Covered Bridge History and Development

The American covered bridge and the open style of timber span are the. products of centuries of development. The idea of erecting a canopy over bridges is believed to have originated in Biblical times when their builders added these embellishments for purely decorative purposes. One of the earliest references to a wooden bridge was the description of Julius Caesar's bridging of the Rhine in 55 B.C. History recorded covered bridges centuries later in early Germany and Switzerland where medieval engineers saw some practical use for the rooftops as a protection against the weather and generally damp conditions which would attack the main structure of their spans.'

Among the first covered bridges in history were two famous medieval spans, the Chapel bridge, and the "Dance of Death" bridge built in Lucerne, Switzerland in 1333. Both were covered timber bridges.

Centuries later two Swiss carpenters, Johannes and Han Ulrich contributed two more famous timber bridges - the Reichenau and Shaffhausen, spans over the Rhine during the years 1756 and 1758. By that time there had been hundreds of covered bridges built in Europe, the greatest number being found in Switzerland, Austria and Germany.

From Europe the idea of covered bridges was brought to America by early pioneer carpenters near the turn of the nineteenth century. The emigrating carpenters found an abundance of timber in the virgin forests of the New World and at one time there was a period of construction of covered bridges which surpassed any such projects in the European countries.

Construction of stone bridges also took place in many parts of the East but they were found to be too expensive to build, requiring far more time in quarrying rock and the actual work than the timber spans.

The first covered bridge in the United States is credited as being erected by Timothy Palmer of Newburyport, Mass., at Philadelphia in 1805. Another of Palmer's bridges was built one year later across the Delaware river, linking the cities of Easton, Pa., and Phillipsburg, N. J.

Several other bridges of this type followed in quick succession in the early part of the nineteenth century, and like trends in architecture the idea was universally adopted. As the idea spread across the states, the structures became bigger, too. Larger and larger bridges came to have this protective covering and several eastern railroads copied the idea for their own spans. A number of covered railroad bridges are still standing in the east.

Different types, styles and changes in truss-work entered into the bridge building trade as the program expanded. Theodore Burr of Torrington, Conn., made one of the greatest contributions in that regard by perfecting a new type of truss which came to be called the "Burr truss." Burr's plan was a simple arch which was stiffened by more adequate timber bracing.

Names of other early famed engineers also figured in the industry. Another great builder of the day was Ithiel Town of Thompson, Conn., who developed a lattice truss type, which was quickly named the "Town lattice truss" and which was widely copied. Town's patent consisted of planks criss-crossed like lattice work.

Later builders who helped to design bridge construction were: Col. Stephen H. Long of the U. S. army engineers and William Howe of Spencer, Mass.

Influence of the Burr, Howe and Town truss designs are noticed in a study of the covered bridges of mid-west states which border the Mississippi river. The Burr and Howe types are prevalent in the Illinois bridges, but the Town lattice truss is more common in the Iowa structures.

Later bridges witnessed the trend toward the use of iron to some extent in the work. Howe was believed to have been the first to utilize iron, perfecting a plan of timber diagonals with vertical tension rods.

The building of covered bridges continued for more than 75 years, but after the Civil war the iron age came to the United States and the construction of timber structures slackened off somewhat although it continued in some states past the turn of the century.

The last of them was built in the Middle West about the time of World War No. one.

excerpted from “Covered Bridges in Illinois, Iowa and Wisconsin“ by Leslie C. Swanson