Experimental investigation on the connection performance of defect detectable and repairable half-grouted sleeve under cyclic loads

Abstract

A defect-detectable and repairable half-grouted sleeve (DDRHGS) was developed to address the detection and repair of insufficient grouting of grouted sleeve connections (GSCs). This research focused on quantitatively evaluating the influence of insufficient grouting on the connection performance of GSCs and validating the feasibility and reliability of DDRHGS under cyclic loads. To achieve these, a total of 52 DDRHGS specimens were tested under two cyclic loading protocols. The influences of two rebar diameters, four defect ratios, two repair materials, and two loading protocols were analyzed, with emphasis on the failure mode, load-bearing capacity, and deformation capacity of the tested specimens. The test results indicated the following: 1) for the specimens with grouting defects, when the defect ratio reached a certain threshold, the bar-slip failure mode, rather than the expected bar-fracture failure mode, was observed. The load-bearing capacity and deformation capacity were significantly lower than those of the specimens without defects. 2) For the specimens with a diameter of 12 mm and a defect ratio of 60% as well as a diameter of 20 mm and a defect ratio of 45%, the connection performance did not meet the requirements of the design basis earthquake (DBE) and maximum considered earthquake (MCE). Specimens with a diameter of 20 mm and a defect ratio of 60% could not perform well under service level earthquake (SLE), DBE, MCE, and wind load. 3) The repaired specimens exhibited the expected bar-fracture failure mode, and the load-bearing capacity and deformation capacity were approximately identical to those of the specimens without defects. The feasibility and reliability of DDRHGS and its repair method were validated, and the research outcome can serve as a reference for the quality control of precast concrete structures using GSCs.