Soil and Foundation Improvement Solutions for Seismic Hazards

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The upgraded seismic loading included in the revised national building code (NBCC 2005) postulates an increased seismic hazard in Canada. Most existing structures, including major infrastructure (e.g. nuclear power plants, bridges, etc.), were designed and constructed prior to these new design guidelines and are susceptible to earthquake damage. Thus there is a need to provide innovative solutions for earthquake resistant foundations for new and existing structures. This research program represents an effort towards resistant seismic design through developing innovative retrofitting techniques for foundations of existing structures as well as developing new techniques for constructing earthquake-resistant foundation systems.Previous earthquakes have clearly highlighted the role of local site conditions and soil-structure interaction (SSI) on earthquake damage. This research investigates the site response and SSI in urban areas and explores a soil improvement solution to mitigate the ground motion at the base of a structure. Considering the growing need for revision of hazard prevention measures for infrastructure facilities and disadvantages of available options, the proposed research also seeks to investigate two innovative techniques using geofoam and sheet piles to retrofit the foundations of existing infrastructures in order to protect them from earthquake damage. Foundation rocking during an earthquake contributes significantly to its response and may involve both uplift at one end and yield at the other. A composite mircopile foundation system, reinforced with fibre reinforced polymer, will be investigated using pile-load tests and numerical modelling for seismic resistant design. The research is expected to provide soil and foundation improvement techniques, efficient foundation systems and design guidelines for retrofitting of existing inadequate foundations as well as new seismic resistant foundations. These techniques are in high demand in the construction industry and transportation.