Live load factors for reliability-based bridge evaluation

In Korea, new load models and load factors have been adopted for the first reliability-based (or limit state) bridge design code. To keep up with new design code and perform proper management of increased number of existing bridges, reliability-based bridge evaluation is essential, which gives more rational and comprehensive tools for evaluation. This paper presents the reliability-based procedure to determine live load factors for strength evaluation of existing bridges. Evaluation load factors are different from design load factors in the fact that they consider local and environmental effects at evaluation point of time, evaluation interval and so on. In this study, various factors are considered including the weight distribution, the number of trucks (average daily truck traffic, ADTT), proportion of each truck type, probabilities of multiple truck presences and so on. Differences between statistical properties of live loads between evaluation and design are also analyzed. The results are compared with other international codes.