Analysis of the Factors that Influence the Maximum Adiabatic Temperatures in I-girder Bridges

Abstract

Bridges are a critical element of the transportation system of a country. To ensure bridge safety and functionality, bridge design is guided by bridge standards which prescribe the loads to be considered when designing a bridge or when assessing its structural performance. However, bridge standards do not make any reference to fire, despite the fact that bridge fires are a real threat and a major concern nowadays. This paper uses Computational Fluid Dynamics simulations to study the parameters influencing the temperatures in the gas surrounding I girder bridges during a fire, since this is a critical parameter governing the response of the bridge. More specifically, the study considers four geometric parameters (vertical clearance, bridge substructure configuration, span length and bridge width) and two fire scenario parameters (position of the fire load and type of fuel). Results show that vertical clearance, type of fuel and position of the fire load are the most influential parameters for the flange temperatures and that web temperatures are also influenced by the bridge substructure configuration.