Source: Informed Infrastructure: https://informedinfrastructure.com/14153/future-forward-interview-applying-research-to-seismic-safety-and-resilience/
Miyamoto International specializes in high-performance earthquake engineering as well as disaster mitigation, response and reconstruction. Informed Infrastructure (I2) Editor Matt Ball spoke with Dr. Kit Miyamoto, CEO and structural engineer at Miyamoto International, about the work they do around the world, and how technology advances help aid resilience regardless of dollars spent.
I2: In the realm of seismic safety, I would guess that the world is your laboratory. Would you say that you’re discovering new ways to apply seismic systems through your work in Haiti and other disaster-impacted areas?
Miyamoto: We apply the latest research into practice on an everyday basis. We are practicing engineers, but we’re also involved in research and development, with strong ties to the University of California, Berkeley, and the Tokyo Institute of Technology in Japan.
For example, we did the seismic awareness and prioritization strategy for schools in Manila, Philippines, as well as the seismic strengthening. There are 3,800 buildings there that are extremely dangerous. If you simply apply seismic engineering and strengthening to these buildings, it would cost several billion dollars. Those numbers stop action, when they see that it is technically or financially unfeasible.
However, what we did in Manila, as part of a World Bank-sponsored program, was to prioritize using a probabilistic risk assessment using the realistic seismic hazard in micro zones in the city as well as understanding the fragility function of the different building structures. Then, with the understanding of the building stock, we were able to see the fatality rate for different scenarios and could prioritize based on the cost benefit and how much we could reduce the fatality risk based on the money spent.
That’s how we communicated with the government. We basically made the case for affordable phases, taking little bites at a time. That’s how we use technology to communicate and convince policy makers to act in order to reduce risk. We also advise on how to implement strengthening using the easiest and most cost-effective means, such as concrete shear walls, and the latest devices, like viscous dampers and buckling-restrained braces.
These technologies have been used widely in places like Japan and California, where people can afford that type of technology. Viscous dampers have proven to be very cost effective, and can even be used in developing countries. We try to use the latest technology for emerging economies all over the world.
I2: Are the software tools to visualize and simulate different scenarios key to communicating what needs to be done?
Miyamoto: Most definitely, and it is particularly critical when speaking to people in the community who aren’t engineers. We do a lot of 3-D modeling for before-and-after seismic strengthening. We show how buildings would fail or collapse, and after that we show how the buildings move much less after the forces are mitigated.
We use this visualization in even the most remote places, like the Miragoane Cathedral in Haiti. The Catholic Church decided that they would do seismic strengthening on this cathedral in a really small village in Haiti. We used seismic isolators, and in this small village nobody understood isolators or even seismic strengthening. We showed them what the isolators looked like and how these large rollers would decouple the building from the ground. With our use of computer visualization, the community understood and accepted that our actions would help save the cathedral.
I2: How about the use of sensors in your work. Are seismic sensor readings helpful in understanding how certain areas react, and how do you model the conditions for each site?
Miyamoto: We measure the ground. Seismologists and geophysicists determine the location of earthquake faults and the potential for their rupture. That detail isn’t good enough for us, because we have to understand the soil where the building sits. We do impact tests, where we basically pound the ground with big hammers to see how the energy is transmitted through the soil and how it gets amplified or de-amplified and what the base motion is like. We measure shear-wave velocity. It’s more a testing machine than a sensor.
I2: In an area like Haiti, where so many buildings were damaged, is the extent of the damage useful in determining what needs to be done to mitigate such damage in the future?
Miyamoto: In the Haiti earthquake back in 2010, the epicenter was in Port-au-Prince, the capital. The earthquake essentially damaged 50 percent of the building stock. I would venture to guess that 99 percent of the buildings have been either built or repaired by now. This happened not only in the rich neighborhoods, but also the poorer areas, because the local masons were taught to use different techniques for mixing concrete and using rebar.
The 2010 earthquake generated a wealth of data about how non-engineered structures perform and behave during a strong shaking. We assessed 430,000 buildings in the affected area for the Public Works Ministry in Haiti, and that data is available.
There is a major fault line in the northern part of the island (both in Haiti and the Dominican Republic) that is way overdue for a major rupture. The United Nations Development Programme engaged us to look at the risks in this area. The seismic zone has been studied extensively by the U.S. Geological Survey and others, but what wasn’t known is how that building stock behaves. Using the data from Port-au-Prince, we were able to very accurately forecast what the impacts will be on the buildings in this area. We lost nearly 250,000 people in the 2010 earthquake, so we’re trying to use that information to reduce the risk in Northern Haiti.
I2: What measures will be put in place to ensure that your recommendations decrease the loss of life?
Miyamoto: In places like Haiti, and other emerging countries, there is very little enforcement. People are going to build where they want to build. Knowing the geohazard risks and zones, you can design buildings that are safe, even if they are close to the fault line.
I2: Where do you draw your motivation, and what got you involved in seismic safety and disaster mitigation?
Miyamoto: I was born and grew up in Tojo, Japan, a place that shakes on almost a weekly basis. That’s something that was always part of my life. I then went to California State University, where I got my bachelor and master’s degrees. Eventually, I went back to Japan and finished my Ph.D. from the Tokyo Institute of technology. Since I chose to be a structural engineer, and studied both in California and Japan, earthquake engineering was part of the curriculum and came very naturally to me.
Practicing in California and Japan, we get a lot of benefit from advancing technology and improvements in the building code, and the quality of construction is probably the best in the world. But there are so many parts of the world that are exposed to earthquake hazard, from Latin America to Asia, from the Middle East to Europe. There are so many people exposed to the risk, but the understanding of engineering and construction practices aren’t as available.
