Holliwell Covered Bridge, Winterset Iowa

Date added: December 14, 2023 Categories: Iowa Covered Bridges Town Lattice Truss

H.P. Jones constructed several covered bridges in the Winterset region. Although his structures were based upon the Town lattice plan popular in New England, Jones added details uniquely his own. Richard S. Allen writes:

"For substructure, he used caisson piers, and he buttressed the sides of his spans with taut guy rods attached to protruding floor beams. Inside, his single-web lattices were usually given the extra reinforcement of auxiliary arches, queenposts, or a combination of the two. Jones' most startling innovation was the virtual elimination of the conventional high-pitched roof. His bridges are tightly weather-boarded to the eaves, and their roofs have only a very Slight pitch...These square tubular covered bridges in Iowa have a unique appearance duplicated only in a few other places in the world".

Madison County's covered bridges are easily the most famous bridges in Iowa. Celebrated in Robert James Waller's best-selling novel, The Bridges of Madison County, and its movie adaptation, the bridges have become emblems of romance and forbidden passion. Tourists from across the United States now make pilgrimages to see the bridges where Robert and Francesca, characters in the novel, met. Forgotten, however, is the transportation role and the technology of these bridges. The Holliwell Bridge, built in 1880, stands as an example of the Madison County bridges and their historical roles.

At six, Madison County has the largest number of remaining covered timber bridges of any county in Iowa. Nineteen covered bridges were erected in the county, most constructed according to standards established by the Madison County Board of Supervisors. In January of 1870, the Board of Supervisors adopted a series of rules governing the construction of bridges in the county. The local paper, the Madisonian, commented: "Our Board of Supervisors has done well in adopting new rules to govern the erection of county bridges. There has been much complaint about the erection of county bridges, as to their stability and make." The supervisors specified that timber lattice trusses be used for all bridges over 40' and that the bridges be covered. Instead of stone abutments, wooden trestles were to form the substructure. In addition, a special committee was formed to evaluate petitions and handle all other bridge matters.

At the time the supervisors were standardizing bridge building in Madison County, the days of the timber bridge were drawing to a close. Production of wrought iron was increasing and iron truss bridges were beginning to appear in Iowa. Madison County would continue to build covered timber bridges until the mid-1880s, when many other counties in Iowa had already turned to iron bridges almost exclusively for bridges of these lengths. Why Madison County persisted in the construction of timber bridges is difficult to pinpoint. Topography, however, seems the most likely answer. Madison County lies in central Iowa, in an area of rolling hills and rivers, which is well-timbered and has a minimum of prairie. The abundant local timber resources and saw mills made these timber bridges inexpensive and most likely contributed to the decision to continue to build large-scale wooden bridges.

The earliest bridges in the United States were simple pile and beam bridges which had serious limits on span or load capacity. The development of timber truss frames allowed for bridges of much greater strength and span, while still using relatively small wooden members. The trusses developed, however, were not based on mathematical calculations, but on the experience of the carpenter-builder.

A number of timber truss types were developed in America during the first few decades of the nineteenth century. Timothy Palmer, Theodore Burr, and Lewis Wernwag all designed early timber trusses, often based on designs developed in the Renaissance. In 1820, Ithiel Town patented his lattice truss. It is constructed with horizontal upper and lower chords and mesh of intersecting diagonals. The diagonals could be made of quite light members and simply bolted into place, which made the truss easy to construct. The web of diagonals gave the truss great rigidity in the vertical plane, but were too flexible under lateral forces. Many hundreds of bridges using the Town lattice were built for use as highway bridges in the nineteenth century.' The Town truss was then superseded by a succession of wood and iron truss designs, leading up to the Pratt and Warren trusses still in use today. The Madison County bridges, however, were constructed using the Town truss which was developed so early in the century.

Covered bridges in Madison County

In Madison County, the North, South, and Middle Rivers formed the most serious impediments to overland travel, but several smaller streams required substantial bridged crossings as well. To bridge the myriad of streams, the county board of supervisors ordered numerous short-span timber pile and kingpost structures built in the 1850s and 1860s. Though inexpensive to erect, most of these spans tended to be structurally suspect and required frequent maintenance to prevent their collapse.

The Holliwell Bridge stands on the site of the first bridge built in Madison County, which was built in the winter of 1854 and 1855. This bridge was part of the mail route and a main pioneer highway. It was washed away in 1876, and the Holliwell Bridge was erected in 1880. With a truss span of 110' and approach spans of 49' and 14' roadway, it is the longest of the Madison County bridges. The bridge uses the Town lattice truss reinforced by a doubled flat arch, a configuration unique to the Holliwell Bridge in the work of Jones and Foster. The upper and lower chords are constructed of two 3 x 13 timbers which are bolted together. The lattice is made up of 2 x 12 timber diagonals. One arch is on each side of the lattice truss with the arches bolted together laterally at regular intervals. The arches are constructed from 6 x 14 timbers. The center top beams of the arch are 39' long and curve from a height of nine feet up to thirteen feet. The end beams, or haunches, are 16' long and arch up from the floor up to meet the center beam at nine feet high. The segments of the arches simply abut each other, with three segments in the haunches and a solid top beam. The bridge is sheathed with lumber and topped with a flat roof, a roof common to the Iowa covered bridges. The bridge was completed in 1880 for $1180.

The first covered bridge in Madison County was built in 1868 by a local contractor, Eli Cox. Cox, with his sons, built several bridges in the county, which were constructed from timber sawn at his mill, and supported by local stone and mortar. Four more covered bridges were built before county standards were established in 1870. A total of nineteen covered bridges were built in the county, six of which survive today. The bridges of H.P. Jones, who was the primary contractor in the late 1870s and early 1880s, have several distinct characteristics, most notably the almost flat roof. This creates a tubular appearance, which is rarely found outside of Madison County. George K. Foster, who worked on the Holliwell Bridge, served as county foreman for bridge construction for ten years.

Madison County

Madison County was first settled in 1846, as a group of men came up from Buchanan County in Missouri. An area of many streams and timber, it was an appealing destination for early settlers.

After 1848, settlers began to stream in from Indiana, Ohio, and states in the east. During the next thirty years, the residents built an effective infrastructure, with a series of sawmills and grist mills, wagon roads, and bridges. The Holliwell Bridge is located in rural Scott Township about four miles from Winterset, the county seat.

The bridges were not noted in the county as important landmarks until 1933. At that time, only ten covered bridges were left in the county. The Madison County Historical Society became involved, and Mrs. Fred Hartsook wrote a complete history which she presented to the County Board of Supervisors. The issue was not resolved, however, until 1950 when the Board of Supervisors decided to preserve the remaining bridges. In 1970, the first Covered Bridge Festival was organized, which became an annual event. The Chamber of Commerce has capitalized on interest in the covered bridges, providing maps, signs, and memorabilia for tourists. With the publication of The Bridges of Madison County, the amount of tourism accelerated and has received yet another boost from the film adaptation.