Abstract
The objectives of this paper are to explain the plastic behavior of steel beam-column, to indicate the influenced factors on the deformation capacity, and to determine quantitatively the relationships between the deformation capacity and these factors. On this part 1, it is showed that the experimental results of beam-columns that have various parameters of steel material, slenderness ratio and axial force. The plastic deformation capacities are limited with the local buckling and lateral torsional buckling of members. In the case that the lateral torsional buckling precedes the local buckling, the deformation capacity of steel members are not large. Whether lateral torsional buckling precedes or not depends on the location of full plastic hinge. The location of plastic hinge is determined by the combination of slenderness ratio and axial force. When the plastic hinge are formed at the end of members, local buckling precedes. The relationships between the deformotion capacity and axial force on the same slenderness ratio are not monotonously decreasing function.
