Engineering Demand Parameters for the Definition of Collapse in Code Conforming Rc Buildings

Abstract

The focus of the paper is on the choice of Engineering Demand Parameters (EDPs) for the definition of collapse limit state in code-conforming Reinforced Concrete (RC) buildings. Different definitions of collapse for buildings are found in building codes and the published literature. The differences derive from the EDPs used to measure collapse and from the EDPs' thresholds to assess if collapse is reaches. Definition of collapse in new, code-conforming buildings is somehow simpler than for older buildings, since the application of capacity-design principles avoids all brittle mechanisms. Still, the selection of the EDP is not unique. There are local EDPs, such as rotation with respect to the chord as suggested by Eurocode 8, or global EDPs, such as inter-story drift or top floor displacement. The study presented in this paper compares different EDP definitions and different limit values of the selected EDPs through the analyses of two case studies, a six-story and a nine-story Moment Resisting Frame (MRF). Both buildings were designed according to the Italian seismic code. Multiple-stripe, nonlinear dynamic analyses are carried out on the two frames modeled with lumped plasticity elements. The results indicate that different collapse definitions lead to different safety assessments, thus pointing to the need for a single definition of collapse, measured through a single EDP value.

Characterization of local and global capacity criteria for collapse assessment of code-conforming RC buildings

“…Similarly, Noh and Tesfamariam (2018) evaluated the collapse risk related to low-and medium-rise bare and infilled frame RC buildings designed in compliance with the Canadian Standards (CSA 2014). Terrenzi et al (2018Terrenzi et al ( , 2019 analyzed a medium-and high-rise code-conforming RC building. As collapse criteria, they considered the first achievement of the ultimate chord rotation θ u (empirical formulation in EN1998-3), various IDR thresholds, and a reduction of 50% in lateral shear strength V h of the PO curve (Camata et al 2017;Ricci et al 2018).…”