concrete shell

A shell structure in architecture is a thin, curved plate designed to efficiently distribute forces like compression, tension, and shear across its surface. Typically constructed from concrete reinforced with steel mesh, often using a technique called shotcrete, these structures began to gain prominence in the 1920s. They became a significant form of long-span concrete construction after World War II.

These structures can achieve impressive spans, with some parabolic shell vaults reaching up to 300 feet (90 meters). More complex designs, such as hyperbolic paraboloids (saddle shapes) and intersecting vaults, have also been created with very thin profiles, sometimes less than 0.5 inches (1.25 cm) thick. Notable architects and engineers in this field include Felix Candela and Pier Luigi Nervi.12