Bridge abutment foundation on a basal reinforced piled embankment

摘要

The application of piled embankments and reinforced earth structures for infrastructure projects is more and more widespread in the Netherlands. For the - generally soft - soil conditions in the western part of the Netherlands, piled embankments offer an efficient building method for settlement-prone roads. Within the large scale A15 motorway widening project, which comprises the widening of the motorway A15 in the Rotterdam harbour area, piled embankments and reinforced earth structures were constructed at a number of locations. The most notable one was constructed at the motorway interchange 'Vaanplein'. For this interchange (connection of motorways A29 and A15) the abutment of one of the overpasses was founded on an embankment of geosynthetic reinforced bottom ash. The reinforced embankment itself was subsequently founded on a reinforced mattress on piles. The abutment was originally designed as a stub abutment supported on piles. By changing the design of the base plate of the abutment, tilting of the abutment and related peak stresses were reduced and the foundation stresses below the base plate were spread more evenly. This enabled a foundation directly on the embankment of reinforced bottom ash and the piled mattress below. Strength and stiffness properties of the bottom ash proved to be favourable as settlements of the abutment during and after construction remained negligible. Close coordination between geotechnical and structural possibilities resulted in a durable construction that could be built efficiently. The application of bottom ash in the embankment adding both a cost-effective and sustainable component to the construction.