Work finally underway on Highway 12 bridge outside Sebastopol

Replacement of the failing Laguna Bridge on Highway 12 outside Sebastopol - set to begin a year ago and then delayed - is on track to start for real next week and to run through mid-October for each of the next two years, Caltrans said.

The $9 million project will result in a wider, more structurally sound span for the more than 23,000 vehicles that cross it on an average day, an agency spokesman said.

But it’s likely to cause some pain in the meantime, contributing to congestion on a stretch of roadway already known for peak-hour backups at the city’s eastern gateway, officials said.

Patti Lacey, manager at the Village Park mobile home park right next to the bridge, said she thinks most area residents are prepared for the project to begin, saying, “It’s been coming for a long time.”

Business owners in the area do not appear especially concerned, either.

Denver Booker, owner of the 1-year-old Sebastopol Bike Center nearby, said the traffic bottleneck is caused by traffic lights through town, irrespective of what’s happening with the bridge.

“I don’t think it’s going to have much of an effect,” he said.

The upcoming work will require routing travel in both directions onto narrower lanes across the existing span this summer, while crews construct the southern, eastbound half of the new bridge adjacent to it, Caltrans representative Allyn Amsk said.

Then next year, traffic will be shifted onto the newer structure while the westbound section is built.

The old bridge will be demolished in the meantime - either late this season, if there’s time, or at the beginning of the next construction season, Amsk said.

While the final product will raise the bridge to modern-day standards - with 12-foot lanes, 8-foot shoulders and 7-foot sidewalks in each direction - the temporary lanes in use this summer, at 11 feet wide, will be a foot narrower than those to which motorists are accustomed, said David Marquez, superintendent for Ghilotti Construction, which is doing the work.

“It’s going to be squeezed down during the staging,” he said.

There also will be occasional periods during which the highway is reduced to one-way travel - every night next week, for example - and rare instances when the road must be closed down completely for public safety reasons , Marquez said.

The 220-foot bridge across the Laguna de Santa Rosa, a 14-mile-long freshwater wetland complex, was built in 1921 and widened in 1949, Amsk said.

Plans to replace it have been in the works since a 2002 inspection revealed underwater scouring and erosion, he said.

Working at the site early Wednesday afternoon, as westbound traffic backed up across the bridge and beyond it, Marquez gestured toward the span, which slumped very slightly upon concrete supports embedded in the laguna.

“They’ve done some shoring up,” he said. “But you can see how it’s settled and, in an earthquake, that wouldn’t be there.”

The plan is to widen the highway from Morris Street to the bridge, with additional roadwork continuing east to a point about 500 feet past the bridge, Caltrans said.

The site was prepped for construction last year, but the project had to be postponed because of a right-of-way problem encountered during relocation of utility lines in advance of the work, Amsk said.

The construction season also is limited because of environmental regulations related to the Laguna’s sensitive wildlife habitat, which permit work between June 15 and Oct. 15, Caltrans said.

Workers this week were setting up wildlife fencing, mowing the construction site, removing tree limbs and moving equipment into the construction area.

Next week they plan to build access roads for construction crews on either side of the Laguna before building a temporary, wooden span for use during the construction period, Marquez said.

They’ll also be demolishing the sidewalk on the north side of the span and moving in concrete rails to serve as barriers, he said.

Next week and the first few days of the following week, one-way traffic control will be in effect from 8 p.m. to 6 a.m. Monday through Thursday and Saturday; 10 p.m. to 6 a.m. Sunday into Monday; and 10 p.m. to 7 a.m. Friday into Saturday, Caltrans said.

Pile driving is scheduled to begin the week of June 22 and continue for about three weeks from ?7 a.m. to 7 p.m.

It’s noisy work, Caltrans said.

Marquez and Amsk said every effort would be made to limit inconvenience for the public but asked for patience and caution.

“From a company standpoint, please just be careful,” Marquez said. “Obey the 45-mile speed limit, or go even slower. We have guys get hurt all the time.”

You can reach Staff Writer Mary Callahan at 521-5249 or mary.calla?han@pressdemocrat.com. On Twitter @MaryCalla?hanB.