Seismic retrofit of vulnerable buildings in Spain with hysteretic energy dissipators

In Spain, there are numerous vulnerable buildings, such as reinforced concrete frames with waffle slabs or wide beams. The use of hysteretic energy dissipators for seismic protection of wide-beam buildings is proposed. This study focusses in 3 and 6-story representative buildings; each building is designed for no, moderate and mid seismicity (design PGA 0.0 g, 0.12 g and 0.23 g, respectively). The mechanical parameters of the dissipators are selected from two approaches: an algorithm aiming to obtain uniform cumulated plastic ductility along the height of the building and a simpler approach where the yielding forces of each dissipative device are chosen proportional to those induced by the equivalent static forces in the Spanish design code. The suitability of the proposed solutions is assessed through dynamic analyses for representative seismic records; the performance criteria are the reduction of the interstory drift, of the base shear, of the absolute accelerations, and of the cumulated plastic displacements in the structure and in the dissipators. Three cases are compared: bare frame (building without any bracing), protected frame (building with dissipators) and braced frame (building with rigid connections instead of dissipators). This research belongs to a wider initiative that includes testing and practical applications.