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Did You Know?

The Old Camelback Bridge

With the third installment of fuel-tax increases that were mandated by Act 89, the legislation that assured Pennsylvania the premier ranking of having the highest gas taxes in the nation, the tax rose from 50.3 to 58.3 cents per gallon. This most recent escalation is expected to generate $299 million next year with $267 million going to state highway and bridge projects and $32 million for local highway and bridge improvements. The “bridge project” portion brings to mind the somewhat bland design of newer bridges with solid white concrete walls that inhibit a driver’s view of much of the waterway being crossed and also brings to mind how long these new bridges are expected to last before being replaced, once again.

Prior to concrete and steel, bridges were a blend of engineering and artistry in wood and stone and generally covered with a roof and sidewalls. Most drivers making passage across the present Market Street Bridge between Harrisburg and Lemoyne could scarcely imagine that its predecessor, the Old Camelback Bridge, which existed from 1816 to 1902, was a covered bridge – a great weatherproof tunnel – in two spans with an interruption of daylight on the roadway of City Island. Not the longest covered bridge in the nation – the Columbia-Wrightsville Bridge further south on the Susquehanna had that distinction – the Old Camelback Bridge, with its two humps, was the best known example of the work of Theodore Burr 1771-1822 (or 1824, no one’s quite sure), the premier bridge designer of the early-to-mid 19th Century.

Burr, originally from Torrington, Conn. was, in addition to being a distinguished bridge architect, a cousin of Aaron Burr, the Vice President of the United States who ended his political career and Alexander Hamilton’s life with one shot in Weehawken, N.J. in 1804.

Curiously, 1804 was the year Theodore Burr constructed the first sizeable bride crossing the Hudson River at Waterford, N.Y. That bridge lasted until 1909 when it was destroyed by fire. What was important about it was that it employed the “Burr Arch Truss” using two long arches, resting on abutments at either end that, typically, sandwiched a multiple kingpost structure.

Given the success of his design, Burr built nearly every bridge that crossed the Susquehanna from Binghamton, N.Y. to Maryland during that time. In the short span of seven years (1811-1818), Burr constructed five bridges across the Susquehanna, four in Pennsylvania at Berwick, Northumberland, Harrisburg and Columbia, with the fifth near Port Deposit, Md.

Burr’s exemplar was so revolutionary that he was awarded U.S. Patent 2769 for his arch-and-truss bridge design. The Burr truss system incorporated reinforced arches tied directly into the bridge abutments with a series of triangular support posts. The design created great strength and allowed, for the first time, longer spans averaging over 100 feet. Of all of the remaining covered bridges extant in Pennsylvania, 122 have the Burr truss system. And, nearly all are in good to excellent condition.

Why covered bridges? Given the material used to construct them, they were vulnerable to rotting, no matter what type of wood was employed. Covering and roofing them served as protection from the weather. Another reason for covering them was to protect the trusses from the environment, which caused them to fail sooner. It was estimated that a housed (covered) timber truss span had three times the anticipated life span than one without. Another reason for covering them was because the roof, as an integral part of the structure, strengthened the entire assembly. Additionally, because the bridge deck was also made of wood, a roof kept the deck boards from getting wet or snow-covered and therefore dangerously slippery.

Nearly 14,000 wooden covered bridges once existed in the United States, with less than 900 remaining today. Often regarded as simply sentimental reminders of the past, the remaining bridges are historic artifacts reflecting not only engineering expertise, but also examples of the largely lost art of wood construction. And, although Theodore Burr is the best remembered designer, there are no fewer than 11 competing truss designs on the books for wooden-bridge construction.

Unfortunately, little documentation exists for the men who physically constructed these spans across the rivers and streams of America. One can only surmise that they were master carpenters, the likes of which exists now in only a small portion of the United States’ skilled workforce. Given the tools of the time, beams had to be hand-hewn and hand-sawn from huge trees to exacting specifications based upon the designer’s plan and notched and pegged together like a colossus of fine furniture. Nails at that time had to be cut from heated iron, which required the efforts of, yet another, largely lost artisan, the blacksmith.

Of the roughly 200 remaining historic covered bridges found in Pennsylvania, Lancaster County has the largest number at 29, although covered bridges can be found in more than half of the state’s counties. The only vestige of the Old Camelback Bridge, save historic photos, is a marker noting that it was a Theodore Burr design, built between 1813-1817, called “Camel Back” because of its unique arch design, and that it was partially rebuilt in 1847 and 1867, finally being demolished and replaced with the present Market Street Bridge in 1902. The marker is located at the intersection of Front and Market streets in Harrisburg. The Old Camelback Bridge was built on nine piers and had the distinction of being possibly the world’s longest covered bridge with a shingle roof.

The late Pete Wambach, Harrisburg radio personality, businessman, writer and raconteur of the first order, once wrote of covered bridges in Pennsylvania: “The old hemlock and white pine the ancient bridge-builders used have amazing longevities, but timber doesn’t last forever. There is beauty in wood and that beauty is still there in the more than 300 covered bridges in the state. The old-timers preferred that beauty – and they left us a nostalgia which remains today in the Pennsylvania countryside. No matter where you are in Pennsylvania – you’re not far from a couple of covered bridges. Make that ride – there is the thrill of echoing voices under the rafters which children will hear when they shout as you drive across. What children can appreciate is worth preserving.”

There are a number of covered bridges easily accessible by travel from Harrisburg. Nearby Juniata County has four remaining covered bridges with one of them having the distinction of being the longest covered bridge in Pennsylvania. The Academia/Pomeroy Bridge went under a complete restoration in 2008, reconstructed to its original design. The bridge is 270 feet in length and 15 feet, six inches in width. An excellent example of the Burr Arch design, it was originally built in 1870 and is owned by the Juniata County Historical Society.

For further reading and enlightenment on the covered bridges of Pennsylvania, there are several excellent web resources: pacoveredbridges.com, coveredbridgemap.com/pa and the Theodore Burr Covered Bridge Society of PA at tbcbspa.com.

One can only imagine what portion of that extra eight cents a gallon will go to the preservation of the remaining covered bridges in Pennsylvania. And, one can only wonder how much longer those unremarkable new bridges they’re constructing would last if they had a roof over them.

Probably not 147 years like that one in Juniata County.

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