Healdsburg Memorial Bridge set to close Tuesday

Come Tuesday, work is set to finally get underway on a renovation of the Healdsburg Memorial Bridge that will close the historic structure for more than a year.

The span across the Russian River will be shut to motor vehicles for up to 14 months for a $15 million renovation approved in 2010 after the city decided to save the bridge, rather than build a new one.

“I’m excited the work is actually at a point where it’s finally beginning,” Mayor Jim Wood said. “It’s taken a long time to get to this point.”

During the yearlong closure, the 8,000 or so vehicles that cross daily will have to use the Highway 101 bridge just downstream. But bicyclists and pedestrians still will have access to the 93-year-old bridge during construction.

The seismic retrofitting and rehabilitation entails replacing the center span pier, bolstering or replacing steel parts, strengthening two large bridge abutments and other safety improvements.

The deck, sidewalks and roller bearings will be replaced, along with the chipped, lead-based paint, which will be blasted away to make way for a new coat of silver paint.

The two-lane span across the Russian River, also known as the Healdsburg Avenue Bridge, was completed in 1921 and became a vital link in the Redwood Highway, the paved route established in the Roaring ’20s stretching from Oregon to the San Francisco Bay.

Since construction of the nearby freeway crossing downstream around 1960, the bridge has served as an alternate route for local traffic and entry into Healdsburg.

Crossing the landmark bridge feels a bit like a throwback to another era. There’s a 15-mph speed limit, allowing enough time to glance around at the river and the nearby beaches where people have flocked for more than a century for recreation and water carnivals.

The vintage steel-truss bridge was in danger of demolition after Caltrans gave it a poor safety grade in 1979. Decades later, the state agency acknowledged the rating was based on faulty calculations and the bridge can carry all legal loads. But its width, height and size limitations also cast doubt on its long-term viability.

Preservationists periodically rallied to save the bridge, and the City Council eventually agreed to strengthen and repair it after a lengthy public process that examined a number of other alternatives, including building a squat, modern structure.

“It was really clear early on that the community didn’t want to see your typical concrete, box-type bridge go across the river there,” Wood said. But he said federal and state officials had a different point of view.

“We were really pushed hard to make a new bridge. The community spoke and we held our ground. It was not easy,” he said.

The date of the actual closure was postponed a couple of times this month before contractor Granite Construction Co. was given final approval on its scaffolding and containment plans.

“We’re all set to go,” Healdsburg senior engineer Mario Landeros said Friday.

City officials expect there will be some traffic challenges, at least initially, as motorists adapt to the bridge being closed.

“There is a pretty good flow of traffic historically over the bridge. With the closure, this is traffic that will have to be diverted to other facilities,” Landeros said.

In particular, he said the Central Healdsburg freeway exit will be more heavily used, leading to more delays on Healdsburg Avenue to and from the Healdsburg Plaza.

“It will be more akin to special- event traffic,” Landeros predicted. “It gets backed up and congested.”

He said traffic signals will be revised to accommodate more north-south traffic. And side streets likely will back up a little more, particularly during peak hours.

“We will make adjustments as needed,” he said. “We will constantly be monitoring conditions out there.”

He said there will be signs directing vehicles to alternate routing.

A protected “portal” is planned for people on foot and bicycle to continue using the bridge, but it may not be possible during all phases of construction.

“There likely will be days when cyclists or pedestrians can’t cross,” said Public Works Director Brent Salmi, adding that a shuttle bus may need to employed.

But in the end, city officials said the disruptions should be worth it.

“After all is said and done, it essentially will be a relatively strong bridge able to meet the current seismic and scour requirements and also maintain legal vehicle loads,“ Landeros said. “Not to mention it will look in good condition with new painting, decking and rust eliminated.”

“We’ll get many more years of life out of this bridge,” he said.