UPCOMING LECTURES

PREVIOUS LECTURES

Performance-based liquefaction hazard analysis and probabilistic liquefaction mapping for the western Metro Vancouver

Alireza Javanbakht, Ph.D., Jacobs

Centennial Room, Executive Hotel, 4201 Lougheed Highway, Burnaby, BC V5C 3Y6. Social Hour @ 17:30, Lecture @ 18:30

Selecting a single combination of earthquake magnitude and maximum ground acceleration to evaluate liquefaction triggering in the Metro Vancouver region is challenging as the area is affected by multiple seismic sources. A probabilistic seismic hazard analysis based on the seismic hazard model of the 2020 NBCC is accomplished to account for all earthquake scenarios and consider the liquefaction model uncertainty and soil resistance variability. The liquefaction hazard curves are generated for the factor of safety against liquefaction and the amount of required soil improvement to prevent liquefaction which provide a comprehensive assessment of liquefaction triggering. The performance-based methodology offers a potential alternative to the conventional liquefaction analysis commonly employed by practicing engineers in BC. In addition, the liquefaction hazard curves from 900 CPT and shear wave velocity profiles are created by incorporating the liquefaction potential index (LPI) and Ishihara-inspired liquefaction potential index (LPIISH) into the performance-based liquefaction assessment. The first probabilistic liquefaction hazard maps of Metro Vancouver are presented using the targeted return periods of 475 and 2,475 years. The maps provide a preliminary evaluation for soil improvement applications.

Seismic Response of Rigid Inclusions considering Strength and Stiffness Degradation of Grout and Improved Boundary Conditions

Armin W. Stuedlein, PhD, P.E. (WA), F.ASCE Professor, School of Civil and Construction Engineering at Oregon State University

Centennial Room, Executive Hotel, 4201 Lougheed Highway, Burnaby, BC V5C 3Y6. Social Hour @ 17:30, Lecture @ 18:30

The use of rigid inclusions (RIs) as a ground improvement technique has increased substantially in seismic regions owing to their cost effectiveness as an intermediate foundation solution. Although recent research by the presenter and collaborator Dr. Matthew D. Gibson, Clarity Engineering, LLC, have revealed critical soil-structure-interaction mechanisms of rigid inclusions under seismic loading, some observations were constrained by constitutive models available at the time and idealized unit cell boundary conditions. This lecture presents an overview of previous findings of the first phase of a Deep Foundations Institute (DFI) Research Project on the seismic response of RIs investigated using 3D numerical simulations. Then, limitations in the Phase I research associated with the previous constitutive model used to simulate RI grout are discussed through demonstration of performance of RIs using an improved constitutive model. Basic unit cell analyses of a single RI supporting a mat foundation and subject to strong ground motion are revisited, concluding with the presentation of inappropriate responses of such models when the RI experiences significant nonlinear inelasticity. New 3D simulations of groups of RIs supporting an isolated spread foundation are then presented under Phase II of the DFI-sponsored research, with performance of the group system discussed in terms of flexural and shear demand due to kinematic loading, displacements, and post-seismic stability. The performance of unreinforced and reinforced RIs are discussed and compared. The presentation concludes with a discussion of next steps in the research program and vision to distill the research into practical design guidelines.

Shifting Tracks: Permafrost Thaw along the Hudson Bay Railway

by Jocelyn L. Hayley, Ph.D., PEng., FEIC, FCAE, Professor, University of Calgary on Wednesday, October 30, 2024

Centennial Room, Executive Hotel, 4201 Lougheed Highway, Burnaby, BC V5C 3Y6. Social Hour @ 17:30, Lecture @ 18:30

Across the Canadian north, access to stable linear infrastructure networks is critical for the well-being of Northern communities and the Canadian economy. The Hudson Bay Railway, the first major transportation infrastructure built over permafrost in Canada, is now facing significant climate-driven stability and drainage issues. The Hudson Bay Railway corridor extends across icy and frost-sensitive glacio-marine deposits through the sporadic, discontinuous, and continuous permafrost zones of Northern Manitoba. After touching on its rich history during construction and operation, we introduce a transdisciplinary multi-year project that aims to identify and characterize permafrost-related hazards along the railway corridor and investigate potential mitigation measures for improving rail stability and minimizing risk. Traveling along the Hudson Bay Railway, we will look at site investigation methods, explore ground temperatures and ice wedge formations, drainage issues, sinkhole formation and more - all with the goal to improve the resilience, sustainability, performance, and safety of Canada’s permafrost railway.

