SS9402C-PR 97112510555 Newkirk Streel
Suite 530
Dallas, Texas 75220
972.831 .1 1 1 !
FAX 972.831.0800
The City of Coppell
255 Parkway Boulevard
P. O. Box 478
COppell, Texas 75019
November 25, 1997
?"'
Mr. Kenneth M. Griffin, P.E.
Assistant City Manager
City Engineer
PROPOSAL FOR GEOTECHNICAL CONSULTING SERVICES
Sewerline Backfill
Bethel Rd, - Grapevine Creek to Royal
Coppell, Texas
PBT Proposal No. 97-379
Dear Ken:
Patton, Burke & Thompson (PBT) is pleaSed to submit this written proposal, in accordance with our
site visit and conversations yesterday, for performing certain geotechnical consulting services for the referenced
sewerline.
GENERAL
It is our understandin& based on our discussion, the site visit on November 24th, review of construction
plans for the subject sewerline, readily available topo maps of the site area, review of construction density test
reports by EWI, City Inspector's (Garreth Campbell) field logs, and our past experience with similar
assignments, that the following baSic information is currently known about the area and problem to be
investigated:
The primary sanitary sewerline to be investigated is along Bethel Road (approximately between
Stations 2+00 through the end of the alignment near Station 73+00), involving approximately
7,100 linear feet of 10-inch to 12-inch PVC piping. The general alignment of the subject pipeline
is beneath the eastbound (i.e., southside) lane of Bethel Road.
Construction for the subject sanitary sewer was started in January-1996 and was completed in
May or June 1996. The construction primarily involved open-cut trenching type construction
utilizing a trenchbox. Furthermore, it has been reported that the trench was dug with a backhoe, ri
1
Pa*~on, hrke d~ Thompson ~
Engineering Consultants ~
The City of Coppell
Sewerline Backfill
Page 2
no groundwater was encountered during construction, the trench was approximately 4-feet in
top width and all trench backfill was compacted with a self-propelled, sheepsfoot, vibratory
compactor. The depth of excavation varied along the alignment but generally was in the order
of 10 to 15-feet.
The subject section of Bethel Road is an old roadway in the City and was part of the original
"Old City of Coppell" area. In this regard, there was an old existing 6 to 10-inch sanitary sewer
line with a profile somewhat similar to the new line but it's alignment was roughly 5-feet south
of the new 12-inch line. This old line extended fi.om the east (i.e., around Station 2+00) only up
to approximately Station 14+00. In addition to the old sanitary sewer line there are numerous
shallower, service lines (i.e., water, gas, etc.) which cross the study alignment for most of it's
length.
Visual observation of the pavement distress/settlement was made on November 24th, primarily
by driving the alignment but with no "on-the-ground" detailed examinations. In general, it
appears that the most severe and obviOUsly largest movements have oCcUrred along the
eastbound lane, and these movements seemed to have occurred in both open roadway sections
and'in the vicinity of various manholes. However, it appears in general that the frequency and
number of patched/repaired roadway areas is relatively l~s we_st of Freeport Parkway.
The City has indicated, and it generally was confirmed by site observations and a review of the
construction plans, that the original grade of the roadway was not modified or changed
significantly by the subject line construction. However, the roadway was repaved with asphaltic
concrete by the County once the sanitary sewer line construction was completed.
Although there are not currently available any records of a geotechnical investigation for the
subject sanitary sewer line design and construction, based upon our past experience in this
section of the City of Coppell the subject study area is believed to be underlain by the Eagle Ford
Shale formation, which in all probability include both the upper weathered clays and shales, and
the eventual unweathered shale section with depth. The depth to the unweathered, parent shale
along .the alignment is not known at this time.
SCOPE OF WORK
The principal purpose of this study, as PBT understands it at this time, is to carry out, a geotechnical
engineering investigation and to provide consulting services to assist the City in quantifying what is causing the
current pavement movements and failures.
The scope of work proposed by PBT at this time, based upon all of the above information and our past
experience with similar trench backfill problems, would consist of the following:
Geot~chnical Field E~xplOrations - Geotechnical-type borings will be drilled and sampled using
a truck mounted drilling rig. The magnitude of the envisioned field program at this time will
consist of a total of 6-borings along the alignment, generally over the centerline of the pipe.
[Note: One (1) of the proposed six (6) borings will be drilled along-the Bethel School Road
PhOton, Burke & Tkompson
[ngi, eedf~§ Consultants
The City of Coppell
Sewerline Backfill
Page 3
sewerline (generally between Plantation and Harris Streets) to serve as a "backfill comparisoff'
to the Bethel Road line.] For the purposes of this proposal, the (,-borings are planned for an
average depth in soil backfill of 10 to 15-feet below the current existing roadway grade.
