A technique for evaluating the effect of beam‐column joint deformation on the lateral flexibility of steel frame building structures

Accurate analysis of steel framed structures requires a careful assessment of the contribution of beam-column joint deformation to overall structural flexibility. Unfortunately, traditional structural analysis has either ignored the deformations by assuming fully rigid joints, or has approximated the effects by using centerline analysis. Some computer programs use a hybrid technique wherein the beam-column joint region is assumed to be partially rigid. Due in part to the fact that the preceding analysis technique violate local equilibrium within the joint, the results produced are unrealiable. In this paper, a new analysis technique is presented for beam-column joint analysis. The method is based on a virtual force analysis of an isolated subassemblage, with local equilibrium within the joint being strictly satisfied. When compared with results of finite analysis of full three dimensional subassemblages, the method has been found to be very accurate.