Seismic Design, Tests and Response Analysis of Steel Frame with Steel Panel Dampers

An steel panel damper (SPD) includes three wide-flange sections using different grades or thicknesses for the webs, namely the middle inelastic core (IC), and the top and bottom elastic joints (EJs) to be connected to the beams. A ductile vierendeel frame can be constructed by incorporating the SPDs into the moment resisting frame (SPD-MRF). This manner, the lateral stiffness, strength and energy dissipation capacity of the MRF can be enhanced. Under a severe earthquake, the two EJs in an SPD-MRF are designed to remain elastic while the IC could undergo large inelastic shear deformation thereby dissipate energy without the failure at the EJ-to-beam ends. The purposes of this study are not only to develop the capacity design procedures (CDPs) for the SPDs or the boundary beams connected to the SPDs, but also investigate the seismic design procedures and performance of a typical SPD-MRF subjected to earthquake ground accelerations of three different hazard levels. The tasks of this study also include investigating the effects of IC’s aspect ratio, height, and stiffener design on the seismic performance of SPDs. In this study, four specimens of 2.6 meter tall are fabricated for substructure pseudo dynamic and cyclic loading tests using the MATS facility at NCREE. Tests confirm that the proposed stiffener design can effectively prevent the premature buckling of the IC web, and the maximum deformation of properly designed ICs can be 0.11 radian before fractures occurred at the IC web near the stiffeners. Tests also confirm that the proposed CDPs for the SPDs are effective to ensure the EJs to remain elastic while strain hardening factor of the IC reaches 1.5. Analytical studies confirm that cyclic response of SPDs can be accurately predicted by using Abaqus shell-element model, and the PISA3D models with either one or three beam elements to represent an SPD. The Abaqus and PISA3D push-over analysis results of a 6-story example SPD-MRF show that when the roof drift reaches 0.01 radian, yielding is developed only in the SPDs’ ICs. When the roof drifts go from 0.01 to 0.015 radians, flexural yielding are gradually developed in the beam ends and the 1st story columns’ bottom ends. SPDs act like fuses to reduce the inelastic deformations of the beams and columns. The beam sections and the panel zones adjacent to the SPDs remain elastic as anticipated before the roof drift reaches 0.04 radian. This confirms the effectiveness of the CDPs proposed for the connecting beams and panel zones. PISA3D analytical studies confirm that the example SPD-MRF performs very well. Under a total of 240 ground motions of SLEs, DBEs and MCEs, the inelastic deformational demands imposed by any MCE on the ICs of the SPDs are substantially lower than the capacity witnessed in the test specimens.