Ciphers Bridge (Bridge 94178)
See features of the bridge
History & significance
Ciphers Bridge (Bridge 94178) was built in 1989 and carries Tangnes Trail, a single-lane gravel road used primarily for logging and fire control access, over the East Branch of the Warroad River. This two-span, continuous, stress-laminated, timber deck slab structure. Bridge 94178’s deck laminates were the first to use native Minnesota material—red pine sawn lumber—instead of lumber from the West Coast. It is the U.S. Department of Agriculture Forest Service test subject for a formal, two-year field evaluation to determine the value of stress-laminated bridges for the viability of the future use of wood in bridge construction. Ciphers Bridge is significant for design and engineering as an early bridge type of which only a small number are known to have been constructed.
Location
Beltrami Island State Forest (Roseau County)
Latitude, Longitude: 48.763547, -95.177917
Bridge features
Longitudinal timber laminates stressed with lateral stressing bars to create a completely stress-laminated slab deck.
Stressing rods with rectangular bearing and anchor plates with anchor nuts.