In 2016, the magnitude 7.8 Kaikoura earthquake significantly affected the Wellington Region, the Ava south over bridge had to be closed. Due to substantial damage sections of the pedestrian over bridge spans over the up and down main were required to be removed. SRL was involved in extensive enabling and investigative works with the engineer. The replacement structure was designed to incorporate a 50-year life cycle, which posed some construction challenges.
Work commenced on 2 December 2017 and are due for completion in September 2018. The works involve the seismic strengthening of the existing piers via the installation of piles within the rail corridor. The bridge requires 66 galvanised 7.6m piles, including 54 tonnes of galvanised steel.
The central piers for the ramp accessing the station platform were too close to the tracks to be installed whilst the trains are in operation, so It was necessary to install these piles during the Christmas Block of Line (26/12/17 – 3/01/18). This meant that the team gave up the traditional holiday period to get the job done.
Due to the efficient onsite management, the programme of works for the BOL was completed well within the constrictive time frame.
The next part of the project was to seismically strengthen the existing concrete columns and complete the foundation pads to the Wakefield and North Street sides with the lifting of the new spans into position on the BOL of the 25th and 26th of August 18. The foot Bridge was opened to the general public in September 2018