Compacting the preload backfill

What we have been up to in Stage 2

Good progress was made over winter completing the wick drains and installing the monitoring equipment. Wick drains provide drainage paths to remove water out of the ground, so it compresses and strengthens faster.

The preload bulk fill is complete for both the northern and southern approach. Over 90,000T of material was imported, placed and compacted. The northern approach preload is now at a 95% settlement phase, allowing us to start on deep stormwater drainage, batter trimming and shaping.

We’ve been doing more preparation such as:

• ground improvement piling trials
• utility investigations
• service re-routing
• assembly of temporary works bridge staging.

In our last update, we talked about how we’d started the Drilled Displacement Piling (DDP ) for ground improvements at the Otaika Creek bridge. In the early stages of this work, we came across unexpected ground conditions, which has made this type of piling method difficult We’ve had to come up with a new way to construct these piles. A lot of work is being done to get this sorted quicky, and we're still on track for completion in early 2025.

Otaika Bridge staging

What’s coming up (October to December 2023)

Towards the end of 2023, the team plans to complete stormwater drainage on the northern approach, and we expect the preload on the southern approach to have finished settlement.

From October, there'll be a lot of visible work and some road layout changes (see update below), as the team starts on the construction of the southern tie-in road widening and pavement surface overlay.

We plan to restart works on the Otaika Bridge, with the installation of the temporary works staging, and then begin the bridge abutment ground improvement piling. A bridge abutment is a structure that supports the weight of the bridge where it connects to the ground.

Temporary speed limit signage

Southern tie-in to Portland Road widening

Early October to mid December 2023

• Work begins on pavement sealing and widening the road at the southbound (eastern) end of the Portland Road intersection.
• Reduced lane widths and speed restrictions will be in place.

Mid December 2023 to February 2024

• Traffic will shift onto the new pavement to allow for works on the northbound (western) side.
• There will be a 50kph speed limit in place.

Construction includes:

• bulk earthwork operations
• vegetation clearance
• deep drainage
• utilities and streetlighting
• kerb and channels and new pavement and surfacing
• building the concrete reinforced retaining wall along Otaika Creek edge following the new pavement.

Temporary speed limits

For safety and efficiency, there will be lane narrowing and a temporary speed limit of 30kph in place between Oaks Road and Portland Road during the week. The temporary speed limit will return to 50kph during weekends, public holidays and over the Christmas shutdown period.

There will be other safety features in place:

• traffic kerb separators
• flexible bollards
• line marking
• signage
• cones along both sides of the highway
• site access points managed by our traffic controllers.

More information

For more information on the SH1 Loop Road improvements, contact us at northlandproject@nzta.govt.nz

Visit our website www.nzta.govt.nz/loop-road