By Neal Buccino, Special to Portfolio

Photos by the Port Authority’s Mike Dombrowski

Six centuries ago, engineers in the Inka Empire designed cable bridges long enough to span Peru’s mountain gorges and durable enough to withstand earthquakes.

They wove these bridges out of grass and made them remarkably strong, using principles of physics that today support modern-day marvels such as the George Washington Bridge and Bayonne Bridge.

Next year, the Smithsonian’s National Museum of the American Indian-New York — located in the historic Alexander Hamilton U.S. Custom House in Lower Manhattan — will help students learn about these technological achievements, with a little help from the Port Authority. The agency recently donated to the museum a five-foot length of steel suspender rope from the Bayonne Bridge, one of the 152 original steel ropes that held up its 9,800-ton roadway for 85 years.

Made of more than 200 tightly wrapped steel wires, the suspender rope was removed as part of the Port Authority’s “Raise the Roadway” project, which will permit ultra-large container ships to navigate the Kill van Kull.

The Port Authority’s Roger Prince and Kevin Gover with the five-foot section of donated Bayonne Bridge suspender rope.

It will live on in the museum’s imagiNATIONS Activity Center, expected to debut next April. There, the steel rope (tensile strength: 950,000 pounds) will be displayed next to a grass rope with a tensile strength of 4,000 pounds, of the kind still used in Peru’s last remaining rope bridge, the Q’eswachaka.

Nearby, suspended from the ceiling, visitors will see a 26-foot section of an actual rope bridge built by the modern-day keepers of the Q’eswachaka Bridge. The 4,500-square-foot imagiNATIONS Activity Center will include interactive exhibits on Native American innovations across fields as varied as engineering and architecture, medicine and nutrition.

The Bayonne Bridge suspender rope had to be tested for lead and other contaminants before donation. This swab test was performed by the Smithsonian’s Mike Hunt.

The exhibit will help visiting students understand how, with flexible strands of any material twisted and braided together, a rope much stronger than its component parts can be created.

“Showcasing a section of Bayonne Bridge steel cable alongside an Inka bridge rope made of ichu grass highlights the continuity in engineering concepts the Inka and their descendants have used for millennia,” said Kevin Gover, director of the National Museum of the American Indian. “Native innovation is everywhere in modern life and this is one instance where we can directly point to it and provide that ‘a-ha’ moment.”

“This steel rope carries all the history of the Bayonne Bridge, which in its day was the longest steel arch bridge in the world,” said Roger Prince, the Port Authority’s Deputy Director of Tunnels, Bridges and Terminals. “We hope it provides an educational experience for everyone who visits the imagiNATIONS Center.”

The museum’s Gerard Breen shows off a model of the imagiNATIONS Activity Center, where the steel suspender rope will be displayed.