Wairoa Bridge – Jacking and Levelling and Locking

Northern Express Link-Wairoa River Bridge, Tauranga


The Wairoa Bridge had suffered from uniform settlement on 4 piers during its initial construction phase.


The challenge was to keep every jacking point synchronised and within a one millimetre tolerance. This was because a topping slab and other parts of the bridge were already constructed and at risk of suffering major damage, if the load wasn’t controlled and jacked evenly.


Meccanico was required to jack at each pier with 6x 250t locking jacks using a synchronised lifting and levelling system to control loads and lift to target heights so central concrete beams could be poured. Our 250t locking jacks enabled the bridge to be locked at the required height to pour concrete without using alternative propping systems like megashore or custom made steel shims. The total estimated weight of the bridge was 1000 tonnes but at each pier 150 tonnes.
A total of 24 jacks were installed under the bridge super tees ( concrete bridge beams ) along with our built in monitoring system ( displacement measurement ) and all loads were controlled via our synchronised computer system. On completion of meeting the target heights the project could resume again.


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