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Prefabricated bridges have been decked with gravel, grass, paving stones, natural flag stone, FRP grate and plate,
various types of metal grating and asphalt. The most common decks by far are wood and concrete.
Concrete: Poured into a form pan provided by Excel, this is arguably the best deck for most situations. For vehicles up to pickup truck size, it only needs be only about 3.75" thick on average. Sometimes dyed concrete is used to mask staining from weathering steel. Another key feature is that a continuous slab with molded in curbs can direct run off away from traffic below, so concrete is always used for overpasses. Excel usually discourages the use of lightweight concrete.
Form pan comes installed |
Concrete bridge decks do not need expansion joints |
Wood: Economical, rustic and natural, wood is specified on about half the bridges Excel builds. Because it is light weight and can be installed with hand tools after the bridge is set, it is the material of choice for bridges that might be moved, or are to be put in sites with difficult access.
Top grade Ipe, or IronwoodŽ, provides the toughest, longest lasting, and least warping/cupping type of wood deck. It will turn gray like all other types of wood.
Treated Doug Fir or Pine is typically treated with water borne ACQ. However, the Forest Service still orders their decks treated with Penta or Copper Naphthenate which are solvent borne and longer lasting treatments. And there are other choices, each with its advantages and disadvantages. Excel will be happy to provide any type that is specified, but it is up you to determine what is best for your project.
Grating: Metal or composite decks are usually used in industrial applications or as a support for paving bricks or stones.
Hot dip galvanized, weathering steel and FRP are the usual materials that grate is fabricated from. Most grates cannot meet ADA
code or carry much more than a 5 ton vehicle, but either can be done at considerable expense and weight.
Asphalt: Usually considered to be an inferior choice for a pedestrian or single lane vehicular bridge. It is expensive because of the structural metal planking needed to hold the asphalt and to support the heavy equipment needed to install the asphalt. Asphalt itself has no structural value and needs maintenance. If matching an asphalt trail is an issue, Excel recommends investigating the use of black-dyed concrete.
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