Evaluating the Residual Lifetime of Road Bridges Through Simulation

In 2015-2016 Destia Ltd conducted a study to examine the stress variations caused by actual traffic on two-lane road bridges. Actual traffic was studied using a purposely developed simulation software. Destia Ltd collected data of the traffic flow from automatic monitoring stations. An article based on the research was presented at the 19th IABSE Congress Stockholm, 21-23 September 2016 [1].

This study expands the previous analysis to include the determination of equivalent stresses that are used to estimate the fatigue damage of structural steel and reinforcing steel bars caused by actual traffic flow and to evaluate the remaining lifetime of the three existing bridges. Two of the bridges were composite bridges and one a reinforced concrete bridge. In addition to the simulated traffic the bridges were also loaded with eurocode’s static load model LM1 and fatigue load models FLM1 and FLM3. At the end, the results were compared to the simulated results.

This article focuses on the results of one of the examined bridges, Liisanniemi bridge, which is a composite bridge with 58m + 78m + 58 m spans and 8,5m width. The main results of fatigue analysis of reinforcing steel bars are also shortly presented at the end of the article.