Implementation of a rotational friction interface for the numerical modelling of a bidirectional rotational fricyion damper (BRFD)

Precast RC structures with poor connections and detailing have a remarkable seismic risk due to high seismic vulnerability and exposed value combined. There is a clear need for effective retrofit techniques to mitigate earthquake risks and improve community resilience in precast reinforced concrete structures, which has been the subject of numerous studies. A novel damping device was patented in 2022, behaving as a frame beam-to-column joint and a damper with bidirectional dissipative capacity simultaneously. This Bidirectional Rotation Friction Damper (BRFD) has been designed to improve the seismic performance of such structures by excluding the failure of structural and non-structural elements. Unlike usual dampers, the BRFD can operate in longitudinal and transversal directions and develop hysteresis cycles, making its numerical modelling sophisticated. The objective of the present work is the validation of a Refined Virtual Lab tool, which reproduces the rotational frictional behaviour of the BRFD, by using a series of experimental bidirectional tests performed at the Heavy and Light Laboratory of the University of Bristol (Bristol, UK). This research has been carried out using OpenSees in two steps: the implementation of a rotational friction interface and the assembling of the whole BRFD geometry, including the rotational friction interface, using the experimental results as a benchmark to validate the Refined Virtual Lab tool and calibrate the friction interface. The results show a good matching between numerical and experimental results, especially when considering friction models with a sliding velocity dependence.