Bus and Coach Association Notifications

Construction Update June 2017: Southern Corridor Improvements

Thursday, 8 June 2017

Welcome to the June 2017 construction update for the New Zealand Transport Agency's

Southern Corridor Improvements Project

This update outlines what works we achieved in May and provides details on what we have planned for June. Photos of progress are provided at the bottom of the update.

PROGRESS THROUGH MAY

Early in the month, a major project milestone was achieved when the additional 3^rd southbound lane was opened to motorists from Hill Road to the Takanini off-ramp; and from the Takanini on-ramp to the Pahurehure Inlet. The lane has improved southbound traffic flow during peak hours. Narrowed lanes and a reduced speed limit will remain in place while improvements continue in other areas of the project.

Later in the month, demolition of the Orams Road Bridge was completed when large deck sections were removed. Construction of the new bridge abutment began with the installation of 20 piles that will provide support for the extended bridge structure.

More detail about works completed in May include:

Orams Road Bridge:

• The eastern span of Orams Road Bridge was demolished. Concrete and wire saws were used to cut sections of the deck, and a large crane lifted each section onto trucks for site removal.
• Flat platforms were constructed to improve access for workers to build the new bridge pier. 
• Piling work for the new eastern abutment was completed. Steel pipes and concrete were inserted in 20 pre-drilled holes to form support structures for the bridge foundation.
• South of the Orams Road Bridge, vegetation clearance continued to prepare the area for a new wetland pond which will help filter motorway run-off.

Hill Road to the Takanini Interchange:

• An additional southbound lane was opened from Hill Road to the Takanini Interchange off-ramp.
• In the southbound shoulder from Alfriston Road Bridge to the Takanini Interchange, noise wall installation continued, and swales and check dams were constructed. Check dams slow the flow of water and filter out larger materials in swales.
• In the median, construction of slipform barriers continued between the northbound and southbound lanes. This is scheduled for completion early June.

Takanini Interchange:

• Scour protection continued along the banks of the Papakura Stream near the new bridge abutments. Soil was removed and replaced with rocks to reduce the risk of erosion and ensure stability of the stream bank.
• On the northbound shoulder between Great South Road and the railway line, sheet piling continued to prepare the area for upcoming works on the additional lane and extended northbound on-ramp.
• Along the southbound shoulder, piling pads have been constructed to provide a stable surface for machinery to install piles at the new SH1 southbound bridge over Great South Road.
• Construction access was established off Great South Road into the existing northbound on-ramp loop. Using this new access, vegetation clearance was completed inside the loop.

Takanini Interchange to Papakura Interchange:

• Asphalting was completed in the southbound shoulder from the Takanini Interchange to the Pahurehure Inlet. Lanes were marked and temporary barriers were shifted to allow motorists access to the new additional southbound lane.
• Noise wall installation continued along the northbound and southbound shoulders from the Pahurehure Inlet to Takanini Interchange.
• Pavement works were completed in the median between the Pahurehure bridge and Pahurehure culvert. This work involved compaction of granular materials and asphalt layers.

UPCOMING WORK IN JUNE

Work over the next month will focus on constructing the new abutment, span and deck at the Orams Road Bridge. The new abutment piles will be capped prior to installing the beams. Once the bridge beams are installed, construction on the new bridge deck will begin.

To add an additional northbound lane and lengthen the northbound on-ramp at Takanini Interchange, six northbound bridges will be constructed. Two bridges will guide traffic across Great South Road, the railway line, and Papakura Stream. Piling works will continue and will provide a safe work area for further road construction.

More details about upcoming works this month include:

Orams Road Bridge:

• Substructure work will continue. Installation of steel reinforcement bars and formwork will allow a concrete capping beam to be poured on top of the piles. The concrete will be poured first in the mid-section, followed by the north side, and finally the south side of the bridge.  
• When the capping beam has cured, bearing pads will be installed to support the steel beams of the bridge deck which will be installed late June.

Hill Road to the Takanini Interchange:

• Slipform median barriers will continue to be constructed between Hill Road and the Papakura Stream. Following barrier construction, new median light poles will be installed.
• In the southbound shoulder from Alfriston Road Bridge to the Takanini Interchange, the noise wall panels will be painted. Drainage work will be completed, including swale and check dam installation. Following this work, permanent guard rails will be installed, and the temporary barriers removed.

Takanini Interchange:

• In the northbound shoulder at Papakura Stream, hollow core concrete beams will be installed on the bridge deck and will begin to form both the new northbound on-ramp and additional 3^rd traffic lane.
• Along the northbound shoulder between Great South Road and the railway line, sheet piling will be completed. Following sheet piling, soil nails will be installed to reinforce the bank prior to the construction of a retaining wall.
• In the eastbound and westbound shoulders along Great South Road, service relocation will begin to move services deeper underground.

Takanini to Pahurehure Inlet:

• Noise wall construction will continue in the northbound shoulder from the Pahurehure Inlet to Takanini Interchange. In the southbound shoulder, permanent guardrails will be installed and the temporary barriers will be removed.
• Between the Pahurehure bridge and Pahurehure culvert, southbound motorway traffic will shift towards the median, allowing a safe work zone to be established in the southbound shoulder. Following the traffic switch, earthworks will commence in the shoulder to construct the additional southbound lane.
• At the Pahurehure culvert, a new safe work zone will be established in the median (location shown in pictures below). This will allow crews to begin widening the culvert. The existing median abutment will be demolished and removed before being replaced.