The Canterbury Earthquake Recovery Authority (CERA) and a number of insurance companies are currently demolishing several hundred crown-owned red-zoned residential properties on the Port Hills of Christchurch. As a result of the Canterbury Earthquakes the properties lie within steep terrain significantly impacted by cliff collapse, debris inundation, rock fall and land slippage.
The situation in the Port Hills is unique. These houses were often architecturally designed, which makes their behaviour during earthquakes and the method of deconstruction different in every case. In addition, their hazardous locations have caused challenges as to how Aurecon’s teams access and assess these sites without putting staff in danger.
As the sites are in residential areas, further challenges were that demolition works have the potential to affect the general public and lifeline infrastructure. Additionally the work is very public, interfaces with multiple stakeholders and landowners, and attracts national media attention.
Working closely with CERA, the Aurecon Geotechnical Team used a Safety in Design approach to promote a zero harm culture from the ground up. A major component of the approach is the System of Site Assessments (the system) designed by Aurecon. The purpose of the system is to identify existing risks and constraints to demolition and land management at an early stage. The system is also easily tailored to each site, but the overall process remains consistent which provides an appropriate level of detail while remaining cost effective. The system takes a multidisciplinary approach and is supported by the project managers and quantity surveyors working collaboratively on the CERA Land Clearance Project.
Aurecon’s approach encourages collaboration and an understanding of risks and constraints, which in turn promotes innovation from all parties. Demolition solutions including cranes, helicopters and remote controlled plant were developed by Aurecon in conjunction with the University of Canterbury, including the use of an unmanned aerial vehicle (UAV or drone) to collect information from high risk areas using high definition cameras. This eliminates the unfavourable option of either sending people into hazardous locations or work uninformed. Our innovative use of UAVs was the subject of a documentary with Discovery Channel and gained Aurecon a position as a finalist in the 2014 New Zealand Site Safe Construction Health and Safety Awards.
Safety and the community are at the heart of everything we do on this project, from identifying hazards to communicating residual risks. The main benefit to the Christchurch Port Hills community is that we minimise disruption and keep everyone safe and informed.