Richards and Oh 2019
The use of a replaceable steel fuse connection was tested through seven specimens that underwent a cyclic loading sequence until failure. It was found that the specimens with fuse plate connections experienced a similar inelastic rotation capacity with limited damage to other structural components, making the replaceable fuse cost efficient and easier to repair.
System Concept
Seven reduced scale exterior moment subassemblies were prepared to simulate a building frame. Of these specimens, one had no fuse, three had fuse plates at the top and bottom connections of the frame, and three had fuse plates only at the bottom connections of the frame. The fuses had the same thickness, width, and pattern of cutouts, but the depth of the fuse plates varied. The use of cutouts within the fuse plates would allow for deformation of the specimen to be concentrated into the replaceable fuse.
Experimental Study, Results, and Discussion
The beams were tested such that they were facing upwards and the columns were vertical. The loading cycles applied to each specimen followed AISC 341 and were applied until specimen failure. An actuator was used to determine story drift, and the specimens were observed to determine buckling. The loading began with 6 cycles at a 0.00375 radian story drift, then 6 cycles at a 0.005 rad story drift, then 4 cycles at 0.01 rad, 2 cycles at 0.02 rad, and 2 cycles at each 0.01 rad increment until failure. It was found that the specimens with fuse plates experienced a similar inelastic rotation capacity to the base structures, and did not experience buckling and plastic deformation of the beam-column connections as seen in the base structures. In specimens with smaller fuses, the fuses absorbed the plastic deformation of the system, but the specimens with larger fuse plates experienced a force from the fuses large enough to produce yielding in the beam-column connections. The concentration of plastic deformation to the fuse plates made the systems easier and more cost-efficient to repair in the case of an earthquake due to the replaceability of the fuse plates.
Reference
Richards, P., and Oh, S. (2019). “Cyclic Behavior of Replaceable Shear Fuse Connections for Steel Moment Frames,” Journal of Structural Engineering, 145. 12, pp. 15.