Dr Pierfrancesco Cacciola, School of Environment and Technology, University of Brighton

Seismic Protection of Existing structures through the Vibrating Barrier (ViBa) device
When Feb 25, 2019
from 02:00 PM to 03:00 PM
Where Department of Materials, Hume-Rothery Building Lecture Room
Contact Name
Contact Phone +44 (0) 1865 273030
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New building structures in seismically prone areas can be readily designed to achieve acceptable level of seismic performance through code-prescriptive capacity/ductile design for earthquake resistance and/or through equipping them with energy dissipation devices including viscous, viscoelastic, and hysteretic dampers as well as with tuned mass dampers (TMD) and/or seismic isolation Nevertheless, seismic protection of existing code-deficient buildings is an appreciably more involved task requiring invasive and expensive interventions to seismically upgrade structural performance through increased stiffness, strength, and/or ductility or through equipping structures with energy dissipation devices or a base isolation layer. In practice, building owners can rarely afford the cost of such interventions leaving much of the existing building stock in major cities vulnerable to future seismic events. Moreover, in case of heritage structures most types of structural intervention for seismic upgrade applicable to ordinary structures are not allowed as they would compromise their architectural/historical value.

One possible strategy is to protect the structures through trenches or sheet-pile walls in the soil for altering the displacement field based on the reflection, scattering and diffraction of dynamic surface waves or through the use of most innovative metamaterials, as the resonant metawedge for controlling the flow of Rayleigh waves. However, this approach is more effective for surface waves rather than body waves as those mainly produced by an earthquake. The recently proposed non-localized solution, called Vibrating Barrier (ViBa), hosted in the soil and detached from the structures will be presented in this talk. Specifically, ViBa comprises a free-to-vibrate mass encased in a rigid containment buried in the ground and connected to the walls of the containment through linear springs and dampers as depicted in Figure 1. It can therefore be viewed as an underground TMD-like unit tuned to absorb portion of the seismic energy before entering the foundations of surrounding structures by exploiting a structure-soil-structure (SSSI) mechanism. The latter involves the dynamic interaction between two (or more) adjacent rigid structures resting on relatively soft/compliant soil media. Recent development of the Vibrating Barrier with relevant case studies will be presented.