Shaking Table Testing of Reinforced Concrete IMRF Structure

Abstract

Multi-level shaking table tests were performed on 1:3 reduced scale two-story RC IMRF frames conforming to ACI-318-19. The exterior joints lacked shear reinforcement to assess the viability of the ACI model recommended for determining the design shear strength of the beam-column joint panel. The Northridge-1994 earthquake accelerogram was input to the frame for multi-level shaking table testing. Plastic hinges developed in beams under base input motion with a maximum acceleration equal to 0.40g. The exterior joints incurred extensive damage under base input motion with a maximum acceleration equal to 0.70g. The frame achieved displacement ductility and overstrength factors equal to 2.40 and 2.50 respectively. This gives a response modification factor equal to 6. The satisfactory performance of the frame is attributed to the high efficiency of the beam-column joint, which was confined by spandrel beams on two faces, and the high strength of the concrete. The inherent minimal confinement is sufficient to ensure good seismic behavior. The analysis confirmed overstrength equal to 1.58 for joint shear strength in comparison to the design strength determined using the ACI model. The data might serve as a reference for calibrating and validating numerical modeling techniques for performance evaluation, which are crucial in the context of performance-based engineering.