Abstract
In the previous paper (Part 2) an equivalent continuous System was proposed as a kinematic model for a framed structure and was able to give a reasonable approximation for the story stress responses that are story shear forces, story axial forces, overturning moments and transverse forces on the beams. The purpose of the present paper is to illustrate how to apply the story stress responses to earthquake resistant design on the steel framed structure and on this basis to show that the equivalent continuous system may be a useful kinematic model for aseismic design. This paper proposed "equivalent cross sectional area" as a measure representing the magnitude of those story stress responses which can be regarded as vectors with four components. The equivalent cross sectional area was used to evaluate the maximum stress sustained in each member of the frame during the course of earthquake excitations. Further a method to proportion member according to the equivalent cross sectional area was so devised as to control the distribution of plastic deformations of members throughout the structure. Two example frames were designed according to this method and seismic responses of these frames were investigated. Although the present method is still insufficient to produce uniform plastic deformations in the structure, the results of the analysis indicate that overturning moments and transverse forces on beams are influencing factors and have to be evaluated in the process of seismic response analysis. From this view point the equivalent continuous system, which represents the story stress responses in a multi-dimensional space, can be an useful kinematic model for the aseismic design.
