PROUDLY SPONSORED BY
AUSTRALIAN STAINLESS STEEL DEVELOPMENT ASSOCIATION Photography: Abigail Harman. Courtesy of Structural Dynamics (Australia).
Stainless Provides Strength and St yle Taking pride of place within Perth’s Optus Stadium Park is the Arbour featuring a stainless steel cable net canopy delivered by ASSDA Member Structural Dynamics. The 60,000-capacity arena is the latest major development to hit Western Australia’s capital, boasting a world-class multi-purpose venue that combines innovative design with community infrastructure. The impressive Arbour stands 10m tall and 20m wide, and stretches 450m around the south side of the Stadium. It connects a new six-platform railway station to the Swan River, over which the Matagarup Bridge is currently being constructed to provide pedestrian access to East Perth. Over a thousand stainless steel cables were installed on the 43 arches that make up the Arbour to create a tensile structure in the form of a canopy. Suspended on the structure using bespoke fittings are 3,076 bronzed artwork panels reflecting Whadjuk and Noongar stories. Stadium Park was constructed on wetlands with cultural heritage significance to the Indigenous community, and its rich Aboriginal history was the inspiration behind the Arbour’s design. More than 13 tonnes of grade 316 stainless steel was used, including in excess of 14km of 16mm and 8mm hammaTM X 1x19 wire rope supplied by ASSDA Member Arcus Wire Group, 20,000 bespoke fittings and over 34,000 screws. Stainless steel was specified for the cable net canopy for its strength and durability to withstand the harsh Western Australian weather conditions, including powerful coastal winds driven from the Indian Ocean. The 16mm edge cables on the structure were tensioned to forces up to 52kN, with the 8mm longitudinal and transversal cables tensioned up to maximum of 11kN. In addition, the high quality and aesthetical value of stainless steel complemented the Arbour’s design in creating an eye-catching structure for patrons. Structural Dynamics provided value engineering and practical advice to the project engineer Maffeis Engineering and project architect Hassell on how to best integrate stainless steel tensile systems into the design. Their in-house team of engineers used structural and finite element analysis as components of the detailed analysis and modelling on how the cable design would behave and interact within a tensile architecture installation. Structural Dynamics also worked with engineering firm Partridge to undertake the final design, review, slip testing of the bespoke cable clamps and final sign off for the project. Each of the eight different types of cable edge clamps were sent to the National Association of Testing Authorities’ (NATA) accredited laboratory for slip testing under wet and dry conditions to ensure their strength and adequacy. The cable fittings were designed to the AS 1170 series: Structural Design Action, AS 4100: Steel Structures and AS 2759: Steel Wire Rope – Use, Operation and Maintenance. Structural Dynamics’ Project Manager Shaun Salmon explained the logistics of the assembly of the Arbour whilst maintaining safe and continued access to the Stadium for more than 1,000 workers. ‘It was important during the installation process that our team of skilled and qualified tradesmen and riggers followed the approved construction sequencing and quality management system processes whilst not impeding access to the Stadium from the primary entry point on the southern concourse. Both temporary and permanent bracing measures were used throughout construction along with sequential tightening and regular cable tension testing to achieve the design intent drape and sag of the cable net canopy and not applying adverse force to any single point on the structure.’ Structural Dynamics’ collaboration with the multiple stakeholders involved in the Arbour design and construction ensured the successful delivery of a custom-designed stainless steel cable net canopy providing the flexibility, tensile strength and structural performance required. Optus Stadium officially opened on 21 January 2018 and is the new home game venue of local Australian Football League teams Fremantle Football Club and the West Coast Eagles.
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Aerial photo of Optus Stadium Park (top) courtesy of MakMax. Arbour photos (above and right) courtesy of Structural Dynamics. Photography by Abigail Harman.
