November/December 2021 - 89

As with other Giken-type press-in
pi l ing machines, the Gyropress
equipment (which Giken co-developed)
does not require a service crane to move
forward or backward from one pile
installation to another. This capability
becomes critical when the overhead
clearance is limited, such as in the first
case study presented.
The Giken Reaction Base (GRB)
System involves a press-in piling machine
with a power unit, a clamp crane and
a pile runner; all work and move on top
of an already installed line of piles, using
that line as a narrow construction
staging area as well as an access path.
The pile runner hauls piles from
what can be a faraway access point by
travelling along the piles to the clamp
crane, which picks up a pile or piles and
brings them to the piling machine. Once
these pile sections are fully unloaded,
the pile runner goes back to retrieve the
next batch of piles. This system enables
pile installation on projects even where
construction access is impossible or
extremely difficult to secure, such as in
the following case study projects.
Bridge Abutment Repair
The Kyushu region of southwestern
Japan exper ienced very heavy,
continuous rain in a short period of
time in June 2016. More than 250 mm
(9.8 in) of precipitation was recorded
during a 24-hour period in the City of
Kagoshima where the Uto Bridge is
located. The bridge section of the
regional highway was immediately
closed when deep erosion of the slope
just in front of one of the bridge
abutments was reported. The highway
agency in charge determined that a
pressed-in pipe pile retaining wall
would be the only safe, reliable solution
to expediently protect the exposed
abutment because of the very steep,
unstable slope created by the flooding
right underneath it, in addition to
extremely tight construction access.
Project Logistics - The bridge has a
slightly curved 138 ft (42 m) long single
span wi th a two-lane highway
Clamp crane hoisting the final pile section
supported by its concrete girder. Fifteen
pipe piles were pressed in to form a very
solid earth retaining structure. The piles'
diameter was 59 in (1,500 mm), and their
length varied from 50.8 to 80.3 ft (15.5 to
24.5 m), with a wall thickness of from
0.59 to 0.83 in (15 to 21 mm). Each pile
was spliced once, twice or three times
depending on the pile's location and
overall length. The pile driving was
started from the downstream side
because of easier logistics compared to
the other side. The Gyropress machine
was assembled on the reaction stand,
which had been set on flat land prepared
on the downstream side of the abutment
(left side in the photo). The soil consisted
of weathered to fresh sandstone covered
with a thin surface clay layer that had
been spared from the stormwater. The
sandstone was expected to have an
average equivalent N-value of 275.
The self-standing height of pile No. 7
was as much as 39.3 ft (12 m). Piles No.
10 and No. 11 had three splices each
due to their lengths and the limited
overhead clearance under the bridge.
A challenge was finding a practical
way to bring the piles to the Gyropress
machine for installation under the
girder. A clamp crane was mobilized to
supply the section involving piles No. 10
through 15, which were installed under
the bridge girder. The crane was first
assembled on piles No. 1 through No. 3,
adjacent to the abutment, after these
piles were installed. Then the Gyropress
machine was moved forward to leave
these pile tops unoccupied. The crane
was equipped with a Y-shaped boom
end, allowing it to lift and hold one end of
pipe section within the minimal overhead
clearance. The heaviest section
lifted by the crane on this project was
slightly more than 11,000 lb (5 m tons).
Once the pile installation was
completed, the clamp crane and the
Gyropress machine were walked
backward on the installed piles to the
reaction stand next to the side of the
abutment and disassembled for
demobilization. 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.
Highway Seawall Retrofit
The Ci ty of Kamakura, located
approximately 40 mi (65 km) southwest
of downtown Tokyo, has been one of the
major tourist destinations in the region
DEEP FOUNDATIONS * NOV/DEC 2021 * 89
November/December 2021

Table of Contents for the Digital Edition of November/December 2021
