Evaluation of Egyptian code provisions for seismic design of moment-resisting-frame multi-story buildings

Shehata E Abdel Raheem

doi:10.1186/2008-6695-5-20

Abstract

Since the occurrence of the Cairo earthquake on October 1992, the design of structures for earthquakes became a major demand enforced in the Egyptian design codes. The seismic response of building structures can be estimated through utilization of a variety of analysis methods that range from simple equivalent static analysis to complex nonlinear dynamic analysis. The traditional approach is to employ equivalent static analysis methods, while current design practice is moving toward an increased emphasis on the nonlinear analysis method. The Egyptian code provisions for building seismic design adopt the traditional approach of equivalent static load method as the main method for evaluating seismic actions and recommend the response spectrum method for nonsymmetrical buildings. This study aims to evaluate the Egyptian code provisions for the seismic design of moment-resistant frame multi-story building through using nonlinear time history analysis. The analysis procedures are evaluated for their ability to predict deformation demands in terms of inter-story drifts, potential failure mechanisms and story shear force demands. The results of the analysis of the different approaches are used to evaluate the advantages, limitations, and ease of application of each approach for seismic analysis.

Highlights

Occurrences of recent earthquakes in different parts of the world and the resulting losses, especially human lives, have highlighted the structural inadequacy of buildings to carry seismic loads
This study aims to evaluate the way Egyptian code seismic provisions treat the consideration of seismic loads and analysis methods during the seismic design of buildings, to discuss the alternative solutions for cases wherein existing provisions do not lead to satisfactory results, and to quantify the effect of building lateral stiffness and diaphragm flexibility on the structural response so that designers can be aware of the likely impact of their decisions
The evaluation of Egyptian code seismic provisions and simplified methods is performed through comparison with a more refined approach whereas an effort is made to quantitatively assess the relative importance of various design and analysis assumptions that have to be made when building seismic design is taken into consideration, based on the study of the dynamic response of different buildings

Summary

Introduction

Occurrences of recent earthquakes in different parts of the world and the resulting losses, especially human lives, have highlighted the structural inadequacy of buildings to carry seismic loads. Nonlinear analysis methods that are capable of realistically predicting the deformations imposed by earthquakes on structures are needed In response to this need, nonlinear static analysis procedures have appeared in national resource documents such as the ATC-40 report on seismic evaluation and retrofit of concrete buildings (ATC 1996) and the FEMA-356 pre-standard on seismic rehabilitation of buildings (FEMA 2000). Such analysis methods are useful for predicting inelastic displacement capacities while simultaneously offering a compromise between the oversimplification of linear static analysis and the inherent complexity of nonlinear dynamic analysis. ECP (2008) recommended the response spectrum method to be used for building seismic analysis and design, which was considered to be a more accurate method of analysis than the equivalent static load method (Chopra 1995; Paz and Leigh 2003)

Objectives

Methods

Results

Conclusion