Civil Construction

Rockhard was contracted by Rodney District Council to undertake the installation of 1200 millimetre, 1050 millimetre and 900 millimetre concrete stormwater pipes to depths up to five metres as part of the Rodney District's stormwater upgrade. The contract was completed using a mixture of open cut, pipe jacking and micro tunnelling methods through several major arterial roadways and private properties. The presence of high water tables in various positions throughout the pipeline was overcome with the use of well point dewatering. Due to poor ground conditions including the presence of running sands, the deep manholes and jacking pits for the project were installed using a combination of sheet piling and caisson sinking.

Rockhard was contracted by Taupo District Council to undertake the installation of 600 millimetre, 525 millimetre and 225 millimetre concrete sewer pipes in place of an existing 300 millimetre sewer line as part of the District's trunk sewer main upgrade.

Due to high flows in the existing sewer line, the proximity to waterways and the sensitive eco system of Lake Taupo, Rockhard had to develop a system of over pumping that would prohibit any overflows to the surrounding areas or to the existing wastewater system. The main concern for Rockhard was the successful operation of the pumping system after-hours, as blockages in the pumps could cause overflows within a few minutes. Rockhard overcame this problem by constructing a plug which enabled the onsite team to re-connect to the existing trunk sewer within 20 minutes thus overcoming the need to run the pumps overnight.

As part of the trunk sewer upgrade a major pipe bridge was required to be replaced. It was comprised of a 525 millimetre diameter pipe spanning 39 metres, supported on columns four metres high. A specific methodology had to be developed to enable the erection of new columns, installation of the new pipe and removal of the old. This work was completed in one day as to do so prevented overnight over-pumping. 

As part of the Christchurch City rebuild following the earthquakes in 2010 and 2011,  Rockhard was contracted by Fletcher Construction to undertake the installation ofsix kilometres of gravity main. The installation of the 375, 300, 225 and 150 millimetre PVC main was situated within the public road reserve and was up to 4.5 metres deep with an average water table 1.2 metres below the surface. As a consequence, extensive dewatering was undertaken by Rockhard.

Additional to the gravity main, the contract also required the upgrading of over five kilometres of 100 millimetre gravity sewer laterals by open cut and pipe bursting methods.

Due to the depth of the excavation works and the unstable nature of the ground Rockhard used trench shields for all trenches over a depth of 1.2 metres as well as sheet piles in specialist situations.

Traffic management was a significant issue for the duration of the entire contract as most of the works were undertaken in Level 2 roads.

Rockhard was contracted by Fletcher Construction in 2013 to install 2.5 kilometres of wastewater gravity main. Situated in the road reserve, the 300 millimetre and 225 millimetre diameter main reached depths of up to 3.8 metres deep and was complicated by a shallow water table which was 1.2 metres below the surface.

Additional to the gravity main, Rockhard was also responsible for upgrading over two kilometres of sewer laterals. This was completed using a combination of open cut and pipe bursting methods.

Due to the depth of the excavation works and the unstable nature of the ground Rockhard used trench shields for all trenches over a depth of 1.2 metres.

SCIRT (The Stronger Christchurch Infrastructure Rebuild Team) is responsible for rebuilding horizontal infrastructure in Christchurch following the earthquakes of 2010 and 2011. As part the infrastructure rebuild programme Rockhard was contracted by Alliance Partner, Fletcher Construction, to install the Aranui Vacuum Sewer. This involved the installation of nine kilometres of vacuum sewer main.

The installation of the 315 millimetre, 250 millimetre, 200 millimetre, 160 millimetre, 125 millimetre and 90 millimetre PE pipe main was situated within the public road reserve and was up to two metres deep with an average water table 1.2 metres below the surface. Due to the shallow water table, extensive dewatering was undertaken.

Additional to the vacuum main, the contract also required the installation of 80 vacuum sewer tanks and the installation of over three kilometres of 150 millimetre and 100 millimetre diameter gravity laterals by open cut.

Pegasus Town is a landmark greenfield development in the Waimakariri District, north of Christchurch in North Canterbury. This entirely new town is spread over approximately 400 hectares and, once complete, will be the domicile of 5,000 residents, with homes centred around a 13 hectare recreational feature lake and town centre, balanced by new wetlands adjacent to the Pegasus Bay beach.

Rockhard was contracted by Hick Bros to install over five kilometres of sewer lines, PE watermains and stormwater lines up to six metres deep for the development. 

The master planned development of Wigram Skies has been built on the site of the former Wigram Aerodrome. Consisting of a business park, a town centre, a retirement village and 1700 residential sites, the new community when complete will house over 4000 residents.  As part of this greenfield development, Rockhard was contracted by Downer Construction to install 46 kilometres of drainage services. This comprised 16 kilometres of stormwater drainage ranging from 2100 millimetres to 150 millimetres in diameter and 30 kilometres of wastewater gravity fed lines ranging from 525 millimetres to 100 millimetres in diameter. In addition to the drainage lines multiple insitu manholes, wingwalls and storage chambers were installed by Rockhard.

Located on State Highway 1 in Auckland, Victoria Park Tunnel is the final link in the New Zealand Transport Agency’s Central Motorway Improvement (CMI) initiatives between the Harbour Bridge and Newmarket. In addition to the three lane, 450 metre cut and cover tunnel through Victoria Park the $340 million project also included a number of roading and property upgrades to the surrounding CBD area. Rockhard were contracted by Main Contractor, Fletchers, to divert all existing drainage services away from the tunnel as well as provide new drainage infrastructure for the tunnel and surrounding roading network.

Te Uku Wind Farm is a wind farm at Te Uku near Raglan. Covering an area of approximately 200 hectares the $200 million project has a capacity of 64MW from its 28 turbines. Rockhard were contracted by Hick Bros to construct all stormwater drainage for the winding and often steep 24 kilometres of new roading and to install large culverts to divert streams and creeks under the road.