RICHMOND -- After days scanning the earth surrounding the closed Dornan Tunnel with radar, engineers are optimistic they won't find other areas of failing concrete and voids surrounding the nearly 100-year-old tunnel.
"So far they've found nothing else," said Melissa Tigbao, the city's project manager. "By next week we'll have more information for the structural engineers to develop a plan to remedy the problem."
The investigation has been ongoing since Feb. 8, when workers for TPA Construction Inc., a contractor hired by the city to shore up leaks in the tunnel and improve drainage, discovered an area on top of the inside of the tunnel that showed "significant concrete failure," including flakes of concrete falling to the road below.
When they looked closer, workers discovered a hollow area 12 feet long by 10 feet wide and 4 to 6 feet deep above the concrete tunnel, which had deteriorated to as thin as 4 inches in some spots.
The discovery shut down the tunnel until at least April 30 and temporarily halted work begun in January.
Along with structural issues, the situation also raises new political questions as speculation swirls about how much the unforeseen repairs may cost the city.
"If we don't find any more large voids, we should be able to reopen on schedule," said Zak Conway, project engineer from Swinerton Inc., one of several contractors on the project. "But the void we've already found will be an extra cost
Conway said a "rough estimate" to fill the void with concrete or do repairs to the failing area of the tunnel would be "up to around $100,000," but he cautioned that there was still more information to gather. Engineers have now scanned about half the tunnel, city officials said.
Conway added that there was never danger of the mountain crushing the tunnel, only of concrete slabs chipping and falling.
"They blasted it through solid rock and poured concrete," Conway said. "It's strong."
Any new costs will likely meet political resistance. The initial work narrowly passed the City Council in October, despite more than half the $820,000 in costs being funded by a federal Department of Transportation grant.
"We paid for an inspection of the tunnel and they told us what the project would cost," said Councilman Corky Boozé, who voted against the tunnel repairs. "Now that they got the contract these contractors find that they need to do more work and it's going to cost more taxpayer money. I don't know what this game is but I want it stopped."
Tigbao said structural engineers from another contractor, The Crosby Group, assessed the tunnel last year before making recommendations, but their "investigations included testing along the sides of the tunnel in order to design the drainage system."
"It was in their scope to go along the sides (of the tunnel), and they may have not touched or looked at the top," Tigbao said. "But I wouldn't point a finger at them."
While the tunnel is closed, motorists and cyclists must detour via Washington Avenue to Western Drive or via Canal Boulevard and Seacliff Drive, which run through the Brickyard Cove and Seacliff neighborhoods. Point Richmond residents have already expressed concerns over increased traffic on Washington Avenue, a narrow residential street through the quaint historic district.
Councilman Tom Butt, a Point Richmond resident, said the city can afford to spend more to ensure the tunnel is able to reopen and be safe.
"We are going to take the money we saved by not having a (special) election and spend it on the tunnel," Butt said, referring to the council's recent decision to appoint Jael Myrick rather than spend an estimated $200,000 to hold a June election to fill a council vacancy.
Butt said Boozé, his council rival, "probably wants to shut the tunnel down forever," adding "That would cause a firestorm of community protest."