Arup and Sutherland Engineers
Victoria and Alfred Waterfront Holdings
Cape Town, South Africa
The grain silo complex, consisting of lightly reinforced cylindrical concrete storage bins and a rectangular working house, has been transformed into an outstanding museum and art gallery through architectural vision combined with structural engineering skill. Transferring lateral stability to new cores in the working house and maintaining a balanced bracing system to avoid unwelcome torsion were crucial to the success of this part of the project. The original silos have been strengthened in order to enable large sections to be demolished for the creation of a stunning atrium. The remaining structure is required to span over the newly created void while also providing lateral stability, and the solution of casting a reinforced concrete skin attached by shear keys and using the existing walls as shuttering, prior to demolition for creation of the void, enables the purity of the architectural concept to be maintained. Thorough analysis of the relative stiffnesses and astute detailing, including cutting chases in the original walls and insertion of a soft joint between old and new structures, are designed to prevent unsightly distress to the delicate original structure, particularly under seismic loading.