The 2008 Beijing Olympics will have the largest and most unusual swimming centre ever built. The structure was inspired by the shape of an array of soap bubbles and is highly repetitive and constructible whilst appearing very random and organic. The Water Cube houses the pools for the Olympic swimming and diving competitions, along with seating and facilities for 17,000 spectators.
A comprehensive 3D structural model was created and imported directly into Strand7. The Strand7 model comprised 24,000 beam elements with 12,000 nodes. There were 750,000 beam loads in 55 basic load cases which were considered in 200 load combinations.
The beam loads are derived from wind and snow pressure loads which were applied to the external translucent cladding and in turn transmitted to the structural members. Using the Strand7 patch element it is a simple procedure to automatically convert these pressure loads to the relatively complex distributed beam load definitions. Strand7 offers a tool that automatically defines the load patches over a gridwork of beam elements, similar to a mesh generator. Once the patches are defined, pressure and other loads assigned to the patches are automatically transferred to the underlying beams according to their associated tributary areas.
The most significant aspect of the analysis was the seismic design. Strand7 has for many years been capable of transient dynamic and spectral seismic analyses. The latest Strand7 Release 2.3 has added the capability to take site specific seismic time histories and simply create equivalent spectral curves. In the case of the Water Cube, a Spectral Response analysis was performed. This used the results from a natural frequency analysis that calculated 4424 modes to achieve the 90% mass participation required for an accurate spectral response solution.
