First Annual Distinguished Lecture

Abstract:Much of Surrey and Langley, southeast of Vancouver, are underlain by deep, sensitive, very soft and compressible clays that have presented major challenges for transportation infrastructure developments over the last six decades. Geologically, the clays were deposited in marine environment following the retreat of the glaciers from this region some 13,000 years ago. Most of the bridges in this area are piled, with approach embankments constructed with mineral fill using staged/surcharged construction, with or without ground improvement. In recent decades, use of lightweight or ultralightweight fill for approach embankment has become popular to save construction time. This presentation describes two bridge (or overpass) failures in Greater Vancouver. The one in Langley involved excessive settlement after construction of the approach embankment built with a combination of expanded polystyrene (or geofoam) and wood waste (or hog fuel). The other in Surrey was damaged by failure of a soil stockpile adjacent to the bridge resulting in cracking and displacement of the bridge structure and its pile foundations. Mechanisms of two bridge failures will be elaborated and the efficacy of remedial measures for both cases will be described. The take-away of this lecture is the lessons learnt from the failures.

Biography of speaker:

Dr. Alex Sy, P.Eng., is Vice President, Technical at Klohn Crippen Berger Ltd. in Vancouver, BC. He has more than 45 years of experience in geotechnical and earthquake engineering around the globe on a wide range of projects including transportation infrastructures, hydroelectric and water retention dams, and mine tailings dams. He has provided forensic engineering and expert witness services for infrastructure failures involving dams, dykes, bridges, pipelines, buildings and landslides. He currently serves on Independent Technical Review Boards for several major water supply projects and mine tailings storage facilities around the world. Alex has a Bachelor in Civil Engineering from the University of Queensland in Australia, and a Master and Ph.D. in Geotechnical Engineering from the University of British Columbia. He is an Adjunct Professor at the University of British Columbia and the University of Toronto. He has authored more than 60 technical papers on various aspects of geotechnical and geoseismic engineering. Alex received the Canadian Geotechnical Colloquium award from the Canadian Geotechnical Society (CGS) in 1996, the VGS Award from the Vancouver Geotechnical Society in 2015, and the G. Geoffrey Meyerhof Award from CGS in 2019. He was the CGS Cross Canada Lecturer in Fall 2018. Alex is a Fellow of the Engineering Institute of Canada.

Cost:

• CGS Members and Students Free
• Non-members $10
• Sponsorship $150

Each Sponsor will have their logo prominently displayed on the first slide of the presentation accompanied with an acknowledgement, as well at the end during the Q & A session.