That’s why Mr. Kenagy was there: to oversee the replacement of the Gerald Desmond Bridge, a $1.47 billion construction project that’s been underway since 2013 and is set to be complete in the middle of next year.

“We’re in the homestretch now,” he said this week.

The original Gerald Desmond Bridge, which carries the 710 freeway from downtown Long Beach over the port’s inner harbor to Terminal Island, was designed and built in the 1960s, before containerization had fully transformed shipping. Over its years of use, it has become functionally obsolete, officials said — even as trucks continue to rumble across, bringing 15 percent of the nation’s incoming waterborne cargo.

The replacement bridge will expand that capacity. It’s just one part of a $4 billion, 10-year port improvement plan and includes a designated bike and pedestrian path with scenic overlooks.

Mr. Kenagy served as our primary tour guide. While we took an elevator up and up, to the top of one of the towers along the bridge’s length, he explained that some of the bridge’s most innovative features were actually built into its foundation, which extends 17 stories underground.