Probability-based assessment of the Stavå bridge

Abstract

This master thesis is about the decision-making process regarding the Stavå bridge. The main aim of the thesis is to find out what to do with the Stavå bridge. Different aspects of the decision-making process are considered. Namely, the organizational process of reassessing old structures, the socio-economics, and the structural capacity. Various decision alternatives have been established. A cost-benefit analysis has been carried out to find the cost of the alternatives. Sev eral of the decision alternatives could already at an early stadium be dismissed because of the high costs. Probabilistic methods were used to calculate the load-bearing capacity. In the project work, it was found that the traffic loads are of great importance for the safety of the bridge. The Norwegian rules on motor vehicles are used as a ba sis for the development of a site-specific load model. The load model takes the number of vehicles into account. The capacity of two different cross-sections has been assessed. The calculations indicate that the probability of failure is too high. Based on the findings, it is recommended to implement measures to reduce the probability of failure. The socio-economic considerations indicate that to strengthen the bridge is the cheapest alternative