Beam design in PR braced steel frames

Abstract

Recent American and European Codes allow the actual behavior of joints to be taken into account in frame design. The AISC-LRFD specifications introduce the concept of partially restrained construction and state the basic design requirements. Eurocode 3 permits 'semi-continuous' frames and specifies basic criteria for the analysis of thei type of structure as well as for the classification and modeling of the moment-rotation of beam-to-column joints. The authors developed a method of analysis of partially restrained beams, permitting straighforward determination of the response as well as a comprehensive checking against the limit state conditions, either elastic or plastic. The approach extends the beam line concept, which most designers are already familiar with; however, the main novelty is that a set of complementary limit state domains is defined and then arranged so that the performance of the joint-beam system can be controlled with simultaneous reference to the different parameters governing the joint-beam system response.