RICHMOND -- A section of El Portal Drive near the Interstate 80 offramp reopened Friday, more than 2½ years after heavy rains opened a mammoth sinkhole on nearby Via Verdi.

Vehicle access from the freeway to San Pablo Dam Road had been cut off since May so construction crews could replace the damaged culvert.

The $12 million Via Verdi repair project resulted from the collapse of a massive metal storm drain pipe on April 15, 2010, during heavy rains. The 30-foot-deep sinkhole swallowed cars, but no one was hurt.

The final phase of the project included the construction of a new 3,000-cubic-yard concrete storm drain.

The massive project required not only road closures but diverting San Pablo Creek.

The new box concrete culvert is about 400 feet long by 22 feet wide by 15 feet tall, according to Tawfic Halaby, Richmond's associate civil engineer.

"Now that the culvert is in place and the earth has been built back up, (we are able) to open up the southern half of the roadway to through traffic, with one travel lane in each direction," Halaby wrote in an email Friday.

While El Portal Drive's reopening will ease congestion for commuters, crews must still finish under-grounding utilities, reconstructing Via Verdi -- which provides access to an apartment complex -- and resloping the hillside.

Work is scheduled to be completed by spring 2013.

"Rebuilding this has been an engineering feat," county Supervisor John Gioia, of Richmond, said in a prepared statement. "But the community's really happy to see the road reopened."

Contact Robert Rogers at 510-262-2726 and follow him at Twitter.com/roberthrogers.