SAN FRANCISCO (KTVU) – Caltrans officials said Thursday they are unclear what caused one fire earlier this week on the Bay Bridge, after initially believing that two were caused by a road flare.
Caltrans spokeswoman Leah Robinson-Leach said they can only confirm a road flare caused the second fire that broke out around noon on Wednesday.
“We are not at that point to absolutely know that the Monday night fire was caused by a flare,” she said.
According to Robinson-Leach, crews have been told to avoid placing road flares near expansion joints.
There are approximately 22 expansion joints on the new eastern span of the bridge, four of which are covered with a rubber seal at the base of the self-anchored suspension. The other expansion joints are covered by steel bars.
A spokesperson for the California Highway Patrol said they were given a similar directive on Thursday about being mindful of where road flares are placed and to avoid expansion joints.
KTVU asked Robinson-Leach why engineers would place rubber seals on the bridge if they are flammable.
“There’s been a great deal of engineering and the bridge has actually been overly designed,” she said. “It’s the highest innovation of bridge engineering.”
All Bay Area bridges have similar expansion joints, mostly made of steel plates or bars, which are meant to protect the bridge in the event of an earthquake.
“The type of seal that’s used is normal for the bridge,” Robinson-Leach said of the rubber seal. “We are looking at the fire resistance with the manufacturer with respect to the seal.”
She said the public’s safety remains Caltrans’s top priority and it’s why they’re taking measure to ensure another fire doesn’t happen again.
“The bridge is absolutely safe,” she added.
There is still no word yet on when the damaged rubber seal and joint will be replaced.