Wednesday, March 4, 2015

Breaking down Wednesday’s I-405 emergency closure

Pavement on southbound I-405 in Renton had been repaired
multiple times but needed a permanent fix.
 by Mike Allende

What started as a fairly routine maintenance call early Wednesday morning, March 4, turned into a bigger issue for our maintenance staff and commuters on Interstate 405.

Here’s what happened:
  • Our maintenance crew became aware that concrete on a bridge deck that had received several temporary repairs on southbound I-405 near the State Route 169 on-ramp in Renton was in imminent danger of falling apart, creating a serious hazard to drivers and requiring immediate repair.
  • Upon beginning the repair and digging into the concrete, it became clear that the damage was more extensive than originally thought, covering a greater area of the road.
  • The dry weather and low traffic volume presented an opportunity to make a permanent fix to the bridge deck and adjacent expansion joint. The feeling was that the work could be completed prior to the morning commute.
WSDOT maintenance crews discovered more damage than
originally expected in the course of repairing the pavement.
Repairing roadways and expansion joints isn’t easy. Our crew had to make precise cuts into the roadway, clear out all the old material deep into the roadway, make the repairs and then cover it back up. This repair job had a few challenges.
  • The location. Had the damage been in an outside lane, our crew could have closed just one lane, using the shoulder to move around. But it was in the center of three lanes, requiring a second lane to be closed to keep our workers safe as they moved around.
  • The temperature. It was cold, with temps in the upper 20s and low 30s. This made it harder for the highway material to set. Our crew felt they’d have enough time but the curing took longer than expected. They tried to heat the area to move the process along but it didn’t work, so they needed to wait until it was firm enough for vehicles to drive over.

Crews heated the repair area to try to help the material to set,
but cold weather still slowed the process.
The permanent repair should give drivers a much
smoother and safer drive through the area.
Our communications staff and traffic management crew went to work alerting commuters and the media of the situation to encourage people to use alternate routes but still, an 8-mile backup formed before all lanes cleared at about 7:30 a.m.

There’s never a good time to close lanes on state highways and as we typically do, we’ll evaluate this closure to see what we can learn to better assess the size of repairs, weather conditions and locations. Our crews did an excellent job of getting the roadway repaired and making the area safe for drivers.

Unfortunately, we can’t promise that lane closures for emergency maintenance work won’t happen again. Our highways are old, in many cases 40-to-60-years-old, and like anything that age, things begin to fail (learn more about our infrastructure challenges in our Gray Notebook). We do our best to plan projects ahead of time to make those repairs, because while it’s still an inconvenience for drivers, we can at least let the public know in advance what to expect so they can plan around it.

Sometimes, though, we encounter a situation that is hazardous for drivers and must be closed as quickly as possible until we can make it safe. That’s always our top priority, because while we never like to see people stuck in traffic, we would trade that for ensuring that people get where they need to go safely.