The pieces, which will connect to the foundation of the bridge, are expected to arrive in the Port of Oakland Friday or Saturday after leaving last month from Shanghai, China, according to Caltrans spokesman Bart Ney.
The four shafts being shipped are about 150 feet tall and each weigh about 1,433 tons, Ney said.
"These are the first parts of the signature portion of the new bridge," he said. "It marks a big milestone for our job."
After the pieces arrive in Oakland, they will be inspected and moved on a barge to the construction site about two weeks later, Ney said.
Deck sections of the bridge are already in place after arriving in the Bay Area from China in January. A dozen deck sections are in place, and more are scheduled to arrive from China in the coming weeks and months.
The new eastern span of the bridge is scheduled to open by the end of 2013, he said.