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A Deep Pile Foundation was installed for the Convention Centre Punt Stop and River Wall as part of the Avon River Precinct development, in earthquake-affected Christchurch.
A Category 1 heritage building “Our City O-Tautahi” was located 10m away, and there were concerns that pile driving vibrations would cause damage to this structure.
Vibration monitoring of the heritage building, using professional, independently calibrated equipment, needed to be carried out for the full duration of the piling.
There was a tight timeline for the overall project so it had to be started and completed within a quick timeframe.
The site was located in central Christchurch so disturbance to the public had to be minimised.
The poles needed to reach the target depth for engineer sign-off (there had already been sections of the river project installed by other piling contractors which had not met the depth requirements and/or had exceeded vibration limits).
The site had limited space, and hazards such as traffic, pedestrians, and the Avon River were present.
Even though the piles were to be installed into the river a small dam needed to be set up to keep water out of the site during piling.
For the river wall we used TTT SED poles (4.8m x 250mm) and TTT Uglie poles (4.2m x 250mm).
The poles we used for the punt stop were TTT SEDs (4.8m x 250mm) and TTT SEDs (4.8m x 175mm).
Using high frequency vibration equipment allowed the poles to be quickly and easily installed into the founding layer through dense intermediate layers.
The front row of piles for the river wall was essentially a retaining wall, so these would be visible and had to line up to make the wall aesthetically pleasing.
The small footprint of the installation equipment allowed for ease of access onto the tight site.
No pre-drilling was required to stand the piles, which in turn minimised disturbed ground in and near the river.
The recorded vibrations were evaluated against DIN4150 to confirm the piling did not reduce the serviceability of the heritage building.
The subcontractor, Markovina Pile Driving South Island was able to install the TTT poles in close proximity to the heritage building with no adverse effect.
The piles were trimmed to height after piling ready for the rest of the structure to be built around them.
Installation of the 49 piles took less than a day.
TDPF01 – Deep Pile Foundations tech sheet
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