LSAA Lightweight Structures Association of Australasia Inc.

THe Tension Fabric Roof of the Perth Optus Stadium

Australian Summer of Cricket 2024-25

We have already witnessed three completely different Test Cricket matches between the visiting Indian team and our perhaps aging Aussie team.

If you ended up here wanting to delve deeper into this fascinating game then I am sorry.

This very brief article is to say that the venues used for these contests - or at least the stadium roof structures - are the focus for much of the work that our members are focused on.

The one sided Perth match was held in the relatively new Optus Stadium (see article in our Projects --> Stadiums page)

Adelaide also has a revamped stadium as described in this article The 2024 match was one-sided the other way.

Onto a rain soaked drawn match at the Gabba cricket ground. This stadium roof was partially converted to a tension membrane roof in the mid 1990s with this style of roof extended in later years. Both teams showed some areas of concern with injuries making the Boxing Day Test in Melbourne an event to be watched keenly.

Some other stadiums around the country are included below - the Metricon stadium and the AAMI stadium in Melbourne are samples.

We have a web page devoted to stadiums that our members have been involved with from design input, fabrication of the tensile membranes and their installation. Some of these projects on the Projects page are overseas work.

If you are involved in this type of architecture, design, engineering or construction your should consider joining the LSAA

Hypar lattice shells form the lower spire skirt of the Victorian Arts Centre

Melbourne Arts Centre Spire and Theatres Celebrate 40 Years

Design Work on the Spire from 1973

Dr Peter Kneen

My initial involvement with Sir Roy Grounds and the design of the Spire followed on from a meeting with senior engineers from John Connell and Associates (JCA) at a Conference about Tall Buildings at the University of Sydney in 1973. As a result I was engaged to carry out a complete design check on the four large spaceframe roof structures proposed for the Collins Place Project and another four roofs for the Canberra Hospital Services Complex.

The Arts Centre Spire and Meeting Sir Roy Grounds

At the end of being briefed on these two projects, we were in Andrew Goad’s office (JCA) and on the wall behind there was a drawing of a tall tapering lattice tower.

It turned out that this was the state of play for the design of the Spire for the Victorian Arts Centre. I had last heard of the spire whilst in High School when pupils were encouraged to save their copper coins for the copper clad spire. John Peyton asked, “do you want to have a go at that one?” I answered with a yes and so John contacted the architect Sir Roy Grounds, and he agreed to meet me the next day where he defined the basic criteria to be satisfied. By this time the concept for a copper clad spire "place marker" covering a relatively small theatre built below street level had been abandoned and a tall open tapering lattice spire was the direction to be followed.

A model of the Copper clad Spire above the Theatres essentially planned to be below street level.

The Sydney Carols in the Domain Stage Canopy

Carols in the Domain Sydney - A Note About the Stage Canopy

Carols in the Domain has become a free pre-Christmas annual Concert which features many popular national and international performers and guests. The concept was started in 1983 by Robyn Anne Hobbs OAM. See more details in Wikipedia

A Principal Sponsor has held naming rights for the event - currently (2024) being known as Woolworths Carols in the Domain.

The event is held in the Domain Gardens adjacent to the Sydney CBD, and each year the quite large stage and the lightweight structure covering canopy is erected.

The founding President of the then MSAA (now the LSAA) was largely responsible for developing the canopy design concept.

Vinzenz Sedlak started with a lycra model at a scale of 1:100 and envisaged four masts located near each corner of the stage. Diagonal cross cables spanned between the opposite mast heads and a long front edge cable gave an uninterrupted view of the stage area.

The 1:100 Lycra Model of the Domain Structure The 1:100 more refined Lycra Model of the Domain Structure with Vinzenz Sedlak

The direct measurements from the model of the xyz coordinates of salient points (anchorages, mast tops and bases) was then fed into a form-finding program developed by Peter Kneen - also a founding member of LSAA. The following plots show the computer model.

Domain VS 11

The next stage was to produce cutting patterns which were joined to form a 1:25 scale model.

Domain VS 14

The final structure (the fabric component has been replaced during the 40 year life) was fabricated by Bert Bilsborough. Bert was still keen on using both sewn and welded seams in the early 1980s but most PVC coated membranes from that time just used high frequency welding. George Clark developed much of the structural details of the supporting structure - masts, cables and anchorages.

Some images of the first structure erected in the domain follow:

The Demountable Stage and Canopy Structure erected for the annual Carols in the Domain. Image from the first erection)

Domain VS 04

Domain VS 06

The Domain Cablenet Sound Shell

Carols by Candlelight at the Iconic Sidney Myer Music Bowl, Melbourne

Vision Australia's Carols by Candelight presented by AAMI is held on Christmas Eve at the iconic Sidney Myer Music Bowl venue in the Kings Domain in Melbourne!

