Tunnelling 101: Probabilistic seismic hazard analysis and Performance-based analysis

Topic: Probabilistic seismic hazard analysis and Performance-based analysis for Design and Analysis of Geo-structural systems: Case Study of sloping grounds in Greater Vancouver, BC

When: Tuesday, July 9, 2024 at 3pm (EST) / 12pm (PST)

Abstract:
In Geotechnical earthquake engineering, performance-based design (PBD) is based on tolerable displacement criteria and has become part of practice and engineering code. It has been widely used for developing remediation strategies for geo-structures such as underground structures, embankment dams and sloping grounds under design seismic loadings. There are two crucial requirements for implementing PBD: acceptable performance criteria and a reliable method of analysis.

Although a nonlinear analysis can be essential for checking the seismic performance of geo-structural systems due to the nonlinear behaviour of soil under strong shaking, simplified analyses are widely adopted in engineering practices and industry as a criterion for selecting areas requiring more advanced analysis and prioritizing remediation interventions. The incorporation of probabilistic seismic hazard analysis (PSHA) in such methods provides a valuable tool to evaluate the effects of local seismicity and tectonic settings on the performance of geo-structural systems.

In this presentation, an example of embankments and sloping grounds in Greater Vancouver, based on the local tectonic of BC are considered where the criterion of acceptable performance is usually specified by tolerable displacements of the soil body. PSHA and local seismicity and their effects are elaborated, and the difference between a probabilistic solution and a traditional pseud-probabilistic method is also shown. Based on realistic and more accurate results of PSHA-based PBD, this kind of analysis is recommended for future seismic evaluations in the area of geo-structural systems.

Speaker Bio:
Ali Fallah Yeznabad, GHD Consultant

Ali Fallah Yeznabad is an Intermediate Geotechnical Specialist with GHD in Toronto, Ontario. After completing his M.Sc. in Geotechnical Engineering in Iran University of Science and Technology, Ali received his Ph.D. from the University of Western Ontario in 2021 and has been working in the Geotechnical Engineering industry since 2016. Ali and his research group have been working on the "Metro Vancouver Seismic Microzonarion", funded by EMBC and ICLR, which evaluates different hazards associated with ground shakings in Greater Vancouver, BC. His research looks at seismic hazards for slopes and geo-structures and whether their performance will be satisfactory during the expected earthquakes.

During his research in university and as an engineer, Ali has focused upon developing innovative and effective methods for assessing seismic hazard on geo-structures. In that capacity, his primary industry works have been seismic assessments such as liquefaction analysis and seismic soil-structure interaction analysis of abutments, retaining walls and buried structures, mainly in North America. Ali has authored several peer-reviewed articles on seismic hazard evaluations in Canada and has spoken at numerous symposia and conferences during his career.