Engineers are scrutinizing Healdsburg's historic Russian River bridge to determine whether it can be saved or needs replacing.
Last week, they began inspecting the rusted, 89-year-old span to determine how much weight it can bear safely.
"This is about finding out the truth about the bridge," said Healdsburg resident Mel Amato, the electrical engineer who questioned the poor grade Caltrans attached to the bridge before state officials were persuaded to revise it.
The old Caltrans report virtually doomed the bridge and gave it the lowest rating of any in the county. But that was revised dramatically two years ago after Amato did his own measurements and discovered the agency made a calculation error involving the location of the pins on the truss connections.
Following a correction, Caltrans acknowledged the vintage, steel bridge can carry all legal loads, even three-axle trucks, semi-trucks and trailers.
The revised rating boosted the spirits of residents who want to preserve the 1921 span, rather than having it replaced by a wider, but less aesthetically pleasing, "cast-in-place, pre-stressed, box-girder concrete structure."
Known as the Healdsburg Avenue, or Memorial Beach Bridge, it was once the main southern gateway to town, before the Highway 101 freeway was built to the west.
But the old bridge, cherished by many, is still considered vulnerable to earthquakes and erosion damage to the center pier that could undermine the stability of its wooden pilings.
The city has kept the weight restrictions in place because of its two narrow lanes.
The location of the pins on the trusses is one item being verified, along with the weight of the bridge, the thickness of the sidewalk and concrete road deck.
"We're also testing for lead in the paint. We're looking for severe areas of corrosion where material is loose," said Todd Goolkasian, lead bridge engineer for Cornerstone Structural Engineering group.
Goolkasian was supervising crew members who climbed up alongside the bridge as vehicle traffic was alternately halted in each direction and funneled into one lane to allow the work to proceed.
The effort is the first of a three-phased, $2.8 million contract approved earlier this month by the Healdsburg City Council.
The contract awarded to Omni Means Ltd. of Roseville, a transportation and civil engineering firm, is intended to conclusively determine whether the bridge should be replaced or rehabilitated, and also identify the environmental impacts and funding for each alternative.
Another possibility is relocating the Memorial Beach Bridge slightly downstream from a new span, and dedicating it to bicycles and pedestrians, although the cost could be prohibitive.
Consultants say they are taking a "blank slate approach" without favoring one alternative.
The $2.8 million contract is expected to be funded almost entirely with state and federal grants and no money from the city's general fund.
By early fall, city officials hope to have a recommendation on the "preferred alternative." Before that occurs, there will be community meetings to discuss the options and allow public comment. The first is scheduled from 5:30 to 8:30 p.m. March 31 at the Healdsburg Senior Center.
For Amato, the ongoing effort has made him "cautiously optimistic" the bridge will be saved. He still believes, however, that Caltrans has not given the bridge a high enough rating. If it makes the correct calculations, he said, the bridge will qualify only for rehabilitation and not replacement, under federal funding guidelines.
Part of the intent of last week's inspection was to get a third party independent assessment, said City Public Works Director Mike Kirn, who credits Amato with "identifying blunders Caltrans had made."
Funding for a project is still uncertain. Estimates to rehabilitate the bridge were estimated a few years ago at $13 million. Replacing the bridge with a modern, wider one was estimated at $23 million.
"This bridge, for its purposes, is just fine. It needs maintenance. I think it's structurally sound, based on Mel's measurements," said Martin Dreiling, an architect and planner who was watching along with Amato as the inspectors worked.
Dreiling said an issue to consider is that the Memorial Beach Bridge is one of the safest ways to cross the river, because its narrow width slows down traffic.
In the summer, he said, families and cyclists who use it could be vulnerable to fast-moving vehicles that a new span would bring.
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