The Portage Lake Lift Bridge was built to accomodate 4 lanes of vehicular traffic, 2 tracks of train traffic, as well as lifting clear of anything from pleasure boat to Great Lake freighters.
From the Michigan Department of Transportation website (
visit link) :
This monumental double-deck, vertical lift bridge is the only one of its type in Michigan. It replaced a 1905 steel swing bridge which had in turn replaced an earlier wooden swing bridge. The demands placed on the design of this bridge were quite significant; not only was it necessary to accommodate automobile traffic, railroad and ship traffic also had to be considered. As a result, the vertical lift design was deemed most appropriate. Suspended between two towers, the entire main span rises vertically between them. As long as the towers are built high enough, a vertical-lift bridge can accommodate just about any size ship that needs to pass beneath it.
Moreover, since it is supported at both ends of the main span it is considered sturdy enough to facilitate railroad traffic. The Houghton-Hancock Bridge was designed by Hazelet and Erdal, consulting engineers, Chicago, as a double-deck, vertical-lift structure, with the railroad passing over the lower deck and automobiles across the upper deck. From the beginning, bridge planners stressed the importance on minimizing interruption of automobile traffic flow across the bridge. Hazelet and Erdal solved this problem by designing a railroad deck that could also accommodate cars. When raised to the intermediate, highway level, the railroad deck allowed automobile traffic to continue across the bridge while small- and medium-sized watercraft passed underneath, thus adequately addressing the traffic flow issue.
The bridge opened for automobile traffic in late December 1959, but it was not fully completed until early the following year. At a cost of $11 million, including a federal appropriation of $1.3 million, it was the heaviest lift bridge ever constructed.
The Houghton-Hancock Bridge was formally dedicated with a large celebration on June 25, 1960. Marching bands and troop columns paraded across the bridge, and the jet tankers and fighters flew over the structure.
While the last train crossed the Houghton-Hancock Bridge in the summer of 1982, officially ending over one hundred years of railroad service across the channel, the double deck design is still used in various ways. The vertical-lift span sits in the intermediate level nine months out of the year, thus allowing small to medium-sized pleasure craft access to either side of the bridge: large watercraft rarely use the channel anymore. As a result, automobile traffic crosses on the railroad deck. In the winter, the bridge is lowered and made accessible to snowmobiles and skiers, while automobiles cross on the upper deck.
While every bridge has its problems, the unique design of the Houghton-Hancock Bridge allows for some strangely amusing ones. On June 24, 1960, the day before the official dedication, the steamer J.F. Schoellkopf almost collided with the crossing. Captain Albert Wilhelmy reported that he sounded the whistle signal for the bridge to open, but it never did. Reacting quickly he ordered the engines reversed and dropped anchor. Unfortunately for the people of Hancock, the anchor became entangled in two of six Michigan Bell telephone cables that crossed the bottom of the channel. The steamer ran aground in shallow water, and telephone service was cut off to 1,000 customers in and around Hancock. The bridge operator said he never heard the signal. The steamer was soon cut loose from the cables, towed back into the channel, and continued her journey.
The vertical-lift span did not always operate correctly. During a test of equipment in the spring of 1983, the bridge stalled partway up the tower due to a loss of power. About an hour and a half later the span was once again moving. In the fall of that same year more tension was created when the lift span froze in place. An oncoming steamer was forced to drop anchor and dock to avoid colliding with the structure. After about seventeen minutes the bridge operators got the span moving again. On September 9, 1989, an ironic twist found Joe Sterbenz, a former bridge operator, and his new bride, Joanne, trapped atop the lift span with their wedding party. Joe and Joanne had decided to get married on the raised bridge; a broken hydraulic line stranded them there for a few hours. Despite periodic problems, the bridge has served its purpose well.