Abstract :
The rigid plastic analysis of plane frame structures is reviewed. The rigid plastic analysis presented has been formulated in a way that it circumvents the need of subdividing the beams, whereby, nevertheless, completely arbitrary loads can be accomodated. It will be demonstrated, that rigid plastic analysis may become an effective alternative to elastic analysis, which is largely due to the author succeeding in developing a new, fast and reliable optimisation algorithm, particularly suited to rigid plastic structural mechanics. Various yield surfaces are considered, with special attention given to the yield surface in DIN18800 for symmetrical rolled I and H profiles. Elastic and rigid plastic analysis results are compared and the cost reducing effect of rigid plastic redistribution of internal forces is examined in the examples.