Case studies – Bridge Replacement, Upper Hutt
Aardvark Concrete Services Ltd were involved in the rebuilding of three bridges along Akatarawa Road, Upper Hutt, approximately 13-17km from the SH2 junction. The Akatarawa Valley road is a scenic route linking Upper Hutt with Waikanae and the Kapiti Coast with the existing timber truss bridges constructed in the 1930s, they had reached the end of their economic life.
The maintenance of the existing bridges had become a significant annual cost to council, and potentially a safety problem for motorists.
The project was started in March 2011 with most of the concrete work being completed throughout July and August 2011.
The Akatarawa Road was reopened in October 2011 at Labour Weekend when the three new bridges were completed.
Rigging the reinforcing and formwork on the northern abutment was completed in July and the concrete was poured in August 2011. The pour began at 3:30am in the morning and was finished at 5:00pm.
The seven metre abutment required 90 cubic metres (20 truckloads) of concrete and was poured in a single continuous pour.
Once the abutment was poured the area behind it was backfilled and the bridge was ready for the beams to be placed.
The formwork (boxing) and reinforcing steel on the northern abutment was poured in August 2011. Construction of the abutment on the southern side of the river was also completed at this time with the nine metre abutment being the biggest of the project and requiring two concrete pours.
This concrete pour put in place the lower eight metres of the abutment and was the single biggest concrete pour of the project. The limiting factor is the ability of the formwork to contain the pressure resulting from the eight metres of liquid concrete.
Once again the team at Aardvark Concrete Services Ltd proved their readiness – the pour began at 4am and required 160 cubic metres (32 truckloads) of concrete.