Ductility factors of symmetrical structures with restricted inelasticity: Fid-Bau Portal

Ductility factors of symmetrical structures with restricted inelasticity

Georgoussis, George K.

10.1002/tal.313.abs

A simple elasto‐plastic analysis of symmetrical buildings composed of different types of bents is presented. Plasticity in bents is assumed to be restricted to the beams, where significant curvature ductility factors may be attained without loss of strength, and the behaviour of inelastic structures may be traced from elastic to ultimate deflections on the grounds that the external load is monotonically increasing with an invariant shape throughout the loading history. The outlined procedure is based on the concept of the continuous medium and a comprehensive consideration of the structural post‐elastic behaviour of common mixed‐bent‐type buildings is possible by means of parameter variations. Therefore it is suitable for a simple pushover elasto‐plastic analysis in a parametric form. The proposed method of analysis is based on the technique of decomposing a cantilever structural system into two components: a flexural and a shear–flexure subsystem. With this decomposition, not only the axial deformations in the column members of all bents are taken into account in the calculation of deflections, but also different types of bents may be combined in symmetrical buildings. Design charts relating the overall ductility factor with the maximum rotation ductility factor at the ends of the beams are presented for the case of a triangularly distributed external load, together with the formulation that defines the post‐elastic load–deflection curve. These data may be found useful for practising engineers at the stage of a preliminary structural application. Copyright © 2007 John Wiley & Sons, Ltd.