Cyclic Tests on External RC Beam-Column Joints: Role of Seismic Design Level and Axial Load Value on the Ultimate Capacity

Abstract

A wide experimental program on beam-column RC joints carried out in the framework of the DPC-Reluis Project (DPC: Department of Civil Protection, Reluis: Network of University Laboratories of Earthquake Engineering) is presented. All the experimental tests were performed at the Laboratory of Structures of the University of Basilicata, Potenza (Italy). The main objective of the experimental campaign is to study and compare the post-elastic behaviour of beam-column joints with different earthquake resistant design levels, indicating the role of some structural parameters such as the axial load value acting on the column, the beam dimensions, and the steel type, on the joint performances and failure mechanism. The analyses have mainly been devoted to improving the assessment procedures regarding existing buildings but also to verifying the prediction capability of the capacity models relevant to beam-column joints contained in literature and in the new seismic codes. Following a short description of the experimental methodologies used in other campaigns, the experimental program is presented, providing a detailed description of the specimens and of the testing set-up. This is followed by a report of the main results of the cyclic tests performed on the beam-column specimens which highlight the role played by axial load and seismic design level in determining the failure mechanism and the global response of the joints

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“…From the viewpoint of the behavior's study, most of the research has been focused on beam-column joint equipped with conventional (the adjective is used referring to beams having the depth larger than the width) beams, either seismically designed [2] or underdesigned (e.g., [3,4]). More recently experimental studies focused on joints equipped with wide beams (also called flat, as they have the width larger than the depth).…”