Abstract

Current seismic design practice is to design structures to avoid collapse and protect life. Buildings are designed to resist seismic loading through strength and ductility. In moment frames, this ductility traditionally comes from inelastic deformation of beams. Moment frame connections move inelastic deformation away from the column and allow a plastic hinge to form in the beam. This plastic hinge prevents collapse but leaves the building difficult to repair. Some proprietary moment frame connections address this issue with replaceable fuse plate connections. These fuse plate connections move the plastic hinge out of the beam and into the replaceable fuse, allowing for more economical and faster repairs following a seismic event. This thesis explores two different fuse plate options. One hundred twenty-seven experiments were performed on reduced-scale fuse specimens with varying geometric parameters. Unrestrained (UR) and buckling restrained (BR) fuses were tested with a 100kip tensile tester in cyclic tests to prove the feasibility of the plate geometry before full scale testing is performed in future studies. UR fuses with slenderness ratios near 8 had the greatest deformation capacity under cyclic loading and similar cyclic tension and compression strengths. Better cyclic performance was achieved with relatively small fillets (half the fuse thickness). Fuse widths that were 1.5 to 3 times the fuse thickness had the greatest deformation capacity. For BR fuses, buckling-restraint bolts were effective in delaying plate buckling so their failure mode was low-cycle-fatigue rather than strength loss from buckling. BR fuses performed best when washers covered most of the width of the yield region and washers were a similar thickness to the plate. When washers covered most of the yield area and were a similar thickness to the fuse plate, the level of bolt tightening was negligible.

Degree

College and Department

Ira A. Fulton College of Engineering; Civil and Environmental Engineering

Rights

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