This project was tendered on the basis of using an open cut methodology to install the pipelines. Auckland Transport would only permit the use of trenchless installation methods due to the combined impact on the traffic of this and other major projects close by.
Working two 12 hour shifts per day, we successfully installed over 400m of 1050 and 1350 diameter pipes using pipe jacking techniques. Two of the drives were in excess of 150m long.
One of the major challenges was to install about 25m of the pipeline in solid basalt. This was achieved by constructing a timber heading and using manual tunnelling methods to install the pipe.
Although this project was competitively tendered for, it was administered under an alliance framework. Monthly payments were received on the basis of actual costs plus nominated margin. This gave the client value for money plus certainty of outturn cost.