Fallasburg Bridge - Design

Design

The bridge uses the Brown truss system, a through truss consisting of diagonal compression beams and (optionally) almost vertical tension members (slanting in at the top toward the center of the span). This system was patented by Josiah Brown of Buffalo, New York, in 1857. The Brown truss is similar to the Howe arrangement of "X" bracing and counter bracing, but uses lighter members and less timber. It contains no upright compression members and uses no iron except for bolt connectors at the timber intersections. Builders used the Brown truss successfully in at least four covered bridges in Michigan, three of which (Ada Covered Bridge, Whites Bridge and this one) are still in existence. The Brown truss was thus briefly popular in Michigan but did not gain wide acceptance elsewhere.

The bridge currently rests on concrete and fieldstone footings at each end put in place in 1905. As is typical for covered bridges, it is a frame structure with a gabled roof that is covered with creosote shingles. Its construction is of the through-truss type, and the white pine (sourced from Greenville, Michigan) trusses are completely sheathed on the outside with rough pine boards. The floor is 14 feet (4.3 m) wide and 100 feet (30 m) long and the bridge has an inside clearance of 12 feet (3.7 m).

The bridge has warning signs on each portal: "$5 fine for riding or driving on this bridge faster than a walk."