When you think of a successful structural engineer – there is one building that symbolizes Australia, it is the iconic Sydney Opera House. Located along the bay of Sydney Harbour, the Sydney Opera House is a performing arts center. Since it opened in 1973 it has come to be seen as a masterpiece of modern structural engineering.
In 2007, it was included in the World Heritage List by UNESCO. The agency has a plaque inscribed with the following words, “…it represents multiple strands of creativity, both in architectural form and structural engineering… it is one of the indisputable masterpieces of human creativity, not only in the 20th century but in the history of humankind.”
It was designed by Danish architect Jorn Utzon (a structural engineer), following an international architectural competition in 1957. Work on the Sydney Opera House started in 1959 and was overseen by Utzon, who worked in tandem with Ove Arup a firm of structural engineers. The Arup team was led by a brilliant designer and structural engineer Jack Zunz who later worked on the HSBC Headquarters as well and his young assistant, the structural engineer named Peter Rice.
It was the structural engineer’s job to translate Jorn Utzon’s distinctive design into reality. At the center of the design was a set of interlocking vaulted shells that became one of the most challenging engineering projects ever attempted by this team of structural engineers.
The design of the shells and later their erection involved one of the earliest uses of computer analysis by the team of structural engineers to understand the complex forces the shells of the Opera house would be subject to. The structural engineers and execution team decided that the shells would be created as sections if joined together would form a sphere. Each of these would be supported by a framework of arched ribs.
The structural engineers after much experimentation and ground testing decided that each of these shells is made of pre-cast concrete rib segments rising to a ridge beam, held together by 350 km of tensioned steel cable. It was further decided by the Arup team to precast the units which would then be tiled at ground level on the site of the Opera house itself.
A total of 2,194 precast concrete roof panels were created. These, in turn, were clad with over 1 million tiles. The tile surface is highly detailed and a delight for a structural engineer – with two types of tiles used – one glossy white, one matte cream – to rightly reflect sunlight.
The shells were to be then set on a podium of concrete.
When the first shell was erected using cranes specially imported from France to hoist them it was learned that the concrete podium columns were not strong enough to support the structure of the shells in their final designs. The team of structural engineers went back to the drawing board and rebuilt the podium. Finally, the structural engineers decided to sink 580 concrete piers down to 25 meters below sea level to create base enough to support the majestic shell structure.
The original cost estimate to build Sydney Opera House was estimated at $7 million. The final cost was $102 million. Construction was expected to take four years. It took 14 years. In the end, it was a structural engineers dream come true. One of the wonders of the world and Australia’s proud Icon.