As an infrastructure manager, one of the last things you want to see is a sinkhole threatening a major roadway in your district. When you do, you know you need to act fast! Having tried and tested solutions, and knowing in advance how others have addressed similar issues, enables you to make quick decisions effectively and successfully.
The New Jersey Department of Transportation (NJDOT) faced one of those emergency sinkhole situations and found a solution that worked well for them. The intersection of Routes 9 and 440 with the Garden State Parkway (one of New Jersey’s busiest stretches of highway) is vital to the state’s transportation system – linking many of New Jersey’s major business hubs. When Hurricane Irene swept through the area, sinkholes began appearing. The stormwater emergency manager for the NJDOT inspected the site immediately and found more than 500 feet of 60-year-old pipe to be failing. Joints were falling apart, surrounding soil was collapsing into large-diameter corrugated metal pipe (CMP) storm sewers and some inverts were completely rotted out.
Clearly, a major overhaul of the sewer pipe system was needed in order to maintain the highway’s structural integrity. To make matters worse, the heavy storms in the aftermath of Hurricane Irene produced torrential rain and repairs would have to be done in miserable, soggy conditions. The pipe diameters were large. There was 300 feet of 72-inch bituminous-lined CMP and about 240 feet of 60-inch bituminous-lined CMP. Since this cloverleaf complex is an integral part of the highway, keeping traffic moving constantly is a necessity. You can ask yourself, “How could such extensive repairs be undertaken without inhibiting the flow of traffic for weeks while it’s constantly raining?”
Options such as open-cut replacement or cured-in-place-pipe (CIPP) posed plenty of issues. Open-cut replacement would stop the traffic, installation could be slowed due to the sloppy, wet conditions, and is an expensive process. With the size of the pipes, CIPP is also expensive and the process also can slump or pull away from the surface during installation.
According to NJDOT’s stormwater emergency manager, the best, most viable option ended up being our centrifugally cast concrete pipe (CCCP) system called, CentriPipe. How the CentriPipe process works is that a spincaster is drawn through the pipe at calculated speeds applying thin layers of fine aggregate composite concrete. Multiple layers bond to each other and are applied to reach the determined thickness according to what’s specified. Calculations are based on depth of cover, pipe conditions, pipe size and shape, soil types and groundwater pressures. CentriPipe ultimately rehabilitates your pipe by giving you essentially a new pipe. CentriPipe gives you a joint-free concrete lining that seals the damaged host pipe and it’s designed to give it full structural support. CentriPipe’s high strength-to-thickness ratio also maximizes the interior diameter and flow capacity, which CIPP can’t do. CentriPipe gives you the ability to completely rehabilitate the large diameter CMP without stopping the flow of traffic and it can be done in all sorts of weather conditions.
CentriPipe requires the applicator to divert the flow of water while the process occurs. Hurricane Irene made it extremely difficult to divert the flow for extended periods of time but because of our self-consolidating, fast curing and high-strength fine aggregate cement products (PL-12,000 and PL-8,000), multiple passes with the spincaster could be done quickly. The ultimate test of the CentriPipe process came when a storm passed through within hours of a pipe being rehabilitated. Five inches of rain dumped within a couple of hours. When the pipe was inspected after the storm passed, none of the rehabilitated pipe was damaged. The CentriPipe process and the PL-12,000 and PL-8,000 products set up quickly enough to withstand the immense pressure of stormwater moving through.
NJDOT was extremely happy with the results of the project. According to NJDOT’s stormwater emergency manager, the project was done on time and the results looked good. The manager said, “We will definitely be using this technology again and especially in emergency situations like this one.”
The NJDOT is just one example of how CentriPipe can help you with your next pipe project. CentriPipe can fix severely damaged pipe faster than you think. Instead of replacing the pipe, try CentriPipe.