Earthquakes and Structures, Vol. 7, No. 2 (2014) 201-216 DOI: http://dx.doi.Org/10.12989/eas.2014.7.2.201 201 Seismic vulnerability assessment of confined masonry wall buildings Fariman Ranjbaran*1 and Mahmood Hosseini2 1 Deptartment of Civil Engineering, Islamshahr Branch of the Islamic Azad University (IAU), Islamshahr, Tehran, Iran 2Structural Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran (Received September 14, 2012, Revised January 3, 2014, Accepted March 5, 2014) Abstract. In this paper the vulnerability of the confined masonry buildings is evaluated analytically. The proposed approach includes the nonlinear dynamic analysis of the two-story confined masonry buildings with common plan as a reference structure. In this approach the damage level is calculated based on the probability of exceedance of loss vs a specified ground motion in the form of fragility curves. The fragility curves of confined masonry wall buildings are presented in two levels of limit states corresponding to elastic and maximum strength versus PGA based on analytical method. In this regard the randomness of parameters indicating the characteristics of the building structure as well as ground motion is considered as likely uncertainties. In order to develop the analytical fragility curves the proposed analytical models of confined masonry walls in a previous investigation of the authors, are used to specify the damage indices and responses of the structure. In order to obtain damage indices a series of pushover analyses are performed, and to identify the seismic demand a series of nonlinear dynamic analysis are conducted. Finally by considering various mechanical and geometric parameters of masonry walls and numerous accelerograms, the fragility curves with assuming a log normal distribution of data are derived based on capacity and demand of building structures in a probabilistic approach Keywords: confined masonry buildings; analytical models of confined masonry; fragility curves; vulnerability of confined masonry; openSees; DIANA 1. Introduction Destructive Earthquakes cause fatality and financial damages in earthquake-prone countries periodically. On the other hand, for risk analysis and retrofitting of structures in order to preventing or decreasing disaster, the seismic vulnerability assessment of buildings is required. Seismic vulnerability assessment and damage scenarios are usually based on macro-seismic method by using macro-seismic intensity hazard map or mechanical methods. In the mechanical methods the seismic vulnerability assessment is acheived by simulating the structural capacity based on mechanical models and represent the hazard scenarios in terms of peak ground ♦Corresponding author, Assistant Professor, E-mail: ranjbaran_far@iiau.ac.ir. Copyright © 2014 Techno-Press, Ltd. http://www.techno-press.org/?journal=eas&subpage=7 ISSN: 2092-7614 (Print), 2092-7622 (Online)