The next phase of Purple Line construction is set to begin Tuesday morning in downtown Bethesda. Crews will be blasting through hard rock between 8 a.m. and 5 p.m. until January to help make way for construction of an elevator shaft in the planned Bethesda Purple Line station. The construction will not occur on weekends or holidays according to the Purple Line Transit Partners website.
When completed, the Bethesda station will be the western terminus for the 16-mile, 21-station light-rail line, which will stretch as far as New Carrollton in Prince George’s County. The line is expected to open in late 2022.
Work has been ongoing on the planned Bethesda station, which will lie just above the existing Metro Red Line station at 7450 Wisconsin Ave. In the current phase, workers will dig a shaft that is 150 feet deep in order to connect the two train lines.
“Blasting is done in a very controlled method. No explosives are kept on-site. They’re brought in in the morning and taken out in the evening,” said John Undeland, spokesman for Purple Line Transit Partners, the public-private partnership constructing the Purple Line.
Undeland said the blasts are controlled in a way that staggers them in increments of six to eight seconds, which means that one single blast is shorter and less intense. The goal is to dislodge hard rock that cannot be moved by another method.
“By spacing them [the blasts] out, they have less of a noise and vibratory impact,” he said.
In addition to the noise of the blasting, sirens will also sound to alert construction workers of when a blast is about to occur. Undeland said he wasn’t sure how loud the noise would be, but that it would “depend on where you are,” in relation to the construction site, which is on the 7200 block of Wisconsin Avenue.
Last month, a number of Silver Spring residents complained of being awakened at night due to noise from drilling occurring as part of the construction of a Purple Line tunnel in Silver Spring’s Long Branch neighborhood. After a group of residents visited Maryland Transportation Secretary Pete Rahn in his office to air their concerns, workers stopped drilling at night.
Undeland said he didn’t think the blasting would have the same side effects in Bethesda as it has in Silver Spring.
“It’s mostly a commercial area. Unlike other areas of the project, we’re not on top of folks’ homes to nearly the degree we are in Silver Spring,” Undeland said.
Undeland added that work on the Bethesda station needs to be done in “close coordination with WMATA,” referring to the Washington Metropolitan Area Transit Authority. He said he was not sure if the Bethesda construction would disrupt Metro service.
Dan Schere can be reached at Daniel.schere@moco360.media
