Sydney Opera House

This building situated in Sydney (Australia) and designed by Jorn Utzon at 1957, is one of the most famous of the XX century and was declared as World Heritage at 2007. Was opened at 1973.

The building has an expressionist design and is compound by prefabricated "shells" each one token from the same semisphere. This shells form the roof which occcupies about 1,8 hectares has 183 meters lenght and 120 meters wide and rest above 580 pillars sunk up to 25 meters under the sea level. The shells are covered with 1.056.006 tilings of 2 different colors forming a chevron and they are made to clean themselves.

The two bigger groups of vaults belong to the Concert Hall and the Opera Theater and the other saloons had the smaller vaults. The smallest vaults covers the Bennelong restaurant.

These are the theaters:
- Concert Hall  with 2670 seats and the bigger pipe organ of the world with 10000 tubes.
- The Opera Theater, 1547 seats.
- The Drama Theater, 544 seats.
- The Music Hall, 398 seats.
- The Studio Theater, 364 seats.

At september 1955 the contest started receiving 233 projects from 32 countries which challeged for a $100.000 price and the winner was announced at 1957 rewarding Jorn Utzon.

First stage: Podium (1959-1963)
Started immediately at 5th december 1959 because the government was afraid to lose the public money and that suposed problems due to the unfinished planes. That caused that a lot of columns for the roof were made with a minor resistance than the necessary and, finally, the roof musted be redefined.

Second stage: external vaults (1963-1967)
The initial construction process thought was an in-situ formwork, but the team realized that it was very expensive and then changed to the prefabricated ribs. The structural calculation was very complicated and it required one of the first uses of a computer. Finally the solution was to project all the vault as sections from a semisphere.

Third Stage: Inside (1963-1973)
This stage started at 1963 but at 1965 Utzon was fired and his job was assumed by Peter Hall becoming the main responsible for the inside design. At 1966, the acoustic counselor, Lothar Cremer confirms that the initial design from Utzon allowed only 2000 seats at the main room and the increasing up to the 3000 seats would be a disaster for the acoustic. After a lot of changes due to the Utzon's initial designs were'nt good enought for the Opera House, there were added two more theaters. Finally, at 1973, the building was finished with a total cost of $102 millions.