Towards a Better Understanding of Behaviour of Bridges with Integral Abutments

One of the issues that has not been completely resolved in bridges built without expansion joints is the influence of seasonal temperature variations and soil characteristics on the maximum bridge length. To study this problem, a 40 meter long road composite bridge over the river Leduân in the north of Sweden was built in 2005. The bridge superstructure was cast integrally with the substructure. One row of piles on each side of the bridge was constructed to support the abutment. The bridge was continuously monitored for 18 months in order to provide information on the strain level at the top of the pile as a function of the air temperature variations. The results from the measurements were compared to results obtained from 2D Finite Element Analysis. Soil characteristics were varied in the FEA to investigate its influence on the overall bridge behaviour as well as on the level of strain variations at the top of the piles. The bridge monitoring was a part of a research project, INTAB, Economic and Durable Design of Composite Bridges with Integral Abutments, 2005–2008. The main objective of the project was to propose recommendations for rational analysis and design of bridges with integral abutments. The total environmental impact and the life cycle costs of the integral abutment bridge were compared with a concrete bridge alternative for the same crossing.