Seismic safety of valuable non-structural elements in RC buildings: Floor Response Spectrum approaches

The seismic performances of non-structural (NS) components belonging to the category of “valuable elements”, i.e. elements characterized by high value in terms of economic, cultural or strategic purposes, represent nowadays a crucial aspect in seismic safety design and assessment of new and existing buildings. Actually, most valuable NS elements are simply-supported objects, which can be classified as acceleration-sensitive NS elements. Frequently, these elements can be considered dynamically uncoupled from the primary structure to which they are connected, thereby justifying the Floor Response Spectrum methods usually adopted in literature and by most of building codes. This paper presents an extensive parametric study of floor response spectra obtained by linear and nonlinear numerical modeling of RC structures. Two sets of 30 horizontal ground motion scaled acceleration records are generated according to the Ultimate Limit State (ULS) and the Damage Limitation State (DLS) spectra adopted for building design. The numerical floor response spectra and those proposed by codes and international standards are critically compared, and the Peak Floor Acceleration (PFA) and the Peak Floor Velocity (PFV) profiles along the building height are discussed. Finally, a simplified method based on the “stability charts” is developed to assess the seismic safety of free standing NS elements located at the upper floors of the host buildings.