SH39 Mangaotama Stream Bridge replacement

The Mangaotama Bridge on SH39 is a single span bridge originally built in the 1960’s. The bridge superstructure was nearing the end of it’s life and subject to temporary speed and weight restrictions. Waka Kotahi wanted to minimise any further disruption to road users and allowed 2 weeks to demolish the old and install the new bridge.  

The old bridge deck was cut into 4 pieces, lifted out and sent to a recycling plant to recover and re-use the steel and concrete.  The new bridge consisted of steel girders and a concrete deck that was built offsite in 2 pieces side by side, each weighing 55 tonnes. The 2 pieces were transported overnight to the construction site and stitched together using a high strength concrete so that it could be open to full road traffic within 7 days.

The bridge and approaches were completed on time allowing the road to be opened without any speed or weight restrictions and received very favourable feedback from the community and road users.