The improvement of the threaded-based mechanical splice by modifying the threaded system: Study of techniques cold rolling and rotating friction welding

Abstract

In this study, by modifying the method of making a threaded splice and combining it with rotary friction welding, two types of patches are introduced. The aim is to modify the failure area of the coupler with a threaded bar and use it in the plastic hinge areas of ductile members in seismic areas. The splice area in the suggested method is oversized. To enlarge the splice area, two techniques-cold rolling and rotating friction welding are used. In total, 96 samples (including three repeated samples of each type) were tested. Threaded couplers (TC), oversize-threaded couplers (OTC), rotary friction welding splices with threaded couplers (RFWTC), and non-spliced reference specimens underwent uniaxial tensile and cyclic testing with and without concrete (NS). The sensitivity to bar diameter, as well as bar strength, ductility, energy absorption, and failure mode performance, were evaluated. In terms of strength, ductility, energy absorption, and failure mode, the RFWTC and OTC performed the best and are suited for usage in high seismic zones. Additionally, the TC is appropriate for use in low-to-medium seismic zones. Also, the predicted model is sufficient to estimate the ultimate tensile strength of the threaded couplers.