The solution to ensuring the structures were suitable was to take a staged approach:
Stage 1: Scan lintel in no. 5 O’Connell St and Spandrel Panels at no. 10. CSI provided a report to the client.
Stage 2: Ultimately there was not enough reinforcing steel to hang the ‘O’ from in the Lintel at no. 5. Therefore CSI came back in and scanned the ceiling and provided an updated report.
Stage 3: CSI were then presented with a design that required precision drilling from the inside! This design was obtained via the engineer’s Point Cloud Survey which he then used to determine the exact position required for the cables. The precision drilling was essential so as not to deface the Heritage Buildings. The precision drilling was also essential to enable the support cable to be hung from the ceiling at no. 5 and pass through the beam, then the cable had to be hung off 2 columns at no. 10.
Before the final install riggers connected the 3 brackets required and it was CSI’s job to proof test these fixings.
To get 10mm cables through 20mm drill holes totally unimpeded. After analysing the Point Cloud information it was clear a perfect angle for the drilling was required.
A special rig had to be put together by CSI to achieve the precision drilling. This was a purpose built rig that took the best part of a day to put together.
CSI successfully drilled 20mm holes through the Oamaru lintel stone without hitting any reinforcement and thus avoided compromising the integrity of the heritage building. This was achieved through a combination of scan analysis, CAD sketch, and the purpose built rig.
CSI tested the fixings where they were able to take the load specified by the engineer, demonstrating that CSI has installed these fixings by accurately following the manufacturer recommendation.
The ‘O’ has successfully survived, anchored since June 2018
Check out the video of the O here.