Water Pollution Control Plant in Painesville, Ohio. Image courtesy of the City of Painesville.
Microtunneling is becoming one of the most common forms of underground construction because it mitigates disruption of the project area. And in 2019, Press-Seal customer Northern Concrete Pipe, Inc., partook in a new US record for a single bore of pipe that rests in Lake Erie and stretches nearly three-quarters of a mile (1.21 km). The project in question? The City of Painesville Water Pollution Control Plant (WPCP) in Painesville, Ohio.
Why Was Northern Concrete Pipe Needed for This Microtunneling Project?
Microtunneling is very niche, and knowledge about pipe jacking among owners and engineers is limited at best. Due to the critical nature of each pipe segment along the line, concrete pipe is well-suited for these types of projects.
Northern Concrete Pipe, Inc., RCP.
Open-cut or trenching-type construction using concrete pipe has been common for decades, but today’s microtunneling contractors utilize jacking pipe with its end use in mind: pipes used in jacking need additional strength. Joints that allow for deflection and pipe gaskets that prevent infiltration and exfiltration are high on that wish list, too.
All this may sound overcomplicated, but plenty of North American concrete pipe manufacturers produce pipe segments that meet or exceed the expectations of microtunneling contractors. Some of these expectations quoted by contractors include:
- Rigidity. Point load obstacles during pipe jacking require a rigid characteristic found in reinforced concrete pipe (RCP).
- Joint design. Maintaining annular space with gaskets prevents sand and soil from increasing friction.
- Axial loads. Microtunneling contractors may need to apply extra force along the axial line to keep the string of pipes moving in the proper direction.
So, why Northern Concrete Pipe? Because the company is more than capable of delivering these expectations of high-quality jacking pipe.
How Was This Record Broken?
In November of 2016, Painesville, Ohio, initiated a $14-million project to improve the city’s pre-existing raw water intake. For more than 60 years, the 4,000-foot-long, 36-inch-diameter (0.91 m) intake pipe could only pull water 1,500 feet (0.46 km) from the shore of Lake Erie, rendering the remaining 2,500 feet (0.77 km) of pipe useless. Its shallow placement at only eight feet (2.44 m) beneath the water’s surface, along with harmful algal blooms in 2014, only further necessitated system repair.
The project’s construction contractor utilized a Herrenknecht AVN 1500 microtunneling machine to bore a path for the new intake line, which required RCP in order to be pushed out nearly 4,000 feet from the lake. Northern Concrete Pipe manufactured this pipe monster, boasting accomplishments such as:
Herrenknecht AVN. Image courtesy of Herrenknecht Tunneling Systems.
- Several 10-foot-long (3 m) pieces of 60-inch-diameter (1.52 m) C-wall pipe
- 395 sticks of RCP
- A resting home of 25 feet (7.62 m) beneath the shale and clay of Lake Erie
- A record-breaking length of 3,947 feet (1,203 m), demolishing the previous record of 3,000 feet (0.91 km) set in 2008 in Portland, Oregon, by nearly a fifth of a mile (0.32 km)
A microtunneling project’s required joint design is critical to the success of the push. Within those joints, it’s also important to utilize the correct pipe gaskets. For this record-breaking project, Press-Seal provided 0.75-inch (19.05-millimeter) isoprene O-Ring gaskets, as well as 1.125-inch (28.58 mm) isoprene O-Ring gaskets for the intermediate jacking stations.
Microtunneling Standards/Specifications
Common standards exist for open-cut construction; however, the microtunneling market is working on writing new specifications related to concrete pipe jacking. Some of these potentially new microtunneling specifications could easily be written based off current standards, such as ASTM C76-19 (Standard Specification for Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe) or ASTM C361-16 (Standard Specification for Reinforced Concrete Low-Head Pressure Pipe). The American Society of Civil Engineers has even published a book called Standard Construction Guidelines for Microtunneling.
The overarching point here is that changes and new developments constantly arise to encourage innovative improvements.
Business with a Record-Breaking Team
As more contractors put microtunneling into practice, they will be looking for success using concrete pipes. Concrete pipes are only as watertight as the gaskets that secure them together—which is why gaskets manufactured by Press-Seal are on the map. Reach out to us toll free at (800) 348-7325 or locally at (260) 436-0521, and we’ll get you started!