ABSTRACT
This chapter concentrates on the logical connection between one-way and two-way spanning systems. The problem of roofing a circular space is one that has taxed the ingenuity of architects, engineers and builders from the beginning of civilization. The weight of the circular dome is transferred to the square in which it is inscribed by spherical triangular elements known as pendentives. Structural difficulties are more likely to arise when a circular building is divided radially as though a cake were being sliced, particularly if the slices vary in height to allow light to penetrate the radial sides. Nervi's 100-metre span Palazzo dello Sport, built after his nearby Palazzetto for the 1960 Olympic Games in Rome, owes its cylindrical appearance to the elevated galleries within the generating circular plan but outside the dome. Despite the ingenuity shown in roofing these and many other non-circular spaces, the square and the rectangle are more likely to generate a solution involving linear structural elements.
