History of Sleepy Valley Loop Bridge

Figure 2

Figure 2
Picture 2 of 11

Figure 2: Components of a truss bridge

The Middle River Bridge – Remembered Forever

Town of Lakeside, Douglas County

One humble Wisconsin bridge has had far more than its allotted 15 minutes of fame, thanks to an artist from another land. The road to that renown was long and winding….

Early Pier Type Bridges in Wisconsin

Rivers, streams and creeks were major impediments for early travelers of the Wisconsin landscape. As settlement in the United States expanded during the first half of the nineteenth century, people built bridges to make it easier to cross such barriers.

An early bridge type (Figure 1) utilized piers constructed of cribs typically filled with stones, across which were laid timbers that extended from shore to crib to shore.  Such bridges were not anchored well to the river bottom and were susceptible to washouts and damage from ice floes.

Early Truss Bridges in Wisconsin

Truss bridges were the next idea for spanning a watery obstacle. The genius of the truss bridge was its use of a triangular shape that allowed short sections of material to be combined into a longer, rigid framework. Now builders had a simple way to design, manufacture and erect bridges. Truss bridges could span greater distances, were stronger, and lasted longer than the older types. Major structural elements of a truss included end posts, top chords and bottom chords, all of which enclosed a web containing vertical and diagonal members (Figure 2). Pins or rivets held components together.

Depending on the configuration of their webs, most Wisconsin trusses are categorized as Pratts or Warrens, named after the men who patented them. Such bridges employ two trusses, between which is a traffic deck. With Pony and Overhead trusses, the deck is usually carried along the lower chord, above which the truss projects. Pony trusses are “U” shaped fabrications that have no height constraints and were typically used for crossings of 40 to 90 feet. Overhead trusses have additional structural components above the deck. They allowed crossings of up to 160 feet (Figure 3).

Bridges designed and built in Wisconsin prior to 1911 stand out in history because they were the unique products of bridge building firms such as the Milwaukee Bridge and Iron Works, Wausau Iron Works, Wisconsin Bridge and Iron Company, Milwaukee Bridge Company, and Worden-Allen Company. The year 1911 is significant in the history of Wisconsin bridge building because it marked the creation of the State Highway Commission, which assumed responsibility for designing bridges that were then erected by the private companies just mentioned.

Unique Because it is One of the Last…

The Middle River Bridge in the Town of Lakeside, Douglas County, is unique as one of the last custom designed and constructed bridges in Wisconsin before the State Highway Commission assumed its new responsibilities. It was designed and built in 1910 by the Worden Allen Company.

The Middle River Bridge is a riveted, Warren Pony Truss that is about 79 feet long and 16 feet wide. It is notable for the “W” created in the truss by the arrangement of the structure’s diagonal members. That design is typical for a Warren Pony Truss, and it repeats for the length of the bridge. The structure is further braced by verticals that are tied to each deck beam and extend from the bottom chord immediately above the deck beam to the top chord (Figures 4 & 5).

Becoming Part of a State Trunk Highway…and Then Not

Douglas County’s rural landscape consists largely of forest and field, broken occasionally by river and stream. East of the City of Superior, two of the rivers carving through the picturesque region are the Amnicon and Poplar, between which is the Middle River. All three rivers had to be crossed as the county’s roadways and the state trunk highway system evolved.

One such roadway extended east from Parkdale, a small enclave about seven miles southeast of downtown Superior. That road ran along a section line and originally ended at the Middle River during the later years of the nineteenth century. It is possible that the road never extended east of the river until 1910, when the Middle River Bridge was built. But by 1919, the route was known as the “Lakeside Road,” which continued east of the Middle River to the Brule-Highland Road about one mile west of the Douglas/Bayfield county line (Figure 6).

An element of the state’s evolving highway network, which generally dates to the late 1910s, was the development of the State Trunk Highway (STH) system. STH 13 extended from Bayfield on the north to Wisconsin Dells (originally known as Kilbourn) on the south. By 1920, the northern terminal point for the roadway had been extended from Bayfield west to Port Wing, and by 1925 further west from Port Wing to Superior using the Lakeside Road and the 1910 bridge across the Middle River. The STH 13 designation had also been extended by 1925 from the Wisconsin Dells south to the Wisconsin/Illinois state line at Beloit.

