Controlled Blasting Planned for Site of SPHHS Building

Blast planned for twice each weekday for three weeks.

September 12, 2012

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As part of the excavation required for construction of the new building for GW’s School of Public Health and Health Services, twice-daily controlled blasting activities are planned for weekdays beginning as soon as Sept. 17 and will continue for approximately three weeks. The extent and duration of the blasting will depend on the amount of rock at the site – located between K and 24th streets, Washington Circle and New Hampshire Avenue— as well as other site and field conditions.

This type of work is common in D.C. for construction of new buildings in areas where rock formations lie near the surface, said Alicia Knight, senior associate vice president for operations. Controlled blasting also occurred last spring and this summer at the Science and Engineering Hall site between 22nd, 23rd, H and Eye streets, and a small number of additional blasting events may occur on the SEH site in the coming weeks. These will be coordinated to ensure there are no more than two blasts on any day. Controlled blasting activities also took place for several months in 2008 at 2200 Pennsylvania Ave., now home to The Avenue apartment, office and retail complex.

”As with projects in the past, we have put into place protocols to monitor noise and vibrations to ensure compliance with regulatory limits and also to ensure the integrity of adjacent structures,” said Ms. Knight.

The blasts are expected to occur at approximately 11 a.m. and 2 p.m. each weekday. Air horns will sound at 15, five and one-minute increments prior to each blast and following the blast to indicate “all clear.” Weighted mats will be used on the blasting site to control dust and vibrations. Blasting activity may not happen on every weekday, depending on excavation progress and weather conditions.

The noise level from the blasts is expected to be comparable to a large truck passing by. Those very near the construction site may also feel a vibration comparable to a door slam or a large truck driving down the street. In addition, weather conditions, such as high humidity or the presence of cloud cover, can cause the air movement from a blast to seem more severe.

Residential housing and nearby office buildings will not be directly affected by the blasting. However, those near the area may hear the air horns and the controlled blasts. Individuals near the construction site when an air horn sounds should follow instructions from site personnel and obey any additional signage that may be posted.

Sidewalks adjacent to the site may be closed temporarily during the blasting events, beginning at the five-minute air horn. Adjacent streets are not anticipated to be closed but this may occur at the direction of D.C. Metropolitan Police, beginning at the one-minute air horn.