Residents of south Old Town Alexandria were able to sleep through the night Tuesday. The third detonation of the old Woodrow Wilson Bridge draw span structure was barely audible ,compared to the first two this past December, because this blast was primarily under water.
At approximately 2:30 a.m. on Jan. 17, a series of blast were set off over a 30 minute period as workers continued demolishing part of the old drawbridge portion of the former bridge. The final two detonations are scheduled for the same earlier morning hours of January 20 and 26.
Those blasts are also expected to produce little noise or no vibration to nearby homes, according to bridge project spokespersons. Seismographs are in place on the Virginia shoreline to measure vibration levels. Crews are demolishing the four piers that supported the drawbridge portion of the old span during these operations.
Timing the detonations during the early morning hours is necessitated by safety concerns, according to the project. Other such measures at the bridge site on the detonation dates include:
* Approximate 30-minute total closure of I-95/Capital Beltway.
* Approximate 90-minute no-fly period for aircraft over the bridge area.
*Minimum 500-foot safety perimeter surrounding the work area including an estimated 60-minute closure of Potomac River navigational channels.
"We are happy that Tuesday night's activity apparently caused no disturbance. We haven't received any phone calls or e-mails of complaint. We are hoping for the same results with the final two detonations," said Alex Lee, community relations manager, Woodrow Wilson Bridge Project, early Wednesday morning.