Roofs Over Rivers

For a hundred and fifty years, the covered bridge has been an old American landmark. Today it is becoming increasingly difficult to find even one, but only fifty years ago the traveler encountered countless numbers of them—at cities, villages, and country crossings from Maine to Georgia and west to California.

The village bridge of the past century was the meeting place of town and country. In its dim interior men argued crops and politics while their womenfolk exchanged gossip and recipes and their children exclaimed over the gaudy circus posters that hung in the bridge long after the show had left town.

Out in the countryside a covered bridge was a good place to save a load of hay in a sudden summer shower. Farm boys found favorite fishing spots in its shade. It seemed as though a high-spirited mare could actually read the signs that were posted prominently over the bridge portals: “Five Dollars Fine for Riding or Driving Faster Than a Walk on This Bridge!”; for often as not she would automatically slow to a sedate pace on coming in sight of the cool, timbered passageway. For years the covered bridge was the country cousin to the city amusement park’s Tunnel of Love. The longer the bridge, the better. Just ask grandpa why they called them “kissin’ bridges.”

But how did bridges come to be covered? To provide shelter for the traveler, some say. Others think the housing presented a homey, barnlike appearance to horses, and thus prevented them from shying at the glint of river water. Actually, the explanation is far less romantic: bridges were originally covered, as one old New Hampshire man put it, “ter perteck the underpinnin’,” the framed wooden trusswork. With the rot caused by continual wetting and drying thus avoided, covered bridges have continued to give useful service for periods that amaze modern engineering experts.

American bridge-designers did not invent roofs for bridges. From biblical days onward builders have added roofs to their spans. In ancient times the purpose was mostly decoration and the protection of the people who crossed them. In Italy. China, and Mexico today, there are stone bridges with wooden roofs, used as market places. Village carpenters in Switzerland and Germany, however, seem to have been the first to evolve the idea of a roof to protect the timbers of the bridge itself; in heavily forested central Europe, covered bridges were built as far back as the Middle Ages.

Americans did not adopt the covered bridge until after the Revolution. In a fast-expanding country where the main routes of transportation crossed a number of broad rivers, stone bridges were too expensive and took too long to build. Since there were vast uncut forests in the eastern states, the giant virgin timber became the bridgebuilder’s material.

The contribution of American designers was the wooden truss, which could carry bridges of a length undreamed of in Europe. The pioneer bridges in America were simple affairs of short trestles set on piles, built to make fat profits from tolls. These were successful in places like Boston, but what sufficed for the placid Charles River was not enough for other coastal cities with swift and navigable streams to be spanned. The need was for sturdy, longer bridges without intermediate supports.

Some of the best minds of the time set to work on the problem. A bridge to span the Schuylkill River at Philadelphia engaged the attention of political pamphleteer Thomas Paine, for example, and he worked out various models, both in wood and—an unheard-of material for bridges—iron. For lack of money, however, nothing was accomplished. The same project also fascinated Charles Willson Peale, the eminent artist, whose famous museum was devoted to developing many of the arts and sciences. He put a Paine model on display and set about designing one of his own. Peale’s plans never got beyond the model stage either, but in 1797 he wrote an “Essay on Building Wooden Bridges,” and was awarded the first United States patent for a bridge design. Charles Peale’s heart was in invention alone, not in engineering, so he turned over the patent rights to his gifted but ne’er-do-well son Raphael. The younger Peale, who had tried his hand unsuccessfully at many other jobs, attempted to build a full-sized bridge on his father’s plan at Beaufort, South Carolina. It collapsed before completion, and Raphael, always ready with an alibi, blamed the failure on “hiring too many Yankee workmen!”

But up in Newburyport, Massachusetts, another “Yankee workman” was more successful. He was Timothy Palmer, a local shipwright’s apprentice. Wooden arches, made of huge squared timbers lapped and mortised together, were his answer to the long-span problem, and he became their first successful designer. Palmer must have come across a copy of an old Italian architectural book by Andrea Palladio, who in the 1550s had devised and built arched wooden-truss bridges over tiny Alpine torrents. Timothy Palmer translated the Italian’s brainchild into great timber arches made from the giant stands of pine in the New England forests.

