First quake, now Irene, but engineers urge calm
By Adam Sege MCT Campus
WASHINGTON — Hurricane Irene already was threatening the East Coast when a rare 5.8-magnitude earthquake struck Virginia on Tuesday, so it didn't take long for many property owners to call in an expert.
The phone calls "started coming in about 20 minutes after," said Lisa J. Kuruvilla, an executive at ADTEK, a Fairfax, Va.-based engineering firm.
Property owners understandably have been eager to assess quake damage in time to make any needed repairs before Irene arrives. Amid reports of cracks in the iconic Washington Monument and fallen ornaments on the National Cathedral, engineers say the hurricane should be cause for caution, not panic.
While they say most area buildings are designed to withstand both the earthquake and the coming hurricane, they say residents can take steps to further reduce the chances of serious damage. Property owners have a few factors working for them, engineers say.
First, by several accounts, engineers have found relatively little structural damage from the earthquake.
ADTEK has sent structural engineers — some working through 1 a.m. — to nearly 100 schools in the Washington metro area. Where they've found damage, most of it has been fairly easy to repair, Kuruvilla said.
By midday Thursday, Washington-based KCE Engineers had inspected 74 buildings since the earthquake, said Allyn Kilsheimer, the firm's president and chief executive officer. About half a dozen had seen problems with large masonry, he said, while 20 to 30 had small cracks.
"There are lots of cracks, but nothing of major consequence," he said.
Even at the Washington Monument, which the National Park Service has closed indefinitely, the cracks are at the top of the 555-foot obelisk, Washington's highest structure _ not near the bottom, which would put it at greater structural risk.
Second, Irene will slam buildings with different forces than Tuesday's temblor.
An earthquake shakes the foundations of buildings, jolting them from underneath, explained Om Sharma, a structural engineer and owner of 3D Structural Engineers in Bethesda, Md. In a hurricane, winds whip buildings laterally and from above. Sherma said he doesn't expect the hurricane to exacerbate earthquake damage on a wide scale.
Still, engineers warn that even in buildings with sound foundations, people can be injured by falling objects or flying glass.
They say residents should bring all outdoor furniture inside, as well as anything else that could be blown away by the wind. If that's impossible, tying objects down goes a long way, Kuruvilla said. Kilsheimer suggested boarding up windows with plywood. He also urged residents to check their chimneys for broken or dislodged bricks and look for other damage in homes where high winds could cause trouble.
For people concerned about the integrity of a particular wall, he suggests a simple at-home test: Tap near the middle of a window on that wall, and you should hear a dull sound, he said. Tap near the edge of the window and you should hear either a similar dull sound or a higher pitched sound.
But if a tap in the middle of the pane makes a high-pitched sound, that could suggest stress within a wall.
If residents sense problems with their walls, chimneys or other parts of their homes, he suggests asking a professional for help.
