Culverts, which are simply large diameter pipes, are used to channel water under roads, walkways or other structures. Culverts can be made from a variety of materials. Two of the most commonly used materials are corrugated metal and concrete.
Nothing lasts forever, but under most circumstances, a concrete pipe will last indefinitely while a corrugated metal pipe, even if galvanized to resist corrosion, will have a finite lifespan depending on the chemical properties of the water flowing through it and the soil in which it is bedded.
The initial price of concrete culverts far exceeds the price of corrugated metal. However, the higher initial price can be offset by longevity, and in situations where a concrete pipe is specified for aesthetic reasons the higher initial price may be insignificant. The price of installation of pipes made of either material will be nearly identical.
The amount of water that can pass through a corrugated pipe or a concrete pipe of the same diameter is the same. However, in a situation where vehicles or heavy equipment will be passing over the culvert, the load each type can carry varies. The determining factor is the amount of soil or other material that will be packed over the culvert. The deeper the culvert under the road, the more load it will carry. In situations where only a small amount of material will be over the pipe, a concrete culvert will carry more load than a metal one.
Corrugated metal pipes come in either round or oval cross-sections. Concrete pipes are available in round, oval, square and rectangular as standard shapes and can easily be formed into custom shapes should the need arise.