PALO ALTO, Calif. (KTVU) - For most of the morning and early afternoon, crews used hammers to chip away, and knock down damaged portions of concrete that surrounded exposed rebar.
The fear was that a loose piece, part of a 27-foot-long crack, would fall and strike a vehicle passing at 60 miles per hour
"It could obviously dent the car or penetrate a window and strike people in the car," said Redwood City CHP officer Christopher Benavidez. "So that's why it's a concern."
The damage was done just before 11 o'clock Thursday night.
A Caltrans subcontractor driving a dump truck dropped off a load of asphalt at a nearby paving construction site.
The driver left the area with container portion of the truck up.
When he went under the Embarcadero overpass at Highway-101, the container hit it and became wedged, causing a 27-foot-crack in the span.
The driver suffered head and facial injuries and was rushed to a nearby hospital.
This afternoon, officials said the damage to the span was worse than first thought.
A hole was knocked into a steel support girder above the far left lane, in addition to broken concrete and damaged rebar.
Caltrans executives say the fix is similar to a dentist filling a cavity.
"Basically just putting in fresh concrete and fresh rebar, if any of that has been damaged," said Bob Haus.
"It’s a standard structure— steel rebar in a steel cage, with concrete set around it, so replacing the part that's been damaged."
A repair job that could have been completed tonight, may take several days to do.
Officials say the girder must be replaced, not repaired. To help prevent further cracking, traffic on the overpass itself is limited to one lane in the westbound direction.
In the meantime, at least one land of southbound 101 at Embarcadero will remain closed, funneling the flow of traffic to no more than three lanes.
There isn't a time frame for when the job will be completed, but it won't start until after the commute at the earliest.
And that's if Caltrans can get the repair materials here.
As for the cost, Caltrans says the final CHP report will dictate which insurance company picks up the bill.