Walsh Construction rented two BAUER Drilling Rigs from specialty foundation equipment supplier Equipment Corporation of America to overcome challenging subsurface conditions during the $89.9-million Crum Creek Viaduct Replacement project in Swarthmore, Pa. Story by Brian M. Fraley, Fraley AEC Solutions, LLC.

1. Viaduct Replacement
With ECA Drilling Rigs
The international deep foundations
and marine construction magazine
EST. 1984
mar/apr 2016
Volume 32, Issue 2
published 6 times a year
PLUS
a young Project Engineer and the Folsom Auxiliary Spillway
Retaining Wall Project
NUMA Faces the Challenge
Emergency bridge replacement
By Condon-Johnson
sheet piling 101Different shapes, production types and project applications
Precision Pile by Meever USA

2. 24 Pile Buck Magazine | Vol.32 No.2 2016 | pilebuck.com
JOB STORY
A
BAUER BG
18 H Rotary
Drilling Rig sits
wedged between
an earthen
embankment,
a shotcrete-covered bridge
abutment, a maze of rusty
steel trestles, and the un-
derside of a historic railroad
viaduct in Swarthmore, Pa.
on a glacial January morn-
ing. The rig, working in a low
overhead configuration, was
supported by a BAUER BG
20 H, both of which prime
contractor Walsh Construc-
tion of Chicago rented from
the nearby Aldan, Pa. office
of Equipment Corporation of
America (ECA).
Rebuilding a
Historic Viaduct
This high-profile
$89.9-million Southeastern
Pennsylvania Transporta-
tion Authority (SEPTA)
project requires the complete
replacement of the 925-foot-
long, 100-foot-high Crum
Creek Viaduct. The structure
Walsh is replacing, built in
1895, underwent repairs in
1983 but was in dire need of
replacement to safely carry
SEPTA’s passengers on the
Media/Elwyn commuter
rail line. The original bridge
on this site was a pre-Civil
War era, five-span timber
arch truss bridge on masonry
piers. It was owned by the
Philadelphia, Baltimore
Washington Railroad (PWB
RR) and later acquired by the
Pennsylvania Railroad.
Walsh began construction
on the substructure in Sum-
mer 2015 and is working ag-
gressively toward an etched
in stone deadline of Summer
2017. Despite the variety of
construction processes in-
volved, drilling the founda-
tions for new footings, piers,
and abutments was the key
to the project.
No Ordinary Site
Conditions, No
Ordinary Drilling Rigs
Walsh and ECA began dis-
cussing the project in March
2015 at The International
Foundations Congress
Equipment Exposition (IF-
CEE). ECA’s Aldan Branch
Manager Tim Dutton and
Engineering Sales Manager
Gordian Ulrich walked the
site in April with Walsh Su-
perintendent Richie Vance
to determine which drilling
rigs would work best on this
challenging site.
It was ultimately deter-
mined that Walsh would rent
the BG 18 H and BG 20 H
Premium Line Drilling
By Brian M. Fraley, Fraley AEC Solutions
ECA Drilling Rigs a Perfect
Fit for Viaduct Replacement
Swarthmore, PA
The BAUER BG 18 H Rotary Drilling Rig works in low overhead configuration to install drilled shafts near the Crum Creek
Viaduct west abutment with limited overhead clearance. Walsh rented the BG 18 H and BG 20 H from Equipment Corporation
of America to install eight 20- to 58-foot-deep, 36-inch-diameter drilled shafts at each pier and 12 at each abutment.

