Many earthquakes around the world have shown that rapid access to a functioning transportation network is among the most critical needs of a region, their businesses, and residents to respond and recover from a damaging earthquake. More work is needed in areas of high seismicity, like British Columbia, to understand seismic behaviour and any lack of resilience of our transportation infrastructure, and to conduct seismic retrofits and renewal of bridges, the key links in our transportation networks.
For over three decades, and in partnership with the Province of BC, the City of Vancouver, many municipalities and agencies, and also with the private sector, every major bridge in the Lower Mainland and many other bridges have seen a level of seismic retrofit. But more seismic resilience is needed to allow the Lower Mainland’s uniquely non-redundant transportation network, spanning rivers and harbours, to continue to function after an earthquake. This is particularly important given that the population of the Lower Mainland continues to grow at sustained rate that will add one million new residents in the next three decades – the short span of one engineer’s career.
Can we seismically update our transportation network while meeting the infrastructure functional and seismic needs of our growing population over the next three decades? Absolutely we can, and this must and will be done in parallel with society’s dramatic reductions in the use of fossil fuels.
In 2017, Associated Engineering along with local and international seismic specialists, worked with the Province of BC and five ministries to complete the Province’s Earthquake Integrated Asset Management Plan. This plan established a vision for working together to improve the seismic resilience of our transportation network across BC. Implementation of this plan is crucial.
In recent years, we have developed and encouraged the adoption of performance-based seismic design methods and codes in Canada. This framework allows, or forces, owners and engineers to communicate much more clearly on societal, owner and the engineer’s expectations for seismic performance and post-seismic recovery. In 2019, the National Bridge Code has been updated to include performance-based and seismic resilience into the practice of bridge retrofit. We must encourage owners of transportation structures to adopt this framework.
What’s next? In the past, climate and weather-related data and statistics were assumed to be ‘stationary’, e.g. their statistical measures did not change appreciably over time. This is no longer true.
How do we design new infrastructure for 75-year design lives when our environmental influences are changing significantly? How do we design for events with various ‘return periods’ that are no longer exist? What was a 50-year return period event can evolve into a 10-year or shorter hazard. How will society and code-writers of all forms of infrastructure deal with these changes?
The Canadian Standards Association for the National Research Council is currently working on a standard which will provide new and specific guidance to code writers to include climate-change resilience measures. These will be implemented into the 2024 National Bridge Code.
Don and other engineers at Associated Engineering are and will continue to work with standards committees, academia, industry associations, and various levels of government to improve the seismic resilience of our transportation structures.
For more information, please contact Don Kennedy.
About the Author:
Don Kennedy has more than 40 years of experience in the design and management of bridge and transportation structures projects across Canada and in New Zealand. A seismic specialist, Don has participated in the seismic assessment, rehabilitation, and retrofit of bridges. He has worked on most of the bridges in the BC Lower Mainland, including the Oak Street, Knight Street, and Patullo Bridges, and award-winning Mission Bridge. As Vice President, Transportation Structures for Associated Engineering, he assists with projects and pursuits across Canada. Don’s passion for seismic engineering extends to his volunteer efforts, including work on the National Bridge Code as well as BC’s Bridge Design Guidelines.