Study On Stiffness Optimization Of Reinforced Concrete Shear Wall Structure Based On Earthquake Response Spectrum

Reinforced concrete shear wall structure with good overall space and fantastic performance of anti-earthquake has been widely used in residences, hotels, apartments and other residential tall buildings. Arrangement of beam and column is regular and presents a good environment without obstruction of space, and appearance is neat. As a result of above merits, interior space is utilized completely. Optimization of structural design is major development in the theory of structure design, for the same design task, can choose the best one from a variety of designs. Optimal design is not at the expense of structural reliability in exchange for economic benefits, but in reliability as the first consideration. After optimization, not only the load of structure is more reasonable, but also the structure is more economical. Therefore, it is necessary to optimize the design plan of structure.This paper, which is based on Code for design of concrete structures (GB50010-2002), Code for seismic design of buildings (GB50011-2001), Technical specification for concrete structure of tall building (JGJ3-2002), takes a shear wall structure (16 layers) of the actual project as an example. Applying finite element software of ANSYS, the paper established three-dimensional finite element model of the structure (taking into account floor, elevator openings to the structure) and adopted control of deformation of structure as constrain, wall thickness as design variables and structure weight of the lightest as objective function. Through optimal design and research on reinforced concrete shear wall structure based on earthquake response spectrum, conclusions are obtained. Here are conclusions:1. Dynamic characteristics are determined with model analysis, and the main mode of the structure is adopted by size of model participation factor.2. Through spectral analysis, maximal lateral deformation occurred on top story. In the corner, concave and convex parts of the top floor produce greater deformation than other parts. The bottom and internal of structure bear more stress. In the corner and central of the top floor roof, and the hole of shear wall occurs phenomenon of stress concentration. The horizontal earthquake action of each floor presents "S" shaped curve with increase of floors. Maximal earthquake action and maximal story drift of the floor occur in the middle of the structure. Whiplash effect happens near the top of structure.3. By optimization analysis, the optimal thickness of shear wall is obtained and the objective of the lightest weight of the structure is achieved.4. Through comparing seismic performance between optimized structure and structure without optimization, the paper found that overall deformation and distribution of effective stress of optimized structure have the same distribution approximately compared with former structure under without any changes on structural system, except for value of deformation and stress. The ductility of the structure is enhanced and the horizontal seismic action of each floor is reduced, but whiplash effect of the structure became stronger because of heavy flexibility.5. For the reinforced concrete wall structure, without changing the structural layout, only optimizing the thickness of shear wall can not realize aim of the effect of increasing the overall deformation of structure fully.This paper provides a method for reinforced concrete shear wall structure optimization design under horizontal earthquake, and for engineering and technical personnel some degree of reference value.