Radio Network House
Following a request made by the Government of New Zealand to the US Department of State, CDI’s President, Mark Loizeaux, lead a team of technical experts from the US Army Corp of Engineers and private sector in review of major failed, yet standing structures following the 2011 earthquake in Christchurch. In that review, the team of experts inspected each major structure, interviewed local demolishers to determine their capabilities and experience and ultimately offered an opinion on the means and methods which could be employed to bring individual structures safely to grade.
While several of the major structures lent themselves to explosives demolition, the City of Christchurch decided to proceed with conventional demolition methods. It wasn’t until the 14-story, reinforced concrete Radio Network House came out to bid that the local authorities considered the use of explosives to bring the structure down.
CERES NZ, LLC was the successful main demolition bidder providing an implosion approach using CDI’s services. Following a preparation plan designed by CDI based on more than 70 years of explosives demolition experience in felling both sound and damaged structural systems, CERES prepared the structure for implosion in less than a week.
A total of 120 holes were drilled into the main concrete support columns in the structure on the lower ground, upper ground, 2nd, 5th and 9th Floors. CDI, working with representatives of Orica NZ, loaded less than 60 kg of explosives into those holes. Precisely on time, the morning of 28 July 2012, the charges were detonated and the structure was brought to grade, exactly per plan.
Vibration recorded by independent third party geotechnical contractors was below conservative estimates that had been provided based on historic data. An earthquake-damaged historic structure across the street was not damaged further by the implosion and a third party property under insurance company demolition protest was not damaged even though it was less than 4 meters away. The perfectly executed Radio House implosion set the stage for further use of implosion technology in bringing down either structures with existing earthquake damaged structures or structures which did not meet new code moving forward. The use of an implosion operation can save time, reduce demolition costs and mitigates the exposure of the public to the duration of what would otherwise be lengthy conventional demolition operations.