Seismic Assessment of Existing Building in Israel

Abstract

Many existing buildings in high seismic hazard zones (including buildings and structures in Israel) have inadequate capacity to resist earthquakes loads. This is because they may have been designed and constructed according to earlier codes, which did not satisfy modern seismic design requirements and current engineering standards, faulty design and improper construction, alteration of building functions, changes of seismic load characteristics in the area, etc. Israel code (as many international codes) adopted the conventional earthquake-resistant design philosophy (force based); the structures are designed for forces which are much less than the expected design earthquake forces. These methods usually don’t consider the expected performance level and seismic risk levels of the structure after an earthquake event. So, need of new method comes which would give the actual performance of the structure after an earthquake event. Performance based analysis and evaluation procedures are used to investigate seismic inadequacy of existing buildings. The improvements of seismic performance of these buildings may be achieved using retrofit systems such as steel bracing, shear walls, concrete and steel jacketing. In this study, extensive literature study of most using retrofit schemes, which improve seismic performance of existing buildings, was introduced including their features. Procedures of performance-based analysis using nonlinear static analysis (pushover) was used to study the performance of G+6 story reinforced concrete existing buildings without/and with different retrofit systems. The seismic response and performance of these cases were discussed. The results of evaluation and analyses of the study cases showed necessity of 3D analysis, steel jacking system was proposed to bypass collapse plastic hinges and to reduce displacements and drifts, and concrete and steel jacketing bypass collapse hinges and keep ductility