The last time Lakisha Woods went to buy a car, she was sold on the safety features: forward collision warnings, automatic emergency braking, and blind spot and lane departure warnings, to name just a few.
“When I went to buy a home a year later, nobody told me about the safety of the building,” she said. “They talked about the countertops.”[i]
As president and CEO of the National Institute of Building Sciences, Woods believes her industry has failed to sell the message of safety in our homes.
“We need to build to a higher standard,” she said. “A standard that lets you not only walk out of a building alive, but to go back inside and continue to live and thrive.”
The science and innovation of resilience
Modern-day civil engineering evolved over thousands of years, as people built structures – saw what worked and what didn’t – and modified them to make them safer.
It’s the same concept that has been applied to many other industries.
Whenever an airplane fails, the Federal Aviation Administration orders the problem to be fixed – not just in new airplanes, but existing aircraft, too. When a consumer product is determined to be unsafe, it is immediate recalled until changes are made. That oversight promotes safer products that build consumer confidence.
“Why is it that it is safer to fly than to perform so many other everyday tasks?” asked Ross Stein, CEO and founder of Temblor, Inc., a company that provides capacity models for the insurance industry and a free public app and news service subscribed to all over the world.[ii]
In absolute numbers, the National Safety Council calculated the odds of dying in a motor vehicle accident to be 1 in 98 for a lifetime. For air and space transport (including air taxis and private flights), the odds were 1 in 7,178 for a lifetime.[iii]
Black box instrumentation, required in all aircraft, helps to identify technological and human weaknesses that can make air travel even safer in the future.
There are no black boxes in homes or commercial buildings, but computer modeling and real-life testing in academic and industry laboratories have seen tremendous success in predictive analysis – identifying structural vulnerabilities, and developing methods for correcting them.
In computer modeling , seismologists, scientists, and engineers around the world have developed sophisticated tools to measure and predict earthquake damage to buildings based on a complex set of data that includes ground motion and soil type, building type, building components, and more.
California State University, Chico professor Curt Haselton, cofounder of the Haselton Baker Risk Group, conducts simulations to calculate hazards and risk assessments to help engineers design structures that will experience only limited damage in a major earthquake.
In the case of seismic risk, his team draws from seismic data that is tested against real episodes from the past. They run tests to predict damage using the historic events to check their work.
“We went back and estimated the damage that would happen to buildings in Northridge at that time, and then compared our findings to what actually happened,” Haselton said. “We found good agreement and in doing so, we were able to upgrade our process.”[iv]
Haselton Baker Risk Group has developed software that can run 5,000 to 10,000 simulations of how a building might be damaged in reaction to a variety of earthquakes — all in just a matter of minutes.
“We’ve actually run simulations of all the buildings in the state of California – 13 million – and with all the Amazon processors we have, that takes four days,” he said in a recent episode of The Resilience Advantage, a leading webinar series sponsored by Optimum Seismic, which features experts talking about the latest advancements in seismic resilience.
Real-life testing is also being done at the University of California, San Diego, where professor Tara Hutchison is conducting research in earthquake engineering. She and her team are testing components, subcomponents, and structural behavior under various earthquake loads using one of the world’s largest outdoor shake tables.
“The reason why physical testing is such an important research tool is largely due to the complexity of these physical structures,” she explained. “We can simulate mathematically, but reality is much more complex.”[v]
Innovation in construction products
As a result of this research, industry visionaries are developing new products that can in some cases help make existing buildings safer.
Steel is an important component to most retrofits, but the amount needed can change when other technologies are also used to help absorb and distribute the forces exerted from seismic activity.
Hybrid frame components, base isolation technology and other approaches can often be done in combination with traditional steel.
Here is California, there are five basic building types that have been proven to be vulnerable to failure or collapse in an earthquake.
Soft-story structures are common among apartment buildings, characterized by open parking on the ground floor and dwelling units built above. In some instances, the ground floor may be used as retail space and enclosed by windows that do not provide any structural support. These wood-framed structures, when constructed prior to 1978, are considered extremely vulnerable to collapse in a major earthquake.
The composition of these buildings lacks the ability to withstand lateral forces that push the building from side to side. The swaying can cause the first floor to collapse, and the upper stories to pancake on top of it.
Retrofit construction for soft-story buildings usually entails the installation of a steel moment frame or frames set in a sturdy foundation to absorb seismic ground motion and prevent swaying.
