FREEDAM

FREE from DAMage connections

 

When considering the behaviour of a building steel structures subjected to earthquake, the beam-to-column joints are playing a key role as they are located at the extremities of the beams, where it is intended to dissipate the earthquake energy according to the so-called “capacity design”. If reference is made to the Eurocodes, it is strongly recommended to design full-strength joints, taking into account possible overstrength effects but such design leads, generally,  to expensive construction solutions.

In the framework of a European project entitled FREEDAM (FREE from DAMage connections), funded by the Research Fund for Coal and Steel (RFCS), the University of Liège, in collaboration with three other European Universities (University of Salerno, University of Naples and University of Coimbra) and two industrial partners (FIP Industriale in Italy and OFELIZ in Portugal) is contributing to the development of an innovative beam-to-column joint solution able to withstand not only frequent and occasional seismic events, but also destructive earthquakes, without suffering significant damages.  The proposed joint solution is equipped with friction pads with a specific coating (Fig. 1), and allows the dissipation of the earthquake energy at the level of an haunch connected to the bottom flange of the beam without any degradation of its dissipating capacity during the whole duration of the earthquake.

In addition, it is intended to optimize the structural properties of the proposed innovative joint solution in order to ensure an appropriate behaviour of the structure in case of exceptional events such as impact, explosion, … leading to the loss of a supporting column. Indeed, in the modern codes for design, and in particular, in the Eurocodes, it is required to ensure an appropriate robustness to a structure in case of such exceptional events; and the proposed joint solution presents interesting structural properties from that point of view, in particular in terms of deformation capacity and ductility. 

As partner of this project, the University of Liege is in charge of investigating the behaviour of the proposed joint typology under static and dynamic loading conditions with the final objective of deriving a design procedure for these joints. To achieve this objective, analytical, numerical and experimental investigations are conducted.