| Gusset plates are elements which connect bracing to beams and/or columns in steel structures. In tests, gusset plates have exhibited load-deformation characteristics desirable of inelastic elements in seismically loaded structures. While the observed load-deformation response indicated potential of gusset plates to act inelastically in seismically loaded structures, they have not been quantitatively assessed in that role. Hence, a program was initiated to investigate gusset plates as inelastic elements in seismically loaded structures. The investigation addressed the interrelationship of gusset plate behavior and overall structural response to earthquakes.; Monotonic tension tests were conducted on six gusset plates of constant thickness and four gussets fitted with a reinforcing plate over the bolted connection. Gusset plates loaded in tension reached ultimate load at first fracture. Unreinforced plates fractured at deformations 2 mm to 5 mm lower than observed in similar reinforced plates. Total deformation at first fracture did not exceed 26 mm in any case. A modified gusset plate arrangement was proposed, employing extended hinge links (EHL), intended to increase deformation at first fracture. Two prototype specimens were tested cyclically. The smaller six link specimen sustained six cycles of loading, to a maximum deformation of 60 mm. The larger ten link specimen sustained 10 cycles of loading with maximum deformation of 120 mm.; Based on test results and analysis, it was concluded that the maximum expected deformation of a standard gusset plate, constructed using readily available materials and typical propositions, would not be expected to exceed 15 mm. EHL gusset plate tests indicate that modified geometry could be expected to increase maximum cyclic deformation to greater than 60 mm.; Non-linear time history analyses of one, two, four and eight storey steel structures and eight storey seismic retrofit concrete structures were performed using scaled earthquake records. For both steel and concrete eight storey structures, maximum gusset deformations ranging from 20 mm to 60 mm were observed in at least one location during one event for the parameters studied (Steel: Zone 3 and 5, R = 2, 3, 3.5, 4, 6, Concrete: Zone 5, R = 2, 3). (Abstract shortened by UMI.)... |
