A Review of the Accuracy of Force- and Deformation-Based Methods in Determining the Seismic Capacity of Rehabilitated RC School Buildings

Introduction

Earthquakes are one of the most powerful natural disasters tragically affecting human lives and environment. In many seismically vulnerable regions on earth, hundreds of thousands of people remain homeless, buildings are being destroyed and worst, lots of people are losing their lives after a destructive shake. Therefore, improving the seismic capacity of existing structures became a vital field of investigation in these countries. It is a known fact that the lack of sufficient amount of attention paid during the design, construction and control phases accompanied by poor structural materials; result many of the reinforced concrete (RC) buildings to have inadequate structural resistance against the expected earthquake demand.

The two main issues during the rehabilitation of RC buildings are the decision of the retrofitting technique to be employed and the analysis method to be utilized. Although many retrofitting techniques such a jacketing of columns; steel bracing; addition of RC infill walls or FRP wrapping are proposed as alternatives for seismic improvement, introducing RC infill walls into the existing structural system is a widely accepted and preferred retrofitting technique due to its effectiveness, relative ease, and lower overall project cost compared to the other methods. In this technique, sufficient amounts of the existing RC frames are converted into RC infill walls, so that an adequate improvement in the seismic capacity is achieved by increasing the existing structural lateral stiffness and strength rapidly and easily.

During the recent years, many analytical researches have been conducted to investigate the seismic behavior of existing RC buildings. Lopez et al. (2004) obtained structural seismic capacity of RC buildings by means of a nonlinear analysis as a part of a project to reduce seismic risks in schools in Venezuela. Postelnicu et al. (2005) studied on the existing RC buildings in Romania and determine the seismic performances of them by using the linear and nonlinear analyses methods. Kuran et al. (2007) preferred linear and nonlinear analyses procedures to determine the seismic performance of existing 1502 type disaster buildings in Bingol (Turkey), which were built after 1971 Bingol Earthquake. Taskin and Tugsal (2014) investigated the seismic performances of the existing RC school buildings subjected to 2011 Van earthquakes by using the linear analyses methods. Ferraioli (2015) performed a case study of seismic performance assessment of RC buildings in Italy considering the nonlinear analyses method approaches. As it is seen, independent from the strengthening technique, linear force-based and nonlinear performance-based analysis procedures have become prominent methods for the determination of the seismic capacity and performance of the retrofitted RC buildings against the seismic demand.