Effects of Subsurface Heterogeneity on Liquefaction-induced ground deformation during earthquakes

by Ross Boulanger, Ph.D., Emeritus Professor of the University of California (Davis) on Thursday, September 26, 2024

Cordova Ballroom, Pinnacle Hotel Harbourfront, 1133 West Hastings Street, Social @ 1730, Lecture @ 1830

The effects of subsurface heterogeneity on liquefaction phenomena during earthquakes are discussed using case histories and nonlinear dynamic analyses with different subsurface modeling approaches. The importance of geologic and anthropogenic controls and the effects of stratigraphic heterogeneity, lithological heterogeneity, and inherent soil variability at the project site scale are discussed. The results of these studies reinforce lessons regarding the importance of subsurface characterization and its representation in analyses for evaluating liquefaction-induced ground deformations and their impacts on civil infrastructure.

1st Annual VGS Legacy Lecture – Celebrating the Legacy of Oldrich Hungr And VGS Annual General Meeting

by Paul Wilson, M.Eng., P.Eng., Partner and Senior Geotechnical Engineer, Thurber Engineering Ltd. and Scott McDougall, Ph.D., P.Eng., Associate Professor, Geological Engineering University of British Columbia.

The VGS is introducing an annual lecture series to honor the legacy of local geotechnical leaders by featuring a different honoree each year. For the first lecture of this series, the VGS is pleased to celebrate the legacy of the late Oldrich Hungr, PhD, P.Eng./ P.Geo. 

Oldrich Hungr was born in Prague, Czechoslovakia, on November 1st, 1947.  He moved to Ottawa in 1969 where he did his undergraduate and masters degrees in civil and Geotechnical Engineering at the University of Ottawa. He did his PhD at the University of Alberta under the supervision of Professor Norbert Morgenstern on the dynamics of rock avalanches. After graduating in 1981, he began a prolific geotechnical consulting career with Thurber Engineering in Vancouver.  During this period, he became a leading expert in debris flows and long runout landslides.  In 1996, he became professor of Geological Engineering at the Department of Earth and Ocean Sciences at the University of British Columbia (UBC) where he expanded on his research and consulting record while teaching hundreds of undergraduates and supervising over 40 graduate students. Throughout his career, he developed, used and made available a number of geotechnical software on slope stability, dynamic analysis and rockfall simulation. He participated in over 1000 assignments worldwide, including numerous slope safety review boards, landslide hazard assessment, stabilization and protection work studies, site investigations, and provided expert testimony in multiple landslide cases. His work covered roads, railways, pipelines, dams and reservoirs, tailings disposal, excavations and tunnels.  He was an invited keynote speaker at numerous prestigious conferences, including the Heim lecture in Naples in 2016. He was awarded the Schuster Medal from the Association of Environmental & Engineering Geologists in 2008 and the Varnes Medal from the International Consortium on Landslides in 2015, amongst others. He passed away on August 17th, 2017, at 69 years of age.

Part I - Consulting Legacy Lecture – by Paul Wilson

Charles Creek, located on the Sea to Sky Highway south of Lions Bay, has experienced several recorded debris flows since highway construction in the 1950s. These include 18 events between 1969 and 2010, with major damage in 1969, 1972, 1981, and two in 1983. Following multiple debris flow incidents along the Sea to Sky Highway corridor in the early 1980s at multiple locations, the BC Ministry of Transportation designed and constructed several large debris flow mitigation structures. Dr. Oldrich Hungr was an instrumental part of Thurber’s design team for these projects. The first mitigation structure constructed was a large debris catchment basin completed in 1985. The mitigation structure includes a zoned earthfill dam with a concrete exterior designed to contain approximately 33,000 m3 of debris, a decant structure and a spillway. The decant structure was designed to stop logs and boulders up to 2 m in diameter, traveling at 7 m/s, while allowing water to pass. The structure was designed to retain water should the decant structure plug. The spillway was designed to accommodate a flow of 700 m3/s. Subsequent debris flows occurred in 1990, 1991, 1995, 2005, 2007, 2009, 2010, with volumes estimated up to 25,000 m3, and were successfully retained in the catchment basin. Oldrich was engaged by Thurber to assist in evaluation of the events, performance of the catchment structure and post-event cleanup details.

Part II - Academic Legacy Lecture – by Scott McDougall

The landslide and broader geotechnical communities lost a key voice with the sudden passing of Professor Oldrich Hungr in August 2017. Oldrich made several major contributions to landslide science and practice over his 40-year career as a researcher and consulting engineer, including the development of widely-adopted methods for landslide stability and runout analysis. His work was characterized by an overarching theme of pragmatism. He approached the complex subject of landslides from a geo-practitioner’s viewpoint, advocating for relatively simple methods that, when combined with factual observations and professional judgment, could still provide powerful insight and a basis for sound decision making. This talk discusses this theme and describes its extension to more recent and ongoing research that Oldrich inspired and helped to develop.