ASSDA MEMBER CONTACTS: Arcus Wire Group David Sheedy, CEO +61 2 9666 5900 firstname.lastname@example.org www.arcuswire.com
Structural Dynamics (Australia) Mitchell Cleary, Business Development Manager +61 7 5568 7084 or +61 458 484 683 email@example.com www.strudyna.com.au
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Thermal E xpansion and Design of Stainless Steel Fabrications Either while being welded or glistening in the summer sun, the three major families of stainless steel behave differently to each other, carbon steels, aluminium and copper alloys because, as shown in the bar chart (opposite page), the coefficient of thermal expansion and conductivity - and their ratio - varies. While alloys of copper and aluminium have equal or higher coefficients of expansion than austenitic stainless steels, it is the unique combination of high thermal expansion and low thermal conductivity that necessitates special precautions and procedures in the design and fabrication of the most commonly used 304/304L and 316/316L grades of austenitic stainless steel in structures and vessels. Information on handling other families of stainless steels is given in ASSDA’s Australian Stainless Reference Manual. Distortion during welding Failure to address thermal expansion and conductivity can result in severe distortion during welding, as differential expansion causes the heat generated by the welding process to remain localised, causing steep temperature gradients and high localised stresses or surface distortion. Standard welding procedures should be adopted to minimise heat build-up in the weld zone. These include using minimum amperage consistent with good weld quality and controlling interpass temperatures using guidelines provided in Table 5.10 of AS/NZS 1554.6. Clamping jigs with copper or aluminium backing bars as heat sinks on the welds may also be feasible. Other precautions to minimise distortion during welding include efficient jigging or the use of an ends and middle sequence of closely spaced tack welds rather than a straight run. The wrinkled guttering below illustrates the shrinkage problems of poorly planned welding. The Design Manual for Structural Stainless Steel2 indicates that austenitic stainless steels suffer from the same types of distortion during welding as carbon steel, but the higher coefficient of expansion (17 μm/m°C versus 12 μm/m°C for carbon steel) and the lower thermal conductivity (approximately 30% of carbon steel) increase distortion of austenitic stainless steel weldments. Duplexes are between carbon and austenitic stainless steels in thermal expansion coefficient, but the thermal conductivity is similar to austenitics so heat control is still important. Ferritic stainless steels have similar thermal welding properties to carbon steel but require more skilled welders for metallurgical reasons. The Design Manual also suggests that a number of additional actions can be considered by both the designer and the
fabricator to minimise welding distortion and mismatches such as illustrated in the manifold. These include designing with symmetrical joints, designing to accommodate wider dimensional tolerance, reducing cross-sectional area of welds in thick sections (e.g. replacing Single ‘V’ preparation by Double ‘V’ or Double ‘U’), ensuring that good fit-up and alignment are obtained prior to welding, and using balanced welding and appropriate sequences such as ‘backstepping’ and ‘block’ sequences. Expansion problems after installation Another problem arising from the high coefficient of expansion of austenitic stainless steels compared to plywood is differential expansion – although water uptake may also be an issue. In the illustrated case of stainless steel bonded to plywood by adhesive, a maximum length of 3m is recommended to avoid failure of the adhesive bond during thermal cycling. Another problem is when panels (even quite small ones) are in full sun and do not have expansion room for the movement since they were installed at (say) 20°C to the 40°C day plus 30°C overheated metal. In architectural applications with long runs such as profiled roofing, expansion clips should be used to permit thermal movement without localised buckling and failures. As with other metal roofing and cladding systems with runs 3-9m or longer, there are limits to the maximum width of formed profile for the thickness of stainless sheet used. The formed profile must have sufficient columnar rigidity and strength to transform thermal expansion stresses into sliding movement in the expansion clips. For longer runs, expansion joints should be provided every 7-12m, with clearances of 6mm at vertical faces and 12mm where a gutter end abuts a wall. The publication Stainless Steel in Architecture, Building and Construction - Guidelines for Roofs, Floors and Handrails3 illustrates roofing fixtures for roll-formed profiles and the traditional standing seam and batten roll types. In contrast, ferritic guttering and roofing have similar properties to carbon steels with about 62% of the expansion of an austenitic structure. In stainless steel piping systems, thermal expansion stresses can cause rupture of the support points, buckling of the pipe, or breakage of equipment connected to the piping if the changes in dimensions are not absorbed by expansion joints or flexibility of the piping installation. The Piping Manual for Stainless Steel Pipes for Buildings4 provides a guide to assessing thermal stresses and reactions at supports and anchor points, as well as a guide to
Distortion caused by welding practice adopted.
