eed earth retention? Whenever you dig into the
ground there are several items that you need to think about:
Protection of the workers during construction
Adjacent structures
Utilities
Public/municipal/private property
Thatcher Engineering provides full engineering and project management services:
We have an in-house licensed Structural Engineer and a Civil Engineering Ph.D. We know
design/build.
Let our experience help you reduce your costs. The earlier we become involved in the project, the
more we can optimize the design. It is not uncommon for us to optimize ourselves right out of work!
For projects in Chicago, we can help you navigate the citys permit process. We can shave days,
weeks, and sometimes months off the process.
How do you know which type of earth retention is right for you? Below is a very basic chart to guide
you through three typical systems:
DRIVEN/DRILLED PILING EARTH RETENTION SYSTEMS MARINE DESIGN/BUILD
T
HATCHER
E
NGINEERING
C
ORPORATION
Soldier Beams
Soil Nails &
Soil Condition
Sheet Piling
& Lagging
Shotcrete
TM
Granular soil, excavation above water table
X
X
Granular soil, excavation below water table
X
Cohesive soil, excavation above water table
X
X
X
Mixed soil, excavation above water table
X
X
Mixed soil, excavation below water table
X
Retaining wall, back filled after installation
X
X
Any soil, excavation next to existing structures
X
X*
*Cohesive soil and underpinning is necessary
Earth
Retention The most common types of earth retention are sheet piling and soldier beams and lagging. They are
usually installed in the following configurations:
Cantilevered for shallower excavations, typi-
cally 8 feet or less if there is no adjacent struc-
ture.
Internally Braced walers and struts transfer
the load to the opposite wall, concrete dead-
men, or sheet piling deadmen. Typical of
deeper excavations, 8 feet or more, or if there
is an adjacent structure.
Tie-backs soil anchors are drilled through
the sheet piling or soldier beams, grouted, and
tested for design capacity. The load is trans-
ferred through a waler. Typical of deeper
excavations, 8 feet or more, or if there is an
adjacent structure. Also used if the excavation
must be free of obstructions.
Combination of all three not all sites are uniform on all sides, therefore, we typically utilize one or
more to optimize the earth retention system and reduce costs.
Thatcher Engineerings goal is to provide the most cost-effective, least obtrusive earth retention system
while affording the maximum protection to workers on the site and minimizing movement of the adja-
cent earth.
I
n the winter of 1958, a very reputable and upstanding General Contactor tried to make an open excavation
along Jackson Street in the west Loop. It was early January and the ground was frozen so they didnt think
that they needed to have any earth retention. After all, the ground was hard as a rock and it was only going
to be open for a few days. Whats the worst thing that could happen?
A
thaw. A couple of days later as temperatures crept above 40°, the ground started to creep into the excava-
tion. Pretty soon water mains were cracking and electric lines were breaking. Thatcher Engineering got a
phone call in the afternoon. We were there the next morning. We set up our Office Trailer in Lou Mitchells
Coffee Shop. The job was completed and order restored. But our work wasnt done there. 45 years later, we
are still providing earth retention all around Chicago, the suburbs, and northwest Indiana - everywhere it is
needed. And you can still find us at Lou Mitchells most mornings at 5:30 a.m. sharp.
T
HATCHER
E
NGINEERING
773-721-9797 Phone
773-721-1011 Fax
info@ThatcherEng.com
www.ThatcherEng.com
Call us today and let us show you how we can help you complete your project on time and on budget.