RICHMOND -- After months of repairs, a tunnel that serves as the main road to Miller Knox Regional Shoreline and the Point Richmond community will reopen to cars, bikes and pedestrians on Friday.

The 101-year-old Dornan Drive Tunnel closed in February after workers found cracks in the concrete lining of the tunnel's inner surface. Richmond's engineering staff, and a hired construction team, later discovered a room-sized void above the tunnel's concrete lining.

Workers probably failed to fill this gap during the original 1912 construction, said Melissa Tigbao, Richmond's project engineer for the tunnel repair. As a result, the tunnel lining was just 2 inches thick in areas, with no structural reinforcement.

The Dornan Drive Tunnel is closed to all traffic in Richmond, Calif. on Monday, Feb. 11, 2013. Crews discovered significant concrete failure in the tunnel
The Dornan Drive Tunnel is closed to all traffic in Richmond, Calif. on Monday, Feb. 11, 2013. Crews discovered significant concrete failure in the tunnel wall, prompting the closure. (Kristopher Skinner/Staff Archives) ( Kristopher Skinner )

"We had residents feeling inconvenienced due to the repairs. But safety is our number-one priority, it overrides everything," said Tigbao.

The city filled the 163-square-foot void with concrete grout and reinforced the structure with a 1-foot-thick concrete band wrapped above the tunnel's inner lining, said Tigbao.

The city financed this near million-dollar repair with grants from Caltrans and the Contra Costa Transportation Authority.

This article was produced by RichmondConfidential.org, a nonprofit news service based in the UC Berkeley Graduate School of Journalism.