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determining if the flexibility of piping can absorb its expansion. The latter involves an empirical formula which requires that the piping anchor points are at the pipe’s ends, the piping system has no branches, and there are no changes along the length of the pipe (e.g. diameter, thickness, material quality, temperature, etc.). If the flexibility cannot absorb the thermal expansion displacement, then expansion joints, flexible joints or ball joints should be used (after a computer stress analysis of the joint). Conclusion Thermal expansion and conductivity are critical determinants when designing and fabricating austenitic stainless steel products and are still important with duplex stainless steels. Early consideration of these elements will ensure a better and longer-lasting product, both aesthetically and structurally. REFERENCES 1. ASSDA’s Australian Stainless Reference Manual See also: Avery, R.E. & Tuthill, A.H. (1992) Guidelines for the Welded Fabrication of Nickel-Containing Stainless Steels for CorrosionResistant Services (NI 11 007) IMOA’s Guidelines for the Welded Fabrication of Duplex Stainless Steels, 3rd Edition (2014) 2. Design Manual for Structural Stainless Steel, 4th Edition (2017): www.steel-stainless.org/designmanual 3. Cochrane, D.J. (1994) Stainless Steel in Architecture, Building and Construction - Guidelines for Roofs, Floors and Handrails (NI 11 013) 4. Nickel Institute and Japan Stainless Steel Association (1987) Piping Manual for Stainless Steel Pipes for Buildings (NI 12 008)
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Stainless Sustains Intricate Brick Facade Stainless steel is playing a vital role in the structural integrity of a new state-of-the-art library at one of Brisbane’s most prestigious boys’ school. The Centenary Library at Anglican Church Grammar School was designed by Brand + Slater Architects, and the ambitious project was part of the school’s master plan to provide a technologyrich, world-class centre for its 1800 students. Comprising four levels, the tertiary-inspired building features an extensive range of learning spaces including a 250-seat lecture theatre, teaching and meeting rooms and over 80 individual study areas. The library stands 23.5m tall on a heritage-listed part of the school campus. Paying homage to the school’s history whilst appealing
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to a contemporary aesthetic, the library exterior features an intricate brick façade backed by a stainless steel support and restraint system custom-designed and manufactured by ASSDA Member and Accredited Fabricator, Ancon. Grade 304 stainless steel was used and specified for its longevity, durability and performance properties to meet the building’s 50+ year design life. Ancon’s specialist knowledge, manufacturing agility and project management service proved invaluable to the contractor when building the detailed façade of the decorative arches and corbelled brickwork with all structural steelwork now unseen.
Shelf Angle Brick Support Ancon masonry support systems enabled the large-scale brick cladding installation on this impressive education facility to be completed to the highest safety standards, while showcasing its architectural brickwork features. Ancon’s MDC and CFA continuous shelf angle support systems carry the intricate brick façade, consisting of freestanding archways and projected brickwork. The MDC stainless steel angles are fixed to the reinforced concrete frame, span a 40mm cavity, and create a horizontal shelf to provide the necessary support for up to 3 metres of brickwork. Cast-In Channel Ancon’s 30/20 cast-in horizontal channels were used to provide the fixing between the concrete frame and shelf angles. The channel enabled the necessary horizontal adjustment for the installer, and its compact size eliminated the issue of potential clashes with the reinforcement steel in floor slabs. Nail holes aided the fixing of channels to timber framework and an infill prevented the ingress of concrete during casting. Castin fixings do not generate expansive forces in concrete. It can therefore be used at close centres and often used closer to the edges than expansion fittings. Wall Ties and Restraint Fixings To restrain the distinctive brickwork details to the reinforced concrete structure, stainless steel L-shaped SPB and SDB frame cramps were fixed into the reinforced concrete using 6mm FBN expansion bolts. FBN single expansion bolts are a cost-effective anchor and fix into a hole similar to the diameter of the bolt. This allows the hole to be drilled through the hole in the item to be fixed. Technical Expertise As part of Ancon’s free design service, plans were produced illustrating the location and reference of all fixings required. Ancon’s early engagement with the project’s structural engineers, Bligh Tanner, enabled a workable and cost-effective design to be agreed upon prior to the build of the complex masonry features. Sharing their expertise with the clients at this stage of the project meant installation difficulties, site delays and unnecessary remedial measures were avoided.
