Bridge 3575 on Ford Parkway over Mississippi River
Bridge number: 3575
Year built: 1925-1927
Engineer: Martin Sigvart Grytbak
Contractor: James O. Heyworth, Inc
Overall length: 1523.6 feet
Overall width: 64.7 feet
Adapted from the National Register of Historic Places nomination form prepared by Robert M. Frame III. The Intercity Bridge was listed on the National Register of Historic Places in 1989.
The Intercity Bridge, also known as the Ford Bridge, is located at Mississippi River mile 847.8 above the Ohio River. At this point the river has a narrow gorge nearly 170 feet deep in loose sandstone rock, with 35 feet of sand, gravel and boulders on the bottom. The setting for the bridge is residential and park land, with several notable exceptions. At the southeast corner of the east approach is the St. Paul plant of the Ford Motor Company. Just south and downstream from the bridge is the upper Mississippi River Lock and Dam No. 1, also known as the Ford or High Dam. At the east end of the dam is the Ford hydroelectric plant. The lock is located at the west end of the dam. The bridge joins the southern neighborhoods of the cities of St. Paul and Minneapolis, Minnesota, linking St. Paul's Ford Parkway on the east bank with Minneapolis’s Minnehaha Park on the west.
Aligned on an east-west axis, the Intercity Bridge is a reinforced concrete, open-spandrel, two-rib, continuous-arch bridge, with an overall structure length of 1,523.6 feet. The three main arches each has two five-centered ribs with a 300-foot span; they are flanked by single arch spans of 139 feet each. The ribs are 32 feet apart, center to center. In all the arch spans, floor beams are supported by twin spandrel columns being uniformly 7 feet 3 inches center to center. On the 300-foot spans, the column pairs are spaced 18 feet 2 inches center to center, while those of the 139 foot spans are 15 feet 9 inches center to center. There are six deck-girder approach spans of varying lengths. The out-out deck width is 64.7 feet, carrying a 50-foot roadway and two 6-foot sidewalks.
All piers, except a few of the smaller approach piers, are on solid sandstone. The two middle river piers being each supported on four cylindrical concrete caissons carried to rock about 70 feet below water level. In the larger piers, the upper body is hollow with 2-foot walls, and was constructed as two units, with the open faces toward each other. The two half piers are tied together at the water line by a heavy wall and at the top by the floor beams. Half-columns corresponding to the spandrel columns face the sides of the piers. An interesting point in the reinforcing is the fact that bids originally were taken on a plan of using five structural-steel ribs in each of the 300-foot arch ribs, but reinforcing bars were found to be considerable cheaper and ultimately were used. AU arch ribs were built on steel centering supported on timber towers. Construction was accomplished using an large and innovative concrete plant on the west bluff and a 15-ton cable way of 1,900-foot span, with movable timber towers 135 feet high. In 1972-1973 the deck was rebuilt and widened.
The Intercity Bridge, spanning the Mississippi River to join the cities of St. Paul and Minneapolis, Minnesota, is historically significant as one of the largest reinforced concrete bridges ever built in Minnesota and is a significant engineering accomplishment. The bridge is an excellent example of the monumental urban, continuous-rib-arch, reinforced-concrete bridges constructed to span the high and scenic Mississippi River bluffs during the early automobile age in the Twin Cities. As such, it is one of the major extant examples of the "golden age" of reinforced concrete, arch-bridge design and construction in Minnesota.
Engineering historian Kenneth Bjork in Saga in Steel and Concrete: Norwegian Engineers in America points to a series of factors that created the special bridges of the great reinforced concrete bridge era between World War I and World War 11 in the Twin Cities. The common transportation obstacle of the high-bluffed Mississippi River, the development of the automobile and the truck and the converging of many highways into the cities placed a heavy burden on early bridges. The result was demanding designs recognizing greater concentrated loadings not only for automobiles and trucks, but support for streetcar traffic. The bridges also resulted in the need for joint, two-city planning and financing in some cases.
With its overall structural length of 1,523.6 feet and its three 300-foot main spans, it is among the largest reinforced concrete bridges ever built in Minnesota and is a significant engineering accomplishment. Notable features in the construction of the bridge were the sinking of the pier caissons and the construction of sheet-pile cofferdams, carried to solid rock 70 feet below water level. The construction-site installation, with its 1,900-foot, 15-ton cableway, large concrete plant and concrete delivery system was innovative. The bridge is also significant as the major work of Norwegian-American engineer Martin Sigvart Grytbak. Although the deck was rebuilt and widened in 1972-1973, the bridge retains full engineering integrity as a monumental, continuous-arch bridge.
The role of the Intercity Bridge in the development of the Highland Park neighborhood at its eastern terminus is an unusual one. It began in an conventional enough manner, being intended to link the area around the massive, new Ford Motor Company plant with Minneapolis and allow Minneapolis residents to have easy access to the Ford works. The Ford complex, with its adjacent hydroelectric plant (Lock and Dam No. 1 had been completed in 1917), had been designed by the architectural firm of Albert Kahn, Inc., and the engineering firm of Stone and Webster. It was built in 1923-1924 and was expected to make that area of St. Paul extremely desirable. As a result, a massive effort was launched to design the inter-city bridge, and an impressive Joint Bridge Committee of politicians and engineers from the two cities was created to shepherd the process, under the chairmanship of the famed Minnesota Commissioner of Highways, Charles M. Babcock.
Although engineering firms nationwide, including J.A.L. Waddell, were interested in designing the bridge, the work went to Martin Sigvart Grytbak, St. Paul bridge engineer, under the general supervision of the two city engineers, George M. Shepard of St. Paul and N.W. Elsberg of Minneapolis. The contractor was James 0. Heyworth, Inc. of Chicago. Thomas Oseth was superintendent of construction and C.R. Hansen was resident engineer for the bridge committee. Construction was commenced in August 1925, the last concrete in the bridge floor was poured in November, 1926. The remaining paving, sidewalks and railing were completed in June, 1927. The bridge was dedicated in July, 1927. The contract cost was $1,324,000, with each city paying half.
The city of St. Paul worked to prepare the amenities for the projected development. Edsel Avenue, the original street connecting with the Ford Bridge, was remade into Ford Parkway in 1928. This complementing the intended park-like setting of the Ford plant and nearby Highland Park (1923-1927). The city also installed and paved neighborhood streets. The development did not follow. It was deterred by the Depression and, ironically, by increased growth in already established Minneapolis neighborhoods across the Mississippi to the west, now easily accessible for Ford workers via the new bridge. Little commercial and residential development occurred on the east side until the World War II period and thereafter, as evidenced in the areas stores and houses that date largely from 1939 and post-1945. Only then did the bridge begin to fulfill its prescribed role instead of its opposite.
The engineer of the bridge, Martin Sigvart Grytbak (ca. 1883-1953), is significant as one of a group of four, major, innovative and influential Norwegian-American engineers that were involved in the design of the great bridges of the Twin Cities (the others are Kristoffer Olsen Oustad, Andreas W. Munster and Frederick William Cappelen). Graduated in 1903 from Trondhjenf's Technical College as a civil engineer, he came to the United States about 1903 and worked as a bridge engineer for the Northern Pacific Railway in St. Paul. He served as bridge engineer for the city of St. Paul from 1913 until after World War II. Not only is the Intercity Bridge considered to be one of the great reinforced concrete-arch bridges in the Twin Cities, but it is the major work of Grytbak. Grytbak's other large work, the 2,100-foot Kellogg Boulevard viaduct built in St. Paul in 1930, has recently been replaced.