Seismic Analysis of Existing School Buildings UsingDifferent Egyptian Seismic ProvesionsI. Ezz El-Arab1aSeismic Analysis of Existing School Buildings UsingDifferent Egyptian Seismic ProvesionsjProcedia Engineering 14 (2011) 19061912Abstract This paper presents a comparative study for seismic analysis of a certain class of existing school buildings which are considered as one of the important and wide spread buildings in Egypt. The study focuses on a comparison between all versions of the Egyptian Code of Practice for loading (ECP-201), versions published in 1993, 2003, and the draft of final version October, 2008, and the Regulations of the Egyptian Society of Earthquake Engineering (ESEE, 1988). Base shear and base moment values are calculated using all of the above mentioned seismic provisions. The controller straining actions of these provisions are then compared with those obtained using response spectrum and time history analyses using real ground excitation of pervious earthquakes (Al-Aqba, 1995, Northridge, 1994, and El-Centro, 1940). All these earthquakes are scaled to be matched with the maximum ground acceleration for the study zone. It has been found that high variation between the base shear and base moment obtained using the ECP versions pecified different analysis methods and in comparison with the ESEE and Earthquake analysis. This high variation make the new ECP-201 (October, 2008) will be need to recontemplate. 2011 Published by Elsevier Ltd.Keywords: Egyptian Code, Seismic, Earthquakes Analysis, Schools, Egypt.1. Introduction It is well known that there are three methods for structural earthquake analysis. These methods are the Equivalent Static Load method (ESL), the Response Spectrum Method (RSM), and the Time History Analysis (THA).The (ESL), and the (RSM) methods are generally used for linear analysis of the dynamic response of structures. In various forms, (THA) method has been widely used in the earthquake-resistant design of special structures such as very tall buildings, offshore drilling platforms, dams, and nuclear power plants. For a number of years; however, its use is also becoming more common for ordinary structures as well. The (ESL), and (RSM) analysis procedures were simplified from the general case by restricting consideration to lateral motion in a single plane. Only one degree of freedom was required per floor for this type of analysis. In recent years, with the advent of high-speed, desktop computers, and the proliferation of relatively inexpensive, user-friendly structural analysis software capable of performing three-dimensional modal analyses, such simplifications have become unnecessary. Consequently, the new Provisions adopted the more general approach describing a three-dimensional modal analysis of the structure. When modal analysis is specified by the Provisions, a three-dimensional analysis is generally required except in the case of highly regular structures or structures with flexible diaphragms.2. Majoir changes of seismic provisions The research will present the significant difference points that have been applied to the seismic provisions in different ECP editions released from 1993 to 2008, and the ESEE. Table 1 illustrates the base shear formulas with the related parameters to present the major changes.Table 1: Major differences between the ESEE, and ECP (1993, 2008). The major difference between the ECP-1993 and the ECP-2003 was remarked by the new adoption of the response spectrum method that presented the pseudo acceleration anchored to Peak Ground Acceleration (PGA). Also, the soil parameter has a big effect on the response spectrum curve. On the other side, the two newest provisions ECP-2003 and ECP-2008 have a similar base shear formulation except the existence of the importance factor I either in response spectrum or in the base shear equation which yields final identical base shear. It is clear from the initial comparison how the base shear value obtained from ECP-2003 and 2008, is greater than the value obtained of ECP-1993. The value of base shear that was obtained from the ECP-2008 and 2003 when used in the elastic theory it must be reduced by a factor of the 1.4 or 1.28 for ECP-2008 and ECP-2003, respectively. The ESEE presented the response spectrum method in additional to equivalent static load with many factors not taken into consideration in the ECP-2003 and 2008 like material, risk, and construction quality factors. All of these factors are still neglected in all ECP editions till 2008.3. Case Study of School Buildings in Egypt The Egyptian General Authority for Educational Buildings has divided the school buildings to seven models according to two main items. The first is the capacity of class rooms, while the secondly is soil classification that depends on the school location. In the present paper, the middle of Delta region has been chosen for the studied cases. Fi