CONTRACTORS REPAIRING EARTHQUAKE-HIT Christchurch are using a hydro-demolition robot in a project to rebuild part of the city’s wastewater system. The Aqua Cutter from Aquajet Systems is playing a key role in a new wastewater system being installed by SCIRT (the Stronger Christchurch Infrastructure Rebuild Team), as part of an $85 million investment in design and construction of new and rebuilt infrastructure in the city’s district of Aranui.
Completion of repairs to the Southern Relief form one of SCIRT’s biggest projects this year. The work entails a wastewater trunk main running through densely populated parts of Christchurch. The challenge is working in confined spaces and SCIRT is using the robot for part of the repair work for efficiency and safety reasons.
The hydro-demolition robot ‘Geo’ (pictured) is providing faster and safer results for SCIRT’s McConnell Dowell team working on the Southern Relief project in Linwood. “The thought of repairing underground pipe cracks with a handheld lance, in a confined space, is enough to make any health and safety officer concerned and a crew member’s blood pressure rise,” says McConnell Dowell’s project engineer Stuart Anderson.
This is the challenge that McConnell Dowell and subcontractor Concrete Treatments NZ (CTNZ) faced when repairing the Southern Relief, a wastewater trunk main that was significantly damaged in the earthquakes. The trunk main is a 1.2 metre x 1.4 metre box culvert that takes wastewater from more than 200,000 households around Christchurch and moves it to the Bromley wastewater treatment plant.
“Using the water pressure at the flow rate required to carry out the repairs combined with the length of lance would pose a serious risk to the operator’s safety,” says Stuart.
“The solution was CTNZ’s purchase of the automated robotic hydro-excavation tool. ‘Geo’ has the ability to use the tool remotely, replacing handheld lancing. The robot’s compact nature allows it to enter and repair the box culvert safely and efficiently.
“Geo’s hydraulic and articulated arm can reach as far as three metres into horizontal, vertical and overhead areas and its use has enabled a safer working environment for the crew. It means that crew members aren’t placed in an unsafe position to deal with flying concrete debris in a restricted space.”