Abstract
With the increasing capacity of electronic computers, elastic-plastic, large displacement analysis of steel structures has now become reality in research level. However, there remain some problems that must be overcome. One of those is to reduce the computation time. It is a usual practice to divide the cross-section of a member into many elements so that the spread of yielding in the cross-section may be taken into account. This is considered to be the main reason why a huge computation time is required. In this paper a new constitutive law is introduced which is expressed as direct functions of stress resultants. With this constitutive law the cross-section need not be divided, yet the penetration of yielding into the cross-section as well as along the member may be taken into consideration in an approximate manner. It has been demonstrated that this newly developed scheme saves computation time considerably.
