March 12, 2013 17:00This information is being shared on behalf of the Multnomah County Communications Office:
Night time blasting is scheduled on March 13 and 14 as part of the Sellwood Bridge construction project. The contractor is excavating the hill on the West side of Highway 43 North and South of the bridge. Blasting is needed to fracture underground rock into smaller pieces that can be excavated during the work day.
The bridge project will construct a new Highway 43 interchange at the new bridge that will be wider than the existing interchange. The West hillside will be excavated over the next few months and then retaining walls will be built to hold back the slope. By 2014, traffic lanes will shift to the West and the contractor will begin rebuilding the East side of the interchange.
The contractor expects rock blasting will be needed as many as four weeks this Spring. Normally, blasting will happen on two or three weeknights in a week. On a blasting night, two or three blasts will typically be detonated. The first blast will happen close to 9:00 p.m. and the later blasts will usually happen between midnight and 3:00 a.m.
Highway and bridge traffic will be held for five to 20 minutes for each blast to keep the public out of the blast area. The outside southbound lane of Highway 43 will be closed near the bridge from as early as 7:00 p.m. to as late as 5:00 a.m. on blast nights. Travelers can avoid delays by using alternate routes.
Blasting is scheduled at night to minimize impacts to traffic. Blasts happen late at night due to procedures the contractor must follow for documenting the first blast and setting explosive charges before each blast.
Five minutes and one minute before each blast, a warning siren will sound. The siren will likely be louder than the blast itself, which happens deep underground.
For more information about blasting, visit www.sellwoodbridge.org/blasting.
For additional information contact Mike Pullen at the Multnomah County Communications Office, (503) 209-4111 or firstname.lastname@example.org
Sgt. Pete Simpson