The truly valid criteria for determining the success of a building design are how safely, beautifully and economically it provides the requested environment. Concrete is the only material that permits designers and owners to achieve the closest approach possible to that ideal. Concrete performs well in rectilinear buildings, high-rise buildings, and curved buildings. The most popular building shape other than rectilinear is the circle. Apart from its pleasant aesthetic aspect, it offers such practical advantages as less exterior wall area (economical in terms of both construction and heating/cooling costs) and provision of more desirable peripheral office or apartment space.
The distinctiveness of a circular building often makes possible a greater return on investment for the owner by making possible higher occupancy rates and higher rents. Concrete even encourages the architect to go beyond the circle to elliptical, sinuous, triangular, free-form or virtually any shape. After years of what has been called the tyranny of the grid, designers and owners are reveling in the beauty and adaptability to occupant needs furnished by building shapes predicated on the curve, rather than the straight line.
In this realm concrete stands alone. Its plasticity enables it to be molded into the most exotic shapes imaginable, and its structural continuity is especially attractive for such shapes. However high you want to go, whatever shape you want to create, concrete is the logical choice for buildings. A partial list of advantages would include: lower first cost, less maintenance, lower insurance premiums, greater design freedom, better responsiveness to owner's space and needs, greater beauty, earlier occupancy, reduced building height per story, fire safety, better sound insulation and lower energy requirements, both to build and to operate.