Sydney Opera House, an unforgettable history

Memes, ironies of all kinds, and a nickname that's still very popular today, more than half a century after its inauguration. It certainly can't be said that the Sydney Opera House, the futuristic and unique opera house in the Australian city, didn't immediately draw attention to itself. And it's precisely its nickname, comical yet affectionate, that best describes this building. "Nuns in a scrum" certainly raises a smile but captures the essence of this architectural project. A World Heritage Site for nearly 20 years, considered one of the new seven wonders of the world, the path that led to its construction was long, tortuous, but at the same time fascinating. 

The design choice fell on a Danish architect, Jørn Utzon, winner of the 1957 competition and assisted in the structural calculations by the English engineering firm Arup. However, three other architects, Peter Hall, David Littlemore, and Lionel Todd, took on the task of completing the project after their Scandinavian colleague was forced to abandon his work in 1966 due to problems with the client.

A few numbers and characteristics better explain the nature of the project. The opera house was to include a hall capable of seating 3 people and a smaller one for 1.200 spectators. The client essentially specified three guidelines: timelines, budget, and quality. However, no specific instructions were provided regarding the first two aspects, while much was expected regarding quality. All this despite complete freedom from the design perspective. Speaking of costs, the total cost exceeded $100 million, although a much lower figure—$7 million to be precise—had originally been discussed. There were essentially three construction phases, each of which remains to be explored in detail.

First phase (1959-1963)

To make room for the future Sydney Opera House, the Fort Macquarie tram depot had to be demolished. The first phase of the architectural design provided the opportunity to build the theatre's upper podium. For Utzon, it wasn't an easy start: he hadn't even completed the final drawings for his project when structural issues arose. It was the most complex phase because this very stalemate contributed to the accumulation of a delay of 47 weeks, mostly due to bad weather. The podium nevertheless became a reality in February 1963, unfortunately there wasn't much room for victory. In particular, the early start of construction, under insistent pressure from the Australian government, caused a setback that would later impact the rest of the design. The podium's pillars proved insufficiently sturdy to support the roof structure, making it practically mandatory to rebuild these architectural elements from scratch. 

Second phase (1963-1967)

During the five-year period under review, Utzon focused primarily on the vaults, which, in the competition-winning design, had an unclear geometry. The idea was therefore to develop them as if they were parabolas supported by prefabricated concrete ribs. The creation of any prefabricated elements, however, proved risky because it would have further increased costs. The team led by the Danish architect then developed the beauty of 12 different configurations for what would become the instantly recognizable vaults of the Sydney Opera House. Parabolas, circular ribs, ellipsoidal ribs—nothing was ruled out in advance to find the most economically viable solution. Then, the final choice was made: the prefabricated concrete roof sections. Among other things, these vaults required the use of computers for structural analysis. It was one of the first uses of this technology in architecture, and it later also proved useful during the assembly of the arches.

A detailed view of the Sydney Opera House. Image courtesy of Stephen Biesty (from the book “The Story of Buildings” by Patrick Dillon)

Positioning the pins on the arches was a significant task. This task, in fact, occupied the team every day during the initial design phase of the podium, with the data collected and then entered into the computer. This allowed them to correct errors from the previous 24 hours, until the correct position was calculated. The right intuition came at a very specific moment: around mid-1961, it was clear how the vaults should be positioned. a peculiar shape, that is, as if they were the portions of a sphere. In this way, it would have been possible to obtain arcs of different lengths from the same mold, then aligning the identical arc segments to form the final sphere.

As revealed in the official design documents, Utzon planned to create all the vaults with uniform curvature in both directions. Wind tunnel tests of the roof structure provided further valuable information. The team understood the actual distribution of the wind pressure on the roof in case of rather intense gusts, a useful detail for creating the right tiles and designing the fixing systems. 

Third phase: (1967-1973)

The final six years of the Sydney Opera House project were undoubtedly the most complex of all. Utzon decided to move his architectural practice directly to Sydney itself, a move that, however, did not bode well. In 1965, the change of government led the Danish architect to clash with the Ministry of Public Works, which openly criticized the project. His resignation was inevitable in 1966, resulting in changes to the ideas initially laid down in writing. First, the main hall, originally conceived as a multipurpose space for operas and concerts, became a concert hall only.

The "minor" hall was instead adapted to operas and ballets, so much so that it was renamed “Joan Sutherland Theatre” in honor of the famous soprano. Other changes involved the flooring and the construction of the glass walls. In the latter case, in particular, Utzon had considered a prefabricated plywood system, a choice that was quickly abandoned. One of the main interventions of the Australian executive consisted in modifying the specific requirements of the project, that is, it moved from two to four roomsSuch a doubling meant making changes to the plans and drawings as construction progressed, but work continued despite obvious difficulties. Among the most insidious obstacles was Utzon's own behavior. Indeed, once he left the assignment, he left no drawings or instructions for the work to be done. The Danish architect was convinced that the new Australian team would soon fail and that he would be recalled. None of this happened; instead, new projects were drawn up that mirrored the existing ones.

The final result was the structure as we know it today. The design is modern and expressionist in style.

The entire building occupies nearly 2 hectares of land and measures 183 meters long and 120 meters wide. There are 588 reinforced concrete foundation piles, each reaching 25 meters below sea level. As for the maximum height, we're talking about 67 meters above sea level, equivalent to a 22-story building.
The prefabricated concrete sections of the roof are 2.194 and each of them weighs 15 tons. For the inauguration it was necessary to wait until 20 October of the 1973, in the presence of Queen Elizabeth II. It was a momentous event for Sydney: the live television broadcast, the fireworks, the performance of Ludwig van Beethoven's Ninth Symphony gave an idea of ​​how majestic everything was, including the great pipe organ inside (it features 10.500 pipes). It was no easy journey, but all the arguments, misunderstandings, and obstacles gave way to the first successes in just two years. In fact, the Sydney Opera House has more than paid for itself. 

Film of the construction of the Sydney Opera House
Made by the Commonwealth Film Unit.
This short film was produced in 1972 featuring historical footage of the Sydney Opera House, including images of its complex construction and the site's former use as a tram depot.
Source: https://www.nfsa.gov.au/
https://www.youtube.com/watch?v=YlSSl5CjGs8

The cover photo is a front view of the Sydney Opera House. The photograph was taken by David Franklin on Depositphotos.com