An energy based method to evaluate reinforced concrete column seismic capacity

Abstract

The assessment of the capacity of reinforced concrete structures plays a central role in defining the performance parameters needed for the design, verification and analysis of existing and new buildings. Since the advent of Performance Based Earthquake Engineering, several methodologies for the definition of limit states have been proposed. Traditional methodologies, based on force or displacement approaches, have been widely investigated. Among others, energy-based approaches have demonstrated significant potential in identifying limit states, due to their enhanced physical coherence in nonlinear response interpretation. This study presents a methodology that employs absorbed internal energy and power to characterize the seismic capacity of structural elements. Two key challenges are addressed: (i) the identification of the impulsiveness associated with individual energy “jumps” in the hysteresis loop and (ii) the quantification of energy dissipated at each jump, which are aspects often insufficiently addressed in existing literature. To this end, two energy parameters are defined to highlight, within a response function, the most significant contributions in terms of dissipation (D) and impulsivity (I). The effectiveness of the methodology is validated through the analysis of an extensive experimental database of reinforced concrete columns subjected to cyclic loads. The results demonstrate enhanced precision in capturing damage levels compared to traditional approaches. Finally, potential correlations between these energy parameters and observed damage states are discussed, outlining the potential use of this procedure in the context of performance-based seismic design.