For a sport Arena roof in Cape-Town in South Africa, a membrane roof was designed to cover the ring of sport hall with an outer diameter of 150 m and internal diameter of about 30m. The main supporting system of the roof consists of cable truss systems supported by back anchored steel masts. The height of the masts was about 25 m and is pin jointed at base. Additionally they are supported horizontally into a ring compression beam, which belongs to the concrete structural system of the ring. Dr. Saad was responsible to run the structural analysis and the design and to determine the bill of quantities and cost estimate of the project in the preliminary design stage.