Experimental and analytical performance of replaceable shear fuse connections for heavy beams

Experimental testing and finite element analysis were used to quantify the inelastic rotation capacity of replaceable shear fuse connections that exceed the current prequalification limits in AISC 358-22. Three experimental specimens with W1000 x 591 beams were tested per the procedures in AISC 341 Chapter K. Fuse plate geometry and the number of fuse plate bolts varied between specimens. All three specimens completed at least one cycle at 0.04 rad, with one specimen completing a cycle at 0.06 rad under the standard AISC special moment frame connection loading protocol. Using extra bolts on the fuse plate to match the bolts at the top flange in one configuration resulted in higher strains in the fuse yielding regions. Finite element models confirmed that about 90% of the moment at the face of the column was transmitted by the horizontal couple at the beam flange levels and that bolt lines should be more centered on the external connection plates. The connections had high post-yield stiffness and had strain hardening factors of up to 1.52. A more transparent procedure for addressing strain hardening in design was developed.