Pole Structures (a division of Steve Bowling Contracting Limited) won a contract in Manukau to complete a package of retaining walls as part of a large land development. The contract was for the construction of 100 retaining walls, some of them up to 4m high and a total face area of 3400 m2. The design of the walls was a galvanised structural steel UB poles, with 200 x 50 rough sawn timber lagging, along with four Compac IV keystone retaining walls. There was over 30,000 lineal meters of timber on these walls.
The challenges involved with this project were working in a land development which included interfaces with other subcontract trades like drainage, roading and earthworks. The development was a hive of activity so co-ordinating the delivery of materials and machinery to ensure it wouldn’t cause problems for other trades or services was crucial.
The most innovative part of the project was the bespoke clamping system in order to get the piles to the correct height and line. Some walls were required to be constructed plumb and others with a rake of 1:10.This saved us significant time in placing the piles and ensured accuracy with minimal tolerances. On the as-built survey all of the walls were constructed well within tolerance. Over more than 1700 poles, this innovation meant we were able to successfully deliver the project to our client the most economically and efficiently.
