J. Vlachopoulos, M. A. Lupke
Papers # 2018 Las-Vegas
A very tight-fitting bell-and-spigot inline coupler, minimizing the gap between connecting pipe segments, and a space efficient pulsating corrugator, requiring just three mold block pairs, were developed.
The author of a recent article in New York Times  claims that some 300 Billion dollars are needed to repair the crumbling infrastructure of pipes for water distribution and sewers. He goes on to describe the lobbying efforts and epic battles between the various professional groups and associations advocating iron or plastic for drinking water. The main competitor to large diameter corrugated plastic pipes is concrete. In articles and reports [2-4] the supporters of concrete have tried to portray plastic as having significant disadvantages, in comparison to concrete, most of them unsubstantiated. They cite liability issues for the engineers, higher Manning roughness coefficient, stress cracking, leakage in the joints and inferior load bearing capacity, without providing any documentation. They claim also that the initial cost advantage of plastic pipes, disappears in the long run. The competition is undoubtedly very stiff. Only significant improvements in corrugated plastic pipe properties and performance, accompanied by cost reduction, will convince the various stakeholders of the superiority of plastic. In this paper, we describe two innovations which are likely to have a lasting impact on plastic pipe corrugation technology. One innovation is the development of a new tight-fitting virtually seamless inline coupler capable of reducing the gap between connecting pipe segments, in case of soil movement after installation. Another innovation is a new production method suitable for large diameter pipes based on a pulsating corrugator, which requires as few as three mold block pairs, for forming the corrugations.