Incorporation of dissipative connections for seismic retrofit of reinforced concrete prefab structures

An advanced seismic retrofit strategy of industrial buildings with reinforced concrete structure is presented in this paper. It consists in seismically isolating the roof and installing fluid viscous dampers at the roof girder-to-column joints, in the girder vertical plan, and at the ends of the longitudinal beams linking the column top sections, in the orthogonal direction. A retrofit solution based on this strategy is demonstratively designed for a representative case study, i.e. a single storey double hall-type prefab structure built in the late 1980s. A synthesis of the results of the analyses carried out in current conditions is offered, which highlights near-collapse conditions at the maximum considered earthquake level, caused by the potential loss of support of several girders from relevant bearing pads, and unsafe stress states in columns. The response in retrofitted conditions results to be safe and undamaged up to the same seismic action level, thanks to the high damping capacity of the dissipative joints. The structural installation details of the protective system are illustrated, along with technological details of the pipes crossing the isolated roof plan.