Comstock Covered Bridge
Built in 1873 by the Towns of Colchester and East Hampton
The Comstock Covered Bridge is one of only three historic covered bridges remaining in Connecticut. With a main span 80 feet in length (measured from the faces of the stone abutments), the Howe-patent truss was a major bridge project for its day. A town meeting held in Colchester on April 7, 1873 authorized "the rebuilding of Comstock's Bridge, with such width of span as the Selectmen shall judge will be sufficient to take the water and ice through." Two weeks later, the townspeople of East Hampton, then called Chatham, agreed to fund their half of the bridge (the Salmon River at this point forms the boundary between the two towns). The total cost was $3,958.59, a substantial sum in an age when common laborers were paid a $1.00 a day. The bridge was listed on the National Register of Historic Places in 1976.
The original resolution called for an iron bridge. Why did the Selectmen choose to build a wooden bridge instead? Perhaps because timber-trusses were a tried-and-true technology, whereas iron bridges were still considered innovative. Also, many people distrusted iron bridges because of some spectacular failures. One example that may have been on the minds of the Selectmen: less than three weeks after the two towns voted to rebuild the Comstock Bridge in iron, an iron-trussed bridge in Dixon, Illinois collapsed, sending 250 people into the Rock River, 50 of whom drowned. Economics may also have played a role in the decision: because the American iron and steel industry was still in its infancy, iron bridges had a higher initial cost than wooden ones.
It is not recorded why the earlier bridge on this site needed to be replaced. exceptionally high rainfall caused a disastrous flood throughout central Connecticut in October 1869, and it may be that the predecessor to this bridge was one of the dozens of bridges heavily damaged or washed away in that event.
The first bridge at this location was built in the 1700s. Bridges of that period typically consisted of multiple short spans of 20 to 40 feet set on piers in the river. During the American Revolution, a legion of French cavalry under the command of Duc de Lauzon, some 300 horsemen in all, camped on the east side of the river at this location, before continuing on to join up with George Washington's army in Phillipsburg, New York. At that time, the crossing was called "Salmon Bridge." Wooden bridges generally had a life span of 20 to 30 years, so it is likely that the earlier bridge was rebuilt several times before the present bridge was constructed in 1873.
In the 1700s and 1800s, bridges took on the names of some family that lived nearby. People may have initially referred to it as "the bridge near where Comstock lives, " and it then got shortened to "Comstock's Bridge" or "Comstock Bridge." Christopher Comstock was a long-time resident on the East Hampton side of the river in the 18th century dying at his farm in 1808 at the age of 82. He and his younger brother, Abner, at one time owned a sawmill and gristmill located a short distance upstream from the bridge. Bridges kept the same name despite being repeatedly rebuilt. "Comstock Bridge" was not only the name of the structure, it also came to be applied to the small settlement that grew up around the various mills at this point on the river; for a time, the village even had its own post office.
This bridge served the traveling public for almost 60 years before being replaced in 1932 by a concrete bridge just downstream. Shortly thereafter, the two towns transferred the bridge to Connecticut as part of the Salmon River State Forest.
The bridge received a major overhaul in the 1930s by the Civilian Conservation Corps (CCC). The CCC was a federal-relief program targeted toward unemployed young men; at its height, the CCC had more than 3,800 people enrolled in Connecticut, and it is believed that some 30,000 state residents participated in the CCC at one time or another. One of the state's 17 CCC camps, called Camp Stuart, was established in the Salmon River State Forest in July 1935. Over the years, the Comstock Covered Bridge had become deteriorated. The CCC installed a new wood-shingled roof and siding boards salvaged from an old barn. A new window on the north side and wooden gates at the portals were added. The project also replaced some of the timbers in the bridges main chords; a remnant of the original remained on display inside the bridge for many years. In addition to repairing the bridge, Camp Stuart's 200 CCC workers built miles of roads and hiking trails through the state forest and fishing-access spots on the river itself.
The bridge was repaired again in the early 1970s. this time, 3/8-inch-thick steel plates were bolted to the timbers to reinforce all the joints, and the wood-shingle roof was replaced. A third program of rehabilitation, undertaken in 2011, is expected to give the bridge many more years of service.
(east side)
Comstock Covered Bridge
and the Evolution of Timber-Truss Engineering
The first half of the 19th century was a period of great innovation in bridge engineering. In place of the traditional king-post and queen-post trusses that had served since Medieval times, and had typically been built in spans of about 20 to 40 feet, clever builders devised a number of new truss designs that could be built in lengths of 100 feet or more. Most of these builders, our nation's first bridge engineers, patented their ideas so that they could collect royalties when towns, and later railroads, mad use of their designs.
Although they varied greatly, these patented timber trusses all performed an identical function: transferring load from the middle of the bridge to the ends, which rested securely on stone abutments. The transfer of load was accomplished by a series of vertical and diagonal members, some of which acted in tension (resisting stretching forces) and some in compression (resisting squeezing forces), between the top and bottom chords.
The truss type used in the Comstock Covered Bridge was invented by William Howe, a carpenter-builder born in Spencer, Massachusetts. Howe (1803-1852) had experience designing roof trusses for large buildings such as churches, and when in 1838 the Western Railroad was being put through nearby Warren, Massachusetts he suggested a new truss design to the railroad's engineers. Howe's truss, incorporating both iron rods and wooden timbers was immediately seen as offering advantages over all-timber types, and the railroad adopted his idea for its bridges. Howe patented the truss in 1840, and in 1850 he took out a second patent covering improvements. Royalties from his bridges, which were built as far away as Russia, made him wealthy.
The key features of the Howe truss was the use of iron tie rods as tension members, with the wooden timbers in compression (in his patents Howe anticipated all-iron versions, but it was chiefly built as a composite wood-and-iron bridge). The use of iron eliminated much of the intricate joinery required by other timber-bridge designs. The Howe truss was widely used for both railroad and highway bridges until the cost of all-metal bridges came down to the point at which they were as inexpensive as wood. Even into the early 1900s, however, railroads continued to use the Howe truss for remote, low-volume locations. The Howe truss can be considered the culmination of covered-bridge technology. As bridge historian Eric Delony wrote, "the Howe truss may be the closest that wooden-bridge design ever came to perfection. For simplicity of construction, rapidity of erection, and ease of replacing parts, it stands without rival."
Why Were Covered Bridges Covered?
Covered bridges have become a beloved part of the traditional New England landscape, and much folklore has grown up around them. One common name for covered bridges was "kissing bridges," suggesting that their dark interiors provided an ideal place for young lovers, away from the prying eyes of their elders. Another story was that bridges were covered so they would resemble barns and therefore be less alarming to horses. Still another is that covered bridges were intended to provide a shelter for travelers during rain and snow storms. But the fundamental reason for covering a bridge with a roof and siding was to protect the timber structural members from the weather, thereby prolonging the bridge's useful life. Wood deteriorates rapidly if it is exposed to repeated cycles of soaking and drying, and by covering the bridge, builders protected the truss members and the floor from the effects of both precipitation and sun. "I'm dry as a covered bridge" was an old New England saying expressing thirst.
Comments 0 comments