Knight's covered bridge

This is a photo of the Knight's Covered Bridge (T3S-R1E-S32) built to replace the Joselyn Bridge which crossed the Molalla River near Canby, Oregon. The bridge was constructed by A. S. Miller & Sons between March and November, 1877, for a contract price of $3,500. Bridge superintendant A. J. Cason provided the plan for the structure. This plan included an 87 foot modified Howe truss and a 123 foot span that was a self styled ""arch-brace"" which was not a true arch but long diagonal braces spanning several panel points. High bending moments were introduced in the diagonals by the hanging of tension rods between the joints. The bridge had one major flaw, the bridge covering was too low not allowing loaded hay wagons or threshers with wheels to use the span. Despite this flaw, the bridge remained in service for seventy years. During the later years the bridge was replaced for use in vehicular traffic, but remained in use as a foot bridge until it was blown into the Molalla River in a severe windstorm on February 1, 1947., "Original Knight's bridge was a picturesque covered structure 210 feet in length and costing $4400 when built 87 years ago. It stood in use for 70 years and was finally toppled into the Molalla River by a gale, Feb. 1, 1947."--Caption., Courtesy of State Library of Oregon.
Abstract/Description: This is a photo of the Knight's Covered Bridge (T3S-R1E-S32) built to replace the Joselyn Bridge which crossed the Molalla River near Canby, Oregon. The bridge was constructed by A. S. Miller & Sons between March and November, 1877, for a contract price of $3,500. Bridge superintendant A. J. Cason provided the plan for the structure. This plan included an 87 foot modified Howe truss and a 123 foot span that was a self styled ""arch-brace"" which was not a true arch but long diagonal braces spanning several panel points. High bending moments were introduced in the diagonals by the hanging of tension rods between the joints. The bridge had one major flaw, the bridge covering was too low not allowing loaded hay wagons or threshers with wheels to use the span. Despite this flaw, the bridge remained in service for seventy years. During the later years the bridge was replaced for use in vehicular traffic, but remained in use as a foot bridge until it was blown into the Molalla River in a severe windstorm on February 1, 1947.
Subject(s): Covered bridges
Oregon--Mollala River
Oregon--Clackamas County