INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING Volume 5, No 3, 2015 © Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0 Research article ISSN 0976 – 4399 Received on November, 2014 Published on February, 2015 216 Application of Pushover Analysis for the calculation of Behavior Factor for Reinforced Concrete Moment-Resisting Frames Mohamed S. Issa 1 , Heba M. Issa 2 1- Professor, Reinforced Concrete Research Institute, Housing and Building National Research Center, HBRC, Cairo 2- Lecturer, Reinforced Concrete Research Institute, Housing and Building National Research Center, HBRC, Cairo drmsisssa@gmail.com doi: 10.6088/ijcser.2014050021 ABSTRACT Modern seismic design codes stipulates a behavior factor (q-factor) to reduce the earthquake loads which the structure is to be designed for. This is in account for the inelastic behavior of the structure when subjected to severe earthquakes. Inelastic dynamic analysis consumes long time in the interpretation of its results. A popular and simple method for studying the nonlinear response of the structure is pushover analysis. Static type of pushover analysis is to be used in this research work where the loads consist of permanent gravity loads and incremental horizontal forces at each storey level. Capacity curves (base shear versus story total drift) obtained from static pushover analysis using a commercially available software called SeismoStruct (SeismoSoft 2014 ) are used for the calculation of some seismic demand parameters such as behavior factor, q, overstrength factor, , and ductility based reduction factor, Rμ . Four reinforced concrete moment-resisting frames each of 7, 5 and 3 stories are used in the analysis. The research work proved the efficiency of the static pushover analysis in studying the nonlinear behavior of structures and that the suggested behavior factor (q) by the Eurocode 8- Part 1 (Eurocode 8 Committee 2003 ) for non-dissipative structures presents an acceptable lower limit. Keywords: Seismic design, Behavior factor (q), Pushover analysis, Inelastic behavior, Capacity curves. 1. Introduction Nonlinear analysis is an important tool for the seismic design of structures. Among the nonlinear methods of analysis is dynamic analysis. However, this type of analysis is complex, time consuming and requires a carful interpretation of results. An efficient and simple method to assess the nonlinear behavior of structures under seismic loads is the inelastic static pushover analysis which is used here in this research work. This method is suitable for structures featuring dynamic responses that are not significantly affected by the levels of deformation incurred. Most of the modern international seismic design codes stipulates a so called behavior factor or force reduction factor (q) to reduce the earthquake loads considering the fact that the structure will show an inelastic behavior which dissipates the earthquake energy. This inelastic behavior will be associated with large inelastic deformations (ductility capacity) which governs the structural capacity in withstanding the earthquake loads. The structural ductility (μ s) is calculated as the ratio of maximum displacement to the displacement at yielding. This ductility capacity (μ s) is to be higher for structures with higher behavior factor (q).