In response to public concerns over a lengthy construction schedule, the California Department of Transportation has unveiled a trio of designs aimed at drastically shortening the amount of time it will take to replace Point Reyes Station’s 86-year-old Green Bridge, which the agency has deemed substandard for modern safety and accessibility requirements and unlikely to be fixed by retrofitting.
Since March, Caltrans has estimated that replacing the bridge would take two or three years; in the meantime, a temporary one-lane bridge would provide a direct route into town, though the agency estimated up to 30-minute traffic delays on the weekends.
But with the three new “accelerated” construction methods, Caltrans is proposing to cut the build time down to about three months while the original bridge is kept open to traffic. The bridge would only be completely closed during intermittent nighttime closures and about two weeks of full, 24-hour closure for the old bridge to be extricated.
Caltrans will not select the actual design for the bridge until an environmental review is completed, which may not be for at least another year. It is not clear, yet, whether any of the accelerated construction methods will be used for the project, as those methods would also be subject to environmental review.
The rough cost estimate for the project has been pegged at nearly $9 million.
During a public meeting on Oct. 15 at the Dance Palace, Caltrans presented an overview of the three methods, which all involve building the replacement bridge deck and truss either adjacent to the original or off-site and then “sliding” those pieces onto a reconstructed foundation that complies with modern design standards.
The proposed methods could expedite the schedule for three of the four project alternatives that Caltrans has put forth—the short truss bridge, the long truss bridge and the concrete bridge options. But the methods are akin to templates that would be tailored to a specific project once Caltrans chooses a specific design.
The fourth alternative—a suspension bridge that departs greatly from the truss model—could also receive the accelerated treatment and still allow traffic to run while the bridge is being built, but would require a longer construction period than the other three.
According to the project’s environmental manager, Jodi Ketelsen, the accelerated methods were developed to address fears that years of construction would cripple traffic in a town already inundated with weekend tourists. Surrounded by a cadre of Caltrans engineers, Ms. Ketelsen sought to calm those fears by reassuring attendees that the agency had thoroughly reviewed public comments over the last few months—noting that she herself had read each and every comment “two or three times”—and was eager to devise a solution that, while not perfect for everyone, would be satisfactory.
“Hearing from you is exactly what needed to happen early in the process to reflect what you think,” Ms. Ketelsen said. “We’re very cognizant of the high traffic volume you have here. We must balance the design with environmental-impact concerns as well as your need to have a bridge and to maintain traffic flows.”
Yet despite a flood of comments from locals who would prefer the existing bridge be retrofitted rather than removed entirely, Ms. Ketelsen reiterated that Caltrans wants to steer clear of retrofitting. Summarizing a report published online in September, Ms. Ketelsen said that a retrofit would necessitate a potentially three-year construction period, a temporary detour bridge, reassembly of the truss and reinforcement of piers in the creek.
“We do not think that is a good idea right now,” Ms. Ketelsen said at the meeting. “But we are studying it.”
Photos propped on easels at the meeting showed rust eating away at the bridge’s old steel, evidence for Caltrans that the bridge does not meet seismic standards. But several attendees at the meeting said that Caltrans might be misrepresenting the extent of the bridge’s wear and tear, as well as the actual mass of the alternative proposals.
Many even questioned why the bridge needed to be replaced at all.
“These [blueprints] don’t really give the correct impression of what a monster this thing will be,” said Bob Johnston, of Inverness, a retired environmental science and policy professor at the University of California, Davis, whose research focused on urban transportation planning. “Given that there’s no strong evidence of the bridge’s deficiencies, why not hold off on completing [a rebuild] until you’ve done a larger study of Highway One?”
Ms. Ketelsen noted that Caltrans is preparing an updated study on the bridge’s overall structural state that will be released to the public upon completion.
Built in 1929, the Green Bridge—officially known as the Lagunitas Creek Bridge—spans 152 feet and has two 11-foot-wide lanes along with a four-foot-wide sidewalk. According to design standards set by the Caltrans Division of Design, the bridge should be expanded to 12-foot-wide lanes, four-foot-wide shoulders on each side and a minimum six-foot-wide sidewalk. To comply with disability access laws, the agency also says the sidewalk must have wheelchair ramps at each end.
In the first accelerated method, called a “traverse slide-in,” a new bridge would be built alongside the old structure, cutting into the neighboring Point Reyes Animal Hospital’s parking lot. The new foundation’s abutment and caps would be constructed around the old bridge, which would be removed and replaced by a new deck and truss that would be slid onto the new foundation. No piers would be placed in the creek, reducing the impact to sensitive red-legged frog and coho salmon habitats.
The second method, a “longitudinal move-in place,” would be comparable to the first, except that the new bridge’s deck would be put together from pre-cast parts at a nearby, as-yet unspecified, staging area. No piers would be installed in the creek, but would require a large space offsite to build the bridge.
Last, the “pre-cast assembly on-site” method would most similarly reflect the current bridge’s appearance but would create more adverse impacts on the creek. Piles and caps would be installed around the existing piers in the creek, prior to the removal of the old bridge and the placement of pre-cast girders, a deck and a concrete barrier.
All three of these methods would result in a bridge wider, taller and longer than the original—but still trussed, except for the concrete bridge alternative. Though official public comments released last month favored either a retrofit or the short truss bridge, some meeting attendees nodded toward the suspension bridge.
“I don’t think the attitude should be that you have to maintain an existing bridge,” said civil engineer Britt Stitt of Inverness. “It’s unreasonable.”
Ms. Ketelsen added at the meeting that the public may still submit comments on the project to Caltrans, all of which will be read and evaluated even though the official public-input period has passed. A recorded public hearing will be held sometime in the future, with updates on environmental reviews in the interim.