TABLE OF CONTENTS The biaxially loaded beam-column problem can be approached from the standpoint of numerical integration for the Column Deflection Curves (CDCs). The concept of CDCs in two dimensions has been discussed thoroughly in Chap. 8 of Vol. 1 for the case of in-plane analysis of beam-columns in which the deflected axis of any beam-column problem can be represented by a portion of the CDCs. The CDC approach was employed years ago at Lehigh University to give needed solutions to various in-plane beam-column problems of interest in plastic design of multistory steel frames (ASCE Manual, 41, 1971), The application of the concept to three-dimensional beam-column problems is presented here.
The first part of the chapter discusses the particular application of the CDC concept for a biaxially loaded, thin-walled beam-column of closed cross section or solid cross section for which the three-dimensional column-deflection-curves can be constructed in space by numerical integration technique neglecting the effect of torsional stress and twisting deformation. A brief description of the numerical procedure follows a rigorous development of the relationship between moments and curvatures for a square and thin-walled box. Studies made of the ultimate capacity of hollow box and circular tube loaded biaxially using this analysis are presented.
The numerical integration method is then extended to solve biaxially loaded beam-columns of thin-walled open cross section for which the effect of torsional stress and twisting deformation upon the overall geometry of the beam-column must be considered. The method is used to predict the behavior...
