CASE STUDY
SEISMIC UPGRADE
PROGRAM
City-wide seismic upgrade program for a portfolio of older residential buildings in Vancouver, including tuck-under parking retrofit, soft-storey remediation, and cripple wall strengthening.
CASE STUDY
SEISMIC UPGRADEPROGRAM
City-wide seismic upgrade program for a portfolio of older residential buildings in Vancouver, including tuck-under parking retrofit, soft-storey remediation, and cripple wall strengthening.
PROJECT OVERVIEW
This project encompassed a seismic upgrade program for a portfolio of older wood-frame residential buildings in Vancouver — a priority initiative driven by Vancouver's Earthquake Preparedness Strategy. The buildings ranged from 1950s single-family homes with cripple wall foundations to 1970s multi-family buildings with soft-storey tuck-under parking conditions.
Zagrosia Engineering performed individual seismic screenings and retrofit designs for each building in the portfolio, developing a standardized approach that could be adapted to each building's unique configuration. The program was coordinated with the City of Vancouver's permit department for streamlined review.
PROJECT DETAILS
- LocationVancouver, BC
- Building TypeMultiple Residential Buildings
- ServicesSeismic Assessment & Retrofit Design
- JurisdictionCity of Vancouver
- CodeNBCC 2020 / BCBC 2018 / VBBL
- ExpertiseP.Eng — British Columbia
THE CHALLENGE
Soft-storey buildings with open tuck-under parking garages are among the most seismically vulnerable building types in Vancouver. Retrofitting these buildings required introducing new concrete or steel moment frames within the open garage storey without disrupting parking operations more than necessary during construction.
Many of the older wood-frame buildings had no original structural drawings, requiring as-built investigation and measurement to establish existing member sizes and connections before any retrofit analysis could begin. Selective destructive investigation was performed at each building to confirm framing sizes and connection details.
ENGINEERING APPROACH
Portfolio Assessment
Rapid seismic screening and detailed assessment of each building in the portfolio, prioritizing structures by vulnerability and occupancy to establish the retrofit sequencing plan.
Retrofit Design
Individualized retrofit designs developed for each building: cripple wall plywood sheathing for single-family homes, and steel moment frames or concrete frames for soft-storey multi-family buildings.
Permit Coordination
Standardized drawing templates developed to streamline permit submission for the portfolio. City of Vancouver coordinated with Zagrosia Engineering to establish an expedited review pathway for the program.
SCOPE OF WORK
Seismic Screening & Prioritization
Rapid screening of all portfolio buildings to establish vulnerability ranking and retrofit priority
Soft-Storey Retrofit Design
Steel or concrete moment frame design for open tuck-under parking storey strengthening
Cripple Wall Retrofit Design
Plywood sheathing and anchor bolt design for cripple wall strengthening in single-family homes
As-Built Investigation
Field measurement and selective destructive investigation to establish existing framing configurations
Permit Package Preparation
Standardized permit drawing templates coordinated with City of Vancouver for expedited review
OUTCOME
PORTFOLIO UPGRADED ON SCHEDULE
The seismic upgrade program was completed for all buildings in the portfolio within the project timeline. All retrofit designs received City of Vancouver permit approval, and post-construction inspections confirmed compliance with the retrofit specifications. The buildings are significantly better positioned to perform in a design seismic event.
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DO YOU WANT TO START YOUR PROJECT?
Every project is unique. Contact us to discuss your specific requirements, and discover how we can help.
DO YOU WANT TO START YOUR PROJECT?
Every project is unique. Contact us to discuss your specific requirements, and discover how we can help.