All-Steel external frame for the non-disruptive seismic retrofit of existing reinforced concrete buildings
The state-of-the-art review in seismic retrofit of existing reinforced-concrete (RC) buildings indicates that a technology that is
non-disruptive and easy to implement, achieves simultaneous control of drifts and accelerations, and overcomes major
issues related to low concrete strength, poor reinforcement details, and vulnerable RC columns, has never been described in
the literature or in seismic design codes (e.g. Eurocode 8). The ambitious main objective against the background of the
state-of-the-art of the project is to develop such a retrofit technology. In particular, the project will develop a non-disruptive
retrofit scheme using an external, modular, steel frame as a facade close and in parallel connected to frames of the existing
RC building. The external steel frame will have chevron braces to support energy dissipation devices, and, connectors to
achieve horizontal coupling with the existing RC building. Strategically, the energy dissipation devices will be visco-plastic
dampers, i.e. novel devices that will offer visco-elastic damping output under low-to-moderate earthquake intensities and
friction damping output with a predefined limit on their peak force under high seismic intensities. The project will develop
sophisticated yet practical structural details and a simplified seismic design procedure for the external steel frame. All these
will be achieved through a carefully planned integrated experimental and numerical research program involving constitutive
modelling, nonlinear finite element analysis, and shaking table tests. The proposed retrofit scheme constitutes a solid
contribution to earthquake engineering that is expected to raise major international scientific and industrial interest.