13-15 Kotzikas Pl, Wigram, Christchurch

Date: July 2016

Client: IAG & Bowker Holdings Ltd

Structural Engineer: Aurecon Group

Main Contractor: Hi-Tech Building Systems

Originally constructed in 1991 this precast tilt slab building located in the Wigram area comprises two tenancies with central row of precast wall panels.

A post earthquake strength assessment by Aurecon identified an area of concern being the out of plane capacity of 8m high 120mm thick, non-ductile mesh reinforced concrete panels that had been damaged in the Canterbury 2010 and 2011 earthquakes.

Given the central position of panels as an inter-tenancy wall,  replacement was not a practical option and the design solution was to repair any cracks and strengthen with carbon fibre strips applied both sides of the wall.

Originally considered in Sika Carbodur, a more cost-effective solution emerged using Sikawrap Hex 103C strips 210mm wide at 1M centres applied both sides of the wall panels.

Working alongside the main contractor the CFRP strips were applied in three stages to accommodate the tenants’ ongoing operations.