Araliya Mosleh - Department of Civil Eng., Faculty of Engineering, University of Aveiro, ۳۸۱۰-۱۹۳ Aveiro, Portugal.
Hamed Hamidi - Department of Civil Eng., Babol Noshirvani University of Technology, Iran.
Ahmad Nicknam - Department of Civil Eng., Iran University of Science&Technology, P.O. Box ۱۶۷۶۵-۱۶۳, Tehran, Iran.
José Jara - Department of Civil Eng., Faculty of Engineering, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Mexico.

Bridges, as an essential part of transportation system, play a special role in economy, politic and military all around the world. Serviceability of bridges is of high importance especially in emergencies, helping injured people and proportioning transportation after earthquakes. Earthquake regulation codes, normally suggest linear methods to conduct the analysis, and nonlinear analysis is barely used by practicing engineers. In this paper, we analyze a typical concrete bridge located in Iran and use both nonlinear dynamic and static procedures at two hazard levels. This study compares both methodologies, analyze the results and presents some recommendations to reduce the seismic vulnerability.

Concrete bridges; Seismic vulnerability; Nonlinear dynamic analysis; Nonlinear static analysis; Retrofitting