Structural Needs of Existing Buildings in Gaza for Earthquake Resistance

Abstract

This study aims at finding a quick and easy way to evaluate Gaza buildings for their resistance to earthquakes and make recommendations for strengthen the existing buildings, and finally to conduct recommendations for the local governorates for designing new buildings in Gaza. To achieve this aim many evaluation methods used all over the word were studied, reviewed and tested onGazabuildings. In this research, a new method was developed to evaluate the buildings in Gaza Strip. The developed method classifies theGazabuildings into sufficient, intermediate and insufficient resistance. In the intermediate resistance criteria, strengthening to the building is needed to make the building sufficient to earthquake resistance. This method has been developed by combination the Israeli method and Turkish method. The Israeli method is suitable to be used onGazabuildings in terms of the similarity of geological situation, the construction methods and materials used in the two regions. It classifies building due to earthquake resistance only into sufficient and insufficient resistance. In the Turkish method a detailed calculation is made to classify the buildings into sufficient, intermediate and insufficient resistance. In order to adopt this method for modification, a detailed comparison is made betweenPalestineandTurkeythrough several aspects of the system such as soil, seismic zones, structural systems and construction quality. In the developed method, the first step is to perform a rapid scanning to the building if the building is classified as insufficient a detailed computation is needed to reach the final evaluation result. If the final result is sufficient the building will be accordingly classified as to have enough resistance to earthquakes. If the result is intermediate, the building is classified as in need for strengthening .If the result was insufficient the building is classified accordingly ,and the recommendation is to demolish it, or it needs major strengthening. The developed approach is applied on thirty three differentGazabuildings which include: residential housing buildings, tower buildings, schools, health clinic and finally for asbestos shelters. Finally, classification for the buildings according to earthquake resistance are made and recommendations for strengthen every kind of the buildings are proposed. Based on this study, it was found that the structural system used on Gaza Strip which is Skelton type is an appropriate system to resist earthquakes of high intensity. The weakness of this system appeared in the case of the presence of soft story. Tower buildings are classified as intermediate and weak in resisting earthquakes, according to the area of shear walls in the building. The reinforced concrete frame system which is used in public buildings is suitable and adequate to resist earthquakes of high intensity. The asbestos buildings are weak and unsuitable in resisting earthquakes forces.