While the big construction team was focussed on the construction of the new bridge over the Tarapahi Bridge on SH25A, a Contech team was working hard to complete the strengthening and upgrade of the seven existing bridges on the route. The route is a critical transport link between Kopu on the western side of the Coromandel Peninsula and Whangamata and Whitianga on the east.

Having previously completed the strengthening of seven bridges across the Bay of Plenty for Beca and Waka Kotahi, the Contech team had the experience and capability to deliver the upgrade of the bridges within the required timeframe.

Working in ECI with Beca, the design of the FRP strengthening work was carried out in parallel with mobilisation and concrete repair work to speed up the programme. Five of the bridges were repaired under live lane conditions with construction and local traffic still using the road during the upgrade. Two bridges were located within the construction zone established for the repair of the road corridor and construction of the new bridge.

With the new bridge due for completion by Xmas 2023, the pressure was on the team to have the road fully reopened for holiday traffic. Bridge repair and strengthening work was overlapped across multiple sites and additional resources mobilised to ensure the deadline was achieved.

The bridges comprised steel beams spanning between concrete piers and concrete decks. The bridges were all constructed in the 1960’s and were generally in good condition.

Strengthening works involved the repair of any concrete cracks and spalls found on the bridge deck and the installation of SikaWrap Hex 103 C to the underside of the bridge deck. Other minor upgrades were carried out while the scaffolding was in place including bearing pad replacements, drainage improvements and structural bolt replacements.

In October, Contech were asked to add the painting of five of the steel supporting beams into the scope of the work. This work was not required to be completed by the Xmas reopening. This work was subcontracted to Intergroup but required interfacing with the other site activities. The team set an objective to complete as many bridges as possible by the Xmas break, despite it not being a contract requirement.

All FRP strengthening work was completed in time for the Xmas road reopening. Two bridges had the painting work completed as well and were fully demobilised. The remaining bridges had additional work completed over the rest of the summer including bearing pad replacement, steelwork strengthening, and the five remaining bridges were painted.

Alongside the drainage and flood mitigation improvements made to the route during the closure, the bridges on the route are now set for an extended period to the next major maintenance upgrade, minimising the disruption to road users and improving the resilience against future flood events.

Visit our FRP Strengthening page to find out more about our structural strengthening services.