Now that an East Coast earthquake has actually damaged the historic Washington Monument, we all have reason to be more acutely aware of the potential danger from the kinds of natural disasters that seem comparatively rare in most regions, but that we know from the news can be spectacularly devastating. Knowing what we do about the amount of damage that serious earthquakes can cause, we should be equally aware of what can be done to minimize some of that damage. Using bamboo as a principle or supplementary building material in appropriate structures is an especially notable example of such attainable solutions.
On average, there are about seventeen large earthquakes a year, which typically result in serious loss of life and property, and consequently high costs of repair. The 1989 Loma Prieta earthquake in the San Francisco Bay area damaged 23,000 homes, making for an average cost of between $25,000 and $35,000 each. Between damage to private homes and other property, the total cost of that quake amounted to $5.6 billion. The 1994 quake in Northridge, California resulted in nearly triple that cost and damaged 46,000 homes. On the other side of the Pacific, the 1995 earthquake in Kobe, Japan exceeded even that cost ten times over, costing $150 billion dollars. Estimates of the cost of Japan’s March 11th earthquake reach as high as more than double that figure.
With a track record like that, and with at-risk regions becoming more densely populated over time, nothing can entirely stop very large earthquakes from being costly or deadly, but careful engineering has prevented recent earthquakes in industrialized nations from being as catastrophic as they might have been, and yet there is more that can be done. One might assume that part of the process of engineering earthquake-proof structures would be placing emphasis on highly modern materials like rebar and plastics. Certainly, the structures that tend to survive large quakes are recognizably modern, but natural or unconventional products can also be utilized in extremely durable home construction, and in ways that offer the same benefits both to impoverished third-world communities without the benefit of high-cost, manufactured construction materials and to private, first-world homeowners with an interest in a greener but equally effective alternative.
Earthquakes in Colombia and Costa Rica have demonstrated that houses constructed of bamboo are capable of surviving disasters that caused more modern houses to collapse. Given that bamboo is extremely flexible but also extremely strong, having a tensile strength comparable to that of steel, it is an ideal support material to resist damage from earthquakes. In the hands of skilled designers, these properties can be utilized to construct homes that are both inexpensive enough to be made available to impoverished communities and durable enough to withstand even the most extreme earthquakes. In 2007, Colorado State University performed shake tests on houses in which bamboo had been used in place of rebar at their bases, and found them to withstand forces exceeding what would register as a 10.0 on the Richter scale. In a further bit of environmental friendliness, those houses utilized recycled tires for shock absorption. They were designed specifically for Indonesian aid and cost less than $1,000 each.
Of course, with a higher price tag in a more affluent nation, the same beneficial aspects of bamboo construction can be applied to making homes that are durable, damage-resistant, and cost-effective, but also aesthetically pleasing. If you think that a house made with natural, traditional building materials has to look pre-modern in order to be earthquake-proof, that’s simply not the case. It can be better in every way: environmentally, structurally, and visually.