Innovation - Spring 2024

FEATURE

“It’s based on the most current science and aims to raise the bar for a higher level of performance in certain buildings in the high seismic hazard areas of Canada.” Why buildings failed in earthquake Many buildings built to the 2018 code performed well in the Türkiye earthquake, team member Dr. Svetlana Brzev, P.Eng., UBC adjunct professor, said. It’s when the builders veered off the code that more damage occurred. A common reason for building damage was because the builders—not the designers—did not use adequate cross-ties, as specified in the code. Another issue was poor quality masonry materials for infill construction. Brzev noted buildings also sustained damage due to soft-storey collapse. In buildings with an open ground floor without infill walls, during the earthquake, the bottom floor collapsed. Buildings experienced extensive non-structural damage, as well, with collapsed masonry infills and partitions, and had to be vacated and replaced. Brzev said Canada should pay attention to non-structural damage as well, noting the example of building overhangs that have all non-structural walls without any concrete connecting elements. Response and rebuilding The magnitude of the re-building can impact lives for several years. As Engineers and Geoscientists BC practice advisor and team member, Allison Chen, P.Eng., P.E., explained, re-building is on a massive scale, rather than one structure at a time. The recovery process may take three to five years—longer for remote areas—before an area may be considered “back to normal.” Said Chen, “Before construction can start, you first need to demolish and remove rubble. Where does it go? Where do the new villages or cities get built? Should it be on the same site as existing or a new location? Where do you find clear land in a metropolis?” From her observations, Chen said, designing beyond life safety is a critical step for recovery as well. “This may not seem like a big deal but when every—or most or many—buildings in an area are damaged, this can be an incredibly long prioritization, design, and construction process and, in the meantime, there is a lasting humanitarian crisis where thousands of people are in need of immediate shelter.”

designed to withstand the smaller intensity earthquakes that come more often, as well as the big ones. BC Building Code updates BC is recognizing the need to address the smaller intensity earthquakes, as well. Updates to BC Building Codes 2024 (BCBC) include seismic provisions that are in line with the National Building Code . John Sherstobitoff, P.Eng., chaired the task group within the Standing Committee on Earthquake Design that prepared the latest provisions for the National Building Code . He said it’s important to be aware that current seismicity requirements for design have increased and new provisions have been included for lower-level earthquakes. “The goal is for certain types of buildings like schools and hospitals to be able to withstand a lower-level earthquake without the need to repair the structural components after an event,” said Sherstobitoff, principal, seismic and structures, at Ausenco Engineering in Vancouver.

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Spring 2024

Innovation