Fire Risk Assessment for Highway Bridge in South Korea

Abstract

This study developed a sequential and universal bridge fire risk assessment procedure for constructed bridges, and countermeasures to reduce the risk level. The bridges of interest are both concrete and steel bridges on highways except special type bridges. The developed fire risk assessment procedure consists of three steps: (1) a preliminary risk analysis (PRA), which is a screening step to determine the likelihood for bridge fire events; (2) a simplified risk analysis (SRA), which utilizes bridge inventory database and checklists; and (3) a detailed risk analysis (DRA), which utilizes computer simulation and collected data. PRA determines whether a bridge requires SRA based on bridge clearance height and roadway conditions under the bridge. SRA consists of a three part analysis: of fire occurrence, vulnerability to fire and bridge importance. Itemized details were developed to evaluate the three parts and determine risk scoring. The SRA procedure identifies which part contributes to the resultant risk level. The reliability indices that are concurrent with the current ISO DP 10252 was used to determine the score of the given bridge, and performed analysis to determine the risk level of 8267 bridges in Korea. DRA is the final step, a detailed analysis of occurrence and vulnerability of a bridge based mainly on computer simulation. This study provided guidelines to determine the DRA levels. Countermeasures were also developed for each risk level and divided into three parts, applicable to occurrence, vulnerability and importance, depending on which part caused the final risk level.