For years, the Indiana Department of Transportation (INDOT) has maintained a robust storm water pipe rehabilitation program for culverts that lie beneath the state’s nearly 10,000-mile network of federal and state highways. These large-diameter corrugated metal pipes typically suffer from corrosion due to debris and constant exposure to the elements. Over the past two years, Orleans, Ind.-based Layne Inliner has been subcontracted to rehabilitate more than 50 of these culverts using Inliner Technologies’ method of cured-in-place pipe (CIPP).
CIPP technology allows for the rehabilitation of damaged underground wastewater and storm sewer pipe without excavation. The process minimizes disruption to the public by reducing noise, traffic disturbances and road closures. The installation can be done within a shorter time frame and usually at a lower cost than replacement. Using CIPP, a felt tube saturated with resin is inserted into the pipe via inversion or the pulled-in-placed method of installation. Hot water, steam or ultraviolet (UV) light then can be used to cure the resin. This creates a new “pipe inside a pipe” and is designed to provide the conduit with an additional 50-year service life.
For this particular project, Layne Inliner was contracted to line segments of storm water pipe varying in diameter from 48 to 96 in. along Interstate 60, state Route 5 and state Route 18 in north central Indiana near the towns of Muncie and Marion.
With the larger segments exceeding the size of wet-out facility capabilities and no space to accommodate an over-the-hole wet-out at the project site, the company constructed a special outdoor staging area to impregnate the liners with resin. The size of the liners exceeded the size limitations of an enclosed refrigeration trailer; therefore, the tube was hauled to the site on an oversized flatbed using approximately 4,000 lb of ice. A specially engineered conveyance container was implemented to control the temperature of the transported tube and prevent any premature activation of the resin catalyst.
For each oversized segment, the wet-out process was initiated at sunset so it would be ready for transport during the cooler hours of the evening. Increased travel time needed to be incorporated into scheduling due to the circuitous routes resulting from oversized load permitting.
Most of the installation sites were located in wooded areas, allowing for little space to set up installation equipment. With some wet-out tube weights approaching 50,000 lb, two synchronized mechanical excavators were used to handle and place the tubes into installation position. Because the corroded culverts might further fracture during a pull-in installation, the crews used the direct inversion process of inverting the tube into the pipe using air pressure to install the tube, then cured the liner with steam.
The rural settings and busy, two-lane highway locations of the pipe segments presented additional challenges. In most cases, the crews were able to maintain traffic flow in both directions for the duration of the installation. The environment also was an important consideration.
“We used great caution to ensure the foliage and natural landscape were not compromised,” said Tyson Crandall, project manager for Layne Inliner.
“Inliner CIPP is ideal for these environmentally sensitive projects,” said Geoff Yothers, director of Inliner Technologies. “Both our steam-[cure] and new UV light-cure technologies are reliable methods of renewing damaged and aging pipe infrastructure with minimal impact on the environment.”
