ST8505-CS 890620GINN, INC.
CONSULTING ENGINEERS
June 20, 1989
/
Mr. Mike AlbUm, President
Ed Bell Co~truction Co.
P.O. Box/540787
Dalla~fl/~X 75354-0787
Re: 'Belt Line Road (South)
Pavement and Storm Sewer Lateral Repairs
Adjacent to the North Lake Park Property
Dear Mike:
Enclosed for your records is a copy of the revised
recommendations of our testing lab regarding the above referenced
subject.
Please correct these areas in accordance with the lab's
recommendations and schedule the testing lab accordingly. Please
indicate in writing which concrete mix design and borrow source
you propose to use for this work if they differ from the original
shop drawings approved for this project: 1) Gifford Hill mix
design (6 sack) for hand pours; 2) Belt Line Road (East) borrow
source.
On another issue, we are prepared at this time to begin review of
your contract closeout submittals immediately upon receipt.
Please call if you have any questions regarding this.
PoE0
KP/dsp X _
cc: Russel~le, P.E.
Steve.~am
H. Wayne Ginn, P.E.
Randy Fleming
File 255
17103 Preston Road ® Suite 100 · LB 118 · Dallas, Texas 75248 · Phone 214/2484900
Consulting Engineers · Ge·technical · Environmental · Construction Materials Testing
DALLAS · FORT V~ORTH · HOUSTON · AUSTIN
Ginn, Inc.
Consulting Engineer{
17103 Preston Road
Suite 100
Dallas, Texas 75248
June 12, 1989
Project No. DE89-047
Attn: Mr. Kevin E. Peiffer, P.E.
Re:
Repairs to Storm Sewer Laterals and Pavements
Beltline Road
Coppell, Texas
Gentlemen:
This letter is to confirm our conversation in the meeting of
June 9, 1989 regarding the above referenced project.
Results of field density tests performed on May 25, 1989 at
this site, as well as the observations of a TERRA-MAR
geotechnical engineer, indicate backfill and storm sewer
laterals generally exhibit high soil 'moisture content and
densities which are relatively low. In addition,' areas of
the natural subgrade have similar moisture contents with
some densities less than what would be specified for
recompacted soils.
It is our recommendation that backfill in storm sewer
lateral trenches which is not in compliance with pro3ect
compaction specifications be removed to the top of the sand
cement in the trench. Backfill should be replaced so that'
compaction is within specified ranges for moisture content
and density.
Based on the fact that the cement modified soil subgrade is
intact and that test results and visual observations
indicate natural soils to be compact, it is our opinion that
replacement of the natural soils outside the trenches is not
warranted. Given the 9 inches of Portland Cement concrete,
the 12 inches of cement modified subgrade, and subgrade
condition as indicated by test results and observations, it
is also our opinion the pavement structure is adequate and
should perform as designed. However~ it 'should be
recognized that there remains a risk of distress resulting
from subgrade movement for any pavement constructed on
expansive subgrade soils.
2679 Lombardy, Dallas, Texas 75220 Phone: 214-352-8352
Repairs should include replacement of lateral line backfill
at the specified moisture content and density. Onsite soils
or off-site soils free of organics or debris and with
similar properties should be utilized as backfill. It is
recommended that excavation of trench backfill extend about
one foot (transversely) outside the trench limits. This
would aid in sealing the trench against future surface water
infiltration.
Where cement modified subgrade has been removed it should be
replaced with sand cement, cement treated base, or a similar
material to grade of the remainder of the treated subgrade.
Any cracks or open joints in the cement modified subgrade
should be sealed with asphaltic cement joint compound prior
to replacing the pavement section.
Excavations for test pits should be repaired in a similar
manner.
We appreciate the opportunity to be of service. If we may
be of further assistance please do not hesitate to call.
Sincerely,
TERRA-MAR, INC.
Mark E. Wyatt, E.I.T.
Staff Engineer
Berry R. Grubbs, P.E.
Principal Engineer
MEW/BRG/sb
Project No. DE89-047
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