Mechanical performance for defective and repaired grouted sleeve connections under uniaxial and cyclic loadings

Grouted sleeve connectors provide a convenient and economical solution for connecting precast concrete elements in engineering site. However, sleeve connections may include insufficient grouting defects at certain conditions which may significantly decrease the bearing capacity and increase the failure risk of connection joints. In order to better understand the influence of insufficient grouting defects, the mechanical performance of insufficiently grouted sleeve connections with predesigned vertical grouting defects is investigated in this study by considering three loadings: uniaxial tensile loading, cyclic loading at high stress and cyclic loading at large strain. Comparatively, the repaired sleeve connections by refilling grout material to the sleeve enclosing insufficient grout material are considered as well. Total 24 sleeve connection specimens are tested and the correlation of failure mode, force-displacement response and the defect level is analyzed and discussed. It is revealed that the failure mode of defective specimens may shift from the tensile fracture of reinforcing steel bar to the interfacial bond-slip failure of rebar with the decrease of the anchorage length of reinforcing steel bar. Additionally, it is found that the loading condition affects the failure mode too. Moreover, the repaired sleeve connections show similar mechanical performance to the fully grouted sleeve connection except deformation. This indicates that the regrouting operation to repair the grouting defect in the sleeve is effective in engineering applications. (C) 2019 The Author(s). Published by Elsevier Ltd.