A plastic hinge method for static pushover analysis of 3D frame structures

In this paper, a nonlinear elasto-plastic analysis method under incremental external loads is presented to determine static pushover curves of 3D frame structures. Geometric nonlinearity is taken into account with stability functions, and the nonlinear behaviour of material is considered by plastic hinge hypothesis. Improved matrices and matrix operations for 3D frame elements are given, and the results obtained from a six-storey 3D frame, which is used as a benchmark example, are given comparatively with the related studies. Furthermore, in order to perform these analyses with the developed algorithms, the upgraded computer program TUNAL is used to present pushover curves of a 2-storey RC building for an assumption on torsional stiffness caused by plastic hinges. It is shown that the proposed methodology and the computer program give accurate and reliable results.