The Middle River Bridge was incorporated into STH 13 through a series of turns and curves, which suggests an effort to avoid building a new bridge at the time the roadway was designated (Figure 7). Not only was the way to the bridge twisty, the structure itself was also only sixteen feet wide. It could not safely handle the growing number of vacationers driving in Northern Wisconsin.

That fact required STH 13 to be rerouted by the mid-1960s. The highway then followed a shallow bow south of the section line along which the original roadway had run – the loop used to incorporate the 1910 bridge notwithstanding. Rerouting meant constructing a new bridge across the Middle River.

The old 1910 bridge played an active role in the development and operation of the State Trunk Highway system for more than 40 years. Before the designation of that system, however, and after the mid-1960s, it largely served the slightly slower-paced local community on what became known as the “Sleepy Valley Loop.” Thus has the bridge been a valued component of Wisconsin’s cultural landscape for 106 years.

The Middle River Bridge as Interpreted and Preserved by an Artist

The Middle River Bridge is historically significant not only because it is one of the last custom designed and constructed bridges in Wisconsin, pre-State Highway Commission. The bridge is also a unique industrial artifact in Wisconsin because it was a recurring element in some of the landscape watercolors and sketches of artist Aarre Niinikorpi (later shortened to Korpi).

Korpi’s Story

Aarre Niinikorpi, born in Finland in 1895, immigrated to the United States with his parents in 1913. He had begun painting in Finland, a pursuit he continued when his family settled in the Poplar vicinity of Douglas County (Figure 8 illustrates Korpi as a young man standing on the top chord of the Middle River Bridge). How long Aarre lived in the Poplar/Town of Lakeside vicinity is uncertain, since he was known to have lived in Duluth in 1921 and 1925. He was identified as a laborer in 1921, married in 1922 and working as a painter in 1925. Aarre and his wife, Hilja, had three children by the time they moved in the late 1920s to Seattle where Aarre continued his painting. He died in 1962.

A Long-Held Love for a Wisconsin Bridge

Despite his move to Seattle, it is apparent from his work that Korpi had a deep respect for the Douglas County landscape in general and the Middle River Bridge in particular. Figures 9, 10 and 11 are images of paintings and sketches he completed, all of which contained images of the bridge.

Wisconsin claimed hundreds of Warren Pony Truss bridges at one time. Only one of those bridges, however, achieved prominence as a recurring subject of artistic interest. Painter Aarre Niinikorpi captured the Middle River Bridge and interpreted it in several of his works, thus assuring that it would be remembered as a unique element in Wisconsin’s artistic landscape.

 Annotated Bibliography

The general information presented in this essay about early bridges in Wisconsin was gleaned from Historic Highway Bridges in Wisconsin, Volume 2, Part 1, prepared and published by WisDOT (1995). That material was supplemented by information compiled over the last approximately 20 years by Heritage Research, Ltd., Menomonee Falls, WI. Much of the information presented about the Middle River Bridge in particular was gleaned from historic Douglas County maps, all of which are digitally available in the “Maps and Atlases in our Collections” component of the WHS website at http://content.wisconsinhistory.org.  A 1938 aerial image of the bridge’s setting, found on the Wisconsin Aerial Image Finder as Image #BRS-5-23, 06 August 1938, was also studied. It is located at http://maps.sco.wisc. edu/WHAIFinder/#. Additional aerial images from 1958 and 1966 were identified and reviewed at http://www.sco.wisc.edu/apcatalog.html. Wisconsin State Highway maps were also used in general, and those from 1920 and 1925 in particular. Finally, a source with supplemental information about the bridge and its description is the Determination of Eligibility (for the National Register of Historic Places), “Middle River Bridge” (P-16-0010), Douglas County, Wisconsin, AHI #133219 (no date), which is on file at the Wisconsin Historical Society, 816 State Street, Madison, WI.  Information on Niinikorpi was obtained from the book The Art of Aarre Korpi, compiled by granddaughter Shirley Vainio (2008). Ms. Vainio also graciously permitted use of several images from her book for this short essay (see Figures 8, 9, 10 & 11). Additional information on the artist was obtained from the 1930 United States Census available on www.ancestry.com.