Preliminary Numerical Study of a Steel Concentrically Braced Frame Equipped with Dissipative Braces and Self-centring Column Bases

The use of dissipative braces in steel structures has proven to be an effective solution to achieve systems characterised by high stiffness, strength, and energy dissipation capacity. Such structures are usually arranged as Concentrically Braced Frames (CBFs) and the dissipative braces are usually composed of an elastic brace arranged in series with a dissipative device, which can be typically classified as displacement or velocity-dependent. Friction devices (FDs) are one type of displacement-dependent device characterised by an almost perfectly plastic behaviour, and benefit from limited damage and easy repairability. Recent studies also demonstrated how the use of such devices can be beneficial for the definition of Self-Centring Column Bases (SC-CBs) in terms of residual drift reduction and reparability. The present study investigates and provides some preliminary results on the response of combined system coupling dissipative braces with FDs and SC-CBs. An experimental campaign has been planned on a two-storey steel specimen for such a system. This paper introduces the preliminary work for the specimen’s design and tries to foresee the experimental outcomes. Non-linear Finite Element (FE) models of the CBF with dissipative braces (DCBF) and the equivalent frame with SC-CBs (SC-DCBF) are developed in OpenSees. Non-linear static and dynamic analyses are performed to obtain the Engineering Demand Parameter (EDPs) of interest to analyse and compare the seismic performances of both configurations. The preliminary numerical results provide useful information on the expected behaviour of the structures. Further numerical investigations are conducted to assess the structural performance, reparability, and resilience of the adopted technology.