There are many products used to construct the drainage infrastructure that we depend upon, and those products have very specific service lives. The challenge of matching service life of materials and products to design life of projects is top of mind with public works officials who must work with, among other things, limited funding, changing standards and specifications, new products and materials, changing technology, political action, and changing weather and climate regimes.
For decades, corrugated metal pipe (CMP) culverts have been installed under most highways and local roads. With a service life that does not often reach the design life of the roads they service, failures are reported by media before scheduled maintenance and replacement can take place. Although failing CMP culverts have been attracting media attention over the past decade, public works officials continue to monitor culverts and cross drains of all materials to initiate repairs and replacements before failure occurs. From safety and economic perspectives, it is important to replace failing and failed culverts as soon as possible to protect associated structures from premature failure.
Conducting a life cycle cost analysis of culvert product and material prior to road reconstruction or construction of a new length of local road or highway, can reveal many of the issues that tend to be overlooked in designing a culvert pipe or box. Issues include traffic delay costs that most often far exceed the actual construction costs. Therefore, any initial savings that occurs by installing a pipe with a lower life expectancy is quickly exceeded by subsequent replacement installations and user delays. By quantifying the additional costs of emergency replacement, it is clear that an inspection/maintenance program provides an attractive cost benefit. It also shows that pipe materials with a longer life are more cost effective than materials with lower life expectancy, even if initial installation is more expensive.