A numerical investigation on the fire response of a steel girder bridge

• Published in: Journal of constructional steel research Vol. 75; pp. 93 - 103
• Main Authors: Payá-Zaforteza, I., Garlock, M.E.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2012
• Subjects: Bridge; Bridges (structures); Carbon steel; Carbon steels; Fire; Fires; Girder bridges; Girders; Mathematical models; Performance-based approach; Stainless steel; Stainless steels; Structural steels; Performance-based approach; Carbon steel; Stainless steel; Bridge; Fire
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2012.03.012

The response of bridges subject to fire is an under researched topic despite the number of bridge failures caused by fire. Since available data shows that steel girder bridges are especially vulnerable to fire, this paper delves into their fire response by analyzing with a 3D numerical model the response of a typical bridge of 12.20m span length. A parametric study is performed considering: (1) two possibilities for the axial restraint of the bridge deck, (2) four types of structural steel for the girders (carbon steel and stainless steel grades 1.4301, 1.4401, and 1.4462), (3) three different constitutive models for carbon steel, (4) four live loads, and (5) two alternative fire loads (the hydrocarbon fire defined by Eurocode 1 and a fire corresponding to a real fire event). Results show that restraint to deck expansion coming from an adjacent span or abutment should be considered in the numerical model. In addition, times to collapse are very small when the bridge girders are built with carbon steel (between 8.5 and 18min) but they can almost double if stainless steel is used for the girders. Therefore, stainless steel is a material to consider for steel girder bridges in a high fire risk situation, especially if the bridge is located in a corrosive environment and its aesthetics deserves special attention. The methodology developed in this paper and the results obtained are useful for researchers and practitioners interested in developing and applying a performance-based approach for the design of bridges against fire. ► This paper contains a parametric study of the fire response of a steel girder bridge. ► Parameters are axial restraint, materials, constitutive models, live and fire loads. ► Times to collapse are small but they significantly increase if stainless steel is used. ► Restraint to deck expansion must be considered. Live loads have little influence. ► Research is useful for applying a performance-based approach for bridge fire design.