Seismic assessment and base isolation retrofit of a modern heritage R/C swimming pool

A modern heritage reinforced concrete (R/C) swimming pool building designed by Pier Luigi Nervi is examined in this paper. The distinguishing feature of the structure is represented by the barrel vault-shaped roof, constituted by prefab R/C curved beams with smoothed-V wavy section, typical of the internationally recognized Nervi’s style. The R/C columns and beams supporting the roof and the lateral aisles — originally designed for gravitational loads only and pursuing a minimal size philosophy with respect to the calculated stress states — have very small cross sections. As a consequence, the seismic performance assessment analysis carried out in this study shows general unsafe response conditions of these members. In order to substantially improve the seismic response capacity of the building, as well as to avoid any intrusive intervention on the exposed structural elements, an advanced retrofit strategy is proposed, which consists in the installation of a base isolation system incorporating double curved surface slider devices at the feet of all columns and below the pool tank.