(m4bridge-truss-wv-stationroad-2014-1024.1437 The Station Road Bridge
A truss bridge is a common type of bridge which has a load-bearing superstructure composed of straight connected elements forming triangular units. Most all types of truss bridges have simple designs which allow economical design, construction and efficient use of materials.
History:
Truss bridges were a common type of bridge built from the 1870s to the 1930s and there are still many examples of these bridges throughout the US even though the number of existing truss bridges are diminishing due to them being replaced with newer structures.
With wood materials in abundance, most early bridges were built out of timbers and usually built as a covered bridge to protect the structure, many of which had iron rods used for tension.
As metal slowly started to replace timber, wrought iron bridges in the US started being built on a large scale in the 1870s. Bowstring truss bridges were a common truss design during this time, with their arched top chords and were marketed by construction companies to cities and towns. Due to its lack of durability, the bowstring truss design was replaced by a stronger design, the Pratt truss.
Wrought iron bridges continue to be built during the 1880s and 1890s, but it was not much longer before steel replaces wrought iron as the preferred material. By the 1900s, many states developed standard truss bridge plans most of which used steel Warren truss and pony truss bridges.
As the 1920s and 1930s progressed, some states continued to build steel truss bridges, including bridges for long spans. Other states, instead started using concrete girder and beam bridges. After concrete proved to be more durable and as the cost of concrete began to decrease, very few truss bridges were built.
Truss Bridge Types:
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