Engineering demand parameters for the definition of the collapse limit state for code-conforming reinforced concrete buildings

This article discusses the main Engineering Demand Parameters (EDPs) found in the litera- ture to define collapse of newly constructed reinforced concrete buildings. Currently, the defini- tion of building collapse is still under debate, as dierent building codes and authors define them with dierent EDPs and even dierent values of the same EDPs.The EDPs can be defined lo- cally (chord rotation, Local Damage Index, etc.) or globally (Inter-Story Drift Ratio, Roof Drift Ratio, Global Damage Index, etc.). A modified Global Damage Index that considers damage in both structural and non-structural elements is proposed in this paper The study compares the outcomes of some of these EDPs when applied to two case study moment-resisting reinforced concrete frames designed and analyzed in the framework of the RINTC - Reluis Project funded by the Italian Civil Protection Department (Ricci et al., 2018). One is a 6-story buildings (in Naples) the other a 9-story building (in L’Aquila). Nonlinear static and multiple-stripe dynamic analyses were carried out on 3D models with concentrated hinges. In addition to the above men- tioned EDPs this study proposes and tests a new economic EDP that that assumes that collapse is reached when the repair costs become larger than the reconstruction costs. Complete validation of the proposed economic EDP requires additional testing on code-conforming and, most impor- tantly, on non-conforming older buildings, where brittle failures become an important issue