From the Historic Bridges of Michigan and Elsewhere web site:
"...it is a large, late example of a riveted plate girder bascule that had its railings replaced with modern railings greatly limiting the bridge's aesthetic value, and showing the value of original railings. This bridge likely had railings similar to those seen on Knight Street Bridge.
This bridge has large deck plate girder approach spans, and features a considerable vertical clearance even in the lowered position, suggesting the original need for a movable bridge here was that large freighters once navigated down the river at least beyond this bridge. The bridge still raises for sailboats, which need a little more clearance that the lowered bridge provides. An interesting comparison is that this bridge when closed, does not offer much less in the way of clearance than the Jefferson Street Bridge in Joliet, Illinois in the raised position. The Blossomland Bridge also shares a characteristic with the Joliet bridges in that it is a rare example of the Scherzer Rolling Lift design of bascule bridge. The structure, regardless of its modifications, is still historically significant for using this Scherzer Rolling Lift design.
Information and Findings From MDOT
The Blossomland Bridge is eligible for the National Register as an example of a rare bridge type, the Scherzer rolling-lift bascule, and for its design by the nationally prominent Chicago engineering firm Hazelet and Erdal.
In the early 1940s, the state highway department decided to relocate US-31, now M-63, to relieve traffic congestion between St. Joseph and Benton Harbor. The problem was compounded by an old moveable bridge on US-31 that frequently broke down during peak summer traffic. Plans called for a new bridge at the St. Joseph River, which carried Lake Michigan steamboats into the St. Joseph harbor. A bascule design was selected to accommodate the river traffic.
During this same period, the department erected a bascule bridge over the Cheboygan River in Cheboygan and was developing plans for similar bridges at Charlevoix and Houghton.
World War II stopped virtually all bridge construction in the state. Even after the war, shortages of steel and cement hampered construction into the late 1940s. Despite these constraints, though, the state highway department made the Blossomland Bridge one of its first major projects after the war ended. The department's Twenty-first Biennial Report published in 1946 noted that "among important out-state projects, further progress was made in developing the detail design of the bascule bridge across the St. Joseph River."
The bascule design was actually generated by consulting engineers Hazelet and Erdal since the department was short-handed from the war and did not, in any event, have the in-house expertise to design a moveable structure. Established in Chicago in 1936, Hazelet and Erdal was a successor to the Scherzer Rolling Lift Bridge Company, a pioneer in bascule design. Rolling lifts, along with trunnion and roller-bearing bascules, were the most popular bascule designs developed in the late nineteenth and early twentieth centuries. With a trunnion bascule, one end of the leaf pivots on a fixed axis. The leaf's rotating axis is also fixed on a roller-bearing lift, but there is no trunnion: instead, the leaf's curved end moves on rollers in a circular track. On a rolling lift, the leaf's curved end rolls away from the river channel on a horizontal track. Engineers patented a number of variations on these basic designs. Scherzer's rolling-lift features a counterweight that keeps the leaf in balance in any position, hence requiring very little equipment to operate.
The design for St. Joseph's Scherzer rolling-lift was apparently finished by the end of 1946. Also, the highway department had obtained financial aid from the federal government, and had reached an understanding with the New York Central and Pere Marquette Railroads regarding the tracks over which the bridge would pass. In December 1946, State Highway Commissioner Charles Ziegler requested bids for the bridge's construction. When the bids were opened 9 January 1947, W. J. Meagher and Sons of Bay City was selected as general contractor with a bid of $747,497. The company was also responsible for paving the south approach. The contract for supplying and erecting the bridge steel went to the American Bridge Company for $512,240. With extras of about $75,000, the total cost of the bridge was over $1.3 million. The north approaches were another $247,520. Louis Garavaglia from Center Line was awarded a $164,615 contract for grading, with the remaining $82,905 going to Carl Goodwin and Sons from Allegan for paving.
The construction continued into 1948. In April, a photograph on the cover of Michigan Roads and Construction showed steel being placed on the approach spans. The completed structure graced the front of the publication's 4 November issue. An accompanying article reported that it was "the largest bridge ever built under the auspices of the State Highway Department." Dedication ceremonies on 27 October included a banquet, parade, and fireworks. Commissioner Ziegler was the guest of honor at the ribbon-cutting ceremony.