Palmer selected his long timbers—sometimes naturally curved—and floated them downstream directly to his bridge sites. He put up three spans over the Merrimack River in Massachusetts, one over the Great Bay of the Piscataqua in New Hampshire, and then went on to conquer the Delaware at Easton, Pennsylvania, the Potomac at Georgetown, Maryland, and the Schuylkill at Philadelphia.

This last was a showcase for Palmer. The merchants of the city had at last been able to raise enough money to finance the long-wanted bridge, and they spared no expense to make it the pride of Philadelphia. The fresh paint on its lower structure was even sprinkled with stone dust to give the appearance of masonry. Since he wished his timber trusswork to be prominent, Timothy Palmer took a dim view of this at first, but when it was done—at the instigation of Judge Richard Peters—he graciously allowed that perhaps the bridge might last “thirty or forty” years as a result of the extra protection from the weather. (Actually, it lasted forty-five.) Finished in 1805, it was dubbed the “Permanent Bridge”; its arched roadway stretched across the Schuylkill in three spans for a total length of 550 feet. It was the first known covered bridge in America.

In 1812, another bridgebuilder got his start at Philadelphia. He was Lewis Wernwag, a German immigrant and designer extraordinary. At Fairmount he planned and erected a monstrous bridge across the Schuylkill with a single span of 340 feet, far and away a record for that day. As it neared completion, reports began to circulate that it would fall as soon as the scaffolding was removed. Soon the rumors were rife, and on the morning of the day set for the removal of the falsework, thousands jammed the banks of the river to see the expected collapse.

The bridge-company managers were naturally worried, and assembled on the porch of Sheridan’s Tavern nearby. when Wernwag arrived, their first words were: “Well, Lewis, do you think our bridge will stand the test today?”

Wernwag smiled and replied: “Yes, gentlemen, it will.” Then he led them out on the new-laid planking and showed them the blocks and wedges on which the arches rested. They were all loose: Wernwag had knocked them free himself, and since the previous day the bridge had been standing alone. The huge span was aptly named “The Colossus.” It stood for 26 years before being destroyed by fire in 1838.

The Colossus made Lewis Wernwag’s reputation, and for the next quarter century he was seldom without contracts to build covered bridges. Moving to Harpers Ferry, Virginia, in 1824, he took his designs into the fast-developing country west of the Alleghenies, and his sons built specially designed Wernwag arch bridges on the turnpikes of Ohio, Kentucky, and Indiana.

A third early builder was Theodore Burr of Torringford, Connecticut. A self-taught housebuilder and millwright, he put up several experimental bridges before finally concentrating on a simple arch, stiffened with timber bracing and supporting a level roadway. Burr’s were the first bridges of any size to cross such rivers as the Hudson, the Mohawk, the Delaware, and the Susquehanna.

An easygoing optimist, Theodore Burr was not awed by having four big bridges across the Susquehanna all under construction at once. He even bid on a fifth, at Columbia-Wrightsville, Pennsylvania. Burr’s proposal for a 5,620-foot span—more than a mile of wooden trusses—was made on a piece of scrap paper. He promised to construct the piers and abutments for $66,000 and the frame, “or superstructure,” for $54,000, to secure the bridge from the weather for $8,900, and to floor it for another $8,500. At the bottom he added: “Superintendence, say $6,450.”

Burr’s bid was a bit high, and the job went to another Connecticut builder, Jonathan Walcott. Thus Burr lost out on the distinction of erecting what was to be the longest multiple-span covered wooden bridge ever built in the world. He had to be satisfied with building the longest with a single span.

This was at McCall’s Ferry, Pennsylvania, a narrow constriction in the Susquehanna where the water ran 150 feet deep. Since scaffolding could not be driven this deep, the resourceful Burr pinned the span together on land and started to move it into position on floats. When, in the dead of winter, the river froze tight, he finished the job by skidding the arch into place on the ice. To secure manpower, he played up sectional rivalry between the counties on either side of the river, and induced the farmers who would ultimately pay for using the bridge to help him erect it. When McCall’s Ferry Bridge was finished, it had a clear span of over 360 feet. Even today’s laminated wooden arches, prefabricated and lifted aloft by derricks in the construction of huge airplane hangars and public arenas, have not yet equaled the length of Burr’s mighty arch of 1815.

