Portage Lake Lift Bridge recognized as historic landmark

HOUGHTON, Mich. – The Portage Lake Lift Bridge between Houghton and Hancock was officially dedicated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers (ASCE) on June 17.

At a public ceremony Friday kicking off the annual BridgeFest, commemorative plaques were presented to officials from the Michigan Department of Transportation (MDOT), which were then given to the cities of Houghton and Hancock for public display on each side of the bridge.

"It's really a big, big achievement for not just the community but for MDOT and the state of Michigan as a whole," said State Transportation Director Paul C. Ajegba. "This bridge was built in 1959 - no computers, all the calculations were done by hand - the heaviest lift bridge in the world at the time."

Two Michigan Technological University (MTU) students and their professor were instrumental in getting recognition for the bridge. Tess Ahlborn, professor of civil, environmental, and geospatial engineering at MTU, and her former students Michael Prast and Emma Beachy, who both graduated in 2019, nominated the bridge and did the research, interviews, and documentation necessary to make it a reality. Officially named a State Historic Landmark in summer 2019, the lift bridge was recognized by the ASCE on the national level later that year. The public dedication was planned for summer 2020 but was delayed due to the COVID-19 pandemic.

"It's a local landmark, right? It's part of the culture here, and it had a really big impact in terms of the movement of mining goods when it was first built and then the movement of people and goods between the towns of Houghton and Hancock," said Beachy. "From a civil engineering perspective, it's a double deck vertical lift bridge, which is really unusual. It has this really unique way that it uses its lift span, so it has this intermediate position that lets it be open to a lot of marine traffic at the same time that it's open to a lot of vehicle traffic. And so, it's a really efficient way to use this really unique kind of bridge."

MDOT has produced a video news release about the award ceremony, available on its YouTube channel.

Construction of the bridge began in winter 1957. It took a little more than two years of continuous activity to complete the project, with crews working through the harsh winters of the Keweenaw Peninsula.

The design of the lift bridge had to meet a difficult challenge: accommodating the automobile, rail, and water traffic that converge between the communities of Houghton and Hancock. Designers came up with a double-deck bridge with the unique ability to be parked in an intermediate raised position. With the lower deck raised to street level, the bridge has a clearance of 35 feet for the waterway, allowing smaller boats to pass without a lift. 

In designing the Portage Lake Bridge to carry heavy loads on both decks concurrently, the lift bridge had the heaviest lift span in the world at 4,584,000 pounds and spanning 260 feet.

The bridge’s original purpose was to provide a connection between the Keweenaw Peninsula and the mainland. It was a critical link for efficiently moving billions of pounds of copper mined from peninsula. This region, cut off from the rest of the country by the canal, provided the nation with native copper, which played a role in the U.S.'s industrial and technological advancement from the mid-1800s to mid-1900s. 

Today, the lift bridge continues to fulfill that mission as the only land crossing over the Portage Canal, seeing an average of more than 25,000 vehicles per day. The bridge is now an iconic, historic landmark for the region, but it’s more than that. The bridge remains a critical link between the mainland and the Keweenaw Peninsula, an island with more than 21,000 inhabitants, a regional airport and two hospitals.

"I would like to just thank MDOT for maintaining the bridge and for keeping in good performance," said Tom D’Arcy, one of the original designerengineers of the bridge. "I'm so happy to see the local community appreciate the bridge and appreciate my work."

At the ceremony, D’Arcy read from a poem he penned about the bridge:

So, here's to our bridge standing so tall, performing so well - better than most.
Our pride in you is like those of our family: performing so well so we can boast.
I really don't know if bridges have a soul and a heart.
But, if they do, you set an example of your love for this land, never letting it part.

ASCE’s Historic Civil Engineering Landmark Program recognizes historically significant local, national, and international civil engineering projects, structures, and sites. More than 200 markers around the world sponsored by the ASCE recognize these sites.

An historic MDOT documentary on the lift bridge's original construction has recently been digitized and restored, also available online at MDOT's YouTube channel.

The Portage Lake Lift Bridge was honored as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers (ASCE) at a ceremony Friday, June 17. At the presentation of memorial plaques (from left) are Hancock Mayor Paul LaBine; Michigan State Transportation Director Paul C. Ajegba; Houghton Clerk Ann Vollrath; ASCE Michigan section president Andrew Rossell; MDOT Ishpeming Transportation Service Center construction engineer Alan Anderson; one of the original design engineers of the bridge, Tom D'Arcy; and ASCE society president Dennis Truax. (MDOT photo)