Thursday, January 28, 2016

Sign foundation work progressing well on SR 99 in Seattle

By Chelsey Funis

Crews used a large drill to dig several 4½-foot wide,
14-to-18-foot-deep holes for new sign foundations on
SR 99 in Seattle.
If you're a regular user of SR 99/Aurora Avenue North between the Aurora Bridge and just north of Mercer Street, we'd like to thank you for doing your part to help keep traffic delays to a minimum during the past two weeks.

Crews are around the halfway mark for the first phase of sign foundation installation work happening on this stretch of SR 99 and are pleased with the progress they've made. Work is continuing on schedule and crews expect to move into the second phase in mid-February as planned.

We've been trying to do our part, too, through daily coordination with King County Metro and the Seattle Department of Transportation. Travel times for cars and buses during peak periods in the morning and afternoon have remained fairly steady – not just on SR 99 but on nearby arterials as well. So whether you've been leaving your house or work an hour earlier, riding your bike, or avoiding SR 99 altogether, we appreciate your efforts.

If you've driven the mile-long work zone during the day you might not have seen a lot of work happening and may have wondered, "What exactly are they doing in there?" We're here to give you an update on what's been accomplished so far.

As of now, crews have completed the following work, the majority of which has taken place at night and over the weekend, when we allow crews to close a second lane in each direction.
  • Placed approximately 1,600 feet of temporary concrete barrier to establish four separate work zones between the Aurora Bridge and Highland Drive.
  • Cut and removed approximately 1,600 square feet of pavement and 800 feet of existing concrete barrier to make room for the new sign structure foundations.
  • Drilled four underground shafts for the sign foundations. Each shaft is 4½ feet in diameter and extends 14 to 18 feet underground. Drilling work went quicker than expected and crews were able to reopen the lanes more than 24 hours ahead of schedule last weekend.
  • Began forming the actual foundations by placing rebar and pouring concrete into the shafts.
  • Began installing underground power and communications lines at two of the sign locations that will support electronic messaging systems and data collection tools.

So what work is left in Phase 1? Crews still need to:
  • Place concrete barriers around each foundation for additional protection and support.
  • Complete installation of underground power and communications lines.
  • Remove the temporary concrete barrier, restripe the lanes and restore SR 99 back to its original configuration.

The second phase of work is scheduled to begin mid-February and includes drilling, placing rebar and pouring concrete for one remaining sign foundation near Comstock Street. Phase 2 will require a localized closure in the southbound curb lane near Comstock Street for approximately three weeks. All northbound lanes will be reopened at that time. This work is not expected to significantly impact traffic.

If you would like additional information about the SR 99 lane closures or ongoing construction at the north end of the SR 99 tunnel, please visit our project website. Thank you again for your patience as we complete this work.