Museum Covered Bridge - Background

Background

While many associate covered bridges with New England, the first covered bridges in the United States were built in Pennsylvania. Artist and inventor Charles Willson Peale received the first patent for a covered bridge in 1797. While his project never came to fruition, seven years later the Town Board of Philadelphia voted to erect what would become the first covered bridge across the Schuylkill River; it was only enclosed by chance after a shareholder of the building company suggested covering it. Roofing a bridge protected the structure from severe weather while adding structural stability, and, as a further benefit, shielded farm animals from frightening views.

In 1804, Connecticut inventor Theodore Burr engineered his design for an arch truss bridge, also called a king-post arch design, and patented it in 1817. Shelburne Museum’s Covered Bridge is an example of Burr’s creative engineering. Because inventors receive royalties from bridge patents based on a bridge’s length, there was great incentive to devise ways of increasing a bridge’s possible span and the frequently used king-post design could only extend so far. Burr’s design, which bolted a single arched timber to the king-post braces, added such stability that not only did the king-post trusses become secondary supports but also the bridge’s possible reach greatly increased.