Integrating soil-structure interaction within seismic design and assesement of buildings in Canada

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Although several international building codes and design guidelines contain provisions to account for soil-foundation-structure interaction (SFSI), they do not address the design of the superstructure, the foundation and the surrounding soil as an integrated engineering system. Understanding and quantifying the global seismic response of building structures is essential to develop design procedures that consider the integrated structural behaviour. Such procedures, applied either within the framework of capacity-based or performance-based seismic design, are needed to put forward alternative cost-effective solutions for new buildings and for seismically deficient older buildings. The long-term objective of the proposed research program is to develop integrated design procedures for the seismic design and evaluation of buildings on shallow foundations that will consider the combined contributions of all components of the soil-foundation-structure system. These procedures will address the seismicity context of western and eastern Canada with special attention paid to the particularities of the structural response to high-frequency seismic motions. The research will be structured around two main themes: (i) the assessment of the effects of soil-structure interaction on the seismic performance of buildings designed according to current Canadian seismic provisions; and (ii) the development of design procedures that include the integrated response of building-foundation-soil systems. Reinforced concrete shear walls and steel braced frames will be studied. These systems are commonly used in Canada to resist seismic loads and, because of their high stiffness, the foundation/soil deformations can contribute significantly to the overall system flexibility. The global structural response to seismic excitations will be examined through extensive analytical studies. The integrated structural models for nonlinear time history analysis will be built in the open-source computational platform OpenSees. Design procedures will be proposed in the context of capacity-based and performance-based methodologies with attention directed to their suitability for practical use. The findings of this study will help to better understand the global seismic behaviour of integrated building systems, contribute to introduce new design methods into Canadian seismic design provisions and provide guidelines and tools for practicing engineers to integrate SFSI effects in everyday practice. They will address seismic context of Eastern Canada for which a limited amount of data is presently available. The economical impact of proposed procedures may be significant particularly for the older seismically deficient buildings, for which the application of developed numerical tools and integrated approach to analyse their seismic performance can avoid unnecessary and costly retrofits.