South Atlantic Street beneath SR 99 reopening soon

Posted on Mar 6 2019 5:01 PM

This week crews are pouring concrete on South Atlantic Street in SODO, near its intersection with Colorado Avenue South. The street has not run east-west beneath SR 99 for years, interrupted by highway barrier and the temporary South Atlantic Street off-ramp WSDOT built as part of the SR 99 tunnel project.

Construction across a wide street with highway overpass in background

Above: The start of work on South Atlantic Street beneath the SR 99 overpass.

With the tunnel open and that SR 99 off-ramp gone, crews are able to restore this street (pouring concrete so the road lasts longer under the weight of trucks coming to and from the Port of Seattle). South Atlantic Street will provide a path between Alaskan Way South and First Avenue South, and a new option for drivers going between SR 99 and East Marginal Way. The street does have a railroad crossing, which is why the overpass we opened above SR 99 in January 2014 provides important congestion relief for trucks coming to and from the Port of Seattle's Terminal 46.

Drivers in the area should expect some road closures this week as crews pour concrete. This work schedule could also change in the event of heavy rain or low temperatures.

Phase 1: Monday, March 4 – Thursday, March 7

  • Crews have begun pouring concrete on South Atlantic Street near its intersection with Colorado Avenue South.
  • The right-hand lane of the southbound direction of the Atlantic Street overpass ramp is closed.
  • By 7:00 am Thursday morning, crews will open a freight-only lane of eastbound South Atlantic Street beneath the overpass.

Phase 2: Thursday, March 7 – Sunday, March 10

  • As soon as the eastbound lane is open, crews will fully close the South Atlantic Street overpass ramp.
  • During the day Thursday, crews will grind down pavement, prep the subgrade surface, and pour new concrete in the intersection.
  • Sidewalks and building access will be unaffected, but drivers entering or exiting driveways and garages on Colorado Avenue South should use South Massachusetts Street.
  • Sunday evening, the South Atlantic Street overpass ramp will reopen and the freight-only lane will close.

Next week, crews will pour concrete for new sidewalk on the north side of South Atlantic Street. Then, on Saturday, March 16, our contractor will work with the Seattle Department of Transportation to install traffic signals and paint the roadway so by Saturday evening, South Atlantic Street can open in both directions beneath SR 99.

This piece of work is one of the final components of the SR 99 Connections Project, one of 30 projects that together make up the Alaskan Way Viaduct Replacement Program.

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