judged in a reasonable range.The structure is analyzed by using the time-history analysis method under four seismic waves. The results show that the maximum displacement curve of floor changes smoothly glossily and continuously, the displacement peak is more reasonable , and the curve of the Inter-story Displacement Angle is no much extrusive and concave, and the structure has no obvious weak storey.③structural transfer beam is an important stressed member with complexity of stress, stress analysis should be carried out using various methods, construction measures have to be taken to guarantee the safety of the structure and no diagonal cracks would take place at the state of serviceability.④Shear walls on the transfer storey is different from shear walls linked with the ground. We should take checking caculation to the partial bearing capabiltiy of the bottom of walls and to the shear capabiltiy of walls under horizontal loads.Since the performance of short-leg shear walls is less than the one of general shear walls, we should control axial compression ratio and enhance the reinforcement in short-leg shear walls.⑤Being an important bearing members of the stucture, frame-supporting columns should be strengthen its ductile ability to ensure these columns would not be the first to damage under an earthquak. In the previous structure there are some weakness in desginingframe-supporting columns, so this structure should be reinforcd and strengthened by using the method of expanding section to improve the seismic performance.⑥There are some pile fundations that do not meet the requirement of bearing capability in previous structures, so we could reduce the loads by unloading method so as to ensure the safety for the stuctures.