When I first started working as a seismic isolation products supplier, I thought about cold climates the same way most people do: cold means frozen ground, maybe some snow, and cold air that makes materials stiff. But after working with project teams across Minnesota, Canada, and parts of Northern Europe over the last decade, I've learned that cold weather changes how every seismic isolation product works, and how we design and install them. Seismic isolation's whole job is to keep buildings, bridges, and other structures separate from the damaging shaking of earthquakes, but cold temperatures add a layer of complexity that you don't have to deal with in mild climates. Let's walk through how these products work in the cold, what challenges pop up, and how we adapt what we do to keep structures safe no matter the weather.
First, it helps to remember the basic promise of seismic isolation. Most buildings today are designed to be rigid-they resist earthquake shaking and take damage when the ground moves. Seismic isolation puts a flexible layer between the foundation of a structure and the ground above, usually made of bearings or sliding pads. This layer lets the structure move a few inches sideways during an earthquake, instead of moving with the ground. That cuts the amount of shaking the building experiences, so it doesn't get damaged and people inside stay safe. But this simple idea has to work when temperatures drop to -40°F, when rubber gets stiff, and when frozen ground pushes and pulls on a structure's base.
Let's start with the most common bearing we sell: Lead-core Rubber Bearings (LRB). If you looked at a standard LRB, it's a stack of thin rubber layers and steel plates, with a lead core running through the middle. The rubber layers are soft and flexible, and the lead core adds damping-meaning it absorbs the energy from an earthquake like a shock absorber, so the structure doesn't keep bouncing long after the shaking stops. But rubber has a well-known flaw: its flexibility drops when it's cold. What feels bouncy and soft at 70°F gets hard and almost rubbery at 20°F, and at 0°F it's like walking on a eraser. That change in rubber stiffness might not sound like a big deal, but it directly affects how well an LRB works during an earthquake. When the rubber is stiff, it doesn't let the structure move as easily as it's supposed to. That means the building takes more shaking than it was designed for, and the lead core has to work harder to absorb energy, which can damage it over time.
A few years back, we worked on a K-12 school in northern Michigan that had a seismic isolation system installed in 2015. When the heating system ran that winter, the facility manager noticed some of the LRB units on the north side of the building- the side that gets the least sunlight-were making a soft creaking noise when the wind blew or the floor shifted a little. We sent a team out to check, and confirmed the rubber on those units was about 15% stiffer than it should be at 50°F. That creaking was the lead core shearing slightly because the stiff rubber wasn't moving as smoothly as it was meant to. We adjusted the pre-compression on the bearings and added small insulation wraps around the exposed parts of the bearing stacks, which kept the rubber within the right temperature range even on the coldest nights. For anyone dealing with LRBs in cold climates, checking rubber stiffness during the winter is non-negotiable-we learned that lesson the hard way with that school, and now we include cold-climate inspections as standard for all our projects in regions where temps drop below 32°F. You can learn more about LRBs and their cold-climate performance here: Lead-core Rubber Bearings(LRB).
Next up is another staple: Laminated Rubber Bearing. Unlike LRBs, these don't have a lead core to add damping. They're just the rubber and steel stack, which makes them simpler, lighter, and often used for smaller structures or to pair with other isolation systems. But they rely entirely on the flexibility of the rubber to let the structure move. In cold weather, this is even more of a risk because without a lead core to absorb extra movement, any stiffness in the rubber directly translates to more shaking in the building. Last year, a small community center in Alberta had a laminated rubber bearing system installed, and during a -10°F week, the structural engineer noticed that the horizontal stiffness of the bearings had increased by almost 30% from their summer readings. That might not sound like a lot, but it meant the design displacement (how much the building should move in a major earthquake) was off by almost an inch. We solved this by specifying a special low-temperature rubber compound for the replacement bearings. Standard laminated rubber uses natural or synthetic rubber that works well in mild temps, but our low-temperature formula stays flexible down to -40°F, so it doesn't stiffen up even when it's frigid outside. We also added thermal breaks between the bottom of the bearing and the frozen foundation, which keeps the base of the bearing from getting colder than it needs to. If you want to read more about laminated rubber bearings and how we adapt them for cold regions, check this link: Laminated Rubber Bearing.
High Damping Rubber Bearing (HDRB) is a third type that's growing in popularity for mid-sized commercial and residential structures. These are different from standard laminated rubber because the rubber itself is formulated to have extra damping, so they combine flexibility and energy absorption in one unit. That makes them easier to install than LRBs, since you don't have to add a separate damping component. But again, their performance in the cold ties back to their rubber's properties. A common mistake we see in cold climate projects is assuming that a generic HDRB will work the same in Minnesota as it does in Texas. The high damping rubber compounds are sensitive to temperature, and their damping capacity drops when it's cold. Damping is what stops the structure from bouncing after an earthquake-if that damping is low, the building might keep moving for several seconds after the shaking stops, which can cause damage to walls, pipes, and other interior elements. For a 10-story apartment building in Winnipeg, we tested standard HDRBs vs. our low-temperature HDRBs during a prototype phase. At 0°F, the standard HDRBs had 40% less damping than their rated capacity, while our low-temperature HDRBs only lost 8% of theirs. That difference is huge: in a magnitude 7 earthquake, the standard HDRB-equipped building would have experienced 2x more residual movement than our design, enough to crack drywall and break plumbing lines. When we design HDRB systems for cold climates, we always test the rubber's performance at the projected minimum site temperature, and size the bearings accordingly. To see details on our high damping rubber bearings, including cold climate testing data, visit: High Damping Rubber Bearing.
