Hawkins/Lower Styx/Marshland Intersection and Bridge Upgrade

Bridge expansion improves junction safety

PROJECT: Hawkins/Lower Styx/Marshland Intersection and Bridge Upgrade CONTRACTOR: Downer NZ CLIENT: Christchurch City Council VALUE: $8.5m

The delivery of the Hawkins/ Lower Styx/Marshland Bridge and Intersection Improvements project for Christchurch City Council (CCC) will support the urban growth and promote safety for road users at this busy junction. CCC awarded Downer the contract in December 2020.

Downer completed the widening of the existing bridge from 10 to 18m, installation of new traffic control signals, dedicated pedestrian crossings and cycle lanes and improved street lighting and line of sight on approaches.

Significant challenges included a sensitive river environment home to rare native fish, nettles and skinks, soft ground conditions, and the

requirement for complex activities to occur simultaneously to complete river diversion, piling, service relocations and culvert installation. Key innovations included the use of aqua dams for in-river construction over traditional sheet piling, minimising environmental impact and allowing bridge works to start six weeks early. We implemented a world 75 3CONSTRUCTION EXCELLENCE AWARDS 2022 CCNZ / HIREPOOL first method to fish for rare native lampreys and relocate them to prevent impact on this breeding site. Flax from the project area was used to create patterns on precast concrete panels instead of using a steel mould. The project achieved Practical Completion after only 11 months of construction, six months ahead of schedule.