September/October 2023 - 18

Excavation and temporary roof shoring
that had not yet been designed when soldier pile work started,
often required the relocation of a tieback for greater access or
to avoid a conflict. The engineering team developed a unique
" stub waler " to be attached between the webs of adjacent
soldier piles in the field to allow for flexibility in the tieback
locations as the team identified conflicts. This ability to adapt
to actual field conditions could have only been achieved using
the soldier pile and lagging system.
Access Ramp
A very significant construction change illustrated the full
flexibility of using the soldier pile and lagging system. Shortly
after the installation of the soldier piles, the contractor found
that it needed to install a temporary ramp into the site. The
ramp was to be located through the snorkel in the southwest
corner of the new arena and would penetrate though the
soldier piles. The need for the ramp was immediate, and a
decision was made to build the ramp
first and then determine how to
accommodate the finished wall and
snorkel construction afterward. A
second row of soldier piles was
constructed parallel to the arena's final
foundation wall to create the ramp into
the arena from exist ing grade.
Temporary tiebacks extending under
the roadway to the west supported the
new soldier piles along this alignment.
However, any tiebacks installed in the
north-south direction would clash with
the permanent tiebacks already in
place, and it was deemed too risky to
use them to support the ends of the
ramp. Thus, internal bracing with
clearances large enough for construction
vehicles was used to support
the ends of the ramp excavation. This
bracing extended directly through the
snorkel. The remaining soldier piles
along the perimeter of the arena were
left flagpoled by excavating on both
18 * DEEP FOUNDATIONS * SEPT/OCT 2023
sides, with no tiebacks installed during excavation. Soldier
piles at the bottom of the ramp were simply cut off to allow for
truck access. The ramp was used for removal of most of the
excavated soil as well as importing nearly all the construction
materials for the arena.
While the construction of the access ramp was a challenge,
it turned out to be easier than finding a way to build the snorkel
and refill the ramp without the permanent perimeter wall
tiebacks in place. The ramp left 65 ft (20 m) of flagpoled soldier
piles with no support against earth pressures once the ramp
was filled. A snorkel structure and a stormwater detention
tank were constructed within the limits of the temporary ramp
while the remainder was backfilled. Once the ramp was no
longer needed, it was decided to construct the snorkel first and
then take on the 65 ft (20 m) high backfill required against the
flagpoled soldier piles. The snorkel daylighted into the below
grade portion of the arena about 15 ft (4.6 m) above the lowest
The southwest snorkel, or west temp ramp showing the crosslot bracing and drive aisle for truck traffic

September/October 2023

Table of Contents for the Digital Edition of September/October 2023