FORCE SPACE PLASTICITY MODELING OF THE CYCLIC CROSS-SECTIONAL BEHAVIOR OF STEEL BEAM-COLUMNS

The present paper is concerned with the force space plasticity modeling of the cyclic cross-sectional behavior of steel beam-columns subjected to the combined axial force and bending moment. The fundamental concepts and formulation of the two-surface type plasticity model in force space (۲SM-FS), which has been developed with extension of concepts used in the two-surface plasticity model in stress space (۲SM-SS), are presented and discusses. The developed ۲S۱V۱-FS takes accurately into account cyclic elastoplas-tic behavior of structural steels such as the yield plateau, Bauschinger effect and strain hardening. [n a companion paper the cyclic plasticity performance of the ۲SM-FS is verified and discussed, both at the cross-sectional level and structural level, by comparing the results obtained from this model with those of the experiments and analyses using ۲SM-SS