Non-ductile concrete buildings built before 1978 are characterized as having concrete floors and/or roofs supported by concrete walls, columns and/or frames. Due to their rigid construction and limited capacity to absorb the energy of strong ground-shaking, these structures are at risk of collapse in an earthquake.
In fact, non-ductile concrete buildings make up the majority of earthquake losses around the world. As they are frequently used for office and retail uses that draw large numbers of people, the potential for death and injury with these structures is of particular concern.
To guard against collapse from an earthquake, retrofit construction usually entails the use of shear walls and column fortification to provide a stronger framework to prevent a collapse of the heavy floors above.
Tilt-up construction began in the early 1900s but didn’t really catch on until the post-World War II construction boom. This cost-effective technique of pouring a building’s walls directly at the jobsite and then raising or “tilting” the panels into position was and continues to be a popular way to meet California’s demand for new commercial buildings.
The walls of a concrete tilt-up building can weigh between 100,000 and 300,000 pounds. Steel plates with headed studs are positioned into the forms prior to pouring the concrete to establish viable connection points that secure the walls to the foundation and the roof trusses to hold them in place.
However, many tilt-up structures built prior to the late 1980s were constructed with limited or weak connections that have been proven to fail in an earthquake, causing severe damage and/or collapse. These building defects can be easily corrected with seismic retrofitting.[vi]
Steel moment frame construction dates back to the 1880s with the very first skyscraper, the Home Insurance Building in Chicago, but this building technique was most commonly used in the 1960s to 1990s.
Steel moment frame construction is characterized by the use of a rigid steel frame of beams connected to columns to support the many floors of the structure.
These structures, when built before the 1994 Northridge earthquake, can sustain brittle fracturing of the steel frames at the welded joints between the beams and the columns. In fact, many moment frame buildings in Southern California reveal cracks and fissures in these frames and may be susceptible to collapse in a major earthquake.
There are several retrofit approaches to consider in these instances, depending on the building. These approaches include boosted beam-column connections and chevron bracing throughout or at various points in the structure.
Unreinforced masonry buildings make up many of the older structures typical in downtown communities. They are characterized by walls (both load-bearing and not) and other structures such as chimneys that are made of brick, cinderblock, or other masonry materials not braced with rebar or another reinforcing material.
URM structures are very vulnerable to collapse in an earthquake, due to a general failure of the mortar or when portions of the masonry such as parapets peel from the building façade and fall onto the sidewalk below.
Mitigation saves money
Hutchison said one of the biggest challenges to establishing earthquake resilient communities is how to deal with the existing building stock.
All too often, people know about their risks, but they choose to hope the worst will never happen rather than preparing to make sure it doesn’t.
Studies show that it pays to prepare. Research by the National Institute of Building Sciences in 2005 found that for every dollar invested in actions to reduce disaster losses, the nation saves about $4 in future costs.[vii]
Later research, conducted in the institute’s 2019 report, “Mitigation Saves,” found that retrofitting approximately 1.8 billion square feet of soft story buildings at earthquake risk throughout the United States would cost about $16 billion – an average of $8.60 per square foot – but would avoid $190 billion in future losses, producing a Benefit-Cost Ratio of 12:1. In many California counties the BCR exceeds 16:1.
Another report, by the Federal Emergency Management Agency, found similar high benefit-to-cost ratios for California, including a scenario of a tilt-up warehouse building in Hayward. “In this example,” the study found, “the benefit/cost ratio is about 10 without the value of life and about 12 with it. The benefit/cost analysis suggests that retrofit is strongly justified economically.”[viii] That return on investment was even higher for tilt-ups with industrial occupancies, the study found.
Billion-dollar natural disasters are becoming more common in the United States. Since 1980, catastrophes of this magnitude have affected all 50 states, hitting five to 10 times annually. Preventive actions to reduce the costly cycle of rebuilding and repair are needed now more than ever. There are steps individuals, communities, and the federal government can take to better prepare for and avoid the worst effects of extreme weather—and reduce costs.[ix]
The small, additional cost required to build stronger, stiffer buildings can pay for itself just in the reduction of earthquake-generated property damage alone, FEMA has determined.[x]
It is even more cost-effective when one includes the savings in occupant safety, building functionality, and interconnections to the larger economy. Federally funded earthquake mitigation grants are also cost-effective when one looks beyond monetary savings, especially when considering improved resilience for the community. The new BCR for public-sector mitigation is higher than the NIBS 2005 study because it better accounts for the benefits of continuity of service to the community by reducing damage to fire stations, hospitals, and other public facilities.
