Over the halfway point for SH6 emergency repairs
We are now just past the halfway point of the emergency repair work on SH6 between Hira and just before the Rai Valley township.
There is a huge amount of work happening on the road, with additional crews at Site One and Site Four and at the river and road realignment works at the Whangamoa River.
Site One
Getting the first concrete pour on Site One has been the key focus for the crew with the first pour being the largest and most complex. The wall is being constructed in a series of blocks each building on the previous block created by pouring concrete into form work (temporary mould). Each of the five vertical concrete lifts are approximately one metre in height and in total contain over 15 tonnes of reinforcing steel and 200m3 of concrete.
Site Two
Additional excavation and drainage at Site Two have been completed. The crew have placed three of nine layers of the reinforced fill (Mechanically Stabilised Earth wall). Substantial drainage improvements are also going in for this site, of which two of the four double catchpits and some rock lined channel has been completed. A catchpit is an empty chamber that is installed into a drainage system to prevent silt and debris from building up and causing blockages. The rock lined channel helps to carry surface runoff in a non-erosive way downstream.
Site Three
Site Three is tracking along well and is a similar block form to Site One. The crew have poured the first and second block (or lift) and are now starting the backfilling and getting ready to start construction of the third and final lift. Once the final lift is complete, construction of the road pavement and asphalt seal can occur, alongside replacement of the guardrail.
Site Four
The focus for Site Four was getting the drilling completed, so the site concrete and formwork for the ground beam can begin. This is our most complex and largest site. Site Four had a larger crew flown in to work over the weekend to get the work done. With the ground anchors and micro piles complete on the lower beam, site concrete was able to be placed last week. With site concrete in place, the crew is now able to start the steel and formwork construction, with the steel columns and timber lagging planned to be done at night.
Culvert replacement near Site Four
The drainage crew have nearly completed the installation of the 1350mm diameter concrete culvert and have started on the inlet structure which consists of a large concrete wingwall, and railway iron driven into the stream bed to stop debris blocking the inlet. Several other culverts are also being replaced throughout the closure zone to make the route more resilient to heavy rain events.
Whangamoa River Scour and Road Realignment
The scour site now consists of two work areas, being the river scour rock work and a 200 metre road realignment. The river works consists of river diversion, 2,500 tonnes of rip-rap installation and granular backfilling. The road realignment consists of a newly designed road curve to shift it away from the river, culvert changes and 200 metres of new guardrail.
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