Investigation of Effects of Capacity Spectrum Method on Performance Evaluation of Multi-Story Buildings According to the IRAQI Seismic Code Requirements

Al-Nuaimi Amer,Mohamed Sobaih,Akl Adel

doi:10.4236/ojce.2016.63036

Al-Nuaimi Amer, Mohamed Sobaih + Show 1 more

Open Access

https://doi.org/10.4236/ojce.2016.63036

Copy DOI

Abstract

The aim of this study is to assess the performance objectives defined in the Iraqi Seismic Code (ISC) in order to make a realistic evaluation related to Performance-Based Seismic Design (PBSD) of multi-story reinforced concrete buildings and also to compare and evaluate structural response demands obtained from nonlinear static analysis procedures according to two versions of the capacity spectrum method (CSM) which are recommended in ATC 40 and ATC 55. Two groups of three-dimensional RC buildings with different heights, designed according to Iraqi Building Code Requirements for Reinforced Concrete (IBC), are investigated. Pushover analyses are carried out to determine the nonlinear behavior of the buildings under three different seismic hazard levels, for two Iraqi seismic zones, of earthquake loads. In order to determine performance levels of the buildings, maximum inter-story drift demands and plasticizing sequence are determined and compared with the related limits using the CSM recommended in ATC 40 and ATC 55. From the results of this research, it can be concluded that RC buildings designed according to the Iraqi codes sufficiently provide the performance objectives stipulated in the ISC. Comparing structural response quantities obtained from the two versions of CSM, effects on performance evaluations of the buildings are investigated comparatively, as well.

Highlights

Building damages and collapses in severe earthquakes have caused huge life and economic losses, in different parts of the world
Single degree-of-freedom (SDOF) system approach is used in determination of demands in nonlinear static analysis procedures (NSPs) recommended in ATC 40 and FEMA 356, which is called as capacity spectrum method (CSM) and displacement coefficient method (DCM), respectively
This study investigated performance of the multi-story RC buildings designed according to the IBC and reviewed the performance objectives defined in the Iraqi Seismic Code (ISC)

Summary

Introduction

Building damages and collapses in severe earthquakes have caused huge life and economic losses, in different parts of the world. The structural engineer is interested in its concepts due to its potential benefits in assessment, design, and better understanding of structural behavior during ground motions It permits the owners and designers to select personalized performance goals for the design of different structures. In determination of response demands for seismic assessments of buildings within PBSD concept, nonlinear static analysis procedures (NSPs) are becoming more popular in structural engineering practice. Single degree-of-freedom (SDOF) system approach is used in determination of demands in NSPs recommended in ATC 40 and FEMA 356, which is called as capacity spectrum method (CSM) and displacement coefficient method (DCM), respectively These procedures have some discrepancy in determination of displacement demand for the same building model and under a specific ground motion [8] [9]. The ATC 55 Project has two objectives: the development of practical recommendations for improved prediction of inelastic structural response of buildings to earthquakes (i.e., guidance for improved application of inelastic analysis procedures), and the identification of important issues for future research

Objectives

Methods

Findings

Conclusion