Load Bearing Stone Panel Fixing System with StoneClip
The above photo is of the internal entry of the Forsyth Barr Building in Christchurch which was hit with a 7.2 magnitude earthquake on 3/9/10. The project itself was constructed by Ambience Tiling Ltd.
The stone is Basult panels 1200mm x 600mm x 40mm THICK=80 kgs, they are supported by 3 only x 8mm adjustable Stoneclips/ panel with a cavity of 50 mm (yes 50mm) and they are secured to the substrate which is 18 mm structural plywood onto timber frame with 3 only 14 gauge Pan headed screws / back plate. The clips used were our galvanised range.
We had done testing at Stoneclip that by doubling up the fixings securing the back plate onto the substrate you could increase the loading of the clip 33 % per extra fixing, so when we used the 3 fixings / plate we actually took the loading of the clip from 14.9kgs/ clip at 50 mm cavity to in excess of 25 kgs/ clip. Even with the extra fixings we were right on the limit of the clip. The joint width was minimal =3mm, so the panels did not have a lot to flex , basically only the 3 mm. Stoneclip supervised the installation.
The building at 764 Columbo st was badly damaged and the staircase partially collapsed and prevented exit during the earthquake, gladly this wall of 40mm stone panels did not fall as the Stoneclips did what they were intended to do -- SUPPORT THE LOAD.
We are offering any installer or specifier who contacts us a sample of the above fixings free for them to assess and test themselves.
PHOTO - Strength Of StoneClip in 7.2 Christchurch Earthquake