3. pilebuck.com | Vol.32 No.2 2016 | Pile Buck Magazine 25
Rigs because they were
light enough to navigate
rough terrain with adequate
hydraulic output to core
through hard rock of up to
25,000 psi. The low head-
room capability of the BG 18
H was determined to be opti-
mal for drilling in work areas
with height restrictions.
ECA delivered both drill-
ing rigs in June 2015. The
BG 20 H, part of the Aldan
location’s existing rental
fleet, worked on site through
Christmas. ECA coordinated
manufacturing and delivery
of the BG 18 H with BAUER
Maschinen and imported the
rig from Schrobenhausen,
Germany. Its unique ability
to work in both low overhead
and standard configuration
kept the BG 18 H on site until
February 2016. ECA brought
in an operator from BAUER
to assist with training,
but all on-site service and
reconfiguration of the BG 18
H was handled by its own
technicians in Aldan.
These Premium Line
rigs offer some additional
benefits over BAUER’s
Value Line that were ideally
suited for the Crum Creek
Viaduct project. The main
difference between the
two is that the Premium
Line features a crowd cable
system with a winch as op-
posed to the crowd cylinder
system on the Value Line.
The Premium Line rigs, as
a result, deliver more crowd
force. They also comply with
the latest Tier 4 emission
standards, and are heavier
machines with greater hy-
draulic output.
Foundation Work
Sets the Pace
Walsh is tasked with
building a new viaduct
beneath the original struc-
ture before demolition can
commence. The keystone
of the project is foundation
work for the substructure,
which includes two abut-
ments and four sets of
piers. Walsh used the BG
18 H and BG 20 H Drilling
Rigs to install eight 20- to
58-foot-deep, 36-inch-
diameter drilled shafts at
each pier and 12 at each
abutment.
Vance indicated in Janu-
ary 2016 that drilling was
a week and a half behind
schedule primarily due to
unexpectedly hard rock
and environmental permit-
ting delays, but he was
The PIPE MILL with FAST SERVICE
Producing:
24”-192” OD
.312”-2.00” Wall
Lengths up to 120 ft.
Straight Seam - DSAW
20 ft. Lengths in Stock
Shipping Nationwide and Canada
with FAST SERVICE
800-821-3475
Fax: 815-964-0045
PipeSales@ArntzenCorp.com
TMRAMMING QUALIT Y
ArntzenBC_AD_Blue_BG_06_11_09.indd 1 7/8/11 2:05:36 PM
Walsh Construction is replacing the 925-foot-long,
100-foot-high Crum Creek Viaduct in Swarthmore, Pa.

4. 26 Pile Buck Magazine | Vol.32 No.2 2016 | pilebuck.com
JOB STORY
confident that Walsh would
be back on track shortly.
Despite the unforeseen
challenges, Vance was
satisfied with the drilling
production rate.
“Drilling is make or
break,” he says, as a SEPTA
railcar rattles across the
viaduct behind him. “De-
pending on how that goes,
it’s almost how the whole
job goes.”
Soil Conditions?
It’s Complicated
Project Geologist Bill
Bradfield of Schnabel Engi-
neering’s West Chester, Pa.
office describes the Crum
Creek site as “interesting.”
“We ran the full gamut of
drilling conditions within
the span of this bridge,”
he says, noting that meta-
morphic rock in this region
can be highly variable over
short distances.
The site contained
primarily Schist, but
production was hampered
when crews hit Amphibo-
lite. This extremely hard
metamorphic rock was
prevalent near the western
abutment and the Crum
Creek channel.
Bradfield recalls watch-
ing production drastically
improving from as little as
two feet per day with an
auger to a foot an hour using
the BAUER roller bit core
barrel, which is recognized
as a respectable rate of pro-
duction in hard rock. Walsh
initially tried a cluster drill
but had no luck keeping the
tool straight. The switch to
roller bit core barrels also
quieted drilling chatter and
reduced the strain on the
drilling rigs.
Roller Bit Core
Barrel Keeps
Production Rolling
Dutton confirms Brad-
field’s observations, noting
that the production increase
was mainly due to the
switch from conventional
tooling to the BAUER roller
bit core barrel. “With con-
ventional tools they were
getting two to three feet per
day,” he recalls, pointing
to an extracted four-foot
Amphibolite core. “When
the roller bit core barrel was
running in optimal condi-
tions they were getting a
foot an hour in some really
hard rock.”
Conventional drilling
tools could not stand alone
on this site, according to
Dutton. “This is the beast
here that did a lot of the
hard rock drilling,” he
says, pointing to a BAUER
roller bit core barrel. Walsh
initially considered down-
the-hole and hammer drills,
but ultimately decided the
core barrel was the right tool
for the job.
Walsh purchased 10 tools
from ECA, including pri-
marily 36-inch augers, core
barrels, drilling buckets, and
roller bit core barrels. There
were a few 42-inch tools for
overburden areas where the
rock was not immediately
below the surface.
Site Access, Low
Overhead, Steep
Slopes Vibration
Monitoring
The topography surround-
ing the viaduct is compli-
cated by steep inclines,
wetlands, the meandering
Crum Creek, and a narrow,
snake-like access road,
all encapsulated within a
densely wooded area that
happens to be a designated
arboretum. This challenging
terrain dictated not only the
selection of rigs, but also the
site preparation.
One of Walsh’s main chal-
lenges; however, was drilling
foundations in hard rock
beneath the viaduct with
limited headroom near the
east and west abutments.
Watching the BG 18 H
drilling below the farthest
western span of the viaduct,
makes it clear why its unique
low headroom capabilities
were essential. The rattling
tip of the mast is within
mere inches of the steel
girders. The BG 18 H worked
in standard configuration
from late June through early
October and was then recon-
figured to low headroom.
Site Geologist Bill Bradfield of Schnabel
Engineering measures the depth of a
recently drilled shaft beneath the viaduct.

