Integral bridge simulator - test series and comparison with design models and bridge monitoring results

Integral bridges are common structures due to their robust structural system and good durability characteristics. The structural behaviour of an integral bridge links together the superstructure, substructure and embankment soil. However, it is not clear what the resulting stiffness of the embankment soil is when the bridge superstructure undergoes daily and seasonal changes in its length, which cause cyclic translational displacements of the bridge ends with stub-type end screens that might be uneven. Using the 'integral bridge simulator', an experimental campaign was conducted to study the behaviour with a single soil material under different compaction ratios. The results of the study indicated that soil behaviour is sensitive to the compaction ratio, which suggests that the compaction ratio may be a contributing factor to the uneven displacements of integral bridge ends from thermal loads. A comparison of empirical design models revealed that the resulting displacement-pressure curve is associated with two factors - the displacement required to mobilise a certain ratio of passive earth pressure and the actual value of the passive earth pressure. The latter in particular varies with the compaction ratio of the soil.