Construction of a two-lane roundabout to link the new Kopu Bridge with State Highway 26 (Thames to Paeroa) is under way - nine weeks earlier than planned.
The four-leg roundabout is part of the NZ Transport Agency’s Kopu Bridge Replacement Project on SH25 just south of Thames. The project includes the roundabout and 2.5km of approach roads either side of the new two-lane bridge.
Construction of the $47m Kopu Bridge was brought forward last year as part of the Government’s $500m Jobs and Growth Plan. Once completed, it will reduce travelling times and reduce costs for all bridge users.
NZ Transport Agency (NZTA) Project Management Services Manager Bryce Carter said the settlement targets were achieved earlier than planned, which has allowed construction to begin.
Prior to construction commencing, an embankment of rock covered the roundabout site. The weight of the rock has been used to compress the underlying soils to provide a solid base for the roundabout.
Excavation of the roundabout site is almost complete, and pavement construction is about to start.
Rock from the roundabout embankment has been used to ‘top up’ the rock embankments on the bridge approaches, along with imported rock from a nearby quarry. Because the soft soils are deeper near the bridge, longer settlement times are required. In the first stage of settlement, the subsoils under the rock embankments have settled approximately one metre so far.
By the end of August, approximately 500 truckloads of additional rock will have been laid on the eastern approach, and 400 truckloads on the western approach – an additional 11,000 cubic metres. The embankment ‘top up’ will continue through to October, when the embankments will be left to settle for a further 9-10 months.
Mr Carter said the project remains on track for completion in mid-2012.