Category: 6 ID Number: 5111
Location: 253 Pacific Highway, Coffs Harbour, NSW
Client: Park Beach Plaza
Completion Date: February 2013
Architect: Red Dog Architects
Structural Engineer: DeGroot Benson
Specialists: Tensys Engineers - Structural Design
Builder: Edwards Constructions
Fabricator: Ronstan International, Locker Group
Installer: Ronstan International
PROJECT APPLICATION AND DESCRIPTION: Facade
Design, fabrication and installation of cable supported perforated aluminium façade on Park Beach Plaza Car Park at Coffs Harbour.
This project is collaboration between 3 parties.
Party 1 is a manufacturer of perforated panels and has developed a new façade system in collaboration with Party 2 who is an architectural rigging specialist and Party 3 who is a light weight structures specialist engineer.
Party 1 is responsible for Project Management and panel fabrication, Party 2 for Construction Management, cable fabrication and site installation and Party 3 is responsible for all aspects of structural design with checking of building capacity to support the façade by the project engineer.
The system is composed of stacks of perforated aluminium panels supported on tensioned cables.
The panels provide shading to facades whilst still allowing for good light transmission.
Panels can be folded and perforation patterns and densities varied to produce different shading effects and images.
For optimum shading effects the upward facing surface is punched with a low porosity perforation pattern and the downward facing surface is punched with a high porosity perforation pattern.
Supporting the panels on cables spanning between floors of buildings is a lightweight support solution.
Cables are tensioned to limit deflections.
Park Beach Plaza is the first project making full use of the system albeit to provide colour and excitement rather than a shaded façade.
DESIGN / FABRICATION / INSTALLATION BRIEF
Park Beach Plaza Redevelopment includes construction of a new multilevel car park structure with extensive frontage overlooked by the Pacific Highway in Coffs Harbour.
Originally conceived with precast concrete fins on the façade, the client’s architect in consultation with Party 1 developed an alternative lightweight, colourful, dynamic, eye-catching and cost effective perforated façade with form and colour combinations to be a stylistic representation of ocean waves breaking on the shore.
The porosity of the panels was critical in achieving the natural ventilation requirements for a car park.
Both frame supported and cable supported facades were considered by the client’s team and the cable supported system was considered to be uncluttered and virtually invisible and so all attention is drawn to the façade rather than the support framing.
Timing was such that the car park was already designed and partially constructed and so the structural system was designed to suit and not overload any existing elements.
Stacks of perforated powdercoated aluminium façade panels are supported on pairs of tensioned vertical cables. The cables are typically anchored at the top onto RHS beams attached to the handrails and at the base to RHS beams attached to vertical elements at slab level. There are also intermediate cable connections attached to slabs and handrails.
Cables are designed to be pretensioned to 13kN to limit panel deflections under wind load.
Cable anchorages were detailed so cables could be easily tensioned and not reliant upon turn of riggings screws under load.
Cable anchorages include articulation with low friction spherical washers and nuts that act to limit the bending in the cable end fittings under wind load deflections.
Panel design was proven with full scale testing of typical panels.
Cable anchorage systems were also tested and this is subject to ongoing investigation and refinement for similar future applications.
Perforated aluminium panels are fabricated using dedicated programmable machines. Perforation patterns can vary in density and position within a panel but in this case the perforation pattern was uniform across all panels except for panels located at handrails where smaller holes were required to make panels non-climbable.
Panels are fabricated from thin–walled aluminium sheet and are lightweight and easily handled by one man. Panels are finished with a highly durable fluoropolymer powder coating.
Cables and hardware are Grade 316 SS for long service life. The support structures (by others) are galvanized steel and we have non-metallic isolation at all interfaces.
All details and elements were shop detailed and coordinated. One CAD model was used which included the support structure (provided by the builder) onto which all details of the façade were added.
All panels, cables and connection hardware were fabricated and finished offsite and shipped to Coffs Harbour.
COLLABORATION, CONSTRUCTION AND MAINTENANCE
Party 3 designed the complete façade structure including development and overview of Panel testing.
Perforated panel capacity to span was proven with full scale testing undertaken by Party 1.
Party 2 developed and adopted a novel method for installation of the panels.
Panel clamps were set out accurately and attached to cables in the factory.
Panels were attached to cables on the ground adjacent to the façade at site. 10 to 12 panel stacks were prepared each day and then crane lifted into position and secured to the façade in one crane mobilization each on the following morning.
This method of handling panels and cables was proven with a trial setup in the factory before shipping.
This process was proven to be cost and time effective and minimized risks of working at height.
Following lifting stacks to position, cables were then tensioned using jacks to nominated tensions and Intermediate supports made good.
Cable tensions were checked using a tension meter.
The system is virtually maintenance free. Painted panels and stainless cables require annual inspection and cleaning to maintain manufacturer’s warranties.