Standing atop a column that will soon support a new bridge over the Petaluma River, Jeffrey Kress reached up, touched the underside of the existing span and felt the vibrations of thousands of motorists zipping along Highway 101 unaware of the work taking place just a few feet below the road.
Constructing a major bridge in the exact footprint of an existing one without disrupting road, rail or river traffic is a highly complicated dance, one that Kress, a senior bridge engineer at Caltrans, and his colleagues have been choreographing for months.
They are overseeing efforts to swap out the 60-year-old twin two-lane spans over the river with a modern, six-lane, $130 million bridge.
Petaluma River Bridge Construction
Next week, the work finally will crest the top of the roadway, making the project — the most expensive single part of the $1.2 billion, 38-mile Windsor-to-Novato Highway 101 widening project — very visible to the passing observer, Kress said.
“Right now, drivers can see the top of a crane, but they can't see anything happening below. They don't know we're building a whole new bridge right under two existing bridges,” he said. “Once we start setting girders, people are going to be very aware.”
Starting on the night of May 27, contractor C.C. Myers will use a huge, 300-foot-tall crane to carry the first of 99 concrete girders, each weighing 90 tons, into place to form the new bridge. Drivers can expect nighttime delays and detours during the current phase of work, through mid-June.
The activity on the span is part of a group of large public works projects that, together, represent the most significant transformation to the North Bay transportation landscape in a generation.
The projects will widen highway segments, prepare train tracks for commuter service and dredge the Petaluma River for improved nautical navigation.
They aim to reshape the busy Highway 101 corridor to ease commuter gridlock, expand transit connections for local businesses and residents and help move goods through Sonoma County.