Campbell's Covered Bridge, Gowensville South Carolina
Campbell's Covered Bridge, built in 1909, was one of four covered bridges built in this part of northern Greenville County in the first decade of the twentieth century; before that time, the only safe crossing over Beaverdam Creek was a narrow rock shoal. Morrow's Covered Bridge and McClain's Covered Bridge spanned the Middle Tyger River on Pleasant Hill Road and S.C. Highway 14, respectively, and a third unnamed covered bridge spanned the South Tyger River between S.C. Highways 101 and 253. Campbell's Covered Bridge was the largest and most sophisticated of the four.
The construction of this bridge connected several rural communities and small towns in the immediate vicinity, so that a 25-mile trip which had once taken a full day before the bridge was completed could be made in about an hour afterward.
Charles Irwin Willis (1878-1966), an accomplished local builder in the northern part of Greenville County, built the bridge. Long and large timbers required for the bridge exceeded the capability of most sawmills, and had to be sawed by a nearby sawmill owned and operated by James M. Suddeth. When completed, the bridge was named for Alexander Lafayette Campbell (1836-1920), a local landowner and millwright who lived at the site and operated a corn grist mill about 50 feet downstream from the bridge.
William Howe, of Spencer, Massachusetts, patented his new wood and iron rod truss design in 1840, then extended the patent with improvements in 1850. His truss was the first to be designed using mathematical stress analysis. The truss consists of wooden upper and lower chords, which are linked together with sets of dual iron rods and wooden braces and counter braces. The braces and counter braces are butted against the chords on angle blocks. The iron rods are adjusted with large nuts.
The Howe truss design is the reverse of the more common Pratt truss design. In the Pratt design, diagonal members all slant toward the closest bridge end, so they are subject to compressive forces. This design requires large steel members, making it an uneconomical choice in many instances. The Howe truss, originally designed to combine diagonal timber compression members and vertical iron rod tension members, was more efficient than the Pratt truss for building longer bridge spans carrying heavy loads. It was adopted by the railroad industry and eventually became one of the most widely used trusses for steel railroad bridges.
Bridge Description
Campbell's Covered Bridge, built in 1909, is located in rural north Greenville County, South Carolina, near Gowensville, and crosses Beaver Dam Creek on Campbell Covered Bridge Road. This wooden bridge with a metal roof is 35' long by 12' wide.
It sits on a rock foundation with a concrete cap, as masons supplemented existing rock formations on each side of Beaver Dam Creek as load-bearing abutments and partial foundations. Concrete was poured atop the rock formations, and 12" x 12" heart-of-pine sills were mounted on the concrete cap with 4.5" iron rods. Once the two trusses were in final position, they were braced or tied in place for the remaining construction of the bridge decking, sides, and roof. Buttresses were then built at each end of the bridge and at the center point of each truss. They rested on the main timbers carrying the floor load and extended three feet past the sides of the bridge to provide stability along the weak axis of the truss.
Campbell's Covered Bridge is a four-span Howe truss bridge with counter braces. The two outer spans are 9' long and the two inner spans are 8' long. Each truss is 4" x 8", and each counter brace is made from 2" x 8" pine boards nailed together in an interlocking pattern. Vertical tie rods called kingposts, made from 1" diameter iron rods, are in between each span, tying the top and bottom chords together. This method of truss construction absorbs and transfers a passing vehicle's weight to the rock abutments on each end of the bridge.
The builder, Charles Irwin Willis (1878-1966), allowed the truss ends to follow the natural lay of the land and built the rest of the bridge to fit; as a result, and according to Willis's design, the bridge is neither square nor plumb.
The siding of the bridge consists of 1" x 6" pine boards with 1" battens covering the joints. Siding covers the three wooden buttresses that jut out on each side of the deck, forming a triangular shape and sheathed with cedar shakes. A gable roof of five-V galvanized steel covers the structure. The bridge is open at both ends, with a gap at the top between the siding and roof to allow for air circulation. The deck is made from 2" x 6" pine boards. The trusses are exposed on the interior of the bridge.
In 1951, Pleasant Hill Road was rerouted, and the historic roadbed was renamed Campbell Covered Bridge Road. It remained a gravel-over-clay road until it was resurfaced by tar and gravel in 1987. In 1964, the bridge siding, deck, and roof were repaired and the bridge was painted, most likely for the first time. Local traffic continued to use the bridge, but most traffic used the rerouted Pleasant Hill Road instead. In 1984, Greenville County closed the bridge to all vehicular traffic.
Retaining walls were built and the dirt was dumped up against each end of the bridge, in effect creating two dead-end roads. By 1990, the bridge needed renovation once more; worn or rotted boards were replaced with fresh rough-cut pine boards, and the tin roof was replaced with a galvanized steel roof.
Since the bridge weighed between 85,000 and 100,000 pounds, a 50-ton jack was used to lift the bridge off the foundation to replace the large sills at each end with new sills of pressure-treated lumber. Cracks between the pressure-treated pieces allow air to circulate, preventing any buildup of moisture in the future.
The bridge was repainted at that time as well.
From the south (2008)
From the north (2008)
From the northeast (2008)
From the northwest (2008)
Full side view of the bridge, from the middle of the creek bed from the west (2008)
View of one of two Howe trusses, showing criss-crossing wooden braces and vertical tie rods (Kingposts), which exemplify the unique Howe design (2008)
Stone abutments with concrete caps on which 12 x 12 heart-of-pine sills sit (2008)
Tie rod brace and criss-crossing wooden braces, which provide flooring support (2008)
One of three buttresses, which extend three feet past the sides of the bridge (2008)
