All lanes on Interstate 5 south of Tracy remained closed Thursday as crews continued making repairs on a massive sinkhole, Caltrans said.
Detours have been set up, and drivers should expect 15-20-minute delays, officials said. Caltrans estimates that the northbound lanes would reopen at 5 p.m. Friday, and the southbound lanes would reopen at 8 p.m. Saturday.
An investigation revealed that a hole in an abandoned irrigation culvert allowed soil to be displaced, causing the sinkhole, Caltrans said.
A 6-mile detour was set up along eastbound Highway 132 and northbound Highway 33.
The sinkhole was discovered late Tuesday morning by Caltrans workers doing routine maintenance along northbound I-5, just south of Highway 33, Caltrans spokesman Greg Lawson said.
Crews have torn up the asphalt with excavators over the past two days, trying to get to the root of the problem. By Tuesday evening, the hole had grown to three times its original size, officials said.
The hole was about 3 feet in diameter when first spotted Tuesday, and one lane of I-5 was shut down as crews began repairs. But an hour later, it was determined the damage was much more extensive, and both northbound lanes were closed around noon as Caltrans workers used heavy equipment to tear up the road and make repairs, Lawson said.
Southbound lanes were closed Wednesday night to investigate those lanes for possible failure.