Despite all the work that went into it, this record-holding bridge stood for only three years; it was destroyed in an ice jam and never replaced. But although the inventor died in 1822, his arch bridges lived on. His boss-carpenters became contractors themselves and bridged countless lesser streams in New York, Pennsylvania, Ohio, and Indiana. Their sons and apprentices took the tried-and-true Burr arch even farther afield, using it for railroad spans in New England and highway bridges from Nova Scotia to California.

The big timbers that went into the elaborate structures of Palmer, Wernwag, and Burr took considerable manpower to put together. There was a crying need for a simple bridge that could be erected by a common carpenter’s gang. Ithiel Town, an architect from New Haven, Connecticut, filled the bill in 1820 with the patenting of his “Town lattice truss” bridge, an all-wood arrangement of planks crisscrossed like a garden fence and pinned together with big two-inch wooden pegs. Weight placed on it only tightened its framework.

Town promoted the bridge throughout the eastern states while carrying out his main work of designing churches and public buildings. The lattice truss caught on slowly, but eventually it became the favorite type of construction in New England. Town received a royalty of one dollar per foot for patent rights, and two dollars a foot if one of his sharp-eyed agents discovered a bridge erected on the plan without prior permission. New England emigrants took the Town lattice truss with them to Ohio and Michigan, and there was even one built (without a roof) over the Jordan River in Salt Lake City.

In these early years, bridge engineering was a matter of trial and error. In 1829, Colonel Stephen H. Long of the U.S. Army Topographical Engineers devised the first scientific wooden-truss bridge in America. It was essentially a series of crossed beams pinned into square frames. The Colonel called it the Jackson Bridge, in honor of the President, and built the first one as a highway overpass over the B&O Railroad outside Baltimore. It was the first railway grade-crossing separation in America.

Since Colonel Long, famed for his western explorations, was primarily a railway engineer, many of his bridges were built on the new rail lines of the 1830s. The first railroad drawbridges—over the Passaic and Hackensack rivers in New Jersey—followed his plans, as did the first combined railroad and highway bridge, over the Raritan River at New Brunswick, New Jersey. It is recounted that, when caught in the inky interior of the New Brunswick bridge while a train rumbled across the roof, more than one horse died of sheer fright!

Long’s bridges enjoyed a popularity of ten years, during which they vied with Ithiel Town’s lattice trusses for use by the growing rail network. The rival promoters exchanged polite notes via the newspapers, waxing eloquent in praise of their respective designs. Colonel Long, busy with army matters, finally left his share of the battle to his brother and “General Agent,” Dr. Moses Long of Warner, New Hampshire. Dr. Long, who was also the town postmaster, used his free franking privilege to blanket the East with advertising broadsides extolling the virtues of the “Long patent bridge.” Ithiel Town countered by appearing in person at bridge contract-lettings to plead the merits of his “mode,” sometimes—if the bridge were to be large or to stand in a prominent location—offering to waive his royalties.

After 1840, both the Town and the Long patent bridges were almost totally eclipsed by another design, using wooden cross-frames and iron rods and invented by William Howe of Spencer, Massachusetts. Howe came from a family of inventors: his brother Tyler devised a spring bed, and his nephew Elias achieved lasting fame for his sewing machine.

The Howe truss had a lot of the features of Long’s bridge, and the Colonel cried “infringement” long and loud, but to no avail. The basic difference was in the introduction of the iron rods and turnbuckles with which the Howe bridge could easily be trued up by tightening a few nuts. This ease of erection and maintenance made the Howe truss a special favorite of the railroads, and enabled them to span a stream quickly during the period when they were hastily laying new track in all directions. All the pieces for a wooden Howe truss bridge could be pre-cut and loaded on a brace of flat cars. Add the iron rods, plus a crew of husky Irish laborers, and the cars could be pushed out to a pair of waiting abutments at the end of the track. Twenty-four hours would usually see a 100-foot bridge in place; it could be roofed and sided while it was in service.

