Oceanbeach, Girven and Maranui Intersection Upgrade

The intersection was rebuilt as a safety upgrade with raised crossings, a centre island and new pavement, all under traffic and alongside a live retail frontage.

I was Engineer’s Representative, engaged through my own business as a subconsultant to Tonic Consulting, who held the Engineer to the Contract role. I issued the notices and instructions. The Engineer issued the payment schedules and extension of time determinations. It ran at the same time as the Welcome Bay roundabout, which I was also on.

The pavement levels

On 26 June 2024 I found that the new pavement, designed at 2 per cent crossfall, met steeper existing pavement at the tie ins and sat about 130 mm below the existing centreline. The lean mix subbase had already been cast to design levels across the whole intersection, the pavement designer advised it couldn’t be built up and the island kerbs were due to pour the next morning. There was no standard fix. Any answer traded asphalt thickness, milling, raised table geometry, design life, cost and programme against each other across 4 parties.

I set out the discrepancy and the 2 families of solution in a notice to the designer and required an urgent design review of the pavement, raised crossings, centre island and roundabout levels. 3 costed options came back. After the team meeting I instructed the one that built the levels up in 3 layers of AC20 under a single 45 mm SMA10 wearing course, with no milling of surfaces already placed and a grid laid over surveyed saw cuts to control reflective cracking. The same notice classified the change as a variation, set out the records needed to value it and opened the extension of time pathway. The next day the Scala and Clegg results set the subgrade undercut under the raised tables. That went out as its own instruction.

What I did on this project

• 71 notices to the contractor, 23 variations, 6 payment schedules and 1 extension of time assessed
• Identified the pavement level discrepancy, ran the urgent design review across 4 parties and instructed the solution with the kerb pour due the next morning
• Instructed subgrade undercut and thickness changes from the Scala and Clegg results
• Verified quantities on site and provided assessed figures for certification

Project details