22 July 2013 - A NZD6.4 million building currently under construction in central Christchurch will feature an engineering first in New Zealand.
The three-storey office building, at 53 Victoria St opposite Christchurch Casino, will use double concave slider bearings to base isolate the building.
Aurecon Technical Director Grant Wilby said the highly engineered bearings would reduce damage from any future earthquakes and would be located below the ground floor in a shallow basement.
Aurecon is providing all consulting engineering services apart from mechanical to the Victoria St building, which has been designed by Thom Craig. The project managers are Priority Projects.
“The isolation bearings are being manufactured in New Zealand. This is the first time bearings of this type have been used here although they are used extensively overseas.”
Dr Wilby said the advantage of the double concave slider bearings over lead rubber bearings was a greater reduction in shaking of the building and its contents and a greater design flexibility as the properties of the bearings could be independently specified.
“The bearings are able to move up to 400mm in a severe earthquake. They’re a much simpler type of bearing and consist of sliding puck housed between curved top and bottom plates. The plates are lined with stainless steel and the top and bottom surfaces of the puck are lined with a material that has well established and durable friction properties.”
He said the top and bottom plates of the bearings were cast in Thames, with the stainless steel liners pressed into shape in Christchurch and bonded to the plates.
“At Aurecon we’re using bearings of this nature in other Christchurch projects and because of their advantages are also proposing to use them on other new and strengthening projects throughout the country. We expect their use to become more widespread.”
“New Zealand initiated modern base isolation with the invention of the lead rubber bearing in the 1970s. Other countries followed us but also branches out and investigated other types of bearings, whereas NZ stuck to the lead rubber bearings.”