Last month marked the five-year anniversary of the devastating Tohoku earthquake that struck off the coast of Japan, causing more than 18,000 deaths, $300 billion in damage and a devastating tsunami that set off the worst atomic crisis since Chernobyl in 1986.
Coastal communities were flattened – more than 400,000 buildings collapsed and another 748,000 were damaged. The tsunami caused meltdowns at three reactors in the Kukushima Daiichi Nuclear Power Plant complex, and at least three reactors exploded when power outages caused the cooling system to fail.
Today, many coastal communities in the Pacific Northwest are studying the quake and its aftermath to help prepare for the likelihood of similar circumstances at home.
This is the natural path of progress: We see a situation and we learn from it.
The Evolution of Building Codes
Researchers at U.C. Berkeley and Stanford University believe earthquakes may have wiped out some ancient communities, including the Mayan civilization (800 A.D.); city of Troy (1200 B.C.); Megiddo, also known as Armageddon (1468 B.C.); and the Harappan civilization of South Asia (1900 B.C.).
The Earth shook. Temples fell. Buildings crumbled, and people started to rethink construction techniques to make their structures more capable of withstanding the Earth’s unannounced and often ruthless movement.
Some of the earliest building codes date back to Hammurabi, leader of ancient Babylon from 1792-1750 B.C. He was the first ruler known to have made public – and in writing – an entire body of laws for the people to follow. His Code of Laws was carved on a basalt stele stone monument 8 feet high and shaped like a pointed index finger. It addressed numerous topics from matters of conduct to wages and family law and is believed to have been displayed clearly for public view. (The stone was found in 1901 in the Persian mountains and is now on exhibit in the Louvre.)
The body of work is a major work of reference regarding the “eye-for-an-eye” law of retaliation. And some of its required punishments seem unreasonable if not cruel:
- No. 228: If a builder builds a house and does not construct it properly, and the house which he built falls in an and kills its owner, then that builder shall be put to death.
- No. 229: If the building falls and kills the son of the building owner, the son of the builder shall be put to death.
- No. 232: If it ruins goods, the builder shall make compensation for all that has been ruined.
Today’s laws are much more forgiving, and the technology available to make buildings safe continues to improve.
Professional Standards Raise the Bar
Since the 1800s, the Building Officials and Code Administrators International, Inc. (BOCA), International Conference of Building Officials (ICBO), and the Southern Building Code Congress International, Inc. (SBCCI) and others have been developing lists of model codes used throughout the United States. They united in 1994 to establish the International Code Council (ICC), which sets many of the building standards used in the world today.
Earthquake engineering continues to advance as well.
Today’s bridges, overpasses and high-rise buildings are masterpieces in mathematics, science and art.
Earthquake engineering is the scientific field concerned with protecting society, the natural environment and manmade environment by limiting the risk of damage from an earthquake. It is the combination of structural engineering, geotechnical engineering, mechanical engineering, chemical engineering, applied physics and more, but it also takes into account the more nebulous fields of sociology, political science, economics and finance.
Surprising to people outside of the industry, a properly engineered structure does not necessarily have to be extremely strong or expensive to withstand an earthquake.
The National Science Foundation created the Network for Earthquake Engineering Simulation (NEES) to advance knowledge discovery and innovation for earthquakes with 14 geographically distributed laboratories that support several types of experimental work:
- Geotechnical centrifuge research
- Shake-table tests
- Large-scale structural testing
- Tsunami wave basin experience, and Field site research.
Participating universities include Cornell, Lehigh, Oregon State, Rensselaer Polytechnic, University at Buffalo, State University of New York, U.C. Berkeley, U.C. Davis, UCLA, U.C. San Diego, U.C. Santa Barbara, University of Illinois, Urbana-Champaign, University of Minnesota, University of Nevada, Reno and the University of Texas, Austin.
Their studies are identifying weak spots in building structures and retrofit measures that will stabilize a building in an earthquake. They are identifying the types of building materials that are best for withstanding an earthquake.
Los Angeles, San Francisco Learn from Disaster
The Northridge and Loma Prieta earthquakes of 1984 and 1989 demonstrated serious weaknesses in the way we constructed many buildings in the past, and those affected have taken steps to be better prepared the next time a major quake strikes.
The City of Los Angeles last year adopted the most sweeping seismic regulations in the nation, affecting some 15,000 buildings and potentially more. San Francisco adopted similar legislation in 2013, and several others have followed suit.
The Structural Engineers Association of California estimates there may be as many as 100,000 buildings in Southern California facing similar mandates as other cities and counties consider adopting retrofit laws of their own. Already, L.A. County, West Hollywood, Santa Monica and many others to the north are in the process of considering similar laws of their own.
Many of these laws focus on multi-unit soft-story buildings permitted for construction before 1978.
In Los Angeles, affected property owners are able to share the costs of seismic retrofits with their tenants.