Performance Assessment of Reinforced Concrete Structural Walls for Seismic Loads

New performance evaluation techniques have recently been developed. As part of the SAC Joint Venture, FEMA-355F describes a new state-of-the-art method for the performance prediction of steel moment-frame buildings excited by earthquake ground motions. That report also presents various performance issues and the basis used for performance evaluation. The goal of this study is to assess the performance of reinforced concrete shear wall buildings designed under current codes and standards of practice and to propose a rational procedure for determining the Response Modification Factor, R. The assessment is based on the performance based evaluation framework from the SAC project. Various parameters needed to be newly derived for RC shear wall buildings because the object of the SAC project was the steel moment-frame building. The floor plans for prototype buildings were selected, and the buildings were each designed for 3-, 9-, and 12-stories. The prototype buildings consist of RC shear walls for lateral load resistance and a flat plate floor system for gravity loads. A reliable analytical model for an RC shear wall was developed for inelastic dynamic analysis based on tests and analytical results. As the basis of performance, the global and local collapses for the prototype buildings have been defined. Global collapse was defined as the failure of shear walls or the failure of the columns in the flat plate system, as determined by a Damage Index. The median drift demands and capacities and the randomness and uncertainty factor for each building height were determined for the performance assessment. The performance of each building was evaluated by calculating the confidence level. The results showed a good performance of RC shear wall buildings designed by current provisions. As a result, the buildings were redesigned using higher R-values, and the performance evaluation procedure was repeated until the desired confidence level was attained.