New technology to improve coastal resilience

An essential issue for coastal planning is survivability of coastal structures. This is a complex matter. For example, wind-driven rainwater can effectively ruin a house if the doors and windows are breached, even if the roof stays intact. Roof design, materials and construction methods need to be tested in a repeatable manner so that a scientifically based set of construction and upgrade standards can be developed. Essential to this effort is full-scale destructive testing analogous to the automobile crash testing done by the insurance industry and automobile manufacturers. The IHRC is developing an apparatus for first-of-its-kind, full-scale, destructive testing of houses and low-rise commercial structures. The 2-fan Wall of Wind (see Figure 10.5) generates 120 mph winds (low category 3) and

Figure 10.5 The IHRC 2-fan Wall of Wind apparatus, capable of generating 120 mph winds for destructive testing of houses

Note: A condemned house in Sweetwater, Florida is systematically destroyed during a test. Source: IHRC.

includes a water injector to simulate horizontally flowing rainfall under hurricane conditions.

While wind tunnel testing of model houses has provided useful information, it also has many limitations — gravity cannot be scaled nor can roofing materials (shingles, tiles) be reduced to a miniature size and provide any useful understanding of wind dynamics and failure mode. Full-scale destructive testing of structures will likely change the public's perception of building safety, just as the visualization of car crash testing led to the adoption of air bags and many other safety features.

The IHRC research team is presently completing a larger and more powerful 6-fan Wall of Wind funded by Renaissance Reinsurance Holdings, Ltd (RenaissanceRe), the largest re-insurer of hurricane-prone areas in the world. The insurance industry is already recognizing the enormous potential of full-scale Wall ofWind testing in the midst of an emerging insurance crisis for coastal areas. The more powerful 6-fan RenaissanceRe Wall of Wind can generate 130-140 mph winds. It will be housed in a fully instrumented building at the FIU Engineering Center in Miami, Florida. This new technology is necessary in order to learn how to build more hurricane-resistant houses, which is paramount in the present situation, and before considering the probability of more powerful hurricanes in response to global warming in the future.

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