ENGINEERING A BETTER CANADA AWARD & AWARD OF EXCELLENCE / SPECIAL PROJECTS Seismic Retrofit Guidelines for BC Schools
October 1, 2013
By Ausenco Engineering, Bush Bohlman & Partners, Read Jones Christoffersen, Genivar, et al
Jury Comments: "This project takes a real problem and finds a solution that allows for priorities to be set for doing retrofits. The technical stakeholder community worked together and the result is a guideline that can be used worldwide."
Jury Comments: “This project takes a real problem and finds a solution that allows for priorities to be set for doing retrofits.
The technical stakeholder community worked together and the result is a guideline that can be used worldwide.”
—————————-
The British Columbia Ministry of Education is implementing a billion-dollar-plus program to mitigate the seismic risks of the province’s school buildings. For this, the Ministry wanted a common engineering approach using innovative methods for assessing and then retrofitting existing schools.
In response, a unique collaboration between government, academia and the engineering community, with key involvement of ACEC-BC firms, has produced the Seismic Retrofit Guidelines for BC Schools, a nine-volume, 300-page manual, together with a companion web-based “Seismic Performance Analyzer.” The Ministry contracted the Association of Professional Engineers and Geoscientists of B.C. (APEGBC) to prepare the guidelines, and APEGBC subcontracted the various other parties involved (see credits below).
Rapid and consistent
assessments
The combined experience of over 150 years of seismic upgrading in B.C. was used to produce two volumes containing a “library” of 35 proven retrofit details and 14 seismic retrofit strategies. This was the result of a collaborative sharing of information from the consulting firms involved.
The state-of-the-art and unique analyzer and guidelines enable structural engineers to rapidly and consistently determine the seismic risks of existing school buildings. The tools also enable engineers to optimize retrofits to achieve a “life-safety” seismic performance.
For example, the use of the guidelines by structural engineers has relieved them from selecting earthquake ground motion records or carrying out non-linear analyses; this is already done with results accessible in the analyzer. The tool allows engineers to focus on determining the capacity of the existing building to better determine risk, and enables them to consider a variety of retrofit options that address issues such as disruption, schedule, phasing, cost, implementation and constructability.
The guidelines also offer the capability of mixing different new structural systems in combination with existing systems.
The “performance-based” guidelines have proven to be effective in selecting a very efficient, cost-effective retrofit scheme for a building. The required lateral capacity for the new structural components, to ensure specific drift limits are maintained, can be as low as 50% of current code force levels for new buildings, thus directly contributing to cost savings.
The use of the guidelines has allowed more school buildings to be upgraded and made safer within the available Ministry budget. By effectively assessing the building’s existing components, fewer buildings are ranked “high risk,” leading to less demolition and replacement (less landfill material, less energy for new materials). More heritage buildings are also expected to be retained.
A key aspect of the approach taken in the analysis and guidelines is that it allows for the contribution of archaic materials that are commonly found in existing buildings but not addressed by current standards. The approach also allows for novel materials and innovative retrofit methods as the guidelines evolve and further research and testing is done.
The Association of Professional Engineers and Geoscientists of B.C. (APEGBC) has endorsed the guidelines for use on all low-rise buildings in the province. This has resulted in private entities, with large inventories of buildings, using the guidelines and developing seismic mitigation programs. cce
Project name: Seismic Retrofit
Guidelines for BC Schools
Award-winning ACEC-member firms
(structural engineering for peer review;
liaison with owner and other project
participants): Ausenco Engineering
Canada; Bush Bohlman & Partners;
Read Jones Christoffersen; Genivar
(John Sherstobitoff, P.Eng.; Clint Low, P.Eng.; Tim White, P.Eng.; Ron Devall, P.Eng.; John Wallace, P.Eng.),
Owner: BC Ministry of Education
Client: APEGBC
Other key players: University of B.C.
(lead developer); TBG Seismic
(subconsultant to UBC); David Nairne & Assoc. (peer review), JWE, EPR
External peer reviewers: Robert Hanson, PE; Farzad, Naiem, PE; Michael Mehrain, PE.
