Culvert Materials and Construction
Culverts are generally constructed out of concrete, galvanized steel, aluminum, or PVC. The pipe material used in a project depends on cost, span, discharge, topography, soil chemistry, climate or state policy.
Structural Steel Plate (SSP), or "multi-plate" pipes are constructed of multiple plates of corrugated galvanized steel and bolted together. While time consuming to assemble they are easier to transport and are generally used for culverts that have a diameter greater than 12 feet. Large span metal arches used in fish passage projects are usually steel plate assembly.
Corrugated Steel Pipe (CSP), or Corrugated Metal Pipes (CMP) are constructed from a single piece of galvanized steel. Single pipes with a diameter greater than 12 feet usually have special traffic requirements for delivery or shipping.
Aluminum pipes are also corrugated and can be constructed as either structural plates or from a single piece of aluminum. Due to their high resistance to corrosion aluminum pipes do not develop rustlines and are often used in high corrosion environments such as saltwater applications.
Concrete (reinforced) box culverts are commonly used on county and state roads. Circular pipes that are precast in segments and grouted together are sometimes used. Circular concrete pipe does not have corrugations and is usually used for sewer applications. Concrete arches are increasing in use for new projects designed for fish passage.
Plastic (PVC, HDPE) pipe is more commonly found in small diameter or emergency applications. Plastic pipe can be corrugated or double sided. Double sided pipe is corrugated on the outside and smooth on the inside, commonly used for irrigation and agriculture.
See also: Culvert Shapes