Shaking table tests of precast RC buildings with added DOUBLEDAMP: A novel 2D dissipative connection for seismic risk mitigation

This work investigates the 3D seismic behaviour of a precast RC struc-ture equipped with the so-called Double Damp (DD) system, a patented and CE-marked post-installed dissipative beam-to-column connection. DD is designed primarily for seismic retrofitting, offering a simple and cost-effective installation. When inserted into the main structural frames, the device can dissipate energy in both the principal and orthogonal directions, addressing the typical lack of 3D structural continuity in precast systems. A series of 3D shaking table tests was performed on a 1:3-scale precast RC structure at the TAMARIS facilities (EMSI Lab) of CEA-Paris Saclay to assess the improvement in seismic performance achieved through DD installation. To analyse the influence of the vertical ground motion component, a Near-Field Earthquake (NEQ) record was adopted as input excitation. Following the table training sequence, NEQ motions with increasing amplitude were applied to both the bare structure and the DD-equipped specimen. Additionally, 3D white-noise signals were introduced after each seismic se-quence to monitor damage progression. A comprehensive dataset was collected, including 3D accelerations and displacements, column rotations, and steel rebars strain measurements from more than 160 acquisition channels. The results sug-gest that DD installation enhances structural performance, reducing accelera-tions, displacements, and damage while increasing the overall damping capacity.