Engineers are set to start trial piling work at the site of Ashburton’s second bridge to test how the ground will handle the new structure’s massive foundations.
Locals have been warned there could be four days of noisy work as steel hits steel.
“It will be loud at times, especially when the steel plug is hammered into place, and while it stays within safe decibel levels, the sounds cannot be fully mitigated.”
NZTA wanted to assure nearby residents that “the noise won’t be constant,” a NZTA spokesperson said.
Once the work begins there won’t be any hiding it as “the hammering part is steel on steel”.
“All going to plan, we expect the loudest part of the work to be finished within four days.
“This will be the closest piling work to residents during the entire project. The piling for the bridge will happen further away.”
Crews have already checked the soil and ground conditions, and from November 3 they plan to install a 1.5-metre-wide steel pipe about 20 metres deep into the riverbank using a cranemounted hammer.
An NZTA project update states that inside the pipe, “we’ll drill out the material inside”.
“We’ll then lift up and drop in a concrete plug with a steel top and hammer it down inside the pipe to test ground strength.
“The results will help us decide the final design of the piles (deep bridge supports) and how far into the ground they’ll need to go – saving time during construction.”
Preparations for the test pile began last week with fencing going up around the trial area and access to the river from Chalmers Avenue narrowed but still open.
After Labour Day, three leaning pine trees will be removed for safety and to make space for the crane, with the wood expected to be donated to the scouts.
A gravel pad will also be laid to stabilise heavy machinery.
Once the trial is complete, the steel casing will be cut off below ground, the hole backfilled, and the site returned to its original state, ready for the real bridgebuilding to begin.
Construction is expected to start in the first quarter of 2026.
Fletchers Construction has been appointed as the lead contractor to refine the design, explore construction methods, and address any potential challenges, before a design and construction contract is expected to be signed at the end of the year.
