Hazeldean Office Development – Commercial – capital value $20m


Design and ground improvement is completed.
Ground improvement comprised 0.7 m diameter stone columns at 1.75m spacing and 0.75m diameter columns at 1.6 m spacing with an ‘Area Replacement Ratio’ of between 14-20%.
Ground improvement was carried out to 8 m below ground level.
Ground improvement removed 67% vertical settlement for a 25-year earthquake event and 37% of vertical settlement for a 500-year event.


Ground improvement was adopted for two six-storey buildings owned by Calder Stewart Ltd to be constructed in the near future. The variable soil conditions along the site required stone columns at closer spacing and larger diameter beneath the west building due to softer soils as compared to the predominantly sandier soils beneath the east building. An added advantage of stone column ground treatment was the subsequent reduction in long term static settlement beneath both buildings.