Demolition of Bay Bridge's old eastern span reaches milestone

SAN FRANCISCO (KGO) -- The demolition of the old eastern span of the Bay Bridge reached a milestone on Thursday -- a major section weighing about 5 million pounds is being lowered down to the San Francisco Bay.

WATCH VIDEO: Largest remaining pier in eastern span of old Bay Bridge demolished

The trusses are those sections between the towers that you used to drive on. Crews have removed the asphalt. The only thing left is steel. Officials say bringing the trusses down is a delicate process.

"Because of the leaning aspect of the towers, all of that is being considered on a step by step basis and that's what the contractors are assessing as to how how slowly or quickly this should happen," said Bay Bridge spokesperson Leah Robinson-Leach. "It's approximately about 25 feet by hour."

An animation shows what they need to do. They have to secure the truss by jacks, level it and then lower it. Two barges will be waiting below to accept it then transport it to Pier 7 in Oakland. Since it will not happen as fast as the video shows, they aren't worried about drivers slowing down to watch.

"It is such a slow process, it is not like a six second implosion where it's very visible in that way," said Robinson-Leach. "It is so slow it will not necessarily be obvious to a passing motorist."

CALTRANS VIDEO: Old Bay Bridge Pier E3 timelapse and implosion

Crews are aware of the significance of this operation.

"We are taking down a huge piece of bay history," said Robinson-Leach. "So it has sentimental value. We have large number of the public that contacts us and shares with us their experience. They have family that worked on erecting old bridge so it is sentimental aspect to this and we are careful to recognize that,"

Caltrans will provide a livestream of the work. Click here to check it out. It will be up around noon on Thursday. Robinson-Leach says the best time to start watching is probably mid-morning on Friday. But it could change, so keep checking in.