Covered Bridges by Joseph Conwill

Author:Joseph Conwill
Language: eng
Format: epub
Tags: Covered Bridges
ISBN: 9781784420109
Publisher: Osprey Publishing

Hemlock Bridge over the Old Channel of the Saco River in Fryeburg, Maine, is an example of the bridges saved through the interest of state engineer Roy Wentzel.

By the late 1960s popular interest in covered bridges had grown to the point that preservation of all of them was at last seriously considered. In some cases when bridges could no longer carry heavy loads, their original floors were cut out and replaced with hidden steel beams. A few covered bridges were modified in this way as far back as the 1930s, but by the 1970s it became almost a standard treatment. As one tourist remarked when looking underneath a southeastern Pennsylvania bridge, “That’s cheating!” Much of the variety of historical floor framing has now been lost. Not everyone agreed that steel reinforcement was the answer, though. One prominent critic was Milton Graton (1908–94) of Ashland, New Hampshire, who began repairing covered bridges in the 1950s using traditional timber-framing skills that had largely been forgotten.

The Cornish–Windsor Bridge over the Connecticut River between New Hampshire and Vermont is the longest historical covered bridge in the United States, at 460 feet. It needed reinforcement in the 1980s, and the job became a battleground between those advocating traditional techniques and those who wanted to use modern materials. Milton Graton prepared a proposal for the traditionalists, who were ably led by David W. Wright (1940–2013) of nearby Westminster, Vermont. His plan called for the addition of laminated arches, which is how a bridge would have been strengthened in the nineteenth century. Here, however, the arches would have changed the exterior appearance of the bridge. The modernists proposed instead to cut out the bottom of the historical trusswork and replace the bottom chords entirely with glue-laminated material. Much of the original structure would be lost, although the bridge would keep the same familiar outward look.

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