ABSTRACT
The New York State Department of Transportation (NYSDOT) has completed several centrifugally cast
concrete pipe (CCCP) rehabilitation projects and is now quite confident that this process results in a high
quality and cost-effective solution for trenchless rehabilitation of culverts. After completing several pilot
projects, the process was specified in early 2014 for emergency rehabilitation of a 300-foot, 36-inch
CMP culvert running under six lanes of Interstate 684, which connects Connecticut with New York City
and is one of the state’s busiest thoroughfares.
NYSDOT most recently leveraged CCCP technology on a culvert rehabilitation project of significant size and scope. With dozens of large culvert projects identified in Seneca and Onondaga Counties, five were awarded to Arold Construction Company as a subcontractor in a standard bid process. Vice-President Ryan Arold (who also performed the I-684 work) has been doing CentriPipe® projects – a NYSDOT approved CCCP solution – since 2011, and has found that this really is the right technology for many large-diameter culvert and sewer rehabilitations.
Figure 1: NYSDOT I-684 Site Location
INTRODUCTION
When evaluating rehabilitation methods for deteriorated culvert pipe, the consideration of several criteria will help determine the best choice. Common options for rehabilitation include dig-and-replace, cured-inplace pipe (CIPP), high-density polyethylene (HDPE) sliplining, and centrifugally cast concrete pipe (CCCP). Criteria for consideration should include surface development, structural requirements, staging area, flow requirements, cost, and pipe configuration. The potential strengths and limitations of each of the possible rehabilitation options must be evaluated within the requirements of a given project.This paper will explore several NYSDOT projects and the purpose, implementation, and results of using CCCP in these situations.
SITUATION OVERVIEW
NYSDOT I-684 Project
Several situational factors made CCCP a good match for the I-684 project. The 300 feet of 36-inch CMP culvert requiring emergency repair runs directly underneath I-684. Steady traffic traveling at 65 mph meant the staging area needed to be minimal.Additionally, the repairs were required during a cold New York December,and the selected repair method needed to provide an efficient, high-quality rehabilitation result within these conditions. A third factor specific to this project was the existence of bends in some sections of the culvert,including a 45° bend in the middle of one section.CentriPipe®, the CCCP solution implemented in this project, easily and flexibly addresses each of these situational elements. Staging area is minimal.
Figure 2: NYSDOT I-684 36″ Culvert
In this case, moving crews from one work area to another sometimes involved crawling through pipe or driving 20 minutes to an exit and back, but actual staging areas were limited to the median and adjoining land.
Cold weather application of the engineered fiber-reinforced liner material PL-8,000 by AP/M Permaform, does require some additional planning and attention, but heating the mix water and having heaters on site were all that were required, enabling the completion of one centrifugally-cast pass per section each day.Further, the CentriPipe process evenly applies material throughout all pipe sections, including those with bends.
NYSDOT Region 3 (Syracuse area) Project The five culverts in Seneca and Onondaga Counties – NYSDOT Region 3 (Syracuse area) – awarded to Arold Construction Company comprise the
largest CCCP contract to date for the subcontractor.While not emergency repairs, most of
the culverts involved rotted inverts and visible corrosion, and were near failure.
Dimensions of the culverts as follows:
• Site 1—500’ of 8’x6’ elliptical CMP
• Site 3—200’ of 6’x4’ elliptical CMP
• Site 5—50’ of 6’x4’ elliptical CMP
• Site 6—50’ of 6’x4’ elliptical CMP
• Site 10—200’ of 5’ CMP
Figure 3: NYSDOT Region 3 Equipment Staging
Site 1, at 500 feet, is an outlier in the above list: a very long, very large culvert, running under several lanes of crowded interstate and a couple of frontage roads. It also features two approximately 40 degree bends at two large drop inlets in medians. The volume, the two bends, and other factors made this project a good fit for CCCP rehabilitation. The bends and size ruled out cured-in-place (CIPP) and sliplining. Additionally, the minimal staging area worked against other methods.
Figure 4: Flow Bypass Set-up on Region 3 6’x4′ Elliptical CMP
ENGINEERING AND DESIGN
CentriPipe is a structural solution. The liner layers build up a brand new concrete pipe inside the old sewer or culvert, and the new pipe does not rely on the old substrate for support.The new pipe is smooth and seamless from end to end, with no joints, even at
bends. The new pipe can be as thin as half an inch, which is useful where culvert capacity is an issue.Design thickness for the I-684 project was specified at one inch from the top of the corrugation. The material adheres tightly to the substrate and culvert capacity is not significantly reduced.For the Region 3 project, NYSDOT specified a total thickness of two inches over pipe corrugations.
