Practical Second-Order Elastic Analysis for Semi-Rigid Space Frames

Based on the finite-deformation theory of continuum mechanics, the stiffness matrix of steel space frame was derived. And by using Kishi-Chen power model to describe the nonlinear behavior of semi-rigid connections, the stiffness matrix for semi-rigid space frame was deducted. Then a program for analyzing the second-order effects of steel space frame has been developed. The case study indicated that semi-rigid connections could augment displacement of frame in two orientations, and such effect increased when increasing the number of the frame floors. So it is necessary to consider the effect of semi-rigid connections in advanced analysis of steel frame.