Minor repairs to this multi-story building were required following the 4 September 2010 Darfield earthquake.
Concrete window surrounds and sections of floor slab required patch repairs, and areas of brickwork needed to be dismantled and rebuilt. The entire building was scaffolded and wrapped in plastic to allow safe access to the damaged areas. Problems with the original wall tie system were soon uncovered and a solution sought.
The project engineers had already specified PatchPin to be used to provide a mechanical key in areas selected for concrete patch repair. Small holes were being drilled into these areas and stainless steel PatchPins were being driven into position using a support tool fitted to an SDS drill. DryFix was soon added to the scope of works when concerns were raised over the state of connection between the external brick cladding and the internal reinforced concrete superstructure.
To re-tie the panels, small holes were again drilled, this time through the existing brickwork panels and into the concrete behind at regular vertical and horizontal spacings. Several thousand self-tapping, stainless steel DryFix ties were then driven into position to produce a secure mechanical connection. Entry points were patched with an oxide-coloured mortar to leave a near invisible retrofit. Installation took less than a week with contractors working outside normal business hours to minimise disruption to building occupants.