The actual final depth of each boring, which depends upon the nature and extent of the backfill
conditions actually encountered, will be determined in the field at the time of drilling. However,
for the purposes of this proposal, the field exploration program will not exceed 90-linear feet of
total drilling and sampling. Groundwater levels, if encountered, will be recorded during the
exploration program, but it is anticipated at this time that all bore holes will be back-filled upon
completion of the field program with cuttings fi-om the borings, and the pavement will be patched
with either asphalt or concrete.
Assumptions Regarding Site and Field Work:
The borings will be located in the fidd based upon measurements fi-om existing features,
and the project plans. The City will assist PBT in locating utilities in the vicinity of any
proposed borings.
No sped'al germit or permission will be_ required of PBT to drill along the_roadway that ._.
will result in any major delays or additional cost.
Final selected boring locations will be flee of both overhead' or underground
obstmctions.
Assignment assumes that only non-contaminated/non-hazardous soils will be encountered
during the field exploration program. Otherwise, the proposed cost for the field and
labOratory investigations will need to be revised.
No extended inclement or severe weather conditions will be encountered during the
actual field program. ShOuld this condition occur, we will contact you immediately
regarding continuing to remain on site, or de-mobilize the field program to a later date.
C~otechnical'Laborato~ Testing - The final laboratory testing program will depend upon the
actual backfill conditions encountered in the test borings and soil samples recovered, but in
general is envisioned to involve the following:
Moisture content, unit weight, Atterberg limits and grain size analysis on selected
samples to evaluate classification and consistency properties of trench backfill soils.
Laboratory compaction tests to compare boring sample densities to field control testing
results.
Consolidation tests to evaluate compressibility of backfill soils.
Other laboratory tests as deemed appropriate upon evaluating findings of borings.
Burke & Thompson
Engineering Consultants
Sewerlinc Backfill
Pa§e 4
Bn~neering Anal_vsis/Written Report - The full extent of the analysis will depend upon the actual
findings of the field and laboratory testing programs, but is envisioned at this time to include the
following:
Backfill stratigraphy, in sim conditions and associated variability.
Evaluation of physical, consistency and compressibility characteristics of backfill soils.
Evaluation of findings and development of conclusions regarding probable mechanism
and cause(s) pavement distress/settlement to date.
Presentation of technical and practical alternatives for the deign and construction of
pavement stabilization remediation.
SCHEDULING OF WORK
Patton, Burke & Thompson will develop a firm schedule for the geotechnical exploration program
immediately upon your authorization of the .services outlined in this proposal. The field program, barring any
bad weather, is estimated tQ be completed in 1-1/2 to 2-working days after mob'dizafion_!o_the site. The
laboratory testing program, for selected soil samples retained l~om the borings, will be completed, with
exception of any consolidation testing, within seven (7) working days after field program completion.
Consolidation tests, depending upon the permeability of the sample, can take up to two (2) weeks to complete.
Preliminary verbal findings, if desired, can be presented within a couple of days after completion of the field
program. The final written report will be submitted within six (6) working days following the preliminary verbal
findings:
PRICING/CONTRACTING
Patton, Burke & Thompson proposes to perform the work for this investigation on a time and materials
basis, for the scope of work outlined above, for a maximum not to exceed budget of $4,800~
Furthermore, we propose to provide all services in accordance with PBT's General Terms & Conditions (Form
1-95/A), and any additions or modifications to the above referenced scope of work, with prior approval by you,
will be in accordance with PBT's Schedule of Charges (Forms 4-96/B and 5/96L).
Patton, Burke & Thompson is pleased to have the opportunity to submit this geotechnical consulting
services proposal to the City of Coppel], and we look forward to being of continued professional service. If you
have any questions in regard to the content of this proposal, or if additional input is desired, please contact the
undersigned.
PattOn, Burke & Thompson
The City of Coppell
Sewerline Backfill
Page 5
To authorize this work, please sign and remm one copy of this agreement to us.
Respectfully submitted,
PATTON, BURKE & THOMPSON
Principal
JW~:jp
97-379.pro
Ene: Assi~t, nme~t Authorization
General Terms and Conditions
SChedule of Charges (2)
ASSIGNMENT AUTHOR IZATION
The City of CoppeH hereby agrees to the terms of this proposal and the attached General Terms and
Conditions (Form 1-95/A), and the attached Schedule of Charges (Forms 4-96/B and 5/96L);,
Proposal accepted by:
City of Coppell*
Company
Title / Date
*Individual with financial authority to commit to this Assi~enment Authorization
Patton, Burke d~ Thompson
Patton, Burke & Thompson
General Terms and Conditions
1.0 General
Patton, Burke & Thompson (PBT) by the performance of services covered hereunder, does not m any way assume any of
those ~_~es or responsibilities with regard to the project's design professionals or any other design agencies or authorities~
Client agrees to furnish or cause to be furnished to PBT, all documents and information known to client that relate to the
identity, location, quantity, nature or eharactefisti~ of any hazardous or toxic materials on or near the site. In the event that
test samples obtained during PBT's work contain substances hazardous to health, safety, or the environment, these, samples
remain in the property of the client.
