Volume 6, Issue 2 June 2021

Case-History

Rapidly Increasing Press-in Piling Projects in New York
Metropolitan Area (Part 2)
Takefumi Takuma
GIKEN LTD., c/o Giken America Corporation

Masashi Nagano
Giken America Corporation

INTRODUCTION
In March 2019, the Giken America Corporation, a U.S. subsidiary of GIKEN LTD., opened a New York City office as its newheadquarters in the Americas with a goal to focus on the most populous region of North America. This article will be
discussing the press-in piling projects along the Gowanus Canal in the Borough of Brooklyn as part of GIKEN’s recentachievements in the New York Metro region.

GOWANUS CANAL – EPA (ENVIRONMENTAL PROTECTION AGENCY) SUPERVISED CLEANUP SITE
The Gowanus Canal is a 2.9km long and 30m wide canal located in the industrial zone of Brooklyn which discharges into
the New York Harbor. It was built in the mid-1800s for the purpose of industrial transportation. Since the mid-20th century,
however, the cargo volume drastically decreased with the main mode of domestic cargo transportation taken over bytrucking. Manufactured gas plants, paper mills, tanneries, and other chemical plants on the sides of the canal operated
and discharged their waste water into it. That in combination with the overflow of surface water and untreated sewage
made the canal one of the most contaminated water bodies in the United States. High levels of toxic chemical compounds,
fecal coliforms, and heavy metals including mercury, lead, and copper were found. Due to its proximity to Manhattan andthe high-end residential neighborhoods in Brooklyn, the area near the canal started to experience rapid gentrification,
prompting the canal’s environmental cleanup. The EPA listed it on the National Priority List of Superfund sites (Federallysupervised priority environmental cleanup sites) in 2010 and the cleanup preparation work started in 2013. Fig. 1 shows
the general location of the canal in the boroughs of New York City and Fig. 2 shows an aerial photograph of the canal andthe surrounding urban areas.

Gowanus Canal ProjectFig.1. Location of Gowanus Canal in Brooklyn, New York

500m
Fig. 2. Aerial View of Gowanus Canal (Google Map)

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The cleanup scope of work involves the dredging of approximately 450,000 cubic meters of highly contaminated sediment,
placement of clean soil material and its capping, and construction of retention tanks to reduce the discharges fromcombined sewer outfalls. In addition, the deteriorated bulkheads facing the canal have to be reconstructed at many
locations at the expenses of the landside property owners before dredging. The pilot work was started at the 4th Street
Turning Basin in 2016.

USE OF PRESS-IN PILING
In 2018, as part of the bulkhead reconstruction of the pilot work, press-in piling was added for testing after the use of avibratory hammer had caused major ground settlement and resultant closure of the promenade of a high-end
supermarket. The one-month-long press-in piling test for the total wall length of 273m exhibited much less noise,vibration, and settlement; satisfying most of the project requirements. Following the test result, the first full-scalesegment of the Gowanus Canal remediation project at the Municipal Works Former MGP Site specified press-in piling for
sheet pile installation. The soil conditions consisted of the top layer of contaminated soft soil and the underlying gravel
layer with equivalent N-values reaching from 20 to 100. In addition, many debris including metal pieces was found to bein the canal floor and the pile line. The use of an auger attachment or water jetting was not allowed because of highly
contaminated soil. Instead, predrilling was done by another method with excavated soil carefully and fully recovered andhauled away for treatment at a different location. Coated Z-shaped AZ46-700N sheet piles in lengths of 15.7m and 20.9m
were installed. Fig. 3 shows a typical cross section of the new sheet pile bulkhead wall and Fig. 4 shows the line of installedsheet piles with the press-in piling machine (Giken F401-1400 model) in the distance. In order to verify the sheet pilewall’s integrity against potential migration of contaminated water, sensors to detect complete engagement of theinterlocks were welded at the bottom of each sheet pile pair as shown in Fig. 5. The total wall length of approximately
226m of this segment was completed with press-in piling in September 2020.

Fig. 3. Typical Cross Section of Existing and New Sheet Pile Walls with Tie Back Anchors

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Fig. 4. Pressed-in Sheet Piles in the Gowanus Canal

Fig. 5. Non-declutching Sensor and Cable Conduit

SUMMARY
The low-noise and low-vibration advantages of the press-in piling method fulfilled the project’s need to minimize thesettlement and displacement of the existing canal frontage and nearby buildings as part of environmental remediationof the highly contaminated Gowanus Canal in New York. Also, the press-in piling’s ability to achieve very accurate
installation contributed to the formation of fully interlocked sheet pile walls as verified with non-declutching sensors.
Other future segments of the remediation work are likely to utilize pressed-in sheet piles.

ACKNOWLEDGMENTS
The authors appreciate the support provided by Ian Vaz of Giken America Corp.