Judging by the small crowd of Old Town residents gathered at Lyles Crouch Elementary School Tuesday night to hear details of the old Woodrow Wilson Bridge detonation set for midnight August 28 it is pretty much a non-event. What was advertised as a two hour briefing end within one hour.
Detonation of the nearly half-mile stretch of steel girders that supported the now denuded old span over Jones Point Park will be more like a nearby lightening strike and clap of thunder than an explosion, according to Dennis Brown, project engineer, Corman Construction, whose subcontractor demolition experts will drop the steel beams.
The operation will also produce a flash or multiple flashes "similar to individual stadium lights illuminating briefly across the length of Jones Point Park," according to the detonation explanation flyer at the meeting. "If you blink you'll miss it," Brown told the 25 citizens present.
"We have removed all the concrete decking from the bridge on the 1,600 foot stretch from the river to S. Royal Street. We will now make engineer cuts in the beams and insert cutting charges. These plastic tubes, surrounded by copper and filled with a liquid explosive, when detonated generate an enormous amount of heat for one quarter of a second. That burns through the steel beams and they drop to the ground," he explained.
The greatest concern for those residents closest to the bridge was the concussion generated by the beams hitting the ground and what impact that might have on their homes. "That concussion should be no more than a tractor trailer driving down Green Street," Brown said.
A CONCUSSION READING of point five can crack the seams in drywall, according to Brown. The bridge demolition experts are expecting no more than point three. "This subcontractor has never had a mistake," Brown assured the audience.
However, to increase that safety factor, arrangements have been made to deploy elements of the Alexandria Fire Department throughout the residential area nearest the bridge. "We have looked at this from every possible angle for your safety," said William A.
Coates, assistant fire marshall, Alexandria Fire Department.
"I really do believe we have dotted all the I's and crossed all the T's," Brown added. Additionally, there will be approximately 14 Alexandria Police Department officers disbursed throughout the area to prevent anyone from coming within the 350 feet "clear zone," according to Brown.
Officers will be deployed at the intersections of Green/Lee, Green/Fairfax, and Green/Royal streets, along with officers at the south ends of Lee and Fairfax streets. For added safety, emergency response teams will be staged at the intersection of Green and South Royal streets as well as at South Street.
Although no residences are within this "clear zone" residents within a 500 foot perimeter are being required to remain in their homes from 11:45 p.m. to 12:15 a.m. as a added precaution. A special viewing area for spectators will be set up on the South Washington Street Beltway overpass, according Alex Lee,
community liaison, Woodrow Wilson Bridge Project.
PRE-DETONATION SURVEYS on the exterior of homes within the safety zone on South Lee and South Fairfax as well as the Hunting Point Towers buildings, Jones Point Lighthouse, and St. Mary's School will be conducted by the detonation contractor, according to the Bridge Project. Seismic monitors will be placed in those areas and structures will be re-inspected following the event.
The so-called "steel drop" date has been changed several times since it was first announced last month. Originally it was scheduled for August 30, then August 29, and finally August 28.
However, the time has remained 11:59 p.m.
The reason for the late hour, according to Lee, is that traffic must be stopped on the Capital Beltway for approximately 30 minutes. There will also be a 30 minute no-fly period for aircraft and a 30 minute closure of that area of the Potomac River from the navigation channel to the Virginia shoreline.
The winner of "The Toughest Bridge Commute Contest," Dan Ruefly of Accokeek, Md., will push the detonation plunger from the top of Hunting Tower at 11:59 p.m. That will set off the series of burn detonations to produce the "steel drop."
Once the steel beams are cut and removed from the site by truck, the concrete columns will be chipped away by excavators with jack hammers known as "hoe rams." All other demolition work, except for the August 28 detonation, is being conducted during daylight hours Monday through Saturday.