Volume 4, Issue 4 December 2019

Series Report: Reports from USA (Part 4)

Applications of the Press-in Piling Method to Emergency
Bridge Foundation Repair
Takefumi Takuma
Giken LTD., c/o Giken America Corp.
INTRODUCTION
Increasingly frequent and severe flooding damages foundations of bridge piers and abutments all over the world. Repairof compromised bridge foundations often requires steel cofferdams to be constructed under low lying bridge girders in
the face of hard soil without generating a high level of vibrations. The Press-in Piling Method can easily satisfy theseproject needs because of the way the method works. This article highlights the advantages of the method with two casestudies of emergency bridge foundation repair; one in the United States and the other in Japan.
CSX BRIDGE PIER REPAIR WORK IN COLUMBUS, OHIO, UNITED STATES OF AMERICACSX Transportation is one of a few freight railroad companies based in the United States, which has more than 30,000 kmof route track in the eastern parts of the U.S. and Canada. One of its rail bridge piers in Columbus, Ohio was heavily
scoured around its foundation, needing emergency repair work in 2015 (Fig. 1). The original pier foundation was on
timber piles with a concrete footing. The repair work was to drive micropiles around the original footing first with a larger
concrete encasement footing to be constructed after a sheet pile cofferdam was built. See Figs. 2 and 3 for the structuraldetails.

5.1m

Fig. 1. Bridge Pier with Damaged Foundation

Fig. 3. Cross-section of Cofferdam and Pier Foundation(Source: Richard Goettle Inc.)

8.4m

31.9m

New Concrete Footer
Fig. 2. Plan View of Cofferdam (Source: Richard Goettle Inc.)(Source: Richard18 Goettle Inc.)Volume 4, Issue 4 December 2019
The sheet pile cofferdam was to create dry working space around the damaged foundation to place tremie seal at thebottom and to construct a new larger reinforced concrete footing inside it. The construction of the cofferdam required
careful planning because of the limited overhead clearance under the bridge girder (5.1 m) and proximity to the damaged
foundation without generating a high level of vibration (White et al., 2002). For these reasons, the foundation
subcontractor chose to press-in sheet piles for the cofferdam. Fig. 4 shows the soil conditions at the pier with N-values
and the vertical location of the 7.5m long sheet piles. As can be seen, the soil was not very hard for the entire penetration
except sand and silt mixed with stone fragments found between 3.6 to 4.5 m below the GL. A water jetting or auger
attachment was not needed.
In order to work under the bridge girder, short sheet pile sections were brought over to the press-in piling machine by asmall track loader with a special arm to hold the short sheet piles in position after their lower sections had been pressedin (Fig. 5). Each new section was then spliced by welding to the lower section in place. With the sheets spliced together,
the press-in piling work continued. Approximately 9 sets of welded sheets were pressed-in per 10-hour shift. Fig. 6 shows
the concrete pier with the existing concrete footing, lines of new micropiles, and steel bar reinforcement placed inside
the sheet pile cofferdam.

Fig. 5. A Short Section Being Placed on Top of the Lower
Section for Splicing Under the Rail GirderFig. 4. Soil Conditions and Sheet Pile Location

Fig. 6. Sheet Pile Cofferdam and Micropiles for Larger
Encasement Footing

The cofferdam construction was finished within a short period of time without affecting the weakened pier foundationor the rail girder above it. Although this project did not encounter very hard soil, emergency bridge foundation repair
often faces gravel, cobbles, and boulders brought over by flooding. The auger attachment becomes essential for safe andefficient installation of sheet piles in these cases (Takuma et al., 2018). Additionally, sheet piles have been pressed in an
extremely low headroom (1.0m) situation in fast running water on a different project (Takuma et al., 2015).

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UTO BRIDGE ABUTMENT EMERGENCY REPAIR IN KAGOSHIMA, JAPANThe Kyushu region of Japan experienced very heavy and continuous rain in a short period of time on June 20, 2016 andthe following couple of days. More than 250 mm of precipitation was recorded during a 24-hour period in the City ofKagoshima where the Uto Bridge was located. The bridge section was immediately closed when deep erosion of the slope
just in front of its abutment was reported. See Fig. 7 for the degree of erosion nearly exposing the abutment’s foundation
at the beginning of the project.
The highway agency in charge determined that a pressed-in pipe pile retaining wall would be the only safe and reliable
solution to expediently protect the abutment because of the very steep and unstable slope created by the flooding rightunderneath it in addition to extremely difficult construction access.
Fig. 8 shows the concept of Giken’s proprietary GRB System involving a Gyropress piling machine with its power unit, aClamp Crane, and a Pile Runner; all working and moving on top of already installed piles while using the line of installedpiles as a construction staging area as well as an access road. The Pile Runner hauls piles from a faraway access point bytravelling on the piles to the Clamp Crane which then picks up one of the piles and brings it to the Gyropress pilingmachine. Once these pile sections are fully unloaded, the Pile Runner goes back to the access point for the next batch ofpiles. This system enables pile installation on projects even where construction access is impossible or extremely difficult
to secure such as this project.
Tubular Pile
Gyro Piler
Power Unit