As engineers, I think we can do a lot to share what works with the world. We’re an engineering company, but at the same time we’re a purpose-driven company. We want to make structures safer and better for people.
I2: In your years of practice, have you been encouraged by the pace of technology advancement in your field?
Miyamoto: It’s been easier to apply advanced technologies in a cost-effective manner for developing countries over the years. We have a better understanding of a structure’s behavior, and we have seen advances in the computational power of software and hardware.
When I began practicing in 1990, it took us a day of computation to do each simulation. You can do that same operation today in less than one second. That kind of technological advancement allows us to apply the mitigation measures in a more cost-effective way. You can do more-intensive analysis much more quickly, and can test a number of options. You can run the seismic model through buildings and see how the components behave and perform. Doing this analysis allows you to take a more surgical approach to building retrofits and repair.
In the past, we would strengthen everything possible, putting in many concrete shear walls and strengthening the foundation, and you would feel good about it. The problem is that this is expensive, and, in many cases, we can’t afford to do that, so it creates a “do nothing” option. Doing nothing creates a much more dangerous situation than in the past.
Having the high-tech devices, such as viscous dampers and buckling-restrained braces, you can actually see and address the major deficiencies in the building, and that level of analysis makes these approaches more cost effective.
I2: The word resilience is becoming more prevalent these days. What is your definition in your own work?
Miyamoto: We have 20 different locations globally, from California to New Zealand to Haiti and Istanbul. Our presence enhances resiliency. As a global CEO, with headquarters in California, I still spend a good deal of time here in Haiti, because I feel that we can make a huge difference here.
For many major new buildings here, both in the public and private sector, they come to us to certify both the engineering and construction quality. We have trained dozens of Haitian engineers to international standards, and they supervise the engineering and construction themselves.
I think that when the people see that level of effort and analysis, it really increases resiliency. Today, I think Port-au-Prince is much higher in resiliency than 2009, prior to the earthquake, because both the public and private sector are addressing seismic risk.
Doing this work in Port-au-Prince is easy in a sense, because they lost 250,000 people, and there is urgency to do something now. There are more dangerous places like Manila, where they are very exposed with a major fault, and there hasn’t been a major earthquake for the last couple hundred years. Since there is a distant memory, applying resiliency is more difficult than where something has happened recently. That’s potentially tragic, but unfortunately that’s the case.
If somehow we can convince the public and private sector to adopt resiliency measures, improve building codes and construction methods, and apply seismic strengthening prior to an earthquake, then we can save a lot of lives. The cost is also much less, because reconstruction is very expensive.
I2: It’s hard to factor the economic impact of a major disaster, because the economy just stops completely, right?
Miyamoto: Absolutely! In California, in both Los Angeles and San Francisco, we are just waiting, and it’s overdue, of course. The chance is very high for a major event in Northern California, where the death toll would be in the thousands, and the cost would be several billion dollars.
The Northridge earthquake in San Francisco in 1990 is considered a moderate quake at 6.9 on the Richter scale. We’re looking at an energy release that is 10 times bigger than that. The Loma Prieta earthquake was also a moderate event.
California hasn’t seen a major urban disaster since the 1906 San Francisco earthquake. We have not been tested yet, and that’s my concern. In Japan, we do have experience with recent major earthquakes in Kobe and Tōhoku, they see the urgency and are more proactive about risk reduction.
We aren’t going to lose the people and structures that we lost in Haiti. It may be more like the Christchurch earthquake in 2011, where more than 2,400 buildings were lost in their downtown. If you go to Christchurch today, almost two thirds of its downtown is empty lots. There was a loss of $13 billion, and it’s a size of 350,000 people, with the loss of life of about 200 people.
In terms of building code, it’s really easy to follow that and provide life safety, but that doesn’t protect the structure. The code successfully reduces the loss of life, however, it isn’t able to save buildings or the city in a way. You’re going to see this big-scale loss in California cities.
I2: It takes a lot of time to replace that level of loss of your building stock, right?
Miyamoto: It’s going to take from 10 to 20 years, because the economy is totally changed. The difference of New Zealand vs. California is that it is protected by earthquake insurance. Almost 90 percent of the building owners had earthquake insurance. In California, less than 10 percent of owners have that kind of insurance. You won’t see the same pace of rebuilding in California. The Japanese government has cash, and they spend the money to repair the damage.
That’s why resiliency is so critical. Preparing for recovery and reconstruction is also critical. Having policies in place for reconstruction makes a huge difference on how quickly the recovery progresses. Little things make a huge difference, because after an earthquake, a large number of buildings need to be repaired or rebuilt. We need to make it easier for investments to be made for rebuilding.
I’m a California Seismic Safety Commissioner currently, and one of our mandates is how we can assess the recovery and make it happen quicker. Resiliency is not just about strengthening, it’s also about preparing for the recovery and reconstruction. In California, we just don’t have the experience.
I2: Your exposure to all of these different regions must really inform your practice. You bring to California and elsewhere the awareness of what others are doing.
Miyamoto: The beauty of being a global earthquake engineering company is having the broad perspective and being composed of many different nationalities around the world. There is good practice and bad practice around the world. We can learn a lot from other places to apply the best practices and modify them to political, cultural and business cultures locally. Our offices are proactively working with our clients to apply best practices.
People talk about resiliency in a public arena, and they talk about building code. People feel that if they have the right building code, then everything will be fine. Building code is the first step in 20 different steps, and people must understand that. The building code is only as good as how the building is designed and constructed.
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