A NEW DISPLACEMENT-BASED SEISMIC DESIGN METHOD FOR SHEAR WALL STRUCTURES

摘要

According to the characteristics of shear wall structures, the destructive story drift ratio is employed to represent the performance index of structures. Then, the performance levels of shear wall structures are quantified and the lateral deformation is controlled by two parameters of destructive story drift ratio and roof drift ratio. Based on the seismic fortification level in Chinese Code for Seismic Design of Buildings, the performance of shear wall structures is divided into three levels: fully operational, performance interruption and collapse prevention. Applying the inverted triangular distribution of lateral force to the cantilever wall with identical section, the displaced curve is regarded as the initial lateral displacement mode. By employing the design parameter of destructive story drift ratio, the determining method of target lateral displacement for shear wall structures is demonstrated and a destructive story drift-based seismic design method is presented. In the "fully operational" performance level, the target lateral displacement is determined by the corresponding drift curve when the shear wall structure reaches the target destructive story drift ratio. Afterward, the equivalent parameters of single-degree-of-freedom system can be calculated, and the base shear and horizontal earthquake action of every mass of multi-degree-of-freedom system can be estimated. In the "performance interrupt" and "collapse prevention" performance levels, the designed structure is adjusted based on the relationship between pushover curve and demand curve and the ductility demands of structure. It is demonstrated the method in this paper is convenient for practical application, which can be employed to control the performance of shear wall structures under different earthquake levels.