Lessons from the earthquakes in Türkiye

By Jeffrey Salmon, Ph.D., E.I.T., Structural Engineer

6 min read

The twin earthquakes that struck Türkiye and Syria in February 2023 were catastrophic events. Both were massively powerful – measuring in at 7.8 and 7.6 magnitude respectively. They struck within 9 hours of each other, just 100 kilometers apart. More than 15 million people were affected. Nearly 60,000 lives were lost, and some 2.5 million buildings were damaged or destroyed.

Türkiye is no stranger to earthquakes; the country straddles some of the most active fault lines in the world. As such, they are quick to learn lessons from their experience and adapt accordingly. Following major earthquakes, the government brought in a new seismic code in 1998, which is considered as the first modern building code in Türkiye. It included requirements for new buildings in earthquake-prone regions to use rebar and high-quality concrete. Hospitals, schools and other important facilities were to be designed to withstand a higher level of seismic activity. The building code was further refined in 2007 and again in 2018.

In 2013, the Ministry of Health issued a law that hospital buildings located in high seismic zones with bed capacities over 100 were to be base-isolated. As discussed later in this article, this mandate had a significant positive effect on the results of healthcare facilities impacted by the earthquakes.

In very simple terms, base isolation works by decoupling the base of the building from the ground it rests on. Base isolators (essentially laterally flexible devices that absorb the energy generated by earthquakes) are placed between the ground and the building. When an earthquake strikes, the building simply moves back and forth on top of the isolation system, greatly reducing the forces on the structure.

Focus in on hospitals

During emergencies, such as after earthquakes, it is crucial that hospitals remain functional. For one, when hospitals are damaged, those injured in the event need to go further to receive aid, often reducing their odds of survival. Furthermore, evacuating patients quickly and safely from a building is a massive challenge.

In June 2023, I joined a team of academics and industry professionals to visit a range of sites across the earthquake affected zones in Türkiye. We visited several hospitals spanning the major fault lines. We saw firsthand the difference in the level of damage and time to recovery between fixed-based (i.e., traditionally built) hospitals and those built with base-isolation technology.

Of seven fixed-base hospitals, just two remained operational immediately after the events. Of five base-isolated hospitals, four remained operational. The one base-isolated hospital that was affected had non-structural damage due to the improper maintenance of the seismic gap, restricting the free-movement at the isolation layer, hindering the performance of the isolation system. Some of the fixed-based hospitals remained vacant up to four months later.

Thanks to updates to the country’s seismic code, none of the fixed-based hospitals (built after the 1998 update) suffered structural damage. But non-structural damage can also shut down a facility. This may include things like fallen ceiling tiles, ruptured pipes, and cracks in walls. It might also include damage to key medical equipment, inventory, and systems. We saw plenty of this type of damage in our visits to Türkiye’s fixed-base hospitals.

Our survey showed that the non-structural damage at the base-isolated hospitals was extremely limited. For the most part, operations continued as usual. One hospital reported that ongoing surgery at the time of the first event was able to continue as soon as the ground stopped shaking. Everyone we spoke with confirmed the value that base-isolation had provided to the country’s health system during this time of crisis.

How does Canada compare?

In Canada, hospitals and other critical facilities are designed to more stringent requirements than ‘normal’ buildings such as residences and offices. These critical facilities must meet more stringent drift limits (essentially a measure of relative displacement between adjacent levels in a building) to address post-earthquake performance objectives of lesser damage and functionality; this is a similar practice to what is done in Türkiye.

In the most recent version of the National Building Code of Canada (NBC 2020), critical infrastructure in high seismic regions is required to meet even stricter drift limits for moderate level earthquakes. The expectation is that the structure will be able to withstand such levels of earthquakes with minimal or no structural damage.

The NBC 2020 serves as a model code for the provinces and territories. While the NBC 2020 doesn’t specifically require base isolation technologies to be used in hospitals, we believe that many government agencies, health authorities, and private companies will want to consider base isolation as one of the options for their projects to meet the new requirements.

There are already some examples of base isolation across Canada. In Ottawa, Parliament’s Centre Block is currently being renovated with base isolation technology being used for the seismic upgrade (we’re part of the team leading this aspect of the project). We also put base isolation into The Lord Strathcona Elementary School in Vancouver, winning us the ACEC-BC Lieutenant Governor’s Award for Engineering Excellence. Other studies to incorporate base isolation into new buildings and seismic upgrades are ongoing.

Three takeaways from my visit to Türkiye

My visit to the affected zones of Türkiye made three lessons clear—learnings that are just as relevant in Canada as they are in Türkiye:

  1. Planning is essential. Türkiye’s disaster recovery is governed by two overlapping strategies – the Türkiye Disaster Response Plan (TAMP) and the Türkiye Risk Reduction Plan (TARAP). These plans have enabled the country to quickly respond to earthquakes and use lessons from previous experiences.
  2. Codes make the difference. By continuously upgrading their seismic and building codes to include technologies like base isolation, Türkiye is ensuring that the newest approaches are being incorporated into building design and delivery. Canada’s NBC 2020 is also a good example of continuous improvement.
  3. Base isolation works. Base isolation allows buildings to better withstand the effects of earthquakes and return to business-as-usual faster. For those hospitals in Türkiye, the investment was well worth it.

Explore your options

To be clear, base isolation is just one of the technologies that can be applied to reduce seismic risk and enable faster recovery. When we work with clients, we always explore all options and approaches— recognizing key influencers like cost, disruption, complexity and safety—to identify the best way forward. It’s part of our Purpose - to find a better way. This encourages us to always strive to deliver the best outcomes for our clients and our communities.

Interested to learn more about our findings, and how we can help you with your seismic challenges? Contact Jeffrey Salmon.