STEEL COLUMN-TO-COLUMN CONNECTIONS UNDER COMBINED LOAD - A QUADRATIC-PROGRAMMING APPROACH

The aim of this paper is the investigation of the mechanical behaviour of bolted steel column-to-column connections under moment and axial loads by means of a method that takes into account the possibility of the appearance of detachment phenomena between the splice plates. As is well known, regions of detachment (called nonactive contact regions below), due to the appearance of the prying-action phenomenon, do appear on the adjacent fronts of such steel splice plates, greatly affecting the mechanical response of steel connections of this type. The significance of the problem under investigation arises from the fact that column-to-column splices are extensively applied in any possible combination to the design and construction of steel structures. It is therefore obvious that, since local failure phenomena on such connections due to undesirable-and not a priori defined-detachment between the splice plates (as consequence of the development of the prying-action phenomenon) may cause a total destruction of the whole steel structure. For this reason, it is important for such a behaviour to be accurately predicted and the previously mentioned nonactive contact regions on the splice plates to be defined. In this sense, such an investigation leads to an amelioration of the design principles for bolted steel column-to-column splices and to a refinement of the respective steel construction standards.