Traditional seismic design for SFSI is still based on static geotechnical and structural engineering's cautious and traditional approach. This relates to the avoidance of exceeding several thresholds that lead to the creation of failure mechanisms in the supporting soil or at the footing-soil interface. There is growing evidence suggesting that soil-foundation inelastic and non-linear response during an earthquake is unavoidable and even required sometimes. By looking beyond conventional methods to seismic loading, the EU-funded DARE (Soil foundation structure systems beyond conventional seismic failure thresholds: Application to new or existing structures and monuments) project proposed an SFSI design that can survive seismically while operating on the verge of failure. Project partners examined and successfully demonstrated the potential of enabling below-ground support systems to respond to strong seismic shaking. This was done by surpassing several thresholds that would lead to failure and that are prohibited by seismic codes throughout the world. Following experimental studies, numerical simulations and field observations at recent earthquake sites, the DARE team developed an economical seismic protection methodology. It also offered proof that SFSI systems can be designed to withstand ground failure due to a tectonic fault rupturing underneath or to other forms of soil failure. DARE introduced a paradigm shift in SFSI by enabling such systems to respond safely beyond their failure thresholds. Engineers now have the option of designing foundations against strong seismic shaking. This should result in a safer, more robust and cost-efficient design.
Seismic, engineering, earthquakes, soil-foundation-structure interaction, failure thresholds