Chapter 6: 1958, the Red Book
After leaving Sydney in August 1957, Utzon travelled to Japan and America, visiting famous theatres and concert halls, architects including Mies van der Rohe, and experts in shell-vault construction.
Utzon was required by the Opera House Executive Committee to produce new plans within six months of the announcement of his win. These plans would become The Red Book, presented to the committee in March 1958.
But before then, several deliberations took place. In November, SOHEC reduced the number of seats required in the main hall to 2,800 for concerts and between 1,700 and 2,000 for opera. The main hall had from the start been required for dual purpose, a style which was already being perceived in the post war world as an inferior approach to hall design. Today, dual purpose halls are rarely constructed.
Utzon would be troubled by problems with the seating capacity of the halls throughout the project. From the outset the shape of the roof in his submission sketches would not have permitted the required numbers to be accommodated. Future design changes would similarly fall short. But in late 1957 the box-like, if discordant, interiors of the major and minor halls accommodated the correct number of seats, and were also the only design route realised.
When the engineers requested that Utzon define the curves of the roof, he took a plastic rule and holding it perpendicular to a table, made it bend. Tracing the curves, he sent them to London explaining these were the shapes he wanted.
The outcome of the first exchanges between architect and engineer produced an initial sketch of the roof in which every curvature is different, a structurally unsound form with difficult bending moments near its footings.
However, this first geometrical approach to the shells was also visually very beautiful in a distinctly different way to the drawings Utzon had submitted for the competition.
The ridge profiles were much higher and pointed now, and the end shell form of his competition drawings no longer cantilevered, like a cliff cave over the sea.
These higher profiles also allowed far more volume for the stage towers, auditoria and acoustics, all of which had been grossly underestimated in the competition sketches.
Utzon's architects re-drew all of the elevations of the House to the new forms and these are shown in the Red Book.
Clearly the profile of the roof had changed considerably, but it was received by the client and the public as a transformation for the better, for both logistical and aesthetic reasons.
The 55 pages contained contributions from Utzon and his architects alongside Ove Arup and Partners, as well as Utzon's group of consultants, detailing stage machinery and acoustics.
The Red Book, which Utzon dedicated to Joe Cahill, was not just a beautiful document. Alongside an undeniable quality of design and aesthetics, the reports from Utzon's consultants and the overall effect of conveying a buildable structure, the Opera House had moved far closer to becoming a real building.