5. 3841 Industrial Drive
Birmingham, AL 35217
205.841.8600
JeffreyMachine.com
That’s what makes every drilling toolJeffrey Machine
manufactures the best in the industry.
QUALITY.
PERFORMANCE.
PEOPLE.
PROUDLY
MADE IN THEUSA

6. 28 Pile Buck Magazine | Vol.32 No.2 2016 | pilebuck.com
JOB STORY
Vance says the height
restricted areas were more
severe than expected
because the viaduct eleva-
tions Walsh was initially
given did not account for
drilling nuances. He indi-
cates that maneuvers such
as putting the drilling rig in
crowd force, or pulling up
a full bucket can require up
to eight inches of additional
overhead space.
One of SEPTA’s key con-
cerns was ensuring that its
commuter trains could con-
tinue to pass safely across
the existing viaduct during
construction. Every pier and
tower on the viaduct has a
sensor to monitor for vibra-
tion. There are also four
inclinometers in each slope
to measure movement.
Custom Casing Drive
Adapter Reduces
Waste Cost
ECA designed and
fabricated a custom casing
drive adapter for Walsh to
facilitate overburden drill-
ing. Dutton watches as the
operator of the BG 18 lowers
the mast, inserts the adapter
into J-shaped notches in the
casing, and begins to seam-
lessly drill it into the soil
from the cab of the rig.
“We fabricated that at
the Aldan shop,” he says,
as the casing descends into
the soil. “You need some-
thing to transfer the torque
against, so Walsh cut those
j-shaped notches in the top
of the casing.”
Vance says this innovation
reduced costs and elimi-
nated wasted material. “We
pulled a lot of the casings out
as we drilled shafts so we
saved a lot,” he says.
Bridging the Gap
Between Utility
Aesthetics
Walsh has demonstrated
considerable environmental
sensitivity throughout the
project because of active
involvement by neighbor-
ing Swarthmore College.
Although SEPTA had the
right-of-way available for
the viaduct, it negotiated
with the college to use a
necessary adjacent piece of
land instead of using Emi-
nent Domain. In addition to
obtaining permitting from
multiple agencies, the con-
tractor will have to rebuild
wetlands, replace up to
6,000 trees and shrubs, and
reconstruct a Stonehenge-
esque circular formation
of Wissahickon Schist
slabs dubbed “Crumhenge”
by locals.
SEPTA will shut down
service for roughly 10 weeks
during Summer 2016 to
allow Walsh to install new
girders, bridge deck, and cat-
enary towers. Rail cars will
travel over the new viaduct
by Labor Day 2016. Walsh
will conclude the project by
Summer 2017 with demoli-
tion of the existing struc-
ture, removal of the access
road, and restoration of the
site to original condition.
As SEPTA passengers,
college students, and lo-
cal residents admire the
towering modern viaduct
that has replaced the rusty,
outdated structure that
once straddled this area of
natural beauty, the critical
foundation work performed
by two drilling rigs with
custom tooling will remain
unknown. The folks at
Walsh, ECA, and BAUER;
however, will relish their
role in providing safe pas-
sage for mass transit pas-
sengers and improving the
aesthetics of a critical piece
of infrastructure.
ECA designed and fabricated a custom casing drive adapter to facilitate the
drilling of overburden. It reduced costs and eliminated wasted material by
allowing Walsh to easily remove and install casings during the drilling process.