ANCON SECTION DETAIL Ancon 30 / 20 Cast-in Channel
Ancon MDC Shelf Angle
Ancon Frame Cramps
Ancon CFA Shelf Angle
ASSDA MEMBER CONTACT: Ancon Jon Bond, Managing Director 1300 304 320 firstname.lastname@example.org www.ancon.com.au
Centenary Library photos (left page and above); Copyright: Christopher Frederick Jones. Section detail (left); Copyright: Ancon.
6mm FBN Ancon 30 / 20 Cast-in Channel
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3 - 4 OCTOBER 2018 | QT GOLD COAST HOTEL
STAINLESS STEEL TRENDS IN URBAN INFRASTRUCTURE AND MODERN ARCHITECTURE Brought to you by the Australian Stainless Steel Development Association, PacRim Stainless is the premier annual conference event bringing together Australiaâ&#x20AC;&#x2122;s stainless steel industry and colleagues from abroad in an exclusive networking environment. This yearâ&#x20AC;&#x2122;s theme will discuss global mega trends in the architectural, building and infrastructure industries and explore new opportunities to drive stainless steel growth. Speakers joining the program include: Jim Lennon
Managing Director, Red Door Research Ltd (UK)
Managing Director C.M. Whittington & Associates (Hong Kong)
Senior Consultant - Commodities, Macquarie Capital (Europe)
The Australian Industry Stainless Steel Supplier and Fabricator Awards will once again be delivered during the conference Gala Dinner, showcasing excellence in supply performance, and local design and fabrication of stainless steel. For more information including sponsorship opportunities, visit www.assda.asn.au.
ABOUT ASSDA The Australian Stainless Steel Development Association (ASSDA) is a not-for-profit industry group that aims to increase the consumption of stainless steel in Australia. Established in 1992, ASSDA represents more than 150 member companies representing the stainless steel spectrum, including overseas mills, stockists and distributors, fabricators, engineering consultants, end-users and service providers. ASSDA aims to foster the understanding and use of stainless steel in Australia by developing the competence and efficiency of the industry through promotion, education and training, the provision of adequate technical advice and industry accreditation. ASSDA could not continue without the valuable support of its members, who work with ASSDA to grow the market for stainless steel. www.assda.asn.au
AUSTRALIAN STAINLESS STEEL DEVELOPMENT ASSOCIATION
ASSDA PLATINUM MEMBERS
ASSDA GOLD MEMBERS Midway Metals, Stanch Stainless Steel Co., Ltd., Stoddart, Ta Chen Stainless Pipe Co., Ltd., Viraj Profiles Ltd, YC Inox Co., Ltd. ASSDA SILVER MEMBERS Arcus Wire Group, Austral Wright Metals, Australian Stainless Distributors, Callidus, Ching-Hann Industries Co., Ltd., Dalsteel Metals, Daming International Import & Export Co., Ltd., Froch Enterprise Co., Ltd., Global Stainless Steel, Metal Centre Australia, Prochem Pipeline Products, Sanwa, Yue-Seng Industrial Co., Ltd. is proudly brought to you by the Australian Stainless Steel Development Association (ASSDA).
MORE INFORMATION Enquiries for further information on any material presented in this publication should be directed to ASSDA: Level 18, 324 Queen Street T +61 7 3220 0722 Brisbane QLD 4000 AUSTRALIA E email@example.com www.assda.asn.au EDITORIAL Contributions of story ideas specialising in stainless steel and its applications are welcome from members of ASSDA. ADVERTISING Advertise in the only publication that reached a targeted group of 5000+ in the Australian stainless steel industry. Rates available at www.assda.asn.au. CONTACT Lissel Pilcher, ASSDA Communications Manager: firstname.lastname@example.org. DISCLAIMER ASSDA sources articles and advertisements from a variety of contributors and accordingly does not accept responsibility for the accuracy of the contents of this publication nor the suitability of specific applications referred to herein for any particular use. Competent advice should be sought before acting on any matter contained in this publication.