Case Study
Project:
Groundworks to support the relocation of Ring Main Unit
Client and Location:
Aurora, Sub-contractor to Electronet. Arthurs Point, Queenstown
Project Description
Relocation of a new Ring Main Unit (RMU) on a raised base, with retaining timber walls. Trenching, laying of conduits to current regulations and backfilling as required. Landscaping and re-shaping disturbed ground.
Project Objectives
The project's objective was to relocate an existing RMU to a new location to ensure electricity supply met the growing needs of the area around Arthur's Point, Queenstown.
Alpine Civil's role
Alpine Civil were commissioned by Electronet to complete the groundworks prior to the removal of an existing RMU. Air excavation was used to reduce the elements of risk around live high voltage cables. Trenching was completed to planned depth for the laying of conduits to safely house the high voltage cables. All were backfilled to specification with the correct materials and Magslab and danger tape laid. Retaining walls to support a raised base was required to locate the new RMUs. All electrical work was undertaken by Electronet.
Alpine Civil's works
Electronet were commissioned by Aurora to relocate an aged RMU to a location approximately 50m from the existing location. The new location for the switchgear was on a sloping grass bank on an adjacent road. The relocation and upgrade was required to support the residential developments and commercial needs within the vicinity.
The work was based in and around a residential area and in very close proximity to a traffic roundabout. To ensure the safety of residents and workers a comprehensive traffic management plan was prepared this stipulated a 4-way traffic management scheme would be required. Whilst providing the right levels of safety, it added complexity to the works that were required.
Within the work area there was a potential archaeological risk zone which again added the need for the excavator operators to take extra care. The work zone also had a multitude of services including; Queenstown Lakes District Council (QLDC) water supply, wastewater and chorus communication cables all in close proximity.
The work area also had a number of trees which had to be protected, both below and above ground.
The base for the two new RMU units had to be constructed on a grass slope and required a H4 retaining wall on three sides. The base was built up carefully with layers of graded material to ensure stability and compacted prior to the area being asphalted.
The entire work area required shaping and landscaping to bring it back to the same condition pre-works. Footpaths were reinstated after disruption.
Outcome
The new RMUs were installed on the base built by Alpine Civil on time. The location was landscaped and footpaths returned to pre-work condition all with minimal disruption to pedestrians and road users. The client recognised the challenging work area and appreciated the attention to detail provided by the Alpine Civil project manager and team on the ground.
