New Approach for the Construction of Inelastic Stiffness Matrix for

Abstract

There seems to be many situations where an inelastic analysis needs to be performed on a<br><br>frame structure. In the last decades, the subject has received much interest from many<br><br>researchers, especially for seismic applications. Different models have been proposed for the<br><br>frame element to represent its inelastic behavior, among which, the one component models<br><br>with inelastic springs are widely used. In such models, each frame member is represented by<br><br>an elastic element, with several nonlinear springs, mostly located at the ends of the element.<br><br>These models suffer several deficiencies, mentioned in the context. To overcome such<br><br>deficiencies, a new approach is suggested for the construction of inelastic stiffness matrix of<br><br>the frame element. In the proposed method, some virtual inelastic springs are attached to the<br><br>elastic element. Such springs model plasticity in the strain states beyond the rigid body modes<br><br>of the element. The stiffness matrix of the frame element, obtained through this procedure, is<br><br>compared with the conventional ones for its priority.