Carols by Candlelight was the concept of Norman Banks MBE with the first event being held in 1938.

The current venue - since its completion in 1959 - is a pioneering example of tensile architecture using stressed cables in a double curvature form to resist environmental loads (wind) and to act as an effective sound shell for music.

General View of the Sidney Myer Music Bowl - a Pioneering cablenet structure.

This is a unique tensile cablenet structure was designed by Barry Patten of the Architectural firm Yuncken Freeman Brothers, Griffiths and Simpson. Engineering was done by Irwin Johnstone.

The venue is named after Sidney Myer, a Russian immigrant who arrived in Melbourne in 1899 and establish Myers. He also started an annual Music for the People with the Melbourne Symphony Orchestra in 1929. He was an important philanthropist and wanted a more permanent home for these annual performances. The setting in the Botanical Gardens would be used for the "Bowl" which was opened in 1959 some 25 years after his death.

For the LSAA, the structure can be regarded as a huge leap forward in freeform tensile architecture. It remains perhaps the largest auditorium for concerts. It was at least a decade ahead of the cablenet structures of the better known Frei Otto who developed freeform cable structures for the 1967 Expo in Montreal and later the best known roof for the main stadium for the 1972 Munich Olympics.

The shape of the surface is defined by the orthogonal grid of opposing pretensioned cables that form a double curvature, or "saddle shape".

The main environmental loading in Australia is from wind. There would have been no guidelines as to the wind pressures exerted on this new shape but clearly one would design for both a downward pressure as well as an uplift. The cables in one direction would resist the downward pressures whilst the opposing cables would resist the uplift pressures. Both sets of cables were pre-stressed so that under any wind loads they would remain taut.

These pre-stress forces are the other main loading to design for.

Computer analysis programs were not yet available and it would be perhaps two decades later before large displacement analysis capabilities were becoming available.

Sidney Myer Music Bowl - Details or the main edge cables and cablenet cladding

Sidney Myer Music Bowl - Details or the main edge cables and cablenet at a mast head

The structure was refurbished in about 2001. It is currently operated by the Victorian Arts Centre.

Further Reading (use Back button to return):

http://www.environment.gov.au/heritage/places/national/sidney-myer-music-bowl

https://architectureau.com/articles/sidney-myer-music-bowl/

https://vhd.heritagecouncil.vic.gov.au/places/64306/download-report

https://vhd.heritagecouncil.vic.gov.au/places/1528

https://www.artscentremelbourne.com.au/about-us/our-history

Introducing the Lightweight Structures Association of Australasia (LSAA)

LSAA Overview

The Lightweight Structures Association of Australasia (LSAA) is a Not for Profit, autonomous, inter-disciplinary group of interested parties involved in the field of lightweight architectural structures. We started in 1981 as the Membrane Structures Association (MSAA) but expanded in 1994 to include other innovative structures such as cable-nets and high-tech glazing facades.

Operating primarily in Australia and New Zealand our basic aim is to promote the proper application of lightweight structures, their design, fabrication, construction and materials and to encourage the development of these and other aspects essential to lightweight structures.

LSAA Mission Statement

Our mission is to "To lead, promote and develop excellence and innovation in lightweight structures by inspiring research and disseminating expert knowledge to expand the industry and opportunities for our members".

LSAA Activities

We do this by holding Conferences and our industry leading LSAA Design Awards.

Our most recent event was the LSAA 2024 Conference and Design Awards September 12-13 2024 at
Swinburne University.

The theme was 'Connecting to Tomorrow' See Menu items for the Conference and Awards
An important new initiative was the creation of the Inaugural Student Design Competition. We are hoping to run this every year as an International Competition.

LSAA Members and Corporate Goverance

Our members have completed outstanding structures around the globe and this enables us to draw on these contacts for our Conference Keynote speakers. These speakers also serve as Judges for our Design Awards and are able to recognize innovation and excellence.

Our members - whether they be architects, engineers, contractors, material suppliers or installers - are expected to adhere to our LSAA Code of Ethics.

In 2022 the LSAA awarded two long term individuals - Dr Paul Joseph and Mike Lester - the coverted Lifetime Achievement Awards

The Association is governed by a committee of volunteers drawn from the membership and supported by a part-time Executive Officer.

When required, specific issues are dealt with by a sub-committee. An example pertains to Fire with fabric structures. Members may access reports.

Members - and non-members - are encouraged to enter recently completed projects for our Lightweight Structures Design Awards. These entries serve as the basis for our growing record of projects. These projects are organized into various categories on the Projects Page of our website.

The LSAA also supports outside events and like-minded organizations - such as the IASS Annual Symposium 2023 - Melbourne - and will list their Events on our website.

About LSAA 1200w