Flaw in Penasquitos Rail Bridge could cost as much as $15 million

County officials are mired in a dispute over a construction error in the $31 million project to replace the four rail bridges that span the Los Penasquitos Lagoon between Del Mar and La Jolla.

When contractors began work to replace the northernmost of the lagoon’s four wooden bridges last March, a section of the new concrete span settled as much as 10 inches the first time a train passed over it, according to the San Diego Association of Governments, which is running the project along with the North County Transit District (NCTD).

The fix is ongoing. It involves injecting a concrete grout mixture around and under the bridge to permanently reinforce the foundation. The lagoon’s other three bridges did not experience any settling, but SANDAG ordered their retrofit “in an abundance of caution,” said SANDAG spokeswoman Helen Gao.

More than 70 commuter and freight trains run the corridor every day, making it the country’s second-busiest passenger line and San Diego’s only viable freight connection. The bridge has remained open, with the repairs coming during weekend closures over the past year. All four bridges have since been inspected by NCTD, as well as state and federal agencies.

The project remains on course for its fall 2017 completion, but the error is expected to cost between $10 million and $15 million. SANDAG and NCTD paid for the repair work last year rather than bog down the entire project and risk running afoul of state regulations, according to SANDAG Executive Director Gary Gallegos.

“The good news is that the fix is working,” Gallegos told the Del Mar City Council last month. “Now, as always happens, the argument starts over whose fault it is and who should pay for the extra work.”

Skanska USA, the New York-based contractor, has said they do not believe they are to blame.

“We are working with SANDAG to resolve this situation at the Los Penasquitos project. Our primary focus right now is completing the project safely and to the benefit of SANDAG, NCTD and the communities they serve,” a Skanska spokesman said.

SANDAG has hired an outside expert to determine who is at fault. That report is expected this summer. It is the largest bridge construction error SANDAG has had, Gao said.

“We do a ton of work. You try to avoid these kind of situations, but it’s also part of doing major infrastructure projects,” said Del Mar Mayor Terry Sinnott, who is vice chairman of the SANDAG board.

Sinnott does not expect taxpayers to shoulder the costs.

“That’s what insurance is for,” he said.