Assesment of Severely ASR Damaged Bridges: From Diagnosis to Structural Effects

During the last decade an increasing number of bridges are becoming severely deteriorated due to alkali-silica reaction (ASR) in Denmark. Some bridges have already been demolished due to lack of knowledge on the residual load carrying capacity. The deterioration of concrete by ASR has been widely documented. The majority of the experimental data are based on relatively small scale laboratory specimens accelerated by various exposure conditions. Research on assessment and influence of severely ASR deterioration on the material properties and residual load carrying capacity of real-life structures is unfortunately limited. This paper presents an overview and discussion of the Danish experiences with assessment of the residual load carrying capacity of severely non-shear reinforced ASR damaged bridges. The discussion is supported by experimental data acquired from large scale in-situ tests of three severely ASR deteriorated bridges. The influence of ASR cracking on the mechanical properties of concrete and the pre-stress effect on the reinforcement due to ASR expansion are discussed.