diligently, monitoring the wall for movement
with all the activity. These lessons
Bergerson Construction, Inc.
Marine & Heavy Civil Construction
55 Portway • Astoria, OR 97103
(503) 325-7130 • CCB# 63328
www.bergerson-const.com
caused us to rethink our strategy.
We asked our engineering team to study
the projections and performance of using
driven H-piles, socketed five feet into the
rock, vs. drilled H-piles socketed five feet.
The answer was within what was considered
acceptable. Upon further investigation,
we discussed our change in means and
methods with the owners and got approval.
This did mean bringing in crane mats,
a larger crane, vibrators and hammers and
installing the driven H-piles from the roadway.
We were very conscious throughout
this project to monitor the existing roadside
wall. Tiltmeters had been installed
from the first day of operations, setting
a baseline and allowing us to remotely
monitor any lateral movement in the roadside
wall.
Continued river flooding made the
H-piles driving challenging. Work was performed
by smaller barges placed in the proposed
loading dock area. The H-piles were
fitted with rock biting tips, to prevent them
from deflecting or walking. The 5’ embedment
criteria turned out to be successful
and the remaining 11 piles were driven to
final elevation.
Phase 3: Sheet piles
This next phase included sourcing
heavy gauge, 79-foot steel sheet piles.
Transportation and logistics were challenging,
as was the spatial constraints on site
in the lay down area. But falsework/template
material was installed, and sheet piles
were fitted with the rock bearing teeth,
to prevent deflection or walking. Next up,
the sheet piles were vibrated down to end
bear on the weathered rock layer. Once
the sheets were installed and end bearing,
extensions were welded to bring the tops of
the sheets to the final “top-of-sheet” elevation.
Again, all of this work had to be done
from barge/platforms, as it was flooded for
the majority of this phase.
Phase 4: Waler beams, tension ties,
drainage and fill
This phase was ensuring the new sheet
pile retaining wall engaged the 14 H-piles
that were previously installed. The design
basically consisted of two rows (top and
bottom) of waler and tension ties. Basically,
as designed by the geo-structural engineers,
a waler beam was installed on the back side
of the H-piles, and the other waler beam
was installed on the outside of the new
sheet pile wall. Alignment was critical, as
the waler beams were pre-manufactured
offsite. This means that final elevations and
the east/west layout had to be about perfect
in order for the tension ties to line up
and the tension ties to be squarely loaded.
Once the waler beams were installed, and
the tension ties connected the two waler
beams, a steel reinforced concrete encapsulation
occurred. Hundreds of cubic yards of
4,500 psi concrete was pumped and vibrated
to fully encompass the steel tension ties, the
waler beams and the steel reinforcement.
Our next priority was dealing with the
drainage and the soil loading. We created
a sloped bottom by pumping hundreds of
cubic yards of a 150 psi flowable fill with 12
inches of fall toward the river. This gave us
a strong bottom grade to evenly distribute
the loads above and ensure water drained
towards the river.
Once the flowable fill cured, we immediately
set up a conveyor system to import
the free draining, crushed stone. The stone
would bed the pipe in place to ensure it
was draining through the weep-holes in the
sheet piles. For maintenance design, piping
was installed vertical about every 18 feet
to provide access for flushing of river sediment
build up.
As the rock was placed, it would be
graded in 12-inch lifts, and compacted with
vibratory plate compactors around the
edges, and sheeps-foot trench rollers/compactors
and tracked equipment.
During fill operations, the roadside retaining
wall was monitored, compaction and
drainage practices were closely managed.
Phase 5: Structural slab on grade
and finishes
The last phase of this challenging project
was wrapping up the top side. It included a
12-inch structural slab on grade, thickened
edges, a grade beam and 35,000 pounds of
steel reinforcement incapsulated. It also
included a cast in place loading dock, boat
mooring, stairs and a ramp. Handrails and
fencing were replaced, and pavement was
placed to ensure safe access.
The operations phases of this project
began 9/1/2018 and was completed on
5/8/2019. There were zero accidents or injuries
on this project. t
MARINE: LESS THAN $5 MILLION
78 | ISSUE 3 2020 www.piledrivers.org
/www.bergerson-const.com
/www.piledrivers.org
