Engineers Australia

Use of stone columns as ground improvement beneath a bridge and embankment – A case study

Jonathan Wardrop and Derek Pennington

Abstract

This paper presents a case study on the use of stone columns as ground improvement beneath a bridge and embankment. The bridge is located on reclaimed land, adjacent to the Swan River foreshore. Abutments and piers of other highway bridges in the area have traditionally been supported on piles. However, significant differential settlement has occurred between the bridges and the non-piled embankments. By using stone columns it is possible to vary the stiffness of the ground response and thus minimise differential settlements. The paper discusses the procedure used to derive in situ ground stiffness parameters, and the relation of these parameters to the current practice of stone column design. The issues of backfill selection, installation procedure and acceptance testing are also discussed, as are the results of ongoing settlement monitoring of the bridge.