Episode 46 David Prevatt (R)

DesignSafe Radio

Raised and schooled in the Caribbean island of Trinidad, from an early age David Prevatt was interested in science and structures. As an islander, he also grew up sailing and windsurfing. He recollects the exhilarating feeling of using wind power to skim the waves. He earned his bachelor’s in civil engineering from the University of the West Indies. After a stint as a civil engineer in Trinidad and Tobago, his curiosity and interest in research took him to Clemson University where he earned his master’s and PhD degrees in civil engineering.

Prevatt describes wind as a natural force, not a “disaster” in and of itself Disaster happens, he says, when we make buildings that are inadequately prepared to resist the wind. That is why he is grateful for the NHERI network. He sees tremendous value in having all types of natural hazards engineers working towards resilient communities.

The community is a force of its own, Prevatt explains. Communities in hazard-prone areas need to start making hard decisions. Should they build stronger? Or should they perhaps build in areas that are not prone to hazards like strong winds? Communities need to assess their risk tolerance.

He discusses his research on extreme wind hazards, hurricanes, in the Caribbean. Our human nature, he says, makes it difficult for us to be rational. We tend not to remember bad events in the past, or at least think the unfortunate event won’t happen in the near-term future.

In fact, Prevatt’s first research paper, written in the early 1990s, concluded that if Caribbean nations did not take steps to address their vulnerability to hurricane risk, hurricane disasters would happen again. Hurricane David destroyed Dominique. Monserrat was devastated by Hugo. Now, 25 years later, many billions have been spent on construction that did not take hurricanes under consideration, he says, so it is not surprising what has happened to these countries in recent storms, he says.

Prevatt discusses human biases that lead poor community decisions. As an engineer, he says accurate data on hazard risks is the best tool for convincing communities to manage their risks. But even with data provided by groups like FEMA -- $1 spent on hazard reduction provides six times the future benefit – he acknowledges that communities continue to spend on immediate things, not on long term preventive measures.

He explains how the market help could convince consumers that they should purchase a house that’s build stronger than the local code, one that will last longer and have an increased level of safety. It is a hard argument for countries in the developing world, he says. He wants people rebuilding in the Caribbean to ask questions from engineers and other experts – and get straight answers -- before they rebuild in the same unsafe ways.

In his reconnaissance trip to of the U.S. Virgin Islands, Prevatt describes seeing new construction going up that did not take future storm damage into account. There were engineering and economic questions that were not considered. He cites an example: new phone poles went in right were the old ones had been. Which means the new poles are just as likely to fail. Post disaster is the time to consider improvements, he says, such as redundancies and backups.

He proposes that island standards perhaps should be different than mainland standards – so they can be more self-sufficient after a disaster. Prevatt cites grim statistics: In Puerto Rico, 93% of the country’s GDP will be going to rebuilding efforts.

He discusses traditional building techniques in the Carribean. Roof-to-wall connections often fail, often due to large eaves, structural elements that provide shade. He discusses ways that the Carribean communities could become more resilient. A wind-resilient neighborhood is safer, and there is a market for that, he argues.

Such communities need to hold their leaders’ feet to the fire to make hard, long-term decisions.

Although Prevatt is generally optimistic, he quotes an ASCE engineer who studied tornado wind loads and proposed building tornado-resistant houses – in 1897.

As a researcher, he poses important philosophical questions about our seemingly irrational inability to apply important lessons that research offers. Nevertheless, Prevatt loves his work as a wind engineer. Given even a small chance that he might succeed in changing the state of affairs, he continues to research and provide data-driven advice. Indeed, he could help a lot. Plus, he says, he has fun.

As well as doing research, he teaches at the University of Florida. He loves guiding really smart students – who are the future of hazards engineering.

One of Prevatt’s most memorable natural disaster experiences was after tropical storm Fran, which caused considerable damage in Trinidad. On a reconnaissance mission, he visited a two-story house had that lost its roof. He remembers that the home owner was jovial at first, making jokes despite her problems. When he investigated, he discovered that although the roof had been designed to be bolted to the walls, the nuts and bolts were not there! The roof had never been properly attached. The discovery shocked and upset the owner – to learn that her damage was preventable. The incident has stuck with him. Prevatt says that he never forgets that the human cost of natural hazards goes beyond physical damage.