As the rescue efforts continue in China after last Monday’s earthquake, Fouad Bendimerad, Chairman of the Board of the Earthquakes and Megacities Initiative (EMI) and professional engineer in California specializing in earthquake engineering and disaster risk management gives his point of view about building collapse and how to improve building resistance to earthquakes.
Building collapses and fires kill people when earthquakes
strike do we have the knowledge to avoid the collapse of buildings?
We have the knowledge and the technology. In fact, we have had it for more than three decades. But there are two fundamental problems:
1. It is not sufficiently disseminated and applied in day-to-day practice. Most engineers, architects, planners, and builders are not adequately trained in the basic earthquake engineering practice.
2. It is not enforced through proper construction control, through implementation and enforcement of building codes and standards of practice. Most countries have seismic codes that are adequate, but these codes are not enforced, because authorities are quite often, not adequately trained to implement them. As a result, buildings collapse and people are killed. What we are seeing in every urban earthquake is a result of avoidable errors. In earthquake prone regions, buildings can be designed and be built to sway and crack but not collapse. There may be a need to repair them after an earthquake, but they will not collapse.
According to your expertise, how do you explain the collapse of so many buildings in China?
What happened in China could have happened in any other urban earthquake region. We must address the structural issues related to the safety of the buildings through integrating disaster risk reduction considerations in urban planning. We have been advocating for years to introduce training programs for construction professionals, engineers, architects, urban planners, builders and field workers, but the message is lost in the midst of all the noise! For us, this is a fundamental issue that must be addressed if we want to make schools, hospitals, buildings, and the urban environment safe. We cannot provide safe urban environments by raising awareness alone. We must also build the competency of the institutions and of the professionals who plan, build, and manage cities. It is much harder to do. But, it needs to be done soon.
Is it possible to resist a 7.9 magnitude earthquake anyway?
One must first recognize that a magnitude 7.9 earthquake is an exceptionally powerful earthquake that would subject buildings to tremendous pressure. We should also recognize that globally we have little experience in dealing with such big devastating earthquakes in urban areas.
Nonetheless, earthquake engineering knowledge has advanced significantly in the last two decades. Seismologists can provide reasonable estimates of hazard impacts to enable the design of buildings to a required level hazard resistance; this is the first step because we know that areas which have experienced large earthquakes in the past will experience them in the future.
Seismologists can also provide a projected level of earthquake impacts which could ensure that buildings are not inappropriately designed to withstand certain hazard impacts. These projected impacts are typically considered in building codes and in special zonation studies. With this information, engineers can provide the adequate design to resist projected hazard impacts. For such large earthquakes, the aim is simply to prevent the building from collapse and to protect the safety of the occupants. The damage could be substantial, and the building may need extensive repairs, if not complete reconstruction. So, yes, with proper technology and adequate knowledge we can construct buildings to resist even the largest earthquakes without collapse. The issue again is with the proper training of professionals, construction control, implementation and enforcement of building codes.
Do you think that the lack of investment in building earthquake resistant buildings is mainly due to financial reasons?
I don't think that is the case because building earthquake resistant structures makes good economic sense. There is a premium in the cost (3-5% for typical buildings), but that additional cost is more than recovered in the reduction of life cycle costs, protecting the property and its occupants, and in avoiding heavy repairs after an earthquake.
Rather, the main impediment is the lack of strict regulation for building code enforcement, the lack of clear accountability, and the lack of competency in earthquake construction among practitioners at all levels. There is also a resistance from both the public and private sector to invest in hazard and vulnerability studies. Many institutions are short sighted and prefer to ignore the problem. It is easier to think that it may not happen during our lifetime.
Do you think that critical infrastructure such like schools, hospitals and chemical plants should be better protected in any prone earthquake region?
Absolutely. These are critical facilities or high risk facilities that are essential for well-being of communities. So are lifeline systems such as water, sanitation and power. Actually, building codes recognize the need for providing better protection to these facilities. Again, the knowledge is there but the practice and the regulations lag behind.
Interviewed by Brigitte Leoni, media officer for the UN International Strategy for Disaster Reduction secretariat. For further information please contact her at: leonib@.org.