The Sydney Opera House is an amazing structure that serves as a landmark to the city and its architecture. The story of its design by Danish architect Jørn Utzon in 1957  and its storied construction are worthy of a Hollywood script, with equal parts intrigue, charismatic personalities and technical innovation that took 16 years to complete. But the precast components that create the iconic "sails" are what lands it on my personal "Seven Wonders" list.

  When Utzon designed the building, the technology to create the roof was not yet available. By using rudimentary CAD design (a design first) the engineering was eventually completed. On the precast side,  the  various roofs contain 2194 precast concrete sections. The revolutionary design changed slightly from the original when the engineers discovered that keeping each section from a hemisphere of the same radius would allow for more repetition within the sections. The smaller sections are supported by precast concrete ribs.

Originally, the design was supposed to take 4 years to build. It was finally completed in 1973.

The story of the Sydney Opera House and the precast that made it possible is well worth exploring in more depth. For more information on this project, and for ideas on how other projects have advanced the engineering of precast concrete, request of boxed lunch from PCI-IW.