With the advent of William Howe, bridgebuilding became big business. Gone were the primitive posters and word-of-mouth advertising. Howe had four brothers-in-law named Stone who set up a family dynasty of bridgebuilding firms with the rights to build Howe truss bridges in specified localities. Amasa Stone had Ohio; brother Joseph, New England; brother Daniel, Pennsylvania and New Jersey. Andros Stone took his brother-in-law into partnership to work westward out of Chicago. In a few short years, Howe truss bridges were practically standard on railroads, and still more companies were formed to build them. (Some seventeen of these spans still stand in the Northwest.) There was enough work out of St. Louis to induce the firm of Stone and Boomer to buy an entire wooded township in Missouri, where they built a model mill town to work the trees into bridge timbers.

With the big towns, the turnpikes, and the railroads provided for, local carpenters turned their attention to the smaller villages and secondary roads. Not wishing to pay royalties, these home-town artisans designed their own bridges. They used, for the most part, simple trusses on the same principles of roof framing and support that had gone into many thousands of houses and barns.

There were odd, one-of-a-kind bridges, of course. In 1841, two Maryland men collaborated in patenting a “puzzle-keyed” bridge. Though never actually built, their whole structure was designed to hang on a single piece, which if removed would send the entire fabrication tumbling into the river!

A Pennsylvania schoolmaster named Herman Haupt, in charge of a girls’ seminary in Gettysburg, experimented incessantly with little bridge models, loading them to the breaking point with dangling lead weights. In 1839 he finally devised and patented one that satisfied him, but due to the inception of the Howe truss shortly afterward, Haupt’s bridge was never popular, and his fame rests more on his work as a Civil War general in charge of military railroads.

The heyday of covered bridges was about 1860. They were common both in country and city, on turnpike and byway. Major eastern centers, such as Hartford, Springfield, Philadelphia, Baltimore, Washington, Richmond, Columbia, and Augusta, as well as Pittsburgh, Cleveland, Columbus, Dayton, and Indianapolis to the west, all had covered bridges. Later years even saw one erected in Los Angeles. Records show that they once stood in all but eleven states.

After the Civil War came the age of iron. The covered bridges—sometimes perfectly sound ones that were simply thought to be old-fashioned—were gradually replaced. Oddly enough, iron-smelting Pennsylvania bucked the trend. Their own wrought-iron and steel channels and beams were all right for building bridges elsewhere, but at home the Keystone Staters kept right on building them of wood. There are more than 1,300 covered bridges still standing in the nation today, and Pennsylvania leads the other states, with 351 as of September, 1958. Ohio had approximately 240 by unofficial count in the same year. In Indiana, where covered bridges were built from 1880 right down to World War I—some of them with fancy embellishments, scrolls, and gingerbread decorations—over 150 covered bridges still stand. Oregon is next with 130-odd, and then comes Vermont with 106. New Hampshire, Alabama, West Virginia, and Georgia still have a good representation, and there are 29 covered railroad bridges in New England and the Far West. In most of the other states, however, the day of the covered bridge has passed, and only a few isolated examples remain.

Yet even today, in areas where steel shipments are costly and wood is plentiful, covered bridges are still being built. In Lane County, Oregon, for example, a few modern ones are planned and built by engineers every year, particularly in newly developed areas where the need for heavier bridges has not yet been established.

Recently, residents of the Massachusetts towns of Charlemont and Sheffield petitioned the Commonwealth’s Department of Public Works to replace their old bridges in kind. The contractors looked over the elaborate plans for modern three-lane covered bridges, and then realized that there were no timbers in all New England big enough to meet the specifications. So both Charlemont and Sheffield have shiny new covered bridges, built in 1951 and 1953, respectively, but the wood that went into their construction came all the way from Oregon!

The Poetry of Bridgebuilding

In 1949 townspeople of Charlemont, Massachusetts, appealed—in somewhat creaky verse—to the state’s Department of Public Works to replace in kind a covered bridge:

The Bissell Bridge is falling down,
Right in the middle of our town
Please view the matter with alarm
And do vote “Yes” unto our plan.

As related in Richard Sanders Allen’s Covered Bridges of the Northeast, the department replied—also in kind:

Struck by the setting’s natural beauty
The Commissioner said ’twas the state’s duty
To save that lovely rustic view
And save the state some money, too.
For it seems the wood bridge can compete And still be cheaper than concrete…