Structural Modelling of Vierendeel Beams with Semi-Rigid Joints

In building construction a significant advantage of vierendeel beam systems is that they can, in portal frames, take advantage of the member flexural and compression resistances eliminating, avoiding the need for extra diagonal members. For this reason, they allow greater interaction with building services, enabling a free space for pipes, ducts, etc. They are also widely used in staggered-truss systems. This work is aimed at evaluating the influence of initial stiffness variation in the joints of a vierendeel girder type beam, carried out with the inclusion of analyses of semi-rigid portal frames. FTOOL/SRC was the program used to model the semi-rigid joints by means of a simple and compact parametric analysis. The main goal of this article is to demonstrate, through a series of analyses of a vierendeel beams, the influence of semi-rigid joints in the structural response. These analyses have involved, in a first stage, fixed and simply supported beams configurations followed by three semi-rigid structures, allowing a better understanding of the force-transfer mechanism in this structural system.