Project Description

The Project

The Garden State Parkway (GSP) is a controlled-access toll road that stretches the north-south length of eastern New Jersey. The GSP connects the state’s southernmost tip near Cape May to the New York Stateline at Montvale. The GSP is the longest highway in the state at approximately 172 miles, and it was constructed between 1946 & 1957.

Garden State Parkway

The New Jersey Turnpike Authority (NJTA) maintains the parkway along with the New Jersey Turnpike.

According to the GSP historical records, the parkway was designed to be more than just a road, it was to be a driving experience like no other. Unlike many roads built before and after, it blended functionality with the sense of freedom and adventure. At the time of its construction, the GSP was a symbol for the strength of American infrastructure and economic opportunity. It is now recognized as a historically significant resource by the New Jersey Historic Preservation Office.

In 2019, the NJTA identified two, large failing culvert structures at Mile Posts (MP) 117.4 and 117.85, in Monmouth County that conveyed the Little Luppatatong Creek under the parkway.

McCormick & Taylor (MT) of Mount Laurel, NJ, was tasked with conducting initial field inspection, alternative analysis, and final design, in order to determine whether to rehabilitate or replace the culverts.

MT was also tasked to perform the required hydrologic and hydraulic (H&H) analyses to obtain the Flood Hazard Area (FHA) and Freshwater Wetland (FW) permits.

The culvert under the southbound lanes at (MP) 117.4 measured 180 ft. long with an existing opening of 10’-11″ x 7’-1″ that was originally installed in an arched shape using Corrugated Metal Plate pipe (CMP).

According to a Culvert Inspection Report dated 09/21/2018, the overall condition of the culvert was assessed to be poor. This was due to numerous corrosion holes at the invert of the CMP culvert, and an area of distortion measuring 6” extending for 15 LF located at the crown of the south side of the culvert.

The culvert was in need of rehabilitation to assure safety and stability of the roadway and to restore the hydraulic capacity of the culvert.

Based on field observations and findings, it was determined that the existing culvert required structural lining to ensure continued service.

The second structure is located at Milepost (MP) 117.85 under the southbound lanes of the GSP.

This culvert measured 90′-0″ long with an existing opening of 14′-2″ x 8′-10″ (170″ x 106″) arched Corrugated Metal Plate pipe (CMP) with a concrete lined invert.

Field inspection of the culvert revealed numerous corrosion holes throughout the entire length of the structure along both edges of the concrete invert slab.

A 10 ft. long section of culvert showed 100% section loss with soil deposits located above the south edge of the invert slab. A 7’ diameter by 2.5’ deep sinkhole developed directly above this deteriorated portion of the structure.

Severe roof distortion was observed at three (3) different locations with a combined length of 72 ft.Due to the severity in conditions of the culvert, MT recommended a structural lining solution.

Armed with data of the failing structural conditions of the two existing culverts, MT assessed 3 viable lining options in order to determine which would provide the most economical and appropriate solution. The three methods evaluated included:

  • Alternative 1  Steel Ribs & Reinforced Shotcrete Liner

  • Alternative 2  Reinforced Shotcrete Liner

  • Alternative 3  InfraSteel Steel Arch Pipe Liner.

All three (3) alternatives exhibited similar hydraulic capacity improvement when compared to the existing structures.

The selection of the most appropriate solution took into consideration certain constructability issues such as; headroom clearance for workers during construction, sensitivity to storm flows, and material lead times. Based on the above criteria, MT recommended Alternative 3 – InfraSteel Steel Arch Pipe Liner as it offered the most favorable ergonomics for the Contractor’s workforce during construction, the shortest construction duration at twenty- four (24) weeks, as well as the lowest overall cost at $2,610,000.

Based on the above criteria, MT recommended Alternative 3 – InfraSteel Steel Arch Pipe Liner as it offered the most favorable ergonomics for the Contractor’s workforce during construction, the shortest construction duration at twenty-four (24) weeks, as well as the lowest overall cost at $2,610,000. InfraSteel Permanent Culvert Rehabilitation Systems, is designed and developed by Precision Pipe & Products, Inc. of Birmingham, Alabama.

InfraSteel is designed to specific shapes and sizes. The liner can be manufactured in arched, elliptical or round shapes. The custom design sizes range from 26″ to over 240″ in diameter.

InfraSteel can range from ½” to 2” thick, and with a Manning’s Coefficient of .012, the new liner would provide greater discharge capacity when compared to the existing CMP and concrete.

With InfraSteel chosen as the preferred liner solution, the project bid was awarded to Joseph M. Sanzari Inc, headquartered in Hackensack, NJ.

Sanzari began site work on the project in March 2020, but were delayed in the culvert rehabilitation due to fish mating that occurs down stream in the spring and summer months. During this time however, they were able to build a service road across the median, which allowed for construction access, and would also allow for future use by emergency and parkway maintenance vehicles.

Sanzari was given authorization to proceed with the culvert rehabilitations in August 2020, which began with cleaning and prepping of the existing structures.

The culvert at MP 117.85 was the first structure to be addressed. The InfraSteel liner was shipped to the site in 8’-10’ long sections.

The new InfraSteel sections were pushed into the host using a hydraulic excavator, and the joints were welded from the inside, utilizing OD bands that were provided attached to one end of each section of the InfraSteel liner. The OD bands helped with alignment and full penetration welding.

Due to the corroded conditions inside the original structures, steel rails were placed in the invert, in order to aid in the slip-lining process.

Once the entire length was slip-lined, the annular space between the new and existing culvert was filled with grout. The grout was injected through 2”ports installed in the InfraSteel liner.

The culvert located at MP 117.4 had to be cleaned of sediment several times due to summer rainstorms. It was decided to double join the liner sections due to the length of the existing structure.

This process called for two liner sections to be welded together prior to installation.

Sanzari’s installation crew also installed wheels to the bottom of the liner to assist in insertion. As with the first culvert, once the liner was positioned in place, Sanzari grouted the annular space ensuring the liner was fixed in place.

Both projects were completed by October 2020.

It is important for all infrastructure professionals and traveling public to be aware, and on the lookout, for the common signs of an impending culvert failure. Many potential failures can be identified from the roadway surface by paying attention to the tell-tale signs of pavement cracking, eroding embankments, and dips or drops in the road and guardrails where there are creeks or streams.