Work begins tomorrow on removing Seneca Street off-ramp

Posted on May 21 2019 5:09 PM

Tomorrow crews will begin removing the Seneca Street off-ramp that looms above Seneca Street between the waterfront and First Avenue. Due to its height and proximity to nearby buildings, the contractor Kiewit will use cranes to bring the ramp’s girders down one by one.

Crews will remove the ramp working west to east toward First Avenue. Hoe rams will hammer out the road deck before crews cut the ramp’s girders and beams. Cranes will lift the cut pieces one by one onto the ground. Machinery will munch the girders and the ramp’s columns into rubble. Kiewit used a similar approach when removing the Columbia Street on-ramp in February and March.

Cranes lifting a beam away from the viaduct ramp

Above: Crews lifting a girder from the Columbia Street ramp that had been cut away with saws

Expect detours around Western Avenue and Seneca Street

Kiewit will need to close the intersection of Western Avenue and Seneca Street while removing the ramp above the intersection. Kiewit, WSDOT and SDOT have coordinated closely on the work plan for the ramp’s removal to minimize road closures in the neighborhood. The current closure plan:

  • Wednesday, May 22: Crews begin site prep and slotting the deck near Alaskan Way.
  • Thursday, May 23: Crosswalk across Seneca Street at Western Avenue closes at 7 a.m.
  • Tuesday, May 28: Whole intersection of Seneca Street and Western Avenue closes at 4 a.m., for up to 20 days total.
  • Saturday, June 1: University Street reopens onto Alaskan Way.
  • Mid-June: Ramp fully removed, and site restoration begins.

Take note: Between Tuesday and Saturday, May 28 – June 1, Western Avenue will be a dead-end street south of Virginia Street. Businesses and sidewalks will be open north and south of Seneca Street, but people walking, biking and driving will need to find alternate paths to cross Seneca Street. See the map below:

Map showing Western Ave closed at Seneca Street, with detours being Wall Street to north and Spring or Madison to the south

When University Street reopens on June 1, it will be a connection point between the waterfront and Western Avenue. The intersection of Post Avenue and Seneca Street will also close for up to seven days in late May or early June as crews remove the ramp overhead.

What to expect from the work

The contractor’s current plan calls for the ramp to be removed in about three weeks, with crews working only during daytime hours. Buildings adjacent to the work will be protected in the air by nets hung from cranes, and on the ground by barriers. Work hours could change based on crews’ progress, but the planned work hours are:

  • 7 a.m. – 8 p.m. weekdays
  • 9 a.m. – 8 p.m. Saturdays
  • 9 a.m. – 5 p.m. Sundays

The work will unavoidably produce noise, dust and vibration, but crews will work to mitigate those effects where possible. The process for removing this ramp is benefitting from crews’ experience working on earlier sections of the viaduct, and Kiewit has refined their methods since the project began.

Follow up work at First Avenue in June

After the ramp is removed, crews will need to conduct follow-up utility work where the ramp once met First Avenue. Crews will also restore the sidewalk on the west side of First Avenue and build a wall and rail in the hole where the ramp once stood. This work has not yet been scheduled, and may involve night work. We will post more details about this work on our website once the plan is confirmed.

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