At high tide, 151 feet of empty air lies between the waters of the Kill Van Kull and the steel deck of the Bayonne Bridge. They may be the most consequential 151 feet in North America.

The kill, a narrow tidal strait between Staten Island and Bayonne, New Jersey, is one of the busiest shipping channels in the country. When the Bayonne Bridge opened, in 1931 (below) , those 151 feet easily accommodated the largest vessels.

But today, even ships that are by modern standards modestly sized, like the Kaethe P (below), can barely squeeze through. And a new, larger generation of ships, due to sail next year, won’t fit at all.

If the bridge remained as is, the port—by far the most important on North America’s Atlantic coast, handling more than $200 billion of cargo each year—would risk obsolescence as other East Coast ports welcomed the bigger, more modern vessels. So the Port Authority of New York and New Jersey, which built the Bayonne, is raising it. The roadway will be elevated 64 feet, to 215 feet above the Kill Van Kull—more than enough to let the big new ships pass beneath.

Joann Papageorgis, the program director, and Dennis Stabile, the program manager, describe the lift as consisting of two distinct components. First, each end of the bridge is getting a slightly steeper approach. Precast concrete columns, shipped from Virginia, have been anchored to the bedrock.

Two custom-made gantry cranes , each 500 feet long and 40 feet across, are now lifting precast sections of ramp into place atop the columns.

Meanwhile, to strengthen the arch in order to support heavier traffic (and maybe, one day, light-rail tracks), additional steel is being installed over the original structure (below). When that’s completed, the new, higher roadway will be hung, two lanes at a time. After the first two lanes are in place, in mid-2016, the original roadway will be removed entirely, allowing the new, larger ships to pass underneath. (At which point, Papageorgis jokes, “Dennis and I can go out and have a glass of wine.”)

The five-year, $1.3 billion project is by far the most ambitious such bridge modification to date. Among other challenges, the road-raising must contend with tight confines—both because the bridge is to remain open to traffic throughout construction and because homes lie less than 20 feet from the work site. Watching the Port Authority’s animation of the project (available online) is like watching a game of Twister played by cranes and concrete blocks.

The project is part of a global transformation. In 2006, the citizens of Panama voted to build a wider and longer set of locks on their famous canal. The dimensions of these locks defined the New Panamax (below, bottom), which will be able to carry about 12,000 standard-size shipping containers. Existing Panamax ships (below, top), like the Kaethe P, can carry just 5,000. The resulting economies of scale should, in theory, encourage more shipping from China—already one of the United States’ largest trade partners—and other Asian countries.

And so ports and municipalities along the East Coast—Miami, Savannah, Charleston, Baltimore, and New York–New Jersey—are spending billions to prepare for the new ships, by deepening channels and installing enormous cargo cranes. Panama’s new locks will likely open next year, and New Panamax ships will sail soon after. The Bayonne Bridge, Papageorgis says, will be ready: “If it gets through the Panama Canal, it’ll be able to come to us.”

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