When it comes to earthquakes, protecting buildings against structural damage gets most of the attention. However, do you know that an earthquake doesn’t need to cause structural damage to knock a building out of commission? Earthquakes that damage critical operational and functional components (OFCs) vital to operations can render a building non-functional. OFCs range from large components like emergency generators and MRI machines to smaller items like sprinkler pipes, vents, computers, or bookcases.
Regardless of size, OFCs share one thing in common: if not properly restrained, they’re prone to moving during an earthquake. This can result in damage, leading to long repair or replacement times, or significant repair or replacement costs. For critical OFCs, the impact could be costly downtime or loss of revenue. In addition, unrestrained or inadequately restrained OFCs pose a risk of injury or even fatalities.
A lack of standardisation
Building owners, particularly in earthquake-prone areas such as the Lower Mainland and Vancouver Island in BC, understand that OFC seismic restraint is key to ensuring operational resilience and safety. However, unlike structural building components, there are no prescriptive building code requirements to guide these activities in Canada. The National Building Code (NBC) for new buildings provides requirements and provisions for the seismic bracing design force, but no specific dos and don’ts for component restraints. Limited guidance is available depending on building location or trade.
In the City of Vancouver, existing building renovations or additions may trigger requirements for owners to invest in certain OFC seismic restraints (and structural upgrades) depending on the size or scope of their workplan. Vancouver is unique in this regard, as no other city (or province) in Canada does the same.
Global industry groups like the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) offer seismic restraint manuals with details focused on their field. The Canadian Standards Association (CSA) S832:14 helps engineers identify and measure the OFC seismic risk but doesn’t expressly translate that into prescriptive actions and details for contractors. As a result, what is deemed acceptable as the threshold for minimum OFC restraint or bracing is open to interpretation.
Deferred responsibility
Currently, the responsibility for OFC seismic restraint falls to the discipline-specific Engineer of Record. However, seismic restraint is usually not their core capability, so they often delegate it through deferred design. For example, a mechanical consultant that has designed a new cooling tower and piping network is professionally responsible for structural support and seismic restraint of those OFCs, but they hand off the requirements to a specialty structural engineer who is usually hired by the contractor. Everyone agrees that seismic restraint needs to be addressed at some point in the development process, but it is typically deferred until construction is well underway.
This approach has two big drawbacks. First, there is the risk that this step is overlooked. Our team was once called in on a job where the design specified a stabilizing pad for a generator to be built on the roof. However, this was forgotten by the contractor, resulting in the owner having to find a costly alternative solution.
The second drawback is that the person responsible for designing and detailing the seismic restraint is often disconnected from the project design team. We’ve seen situations where contractors bolted equipment into roofs to meet requirements but, in doing so, compromised the integrity of the roofing system leaving the building susceptible to leakage. A well-coordinated seismic restraint effort would not have led to this outcome.
Giving seismic a seat at the table
At Ausenco, we believe that OFC seismic restraint is critical to ensuring the operational readiness and resilience of buildings, and that seismic specialists should be involved at the outset of a planning cycle.
By considering these seismic restraints at the start of a project, owners and engineers can identify and drastically reduce the earthquake risk to OFCs. For example, by purposefully locating an electrical room in the basement where seismic demand is lower or adding restraints at the beginning of the design (such as that stabilizing pad that the contractor forgot in the above example), can reduce both risks and costs on the project.
Bringing an OFC seismic specialist on board early in the process helps identify risks upfront and establish clear lines of responsibility. They can assist in setting up performance requirements and expectations, prioritizing investment based on the most critical risks, and help sequence requirements when multiple OFCs require attention.
The need for early engagement with seismic specialists holds true not only for new builds, but also for building upgrades. The majority of the work our team delivers involves supporting building owners―particularly municipalities, real estate investors, institutions and infrastructure providers―in addressing their OFC seismic restraints as part of an upgrade or renovation.
A holistic approach
Ausenco has built a specialised center of excellence focused on seismic risk management, leveraging our extensive expertise in key areas such as performance-based seismic design, base isolation and OFC seismic restraint. Our structural experts collaborate closely with our multi-disciplinary design teams, to produce holistic solutions that help clients find better ways to improve their seismic resilience.