Howe Truss Bridge
Howe Truss: this truss structure is the reverse of the Pratt Truss. Here, the diagonal members all slant toward the closest bridge end, so they are subject to compressive forces. This design necessitates large steel members, rendering it an uneconomical choice for steel construction.
William Howe patented a wood and iron rod truss in 1840 and extended the patent with improvements in 1850. The truss was the first to be designed using mathematical stress analysis. The Howe truss, suitable for heavy duty bridge spans, was adopted by the railroad industry and became one of the most widely used trusses for railroad bridges.
The truss consists of wooden upper and lower chords, the chords linked together with sets of dual iron rods and wooden braces and counter braces. The braces and counter braces are butted against the chords on angle blocks. The rods are adjusted with nuts.
William Howe, born in 1803 in Spenser Massachusetts, came from a family of inventors. Tyler Howe invented a spring bed and Elias Howe was the inventor of the sewing machine. |
