Hopkins team hopes building stands up to winds Test structure in N.C. may lead to advances in coastal home design

August 26, 1998|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

If Hurricane Bonnie slams into North Carolina's Outer Banks today, a Johns Hopkins University civil engineer will be ready to make unprecedented measurements of the storm's fury.

Professor Nicholas P. Jones and his students have fitted a test building in Southern Shores, just north of Kitty Hawk, with a flock of instruments designed to monitor the structure as it strains in the storm's winds.

If the building and its sensors survive their first test under hurricane conditions, they should provide a wealth of data on how low-rise structures respond to high winds, and how their designs might be improved.

Scientists have wired up buildings before to gauge stresses, Jones said, "but nobody has had the opportunity to instrument a building this comprehensively that has actually seen a storm of this magnitude."

Bonnie could be a scientific boon, even as it wreaks havoc on the coastal community.

"My hope is that, whatever happens, we are able to obtain quality data," Jones said. "After that, I just hope for the best, as all of us are, for the people who live there."

The $106,000, three-year study is supported by the National Science Foundation, and by the town of Southern Shores.

As part of the nonprofit Blue Sky Foundation, the town is working with insurers, developers and emergency management officials to reduce storm losses and to train builders in better construction technologies.

"Their main industry is tourism," Jones said. "If they take a serious hit in a hurricane it sort of knocks them out of business. And they want to plan prudently and appropriately for an event like this."

To these ends, the foundation several years ago built the Kern P. Pitts Center. It looks like a large vacation home, but was designed to demonstrate good storm design and construction. Among the features are steel tie rods anchoring the roof to the foundation. Many of the details were left exposed so that builders can see them and learn.

Jones' instruments are positioned to gather data on stress loads in high winds. The results will help engineers develop a new generation of building codes for low-rise buildings. During Hurricane Andrew in 1992, inadequate or unenforced codes in South Florida contributed to the devastation of thousands of homes, many deaths and injuries, and to $15.5 billion in private insurance claims.

To find out how well the improved designs actually perform, Jones has fitted the Pitts Center with:

A dozen pressure sensors on the building's exterior to measure wind forces -- "what you feel when you put your hand out the window of the car on the highway," Jones said.

Ten wind-speed sensors, both on the house itself and on a pole 60 feet away. Barometric pressure and rainfall are also measured by other instruments at the site.

Ten strain gauges measuring the forces exerted on the JTC structure's rafters and walls by high winds. From these, Jones and his students can develop a comprehensive understanding of the forces trying to rip off the roof and blow down the walls.

The last sensors were installed in October, and last winter's northeasters provided their first test. But the winds never topped 50 mph. Bonnie would be the experiment's first big challenge.

"We would like to think this structure has a better-than-even chance of surviving a major storm," he said. "The last thing we want to have happen is that the structure is destroyed along with our instrumentation. But of course there we're in God's hands."

The sensor data go to a computer secured in a utility room on an upper floor and, as long as phone lines stay up, to Hopkins. The measurements are also recorded on backup disk drives. The hardware, Jones said, "will last as long as anything in the building."

If everything works, the system will switch on when winds top 20 mph. If there is a local power failure, a battery pack will keep the data collection going for four hours -- long enough, Jones hopes, to get important data. A gasoline generator is also available, if Jones can get anyone to go turn it on during the storm.

Yesterday, Hopkins graduate student Michelle Porterfield, 26, of Binghamton, N.Y. -- whose doctoral dissertation is riding on this experiment -- drove to Southern Shores with undergraduate Marguerite Jeansonne, 19, of Louisiana, to make sure the building was secure and all the equipment was working. That done, they were under orders to get out.

"This is not a time for heroics or goofing around," Jones said.

Pub Date: 8/26/98

Baltimore Sun Articles
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.