ORA Dolls Point is a new high-end multi storey residential development currently under construction in Sydney. Once complete this property will feature a total of 36 one, two and three bedroom beachside luxury apartments overlooking Dolls Point Beach in Botany Bay.
Coates Hire was enlisted by residential developer HELM to deliver a high performance and highly customised full basement retention system, working as part of a multidisciplinary team.The problem
One of the most challenging aspects of this project was to achieve a feasible design that would stand up to the scrutiny of the consulting engineer. “To accomplish this, a rigorously tested and highly customised solution was required,” says Darren Browne, Coates Hire Engineer – Temporary Works.
Site restrictions further complicated delivery, with little flexibility for crane positioning on site – an issue that was compounded by the size of some of the shoring struts. “One of the super-tube hydraulic struts weighs nearly 16Tonne, which meant the crane positioning was critical to lift and extend that particular strut into place” Darren explains.The solution
Following a rigorous design and approval process, installation commenced on site in June 2019. In place of a conventional structural steel shoring system or soil anchors, a unique solution was devised utilising Coates Hire’s proprietary MP150, MP250 and MP250 Super-Tube hydraulic knee struts connected to the heavily reinforced perimeter capping beam.Complexity
For maximum strength and accuracy and minimum deflection requirements, the ORA Dolls Point shoring solution featured a lot of bespoke fabrication, casting and engineering components – largely designed in-house by our experienced engineering design team. And although a highly customised solution was necessary, the uniqueness of the design made the testing and approval processes quite time and cost efficient – in a tight design and construction schedule.Precision
Precision was an important factor during design and installation to prevent any damage to the wall, Darren explains. “For the shoring solution to work, the hydraulics struts had to be pre-stressed to apply positive pressure into a number of different struts along the wall,” he says. “This pressure had to be applied very carefully, in a predetermined sequence to minimise the deflection on certain walls and boundaries.”
Telemetry sensors embedded in the struts allowed for great precision during installation, and enabled real-time, 24x7 monitoring of the entire retention system. “The use of telemetrics meant that we always knew how the wall would react,” says Darren. “It also ensured the loads remained acceptable at all times, providing peace of mind for the entire project team.”Problem solving
Our problem solving approach and ability to collaborate and share ideas across the business, are points of difference when working with Coates Hire – strengths that worked in our favour during the installation of the ORA Dolls Point shoring solution.
“The bespoke nature of the design solution meant there were a few issues at the start,” explains Luke Niven, Installation Supervisor, Coates Hire. “It wasn’t an entirely straightforward installation, but it never is!” he says.
“Some discrepancy between the cage design and our brackets meant that we had to make some minor modifications on site,” says Luke. “There was a lot of cutting and adjusting but we worked closely with HELM and our installation team to resolve the issue and make it work.”
“No matter how much planning and testing goes into a design, there can always be surprises like these that affect installation once you start on site,” says Darren. “But Coates Hire is tenacious in finding solutions when things don’t go strictly to plan. Our design teams never close themselves off to just one concept, and we have access to vast knowledge and experience across the business when problem solving is required”.
According to Darren, working with a top tier developer like HELM also presented a great opportunity for Coates Hire. “Our client set exceptionally high standards in all aspects of delivery, from contractual arrangements through to the quality and robustness of our designs,” says Darren.
“At times we felt the weight of these expectations, but working alongside HELM taught us a lot and in many ways it helped us to grow,” Darren continues. “It was a challenging project at times, but we worked really hard and pushed ourselves to perform better – and in the end we were able to make it happen and deliver a successful project for our client.”
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