Government Investing in preparedness saves taxpayers money, the Pew Trust Charities affirmed[xi].
The benefits of resilient design in reducing injuries and deaths, property losses and financial catastrophe are well documented. In addition, the NIBS report demonstrates there is a very high net positive return on such investments over the long-term.
Some building owners, buyers and occupants may be full of remorse when faced with extraordinary financial losses — including potential bankruptcy and liability exposure —because they did not embrace earthquake retrofits and resilient design today. They may also be surprised that these losses could have been avoided at a reasonable cost.
Consider a $100,000 investment in a $10 million retail property that would, in the event of a major earthquake, reduce damage from $5 million to $1 million and recovery time from one year to one week. This investment would likely spell the difference between bankruptcy and the ability to weather the disaster.
It’s a decision commerce and industry should take to heart: Some 40% of businesses that close for more than two weeks after a disaster never re-open.[xii]
Keeping what you care about
Most people discuss seismic resilience in terms of earthquake likelihoods.
“But a more relevant questions would be, “What’s going to happen? How will it affect me?” said Stein.[xiii]
According to the California Earthquake Authority, there is more than a 99% chance a magnitude 6.7 or greater earthquake will strike the state in the next 30 years, a 75% chance a quake of M7.0 will strike Southern California, and 76% chance an M7.0 or greater will hit the northern part of the state.
But when many building owners hear those odds stretched out over the next 30 years, the message to them seems less dire.
Stein once conducted an analysis for a client with 185 facilities around the world – calculating hazards and marking them on colored maps.
He called it a very “humbling” experience.
“The people were looking at a 2% chance in 50 years that it would happen,” he recounted. “But rather than look at what they might lose, they said, ‘We don’t have a problem. At all. Go away.’”
Earthquake risk is roughly the same as the threat of a 100-year flood, and yet people living in those flood plains are required to purchase flood insurance, Stein said.
Rather than rattling off probabilities, Stein said, the more effective messaging is to illustrate the worst case scenario.
If a major quake meant you would lose your home, possible even loved ones, your business and/or employees, your source of livelihood and everything that’s important to you – wouldn’t you take action?
[i] The Resilience Advantage, Episode 7, https://www.youtube.com/watch?v=DYb9HaxYVAY
[ii] Ibid.
[iii] USA Today, “Is air travel safer that car travel?” https://traveltips.usatoday.com/air-travel-safer-car-travel-1581.html
[iv] The Resilience Advantage, Episode 7, https://www.youtube.com/watch?v=DYb9HaxYVAY
[v] Ibid.
[vi] Optimum Seismic, https://www.optimumseismic.com/commercial-building-retrofit-services/
[vii] National Institute of Building Sciences, “Natural Hazard Mitigation Saves: An Independent Study to Assess Future savings from Mitigation, http://c.ymcdn.com/sites/www.nibs.org/resource/resmgr/MMC/hms_vol2_ch1-7.pdf?hhSearchTerms=Natural+and+hazard+and+mitigation
[viii] FEMA, “A Benefit Cost Model for the Seismic Rehabilitation of Buildings.” https://www.fema.gov/media-library-data/1403228695368-210f1be4cbc6a07876a737a02c69a543/FEMA_227_-_A_Benefit-Cost_Model_for_the_Seismic_Rehabilitation_of_Buildings_Volume_1.pdf
[ix] Pew Trust, «It Pays to Prepare for Natural Disaster,” https://www.pewtrusts.org/en/research-and-analysis/fact-sheets/2017/05/it-pays-to-prepare-for-natural-disasters#:~:text=Investing%20in%20preparedness%20saves%20taxpayers,about%20%244%20in%20future%20costs.
[x] FEMA, Mitigation Saves Fact Sheet, https://www.fema.gov/sites/default/files/2020-07/fema_mitsaves-factsheet_2018.pdf
[xi] The Resilience Advantage, Episode 7, https://www.youtube.com/watch?v=DYb9HaxYVAY
[xii] Federal Emergency Management Agency, https://www.fema.gov/protecting-your-businesses
[xiii] The Resilience Advantage, Episode 7, https://www.youtube.com/watch?v=DYb9HaxYVAY
