When do I need to Seismic Retrofit?

The National Building Code has increased the seismic loads in the most recent revision. Eastern Ontario has some of the highest seismic loads in Canada next to the West coast. The City of Ottawa has a fault line that runs through the city and the St. Lawrence River Valley is an old seismic fault line.  The seismicity of the region combined with some difficult soils in the area result in high seismic loads on structures and equipment within structures.

While Part 4 of the Ontario Building Code (OBC) [Ontario 1997] is similar to Part 4 of the
NBCC 1995 in terms of seismic requirements for new buildings, the OBC 1997 includes a new
section (part 11) specifically for the renovation of existing buildings. The intent of part 11 is  4
two-folded; (a) to ensure that the performance level of the existing building after renovation is
no less than the performance level before renovation, thus extending the service life of the
building, and (b) to provide a reasonable and acceptable approach to allow renovations. Part 11
applies to buildings that have been in existence for at least five years and are undergoing
renovation.
According to Section 11.3.1.1 on “Material Alternation or Repair of a Building System” and
Section 11.4.1.1 on “Performance Level,” “the performance level of a building after
construction (alteration) shall not be less than the performance level of the building prior to
construction (alteration).” If after the construction (alteration):
• the major occupancy changes to a different major occupancy;
• the occupancy load increases by more than 15%, or
• live load increases due to change in use within the same major occupancy,
remedial measures shall be taken to maintain the performance level prior to construction.
However, section 11.5 allows compliance alternatives. Accordingly, provided the
municipality’s chief building official is satisfied that it is impracticable to comply with section
4.1.9 on “Live loads due to earthquake”, the seismic provisions do not apply. 
Ref: Seismic Hazard, Building Codes and Mitigation Options for Canadian Buildings, National Research Council of Canada, http://www.publications.gc.ca/collections/collection_2008/ps-sp/D82-73-2002E.pdf, 2001

Seismic Review, Analysis and Design

Most buildings and equipment in Eastern Ontario will require some sort of seismic design. If you are renovating or updating an older building then you may have to seismically restrain HVAC units, sprinklers or have the building analyzed to ensure it is compliant with the most recent building code.

Every structure is different when it comes to seismic retrofitting due to construction types, location, and local soil conditions. If you require a seismic review of equipment, racking, or the structure of your building, contact us. Our experienced engineers and surveying team will take detailed measurements, review site conditions and come up with a cost effective solution for your design.

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