Assessment of a novel hysteretic friction damper for the seismic retrofit of reinforced concrete frame structures

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

“…Figure 6 shows the capacity curves of the case study buildings and the relative d p s which correspond to the ending point of the elastic branch, or at most at the beginning of the second branch relevant to the cracked concrete [43]. In this study, the two structures are retrofitted by using hysteretic steel dampers installed into diagonal steel braces (Figure 7), which is a common configuration for frame buildings [1,5,6,[43][44][45]]. An elastic-perfectly plastic constitutive behavior is assumed for the dampers, similarly to other studies [1,6,41,43,44].…”

“…In this study, the two structures are retrofitted by using hysteretic steel dampers installed into diagonal steel braces (Figure 7), which is a common configuration for frame buildings [1,5,6,[43][44][45]]. An elastic-perfectly plastic constitutive behavior is assumed for the dampers, similarly to other studies [1,6,41,43,44]. Four units on each floor in both X and Z directions are installed in the external bays according to the layout shown in Figure 7.…”

“…The case study structures are modelled as 3D buildings in the OpenSees software program version 3.6.0 [47,48], adopting the modelling procedure presented in [49] and validated in [1,5,6,41,43]. Beams and columns are implemented through the forceBeamColumn element object [50], assigning a non-linear behavior to the external sections and a linear elastic behavior to the internal section of the element, as shown in Figure 9.…”

“…Hysteretic dampers are widely used for seismic passive protection of both new and existing structures [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. According to the European standard EN 15129 [16], hysteretic dampers, which are further classified in steel hysteretic dampers, friction dampers and metal extrusion dampers, belong to the category of Displacement-Dependent Devices (DDDs).…”

“…In a structure equipped with damped braces, ξ eq , and consequently η, depends upon the damping capacity of the dampers. In this regard, it must be emphasized that steel hysteretic dampers available nowadays, such as Buckling Restrained Braces (BRBs), friction and extrusion dampers, are characterized by high damping capacity, with ξ eq > 28% [3][4][5][6][32][33][34][35][36]. Therefore, the contribution of such dampers to increase the overall damping ξ eq of the combined structural system may be not completely considered in the analyses due to the limitation on η [30].…”