About 136 trucks delivered enough concrete to fill a nearly 2,000 foot-long section on the Oakland side of the new bridge, according to a statement from the Bay Bridge Seismic Safety Projects, which is comprised of Caltrans, the Bay Area Toll Authority and the California Transportation Commission.
Now that the concrete has been poured, it will undergo a weeklong "water curing" process that will prep the concrete for further construction.
Transportation officials say the massive concrete pour was more than two years in the making.
Because of detours put in place two years ago, construction crews have been able to ensure that both eastbound and westbound lanes of the new bridge will open to traffic at the same time.
Under the original building plan, the eastbound lanes would have been finished up to six months after the westbound portion opened to traffic, according to transportation officials.
Colorado-based Firestone, Inc. is the main contractor working on the easternmost part of the new bridge.
The new bridge is set to open to traffic in September.