Pile RunnerClamp Crane
Unit RunnerFig. 7. Severe Erosion in Front of the Abutment

Pile StageFig. 8. Concept of GRB (Giken Reaction Base) System

Uto Bridge has a slightly curved 42-meter-long single span with a two-lane highway supported by its concrete girder. Fig.
9 shows the plan view of this emergency repair work to prevent further erosion around the foundation. 15 of 1,500mm
diameter pipe piles were pressed in to form a very solid earth retaining structure. The pile’s length varied from 15.5 to24.5 meters with the wall thickness from 15 to 21 mm. Each pile was spliced once, twice, or three times depending on
the pile’s location and its overall length. The
pile driving was planned to start from thedownstream side because of easier accesscompared to the other side. The soil
condition was from weathered to fresh
sandstone covered with a thin surface clay
layer spared from the storm water. The
sandstone was expected to have an average
equivalent N-value of 275. See Fig. 10 for
the cutting shoe of the pile that enabled thepile installation into the sandstone. The
Gyropress piling machine rotated andsimultaneously pressed pipe piles into theground (Takuma et al., 2013). Fig. 11 shows
the installation of one of the piles in themiddle of the heavily eroded and unstableslope.
Fig. 9. Project Plan View
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Fig. 10. Cutting Shoe of Pipe Pile (Sacrificial)

Fig. 11. Pile Installation on Heavily Erodedand Unstable Slope

The highest self-standing height of these piles was as much as
12 meters. Since there were no other practical ways to bring
the piles to the Gyropress piling machine for the piling locations
under the girder, a Clamp Crane was mobilized to supply thesections to those locations. The crane was equipped with a Yshaped boom end, allowing it to lift and hold one end of pipe
section in the minimal overhead clearance as shown in Fig. 12.
The heaviest section lifted by the crane on this project wasslightly more than 5.0 metric tons.

Fig. 12. Pipe Section Supplied by Clamp Crane
Fig. 13 shows installation of the last pile under thegirder with the pile supplied by the Clamp Crane. Oncethe pile installation was completed, both the ClampCrane and the Gyropress machine were walked
backward to the reaction stand next to the side of theabutment and dissembled there for demobilization.
Fig. 14 shows the completed pipe pile wall after theequipment was removed off the piles. 200 mm wide
steel strips were welded onto both sides of each pile
to fill the 80 mm wide gaps between piles as designed.
The press-in force and torque were closely monitored
real time for smooth installation with minimal
vibration. Thanks to the combination of the rotating
cutting shoes and the press-in force simultaneously
exerted on the piles, the necessary press-in force forinstallation was relatively small, considering that thepiles were installed deep into fresh sandstone. The
piles were not for carrying vertical load so the verticalloading capacity was not calculated or tested.

Fig. 13. Last Pile Supported by Clamp Crane during Splicing

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Fig. 14. Pile Installation Completed
Finally, a reinforced earth embankment was placed against the abutment inside the retaining wall for its stability. The
pressed-in pipe pile wall provided a highly reliable earth retaining structure to secure the once threatened abutment.
CONCLUSIONS
Press-in piling can provide very safe and highly reliable bridge foundation repair solutions even in the face of extremely
difficult site conditions, such as low headroom, steep and unstable slopes, and very hard soil. A watertight cofferdam canbe built quickly with pressed-in sheet piles even in running water.
ACKNOWLEDGMENTS
The author appreciates the support provided by Richard Goettle Inc., Zefiro Corporation, and Masashi Nagano and Ian
Vaz, both of Giken America Corporation.
REFERENCES
Takuma, T, Nishimura, H., and Kambe, S. (2013), “Low Noise and Low Vibration Tube Pile Installation by the Press-in PilingMethod”, Proceedings of Deep Foundations Institute 2013 Annual Conference, Deep Foundations Institute.
Takuma, T., Nishimura, H., and Kambe, S. (2015), “Development of Very Low Head Room Press-in Sheet Pile Driver”,
Proceedings of the International Foundations Congress and Equipment Expo 2015 (GSP 256), ASCE.
Takuma, T. (2018), DellAringa, C., and Nagano, M. (2018), “Retrofitting Drainage Systems with Pressed-in Sheet Piles inVery Hard Soil In Southern California”, Proceedings of Deep Foundations Institute 2018 Annual Conference, DeepFoundations Institute.
White, D., Finlay, T., Bolton, M., and Bearss, G. (2002), “Press-in Piling: Ground Vibration and Noise During Piling
Installation”, Proceedings of Deep Foundations 2002 Conference (GSP 116), ASCE, Reston/VA: 363-371.

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