INSTALLATION AND QUALITY CONTROL
The first step in preparing the I-684 culvert for repair, began with Arold pouring new inverts in the failing CMP to provide the CentriPipe spincaster with a smooth surface for the withdrawal process. The inverts were
filled with PL-12,000, a self-leveling mortar also manufactured by AP/M
Permaform. With the inverts repaired, the spincaster was pulled through the pipes with a high-pressure washer to clear out debris.
Figure 5: I-684 Culvert with severe corrosion and deterioration prior to
new invert and rehabilitation
Spot repairs were made where needed to even out damaged areas and ensure even application of the centrifugally cast liner. The 300 feet of culvert was repaired in five sections, working from manhole to manhole. Two passes, each
centrifugally applying a half inch layer of PL-8,000, attained the needed thickness. To ensure uniform application, interior diameter measurements were taken at spots along each section, and then remeasured after each pass. The relatively smaller pipe diameter for this
project necessitated that the sled operator follow behind the sled, rather than ride on the spincaster itself. The sled operator communicates with exterior crews to speed up and slow down as needed. In this case signals were facilitated by radio communication.
Figure 6: Conducting high pressure scouring and debris removal with
Vactor truck on Region 3 pipe.
In the case of the Region 3 pipes, preparation began with dewatering by the general contractor. Next, actual work on the culvert began with highpressure scouring, and the pouring of a new level invert, required for applying smooth, even layers in the spincasting phase. The material specified adheres well to host pipes, even when damp, bonds uniformly with previously applied layers, and cures quickly.
Figure7: Region 3 Staging area with small crane truck
For this project, Arold worked from both ends of the culvert, pulling the spincaster from the middle out to each end, applying a total of eight layers of PL-8,000. As with the I-684 project, the staging area was very limited, with only medians and narrow shoulders available. The shoulders were expanded slightly with small temporary pads to increase the staging area a bit. To further assist with logistics, the firm brought in a small truck crane capable of lifting material pallets, equipment, and even the pump trailer, and setting them up to 70 feet away. The crane was brought in mornings and evenings to set up and take down job sites in the median and on shoulders, without taking down guardrails or keeping other trucks onsite. It also eliminated forklift use, a good thing on highway projects.
Arold also completed structural repair of two large drop inlets feeding the culvert from the medians. Both inlets were covered by 10’ x 10’ grates, with
drops over eight feet deep. For the rehabilitation, Arold hand-sprayed PL8,000 in several thin layers, working from the inside of each inlet, and
troweling after each layer. The completed inlet walls were clean, structurally sound, and smooth enough to look like new construction. Arold was on Site 1 for about seven weeks. Work on all five culvert sites began on June 8th, 2015, and was completed on September 22nd.The applied thickness for each pipe was verified by daily onsite inspection, and by measuring internal pipe diameter after each pass
Figure 8: Region 3 Rehabilitated 10’x10’x8′ Drop Inlet
CONCLUSION
NYSDOT has completed pilot tests, the I-684 project, the Syracuse region pipes, and other projects using the CentriPipe solution. The rehabilitation process creates a monolithic, structurally sound concrete pipe cast within each of the failing pipes, leaving no gaps or annular space between the new
pipe and original substrates. The ability to apply the material in a variety of weather conditions, with
Figure 9: Rehabilitated I-684 culvert section
Figure 10: Rehabilitated I-684 culvert section
Figure 11: Region 3 Elliptical CMP before rehabilitation
Figure 12: Region 3 Elliptical CMP after CCCP rehabilitation
limited staging area, and in pipes with sharp bends and severe corrosion, makes CentriPipe a very versatile solution. This method provides NYSDOT with a cost-effective, long-lasting, trenchless solution to their culvert renewal program.
BIOGRAPHY
With fifteen years of trenchless construction and marketing experience in the Northeast, Tom Perry has
a strong background in the utility/infrastructure field. His enjoyment of what he does has been a
tremendous asset in his endeavors with municipalities, contractors, counties & DOT’s. If you have a
challenge or just a question, Tom will be available with a solution or help you find one.