No. 22. - Second fib Congress Proceedings - June 5-8, 2006 - Naples, Italy - Condensed Papers - Session 1-9

In reinforced concrete structural seismic design, a structural wall system is often preferred over a frame system, as it is well known that buildings braced by structural walls are invariably stiffer than framed structures. In this case, columns and beams carry only gravity loads, so it is possible to reduce their cross-sectional dimensions. Moreover, damage under serviceability-level earthquakes is generally less serious.

Uncertainties regarding the ductile behaviour of shear walls may arise, but proper reinforcement design can ensure a good capacity for energy dissipation in a stable manner.

On the other hand, problems arise in the foundation because a large eccentricity of gravity loads usually occurs at basement level. As a consequence, very large spread or raft foundations are required.

In the present paper, an alternative foundation solution is proposed, consisting of the structural organization of a box-type basement, made up of peripheral underground walls, with the raft floor and ground floor acting as horizontal diaphragms. All these structural elements are already present in buildings; they only require appropriate design to achieve the intended performance.