Braced ductile shear panel: new seismic-resistant framing system

The conceptual design of an innovative seismic-resistant steel framing system capable of providing stiffness and ductility to new or existing structures is presented. The bracing system consists of concentric X-braces connected in series with rectangular sacrificial shear panels. The braces are designed to remain elastic during seismic events while the shear panels are sized and configured to dissipate ample energy through plastic deformation-induced stable hysteretic behavior. Detailed three-dimensional nonlinear finite-element analyses using ABAQUS are performed to characterize and quantify the effects of the design parameters on the local response of the bracing system and to adjust the design so that potential buckling of the elements is mitigated. The finite element predicted force-displacement curves of bracing systems that achieve the desired local behavior when subjected to a specified interstory drift are in turn translated into a SAP2000 nonlinear link element. Embedment of the link element in a two-dimensional steel frame model enables the assessment of the performance of the bracing system as applied to a seven-story steel frame subjected to different intensity levels of seismic excitation. The results demonstrate that the braced ductile shear panel framing system offers promise for decreasing the lateral displacements of structures subjected to earthquakes while minimizing damage to all structural elements other than the sacrificial panels.