Lin, Li, He, and Zhang, 2022
Six different dog-bone shaped steel plate fuses were tested under three loading conditions in order to test the effects of the width to thickness vs. slenderness ratios, cyclic loads of varying amplitudes, and cyclic loads of constant amplitudes for application in steel moment resisting frames (SMRF’s).
System Concept
The system consists of SMRF’s with dog bone fuse connections at the beam to column T connections. The fuses are each between 8 and 16 mm thick and have an effective length of 200 mm in the 50 mm reduced section. This reduced section is proposed to deform and dissipate seismic energy when loaded with lateral seismic energy such to reduce the energy applied to the main structural components.
The fuse itself is designed with the priorities of energy dissipation and replaceability. Because of the small width to thickness ratio and large unbraced length, the high ductility fuse is designed to deform and buckle under lateral loads and concentrate its deformation into its reduced dog bone section. Furthermore, the larger sections of the fuse have holes through the plate, through which the plate can be bolted to the T connections. With bolted connections, the bolts can be removed after the fuse undergoes significant damaged and easily replaced with a new fuse. This system therefore reduces damage to the main structural system and concentrates it into a section that is easily replaceable after seismic events.
Experimental Study, Results and Discussion
The intent of this study is to understand the behavior of the individual fuse in order to determine its effect in the overall system. Therefore, the fuses are manufactured individually and tested without being placed in a system. The study looks at fuses with the same plate measurements, that differ only between the 8 mm, 12 mm, and 16 mm plate thicknesses.
Once fabricated, the fuses were placed in an actuator system with load cells applied in order to determine the stress and strain of the tested fuse. The plates are then tested under either cyclic loading or monotonic loading. The cyclic loading had either equal or varying amplitudes, and the monotonic loading tested the fuses in either compression or tension.
It was found that most of the fuses failed after considerable maximum deformation of 5% from their original length, demonstrating high ductility. This allowed for the fuse to dissipate large sums of seismic energy through ductile plastic deformation prior to failure, therefore preventing damage to main structural components. The most common form of failure was demonstrated through buckling in the reduced section of the dog bone shape of the plate, and the buckling produced a visual damage that allows for visual inspection and replacement of the fuses in the event of seismic fueled damage. The fuses did, however, display asymmetrical hysteretic behavior, with a reduced capacity in compression rather than tension.
Reference
Lin, X., Li, H., He. L., and Zhang, L., (2022). “Experimental study on seismic behavior of the damage-control steel plate fuses for beam-to-column connection,” Engineering Structures, 270.