Truss Bridge 30 Facts

-          A truss is an arrangement of structural members that are connected together to form a rigid frame work.

-          Trusses have been used extensively in bridges since the early 19th Century.

-          Truss bridges are usually categorized in two different ways according to the location of the deck and according to the orientation of the vertical and diagonal members.

-          The Structural Stability of a truss is stable if all of its members are arranged in a network of interconnected triangles.

-          The triangular arrangement of members ensures the rigidity of a truss structure.

-          To fix an unstable truss, look for any "panel" of the structural model that is not a triangle, then add one or more members to transform that panel into a series of interconnected triangular  shapes.

- Modern trusses are made of structural steel.

- Some other types of bridges include arch, suspension, cable-swayed, and beam.

- Dunlap’s Creek Bridge was the first iron bridge built in the United States.

- The bridge was a vital link in the newly constructed National Road, which was the first important road built with Government funds.

- Dunlap’s Creek Bridge consisted of five parallel cast iron tubes spanning 80 feet.

- Dunlap’s Creek Bridge was built by Captain Richard Delafield of the Corps of Engineering.

- Dunlap’s Creek was designated a National Historic Civil Engineering Landmark in 1978.

- Truss bridges are usually categorized in two ways depending on the location of the deck and orientation of diagonal and vertical members.

- The deck truss has its deck located at the top chord.

- A through truss has its deck located at the bottom chord.

- A pony truss is like a through truss, but not as high and has no lateral bracing.

- Truss configurations are based on orientation of members.

- A number of standard truss configurations are commonly used in bridge structures.

- These configurations are defined primarily by the geometry of their members.

- Three of the most common standard configurations are Howe, Pratt, and Warren trusses.

- These trusses are named after the 19th century engineers who developed them.

- The major components of a typical truss are verticals, chords, diagonals, floor beams, deck, pinned support, roller support, and abutment.

- Loads include the weight of a bridge and vehicles that are on them.

- Loads can also include weather, such as snow.

- These forces must all be considered when developing a bridge.

- Yield stress is the strength of a metal.

- The strength of a metal must be determined before building a bridge.

- Supporting structures, such as beams and wires, are used commonly in bridges.