Construction on the opera house began in the spring of 1959. Work crews laid the opera house foundation by sinking 588 concrete piles (columns) into the ground. The piles supported the podium. The opera house’s two main buildings would sit on the podium facing the harbor. Smaller buildings would be built to the sides. Soon after work began, Ove Arup engineers ran into problems. They were having serious trouble making a construction plan for the large curved shapes that Utzon designed. Utzon changed his design to use shapes that would be easier to build.
He used a sphere as the basic shape of his design. The roofs would all be segments-