Performance Based Seismic Assessment Of A High Rise Reinforced Concrete Core Wall Building

Abstract

Performance based design approach is becoming common in analyzing high rise RCC core wall buildings. In Performance based design, demand coming on structure during earth quake is carefully modeled so as to assess the real capacity of structure with a clear motive that certain loss in capacity is expected but it should be within allowable limits. This study focuses only on High rise core wall RCC regular building. Demand curve taken for pushover analysis and for matching time histories in NLTHA is UBC 97 RS curve for zone 2b can be unrealistic and needed to be worked upon by doing Probabilistic seismic hazard analysis. UBC 97 code gives unrealistic value of R especially for tall buildings. In this study actual value of R is calculated by comparing the elastic and inelastic response. UBC 97 implicitly satisfy the performance objective while in this study performance objectives are explicitly satisfied at different levels of earthquake using performance based design. This study focuses on performance based design of 50 story building supposed to be located in Islamabad, Pakistan, analyzed and designed using UBC 97 code (RS analysis) and subjected to predefined pattern of monotonically increasing lateral demand until we will reach to predefined target displacement using FEMA guidelines. The building is then subjected to NLTHA for different levels of earthquakes by using UBC 97 matched time histories extracted from PEER data base using different de-aggregation studies. Structure is made more efficient and economical by increasing ductility in structure. This is done by increasing confinement and reducing extra longitudinal reinforcement in traditional code based design.