As part of the EPPS Precinct redevelopment by DevelopmentWA, ATCO’s current assets must be relocated in order to continue supply of natural gas to the Perth CBD.
The Pressure Reduction Station located on the East Perth site needed to be relocated to Bayswater. To accomplish this, DM Civil was contracted to build a 7.4km section of DN250 high pressure steel gas pipeline from Bayswater to Dianella, as well as a short realignment in East Perth itself.
The works were carried out by DM Civil and their subcontractors, and involved a mixture of horizontal directional drilling, pilot boring and open excavation to install the pipeline. Much of the installation occurred along Grand Promenade including under the Beaufort Street and Walter Road intersections, with HDD carried out while traffic remained operational. The remainder was installed in the narrow residential streets of Bayswater/Dianella and the Bayswater Light Industrial Area, with no disruptions to businesses or to multiple other civil projects operating in the same area.
The construction of the EPPS Pipeline represented a synthesis of DM Civil’s capabilities. Namely, a diverse mixture of well-planned construction methodologies combined in order to carry out a complex project in a built up and difficult location.
The bulk of the works constituted HDD installation of the DN250 steel line pipe. This involved strategic positioning of HDD entry/exit pits for fabrication of the HDD pipe strings and in-house drafting of the HDD profiles to account for ground conditions, pipe bending and the constrained working areas. Despite drill shots up to 330m long, and in varying ground conditions, each shot was ultimately successful and high rates of productivity were achieved despite encountering groundwater, coffee rock and working amongst many live congested streets.
The open excavated portion of the works constituted an approximately 1km work front through the narrow suburban streets of Bayswater. Dealing with very sandy ground conditions, tight working spaces, well established trees and verges, re-designs and re-alignments, the construction team completed this portion of the works with minimal issues.
Pilot boring to install line pipe for high pressure gas applications is not a typical method utilised by our client ATCO Gas. However, pilot boring was successfully carried out across this project with 13 bores completed. This method proved most useful in areas too tight for HDD strings to be fabricated, but where trenchless installation was still necessary due to the presence of high-profile existing services and roads.