The Kaikoura District Council (KDC) building, also known as 'The Craypot' due to its unique design inspired by traditional woven craypots, is a recent addition to Kaikoura's cityscape. Completed in 2014, the building employs a range of timbers for both the facade and structure, including a Potius floor and roof structure, LVL beams and columns and XLam Cross Laminated Timber (CLT) walls.
Key to the building's seismic performance are fifteen 13 x 3.5m CLT/LVL composite rocking shear walls from XLam, constructed with continuous Macalloy Post Tensioning Bars running down the centre. The shear walls have fuses (threaded rod energy dissipators) fixed to each side to dampen seismic energy from the earthquake. By locating the fuses on the outer faces of the wall panels, they can easily be replaced if activated.
A lighter solution than precast concrete, XLam’s rocking shear walls are designed to rock back and forth during earthquakes, significantly reducing loads on both the building and its foundations. The combination of dissipation and post-tensioning aims to minimise damage and reduce downtime following seismic events.
On Monday 14 November, 2016, following the 7.8 magnitude earthquake in Kaikoura, a team of engineers visited the KDC building to assess the impact of the earthquake. The team was confident of the building's seismic strength, but suspected that there may be some minor damage and yielding of the fuses. On inspection, few signs of damage were found other than some movement at the joints between elements, and minor cracking of the pavement outside the building — suggesting the building would be able to withstand an earthquake of an even larger magnitude. The building was in such good shape that following the earthquakes, a number of military, police and hospital staff were able to use the office spaces as a post-disaster headquarters.
XLam is the sole supplier of cross laminated timber in the Southern Hemisphere. They are able to provide custom built solutions to meet designers' specifications. For further information on how XLam's CLT products can be incorporated into seismic design and buildings in earthquake prone areas, contact XLam.
Developer: Commercial PM (Stuart Chadwick)
Architect: Design Base
Engineer: CGW (Cameron Gibson & Wells)
Engineer: Gavin Robertson Engineer
Cross Laminated Timber Supplier: XLam
Laminated Veneer Lumber Supplier: Nelson Pine
Cassette Panel Supplier: Potius