After concrete falls, Caltrans inspecting I-80 overpass in S.F.
Caltrans crews are inspecting an elevated section of Interstate 80 where a chunk of concrete broke off Tuesday night, falling 25 feet onto a street in SoMa.
The stretch of freeway that links the Bay Bridge to the Highway 101 split has dogged city and state officials for years. Officers who manage police parking lots adjacent to the Hall of Justice say that they have found large pieces of debris and bolts on the ground but that their complaints to Caltrans have gone largely unaddressed.
“These are the kind of challenges that we’re facing on a daily basis because of the age of our freeway structures and our bridges,” said Caltrans spokeswoman Lindsey Hart. The section of I-80 that runs over Harriet Street, where the concrete fell, is at least 50 years old, she said. It’s a contemporary of the troubled Richmond-San Rafael Bridge, which is undergoing major joint repair because the outer layer of its deck keeps crumbling.
The fist-size bit that peeled from I-80 on Tuesday may have shaken loose over time, likely
after a car hit that area of the structure, Hart said. She described the incident as a “surface-level spall” — transportation-speak for concrete separating from a steel bar or other surface.
San Francisco police reported it to the California Highway Patrol at about 6 p.m., and CHP officers called Caltrans to inspect the area. A bridge crew that examined the area Tuesday night said the damage didn’t extend beyond one crack, and determined that the structure is safe.
Hart said the agency is constantly performing maintenance on its bridges and freeways, but that it’s fighting the effects of time, increased traffic and deterioration. Much of this infrastructure dates to the 1950s and 1960s, when policymakers had enthusiasm for the interstate highway system and “no sustainable plan” for repairs, Hart said.
Planning and funding aren’t the only challenges. Construction techniques during the 20th century freeway boom were more primitive than they are today, said Andrew Fremier, deputy executive director of operations at the Metropolitan Transportation Commission. Whereas modern bridges and overpasses have shear studs that connect the deck to the floor beams, their 1960s counterparts had a simpler design.
Fremier noted that some of the concrete on the I-80 overpass in SoMa appears to lack steel reinforcement. It’s structurally sound, but “less composite” than a more contemporary structure — and more prone to crack, he said.
“It’s sort of a hanging chad out there with a lot of connectivity,” he said.
Retired San Francisco Police Officer Richard Lee said spalling has been a little-noticed issue at that overpass for years. He’s collected hunks of concrete, bolts, washers and nuts that dropped from I-80 onto the parking lots that line Harrison Street between Sixth and Seventh streets. Many of them are coated in blue paint that matches the other bolts on the freeHarrison way structure.
The police fleet supervisors stow the rubble in a cardboard box, tucked in a basement closet at the Hall of Justice. It includes six bolts and concrete blocks about the size of a toaster, scabbed with rust.
Lee, who left the police department in 2015, began gathering pieces in the early 2000s. He managed the motor pool and parking facilities along Street, where concrete slabs would occasionally fall onto vehicles and smash windows.
It seemed the exterior parts of the structure “were just deteriorating” and chipping away, Lee said. He kept two thick binders of old correspondences with Caltrans and photographs of freeway damage. One, taken in 2008, shows a basketball-size cavity on the side of the overpass.
Records in the Hall of Justice basement show that the sheriff ’s department called Caltrans that year to complain about concrete spattering the parking lot between Sixth and Morris streets. Engineers from the state agency set a date for repairs and “never showed up,” said the email from sheriff ’s department representative Kevin Lyons.
“I was later notified ... that they could not perform the work due to budget issues, and would follow up as soon as they could,” Lyons wrote, adding that he was still waiting for “some type of response.”
Caltrans did intensive maintenance of the I-80 SoMa overpass in 2013, including repairs to the concrete, Hart said. The agency conducts inspections of each of its structures every two years and submits its findings to the Federal Highway Administration.