Experimental Analysis of the Behavior of Composite Column-Reinforced Concrete Beam Joints

Abstract

This study assesses the seismic performance of steel-reinforced concrete (SRC) composite columns connected to reinforced concrete (RC) beam joints, and their ability to dissipate seismic energy through inelastic deformations. In this article, experimental aspects regarding the seismic performance of high-ductility and low-ductility steel-concrete composite frame were investigated. The principle design parameter in this study was ductility, which is considered a conceptual framework in Efficiency-Based Seismic Engineering. Thus, attention was focused on assuring various ductility ranges of joints obtained through a detailed study of the Turkish Earthquake Code (TEC 18) [Ministry of Public Works and Housing.: Turkiye Bina Deprem Yonetmeligi (Turkey's Earthquake Code for Buildings). Official Gazette (2018) (in Turkish).]. After identifying deficiencies and the energy dissipation capacity in the newly proposed joints, two half-scaled frames with specific ductility-related designs were constructed, instrumented, tested, and analyzed. The specimens were tested under displacement-controlled lateral cyclic loading that incorporated constant axial loading to create cyclic tension and compression facets across the joint areas. The test results proved that the SRC column-RC beam frames employing an extra column reinforcement ratio exhibit slightly better seismic performance. Due to the presence of structural steel, the shear failure of the joint was effectively prevented, even after the formation of the plastic hinge on the interface of the beam. During the testing, the column rebars, to some extent, made a minor contribution to the joint strength of the specimen compared to the structural steel that absorbed almost all of the load applied to the frame.