The Egyptian Building Code: Recommended Modifications for the Input Seismic Hazard Parameters Rashad Sawires(1), José A. Peláez(2) and Raafat E. Fat-Helbary(3) (1)
[email protected] gmail.com Geology Department, Faculty of Science, Assiut University, 71516-Assiut, Egypt, rashad.sawires@ Department of Physics, University of Jaén, Jaén, Spain,
[email protected] Spain,
[email protected] (3) Aswan Regional Earthquake Research Center, 152-Aswan, Egypt, fat_helbary2@y
[email protected] ahoo.com (2)
ABSTRACT
Some Egyptian building codes have been published in Egypt during the last three decades. These codes are the Regulations of the Egyptian Society of Earthquake Engineering (ESEE, 1988), and the Egyptian Codes for the Calculation of Loads and Forces (ECP-201: 1993, 2004, 2008, and 2011). Great variations in the representation and values of the seismic action parameters can be observed among them. The current representation of the seismic action (ECP-201, 2011), which is based mainly on the seismic hazard study done by Riad et al. (2000), and follows the same framework adopted in Eurocode 8 (2004), do not give a specific ground-motion value for each Egyptian city, but it just divides the whole territory of Egypt into six broad zones, assigning to each of them a unique seismic action value. For zones 1, 2, 3 and 4, the peak ground acceleration (PGA) values are 0.10, 0.13, 0.15 and 0.20 g, respectively. Zone 5 is subdivided into two sub-zones, 5a and 5b, with PGA values of 0.25 and 0.30 g, respectively. Recently, an updated probabilistic seismic hazard for Egypt, in terms of PGA and spectral acceleration (SA) values, for both rock and stiff-soil site conditions, has been assessed. Seismic hazard results have been computed for the whole territory, and specific seismic hazard values have been estimated in detail for mostly important cities in Egypt. Moreover, taking into account the noticeable differences among the input seismic actions in the previous building codes, a new approach for establishing the design spectra, using only two SA values for oscillation periods of 0.2 and 1.0 s, is suggested and recommended for the upcoming building code in Egypt. The procedure developed by Malhotra (2005) for the establishment of the design spectra was used here. The obtained design response spectra using this approach have been analysed, comparing it with the computed uniform hazard spectra and the ECP-201 (2011) design spectra for several selected Egyptian cities. It clearly appears that, for a specific location, it is a good approach to include a design spectra defined by only two values (the computed computed SA values for 0.2 and 1.0 s) in the building code.
KEYWORDS
Building codes, Design spectra, Seismic hazard, Peak ground acceleration, Spectral acceleration, Egypt.
