Sponsor: NC Department of Transportation
Start Date: 8/01/19
End Date: 7/31/21
Abstract
A large number culvert pipes are installed every year in North Carolina. While the loading and structural requirements for these pipes are considered during the selection process, the exposure condition of these culverts receives less attention. Many pipe choices exist including reinforced concrete, galvanized steel, aluminum, aluminized, and various types of plastic. Choosing the right pipe for the right installation is a non-trivial task that carries significant financial impact. Factors such as structural capacity, environmental durability, anticipated life-span, required pipe size, site conditions, and available construction expertise are all important when selecting a pipe. Existing NCDOT selection tables provide some limited guidance, but often result in highly-conservative selections being made, particularly from the perspective of matching pipe materials to site environmental conditions. Selection of the wrong pipe material (or an overly-conservative pipe material) can result in significant excess cost. If materials degrade too quickly, costly re-work is required, and additional costs and risks may be incurred due to reduced performance of the degraded pipe. If high-cost and high-performance materials are selected in areas where they are not needed, then initial construction costs can increase dramatically. For example, in many situations, aluminized corrugated steel pipe can likely provide the same useful service life as corrugated aluminum pipe at a dramatically reduced cost. Aluminum pipe may be justified in regions with salt-water exposure, however, it is likely an over-conservative choice for regions where contact with salt will be incidental. Accounts from NCDOT personnel have indicated widespread use of aluminum pipe in regions where it is likely not needed (i.e., regions with limited salt exposure).
