Exterior RC beam-column joints : experimental outcomes and modeling issues

The attention of the scientific community toward the evaluation of the seismic safety of existing RC buildings is testified by the amount of studies available in the current literature and, also, by the frequent updates of national codes. Indeed, the extended damages and collapses exhibited by RC buildings during the last decades earthquakes, highlighted the need of better understanding the influence of structural details on the seismic response in order to improve guidelines and, at the same time, to carry out efficient strengthening techniques for existing buildings. In this context, the beam-column joint assumes a relevant role since it could particularly affect the seismic vulnerability of RC buildings. The present paper is part of a research activity involving different universities, aimed at investigating the behavior of RC beam-column joints of buildings designed in agreement with past Italian codes and, in particular, the efficacy of strengthening interventions based on the use of innovative composite materials.The paper presents the experimental and numerical results carried out with reference to an unstrengthened joint, designed with the aim to simulate the behavior of an exterior joint. After the introduction, reporting a brief state of art, a description of the main outcomes emerged from the experimental tests and numerical analyses are presented in detail.