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Inelastic panel zone deformation demands in stell moment resisting frames

Tuna, Mehmet
Panel zone is one of the significant parts of beam-column connections in steel structures. Until the 1994 Northridge Earthquake, a few experimental research and parametric studies had been carried out to understand the behavior of the panel zones. However, after the Northridge Earthquake, it was observed that beam-column connections were unable to show presumed seismic performance. Therefore, current design codes needed to be revised to improve seismic performance of connections in general and panel zones in particular. In this research, panel zone deformation demands are examined using explicit three dimensional finite element models and considering different parameters. For this purpose, a frame model with two different beam-column configurations was developed in order to observe the effects of beam depth, the axial load level and the level of seismicity. The frame models were analyzed under twenty different ground motion records. Local strain demands at the panel zones as well as the global frame deformation demands are evaluated. Analysis results revealed that AISC Specification designs allowed panel zone yielding; however, panel zones designed according to FEMA 355D showed minimal yielding for both shallow and deep beam configurations. Based on the analysis results, local shear strain demands in panel zones were expressed as a function of interstory drifts and normalized panel zone thicknesses.