Seismic Behavior of Welded Beam-to-Column Joints of High-Strength Steel-Moment Frame with Replaceable Damage-Control Fuses

Abstract

This paper first proposes a high-strength (HS) steel-moment frame structure with replaceable damage-control fuses, which utilized the very large elastic deformation capacity of HS steel and damage-control functions of fuses. The damage is basically concentrated to fuses even under very rare earthquakes, and the damaged fuses can be easily replaced after earthquakes. A test program including 11 full-scale specimens was carried out to study the seismic behavior of HS steel beam-to-column joints either with or without fuses. The investigated parameters include different types of fuses, different thickness of the fuse plate, and different ways to strengthen the out-of-plane stiffness of fuse plates. The failure mode, deformation progress, hysteretic responses, skeleton curves, bending strengths, and energy-dissipation capacity of these full-scale tests were reported, analyzed, and discussed. Test results showed that the HS steel joints with fuses were able to provide large damage-free deformation. The application of proposed fuses in the HS steel-moment frame effectively shifted the damage from beam-to-column welds to replaceable fuse plates. Meanwhile, the shape of fuse plate exhibited marginal influence, but its thickness has significant influence on the T-joint. Formulas were proposed to estimate the yielding and ultimate bending strength of T-joint with fuses. Finally, a step-by-step procedure is given to design the proposed fuses.