The Concourse Beams
The most notable technical feature in the design of Stage 1 was the single span concrete beams, some 49m long, which are visible under the Monumental Steps. Utzon's submission sketches suggested that the Concourse area under the Monumental Steps would require some form of colonnade to support the weight of the structure above. When Ove Arup, the engineer overseeing the project, saw this detail, he dismissed the need for the columns and instead proposed the undulating shape of the now famous Concourse beams.
The beams, in their final design, so successfully dispersed moments of stress that no additional vertical support was necessary. They provide a beautiful and dramatic sweeping form to the underside of the Monumental Steps, which continue up through the levels of entrance finishing just under the beginning of the vaulted arches.
The shape of the beams, when seen in cross section, is best described as a progression of capital letters, from U to T to V and back again. The powerful, elegant form that emerges utterly thrilled Utzon, who henceforth called them “Ove's invention” in recognition of his contribution to the finished design of the Sydney Opera House.
Pictured here in the Utzon Room, one of only two internal spaces of the Sydney Opera House entirely finished to Utzon’s design and specifications, the form of the beams dominates – a reflection of how valued a contribution to the finished building it was considered by the architect. The Concourse beams also represent a lasting reminder of the close relationship between Jørn Utzon and Ove Arup, despite their later estrangement.