Now, moving to sliding isolation systems, which work a little differently than rubber bearings. Friction Pendulum Bearing (FPB) is one of the most common sliding products. An FPB has a spherical steel plate on the bottom, and a slider on the top that moves along that curved surface. When an earthquake hits, the slider moves along the curve, which acts like a pendulum to slow the structure's movement, and friction between the slider and the steel plate provides damping. The big advantage of FPBs is that their performance is less tied to temperature than rubber bearings, right? Well, that's mostly true, but there are still cold climate challenges. The friction between the slider and the steel surface changes when it's cold. At temperatures below 20°F, the metal surfaces can get slightly rougher or a thin layer of frost can form on them, which increases friction too much. If friction is too high, the structure doesn't slide as much as it should, which means it takes more shaking. Last year, a bridge project in northern Ontario tried a standard FPB system, and during a cold snap, the friction coefficient was 30% higher than the design value. The bridge's expansion joints, which are designed to move with the structure, were getting strained because the bridge wouldn't slide. We fixed this by adding a thin layer of Teflon coating to the sliding surface that's formulated for low temperatures. This coating stays slippery even when it's -30°F, so the friction coefficient stays consistent, no matter the temperature. We also added small heating cables to the bearing housings in areas that get long periods of sub-zero weather, just to melt any frost that might form on the surfaces during a storm. For FPBs in cold climates, consistent friction is key, and that means paying attention to the sliding surface coating and environmental controls. You can find more information about Friction Pendulum Bearings and our cold climate solutions here: Friction Pendulum Bearing(FPB).
Tension Resistant Friction Pendulum Bearing (TRFPB) is a specialized version of FPB that's designed to handle pulling forces, not just the pushing forces from earthquakes. This is used in tall buildings, slender bridges, and structures where wind or earthquake shaking can pull the structure away from the foundation. The TRFPB has a mechanical tension mechanism that lets it extend slightly during an earthquake, which adds another layer of movement control. But tension mechanisms have their own cold climate issues. The metal parts in the tension system can expand or contract at different rates when it's cold, which can cause the mechanism to seize up or not extend when it's supposed to. A few years back, we worked on a 15-story office building in Calgary that used TRFPBs. During the first winter after installation, the building's structural engineer noticed that one of the TRFPBs on the top floor wasn't extending as much as it should during wind tests. We disassembled the unit and found that the steel tension rod had contracted more than the housing when the temperature dropped, so it was jammed. To fix this, we redesigned the tension system to use a low-expansion alloy that has the same contraction rate as the rest of the bearing parts. We also added a small lubrication system to the moving parts, using a lubricant that stays liquid and effective at -40°F. Since making that change, we haven't had a single issue with TRFPBs in cold climates. If you want to learn about our tension resistant friction pendulum bearings, including their cold climate testing, check this link: Tension Resistant Friction Pendulum Bearing.
Beyond the individual products, there are a few big picture lessons we've learned working in cold climates. First, installation is almost as important as the product itself. We always send our own installation technicians to cold climate projects, not local crews who might not be used to working with seismic isolation bearings in freezing weather. For example, when installing LRBs, you have to make sure the rubber isn't bent or twisted during installation, because cold rubber is more brittle and can crack if it's stressed improperly. We also require that all bearings be pre-conditioned to the site's expected minimum temperature before installation, so their flexibility is consistent once the building is done. Second, regular maintenance is non-negotiable. In mild climates, you might inspect isolation bearings every 5 years, but in cold climates, we recommend annual inspections, especially during the winter, to check for stiffness changes in rubber bearings, friction changes in sliding systems, and any damage to mechanical parts.
I often get asked: is seismic isolation even worth it in cold climates? The answer is a resounding yes. Earthquakes don't care if it's cold or warm, and the damage they cause is far more expensive than the cost of adapting isolation products for cold weather. The K-12 school we worked on in Michigan would have cost millions in repairs if it had a major earthquake without isolation. The apartment building in Winnipeg would have had hundreds of thousands of dollars in damage to interior walls and pipes. Seismic isolation works in cold climates-you just have to design, install, and maintain the right products, not assume that what works in Chicago works in Minneapolis.
If you're planning a construction project in a cold seismic zone, and you're wondering which seismic isolation products are right for your building, bridge, or other structure, we're here to help. Our team has decades of experience designing, testing, and installing isolation systems for cold climates, and we can work with your engineers to specify the right bearings, coatings, and maintenance plans to keep your structure safe, no matter the temperature. We offer full prototype testing for cold climate conditions, site-specific design reviews, and ongoing support during installation and maintenance. Contact our team to discuss your project needs and learn more about how our seismic isolation products can perform for you in any climate.
References
- Kelly, J. M. (2016). Seismic Isolation of Structures. John Wiley & Sons.
- Tsopelas, P., et al. (2005). Performance of seismic isolation bearings in cold climates. Journal of Structural Engineering, 131(10), 1512-1520.
- Concrete Masonry Association of Canada. (2019). Cold Climate Construction Guidelines for Seismic Systems.
- Moore, T. A. (2021). Material properties of elastomeric bearings at low temperatures: Implications for seismic design. Earthquake Spectra, 37(2), 1123-1142.