Volume 5, Issue 2 June 2020

Serial Report: Reports from USA (Part 5)

Improving Florida’s Drainage Channels with Pressed-in Sheet
Piles
Takefumi Takuma
Giken LTD., c/o Giken America Corp.

Shigeru Kambe
Blue Iron Foundations and Shoring LLC

INTRODUCTION

Drainage is becoming a more pressing matter, especially in low-lying urban areas in many parts of the world due to thesteadily rising sea level. For example, major streets of the City of Jacksonville Beach, which is located on the Atlantic coastof northeastern Florida, have been inundated often enough to need a comprehensive upgrade. The agency in charge ofFlorida’s state highways (Florida Department of Transportation) is improving State Road A1A (3rd Street), which runs
through the city from north to south, and its drainage system in the northern part of the city. The entire city was originallybuilt on a large sandbar and marshes and therefore, the area’s drainage has been heavily relying on a system of drainage
channels. The State Road A1A (3rd Street) Drainage Project is to widen and to improve a part of the existing drainage
channel in the densely populated residential neighborhood of the city.
PROJECT’S SCOPE OF WORK AND SELECTION OF PRESSED-IN SHEET PILE WALLS
The channel improvement involves the following work items.
 Tree and vegetation clearing and removal
 Steel sheet pile installation
 Dewatering Excavation and removal of roots, stumps, debris, and soil
 Placement of bedding stone and rip raps Placement of concrete capping on top of the new sheet piles walls New fencing and sod placement after regrading Replacement of 5 roadway bridges
See Fig. 1 for the typical conditions of the channel prior to construction.
The project is being worked on in Phases 1 through 7 including 5A and
5B to minimize the road closures and their associated detours. The work
area is very narrow between rows of houses, limiting the size of new
structures and the space available for construction activities. Therefore,
the self-standing vertical steel sheet pile walls were selected for thedrainage improvement for the majority of the locations. The project’splan specified “Non-vibratory Press-in Method Required” for most of
the sheet pile installation because the drainage channel runs directlybehind densely built homes and a high school campus where pilingrelated noise and vibration would be minimized with press-in piling(White et al. 2002). Some sections have a sheet pile wall just on one side
while the other sections have them on both sides as Fig. 2 depicts. The
project is designed by the Jacksonville, Florida office of Parsons
Transportation Group.
SOIL CONDITIONS AND SHEET PILE LENGTHS

Fig. 1. Typical Conditions of the Drainage
Channel before Construction

The project’s typical soil conditions are predominantly fine sand with N-values varing between 3 and around 30 to 35.
There are stiffer sand layers at some locations with N-values up to 47 at the depths of 7.6 to 8.5m, which are at near thepile tip elevations. The goundwater level is about 0.9 to 1.5m below the grade. The design sheet pile lengths are between
6.1 and 13.1m. Fig. 3 shows the vertical location of the project’s longest sheet pile in the corresponding soil conditions.

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Fig. 2. Typical Single and Double Sheet Pile Wall Configurations(Source: http://nflroads.com/ProjectFiles/5057/Sheet_Pile.pdf)

Fig. 3. Typical Soil
Conditions and VerticalLocation of Sheet PileSHEET PILE WALL INSTALLATION
Although the soil’s N-values were above 35 at certain locations, thepiling subcontractor (Blue Iron Foundations and Shoring LLC) wasable to complete all the piling work without use of a water jetting
or auger attachment, which would be essential for sheet pile
installation in denser granular or other types of hard soil (Roesneret al. 2006 and Takuma et al. 2018). The press-in piling quantity wasapproximately 23,100m2 (2,458m of wall length) with NZ19, NZ26,NZ28 sheet piles and NZ28 with plates welded on its flanges. Fig. 4shows the section of a coupled NZ28 sheet piles with welded plates
as an example. All the surface of the sheet piles was treated with azinc primer plus a tar-epoxy coating on the exposed area on thewater’s side for corrosion protection.
Fig. 5 shows a Giken ECO1400S press-in piling machine installing apair of sheet piles in a very narrow work area. The piling contractor
utilized a movable working deck which straddled between finished10Fig. 4. Section of NZ28 Sheet Piles with
Steel Plates(Source: Nucor Skyline)

Volume 5, Issue 2 June 2020
sheet pile walls on both shores for keeping the piling machine’s power unit safe and dry. Fig. 6 shows two sets of pilingmachines side by side; one extracting the old sheet pile wall with the other simultaneously installing a new wall where
the channel’s unsupported slope was kept minimal to avoid a potential collapse of residential properties behind it. Thefact that two sets of press-in piling machines could work in tight working space was also essential for the section behindthe high school, which needed the piling work finished during its summer break with two machines working
simultaneously.

Fig. 6. Extraction of Old Sheet Piles (Left) andInstallation of New Ones (Right)

Fig. 5. Press-in Piling of Sheet Piles

Once sheet piles were installed, capping concrete and fencing wereplaced on top as shown in Fig. 7. The sheet pile walls’ top elevations
were designed to meet the existing grade, therefore, the capping
concrete’s top surface also undulates over the longitudinal distanceaccording to the surrounding grade. The press-in piling work wasstarted in July 2018 and safely completed in late May 2020 with an
8-month break due to the work of the general contractor (The deMoya Group Inc.).
CONCLUSIONS
Pressed-in sheet piles can make highly reliable and space savingdrainage channel improvements safer even in densely populatedareas with very confined working space as exemplified by the casestudy project. There appear to be more of these types of channeland levee improvement projects in line not only in coastal Florida
but also in low-lying communities in the rest of the world; possibly
due to climate change and oncoming sea level rise.

Fig. 7. New Sheet Pile Walls with Capping
Concrete

ACKNOWLEDGMENTS
The authors appreciate the support provided by the Florida Department of Transportation as well as Masashi Nagano andIan Vaz, both of Giken America Corporation.
REFERENCES
Roesner, L., Sakai, T., Sjulin, B., and Takuma, T. (2016), “Deep Sheet Pile Bulkheads and Open Trench Shoring Driven by
the Press-in Pile Driving Method”, Proceedings of 2016 North American Society for Trenchless Technology AnnualConference, North American Society for Trenchless Technology.
Takuma, T., DellAringa, C., and Nagano, M. (2018), “Retrofitting Drainage Systems with Pressed-in Sheet Piles in Very Hard
Soil In Southern California”, Proceedings of Deep Foundations Institute 2018 Annual Conference, Deep Foundations
Institute.
White, D., Finlay, T., Bolton, M., and Bearss, G. (2002), “Press-in Piling: Ground Vibration and Noise During Piling
Installation”, Proceedings of the International Deep Foundations Conference (GSP 116), American Society of Civil
Engineers.
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