The PGF funding agreement identified scope to address the retaining wall assets on the two roads by lifting them to accommodate HPMV loadings and increasing resilience. Stantec undertook a series of retaining wall condition assessments to prioritize the walls and identify other geotechnical risks evident along the route.
There have been more than thirty retaining walls and geotechnical risks identified as significant along the route, with a dozen of these being recognized as being critical or high risk needing remediation or replacement.
RW184 Porangahau Road - COMPLETE
RP@27488 Porangahau Road - COMPLETE
RW177 Porangahau Road - COMPLETE
RW283 Wimbledon Road - COMPLETE
RW277 Wimbledon Road - COMPLETE
RW440 - Porangahau Road - COMPLETE
RW444 – Wimbledon Road - COMPLETE
The retaining wall sites are across Porangahau and Wimbledon Roads.
There are 8 sites being investigated for future retaining walls, one site covers essentially 3 features (two retaining walls with pavement deformation behind and a shoulder slump, 4 boreholes, over 140 m of road). These have ended up as one “location’ as they are all part of the same feature, being a wide unstable slope through which the road passes.
Some photos of drilling this week so far for Retaining Walls:
The two retaining walls constructed by Downer on Porangahau Road are complete, one awaiting a guard rail.
Backfill and road rehabilitation prep is underway, the project is close to completion.
Poles are due to go in this week.
Holes for poles are currently being dug and augered.
Work is progressing well on site, last week the new poles were set out and concrete was poured at site #1 to set the poles in place.
Work is progressing on two sites along Porangahau Road where new retaining walls are being installed to improve road resilience, stability and safety.
Central Hawke’s Bay District Council has contracted Downer to strengthen two existing retaining walls on Porangahau Road, to account for the increased traffic being experienced along this major thoroughfare, and future proof for further growth.
Located 27.5km from Waipukurau. Works due to start Monday 22 June (weather dependant).
Located 28.5km from Waipukurau. Works due to start on Monday 29 June (weather dependant).
Please account for minor delays to your journey, with the potential for single lane traffic being controlled by a stop/go system, through the course of the works.
Work is scheduled for completion Sunday 23 August, (weather dependant). Council apologise in advance for any disruption to your travel through this time. Please obey road signage on the work sites for the safety of all road users and construction staff.
For further information please contact the following:
John Patten, Contract Manager – 027 232 5946
James Paston, Project Manager – 027 447 0221
This project is progressing well and is now at about 85% complete. The road now needs to be reinstated and a safety guard rail installed.
24 of the 39 piles have been installed and the project is 70% complete, the site is now safe over the festive season and will be monitored over the break. Works are expected to restart onsite on the 11th Jan 2021 and be completed by early Feb 2021.
Ongoing management of the site to install the retaining wall is underway.
Some concerns with the drop off and ability to manage the cut to establish the retaining wall is underway this week.
Backfill commences and culvert install is underway.
Site is being established
Ongoing preparation for the retaining wall posts continue.
Ongoing preparation for the retaining wall posts continue.
This week the team are removing fill to prepare for the retaining wall set out.
Currently the team continues to excavate out for the retaining wall and does this in stages (known as benches). The next week will see this continue along with the installation of basecourse layers.
The project is progressing well and the contractor is currently installing subsoil drainage before the retaining wall is constructed.
Russell Roads have commenced our second Quick Win project along this route - these projects have been identified as areas where we were able to deliver project fairly quickly along the route - the other projects along the route would take a bit longer the physically commence as we develop scope and design before getting a contractor onsite.
The linked letter has been delivered to residents around the planned project sites - works are expected to commence shortly.
The locations of the two retaining walls are outlined below.
Retaining Wall 177 on Porangahau Road
Retaining Wall 283 on Wimbledon Road
The overall construction of this retaining wall now sits at 75% completed. The riprap stone wall is completed and the work on the road reinstatement and the installation of a guard rail will commence this week.
Last week the team made great progress on the installation of the Riprap - a permanent layer of large, angular stone, used to stabilize and protect the soil surface against erosion and scour. The riprap on the face of the wall is expected to be finished this week with the overall project now 70% completed.
Last week Fulton Hogan commenced work on our fifth retaining wall in the upgrade programme, the other four being undertaken by Downer and Russell Roads.
Fulton Hogan will be working with local contractor Tuck to build a new retaining wall on Wimbledon Road to safeguard the road from slips, and to build further safety and resilience on the route. We are finalising our programme scope, but expect to be building another 4 retaining walls along the route as part of this programme of works.
We identified three risk sites along this 500m stretch on Wimbledon Road. During planning, it was found to be better value to undertake a retreat rather than address each site individually. This meant we needed to push the road 7m into the neighbouring paddock, moving it away from the subsiding edge, therefore alleviating risk of slope failure and further road degradation.
Trees were removed and the 500m retreat was built and completed in September 2022.
123m3 concrete poured
2536m3 of granular fill used
290m of guardrail installed
268m of timber used
3620m2 of chipseal used
26 people working across the retaining walls programme
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