2.O Billing
PBT will submit progress invoices to client monthly and a final invoice upon completion of services. Each invoice, on
presentation, is due and payable by client or his authorized representative. Payment is past due 30 days from invoice date.
Client agrees to pay interest of one and one-half percent (1-1/2%) per month, (but not exceeding the maximum rate
allowable by law), on past due accounts. Any attorney's fees or other costs incurred in collecting any delinquent amount
.shall be paid by client.
3.0 Standard of Care
PBT services will be perfonaed, within the limits prescribed by its clients, with the usual thoroughness and competence of
the engineering consulting profession, and in accordance with the standard for professional services at the time and under
similar conditions that these services are rendered. No other warranty or representation, either expressed or implied, is
included or intended in PBT's proposals, contracts, ur reports.
4.0 Liability
PBT's liability shall be limited to injury or loss caused by the negligence of PBT, its subcontractors, and/or agents
hereunder. PBT has neither created nor contributed to thc creation or existence of any hazardous, toxic, pollutant, or
otherwise dangerous substance or condition at the site, and its compensation hereunder is in no way commensurate, with
the potential risk of injury or loss that may be caused by exposure to such substances or conditions.
PBT's liability 'for injuo, or loss arising from (1) professional errors or omissions and/or (2) any hazardous, toxic, pollutant,
or waste gases, liquids, or solid materials shall not exceed $5,000 or our fee, whichever is greater.
PBT's liability for inju~ ca' loss arising from comprehensive general and automobile exposures shall not exceed $100,000.
The client agrees to defend, ind--, and hold PBT harmless from any claim, liability, or defense cost in excess of the
limits stated herein for injury or loss sustained by any party from exposures allegedly mused by PBT's performance of
services hereunder.
In the event the client makes a claim against PBT, at law or otherwise, for any alleged error, omission or other act arising
out of the performance of its professional services, and to the extent the client fails to prove such claim, then the client shall
pay all costs, including attorney's fees, incurred by PBT in defending itself against the claim.
5.0 Applicable Law .
All general terms and conditions shall be govemed by the laws of the State of Texas.
Form(l-95/A)
PATTON, BURKE & THOMPSON
SCHEDULE OF CHARGES
The compensation to Patton, Burke & Thompson (PBT) for professional services is based upon and
measured by the following charge elements.
1.0 Personnel Charges
Charges for PBT employees and consultants are based upon hourly rates for the following general labor
categories:
Engineering Technician I ..................................... $29/hr
Engineering Technician II ..................................... $31/hr
Engineering Technician III .................................... $33/hr
Senior Engineering Technician ................................. $35/hr
CWI/Stmctural Steel Inspector ................................ $40/hr
Word Processor/Secretary .................................... $30gar
Drafting ................................................... $35/hr
Staff Engineer .............................................. $45far
Geologist .... $551hr
Project Engineer ............................................ $55far
Senior Engineer ............................................ $85/hr
Principal ................................................. $105/hr
Expert Witness (Deposition & Trial) ........................... $125/hr
[Note: Time spent in either local or inter-city travel, when travel is in the interest.of the work, will be
charged for in.accordance with the foregoing schedule; however, for non-local travel by public carder a
maximum of eight hours per day will be charged.]
2.0 Equipment Charges
PBT equipment, if used, will be billed at the rates noted in the proposal.
3.0 Other Services and Supply Charges
Charges for services, equipment and facilities not furnished directly by PBT, and any unusual items of
expense not customarily incurred in PBT's'normal operations, are computed as follows:
Cost plus 15 percent includes surveying services, land drilling equipment, construction equipment,
testing laboratories, shipping charges, subsistence, transportation, outside printing and reproduction,
long distance communication, special supplies and rentals.
Cost plus 20 percent includes aircraft, watercraft, and marine drilling equipment.
FORM (04-96/B)
.'ATTON, BURKE & THOMPSON
SCBEDULE OF LABORATORY TESTING CHARGES
Visual Unified Classification, sample ............................ $ N/C
Natural Moisture Content ........................................ $.00/ea
Unit Weight ................................................. 10.00/ea
Specific Gravity .............................................. 40.00/ea
Atterberg Limits (Wet Method) .................................. 35.00/¢a
Grain Siz~ Analysis, #200 sieve only ............................. 20.O0/ea
Grain Size AnalYSis, 1-inch to #200 sieve ..........................35.00/ea
Hydrometer Analysis .......................................... 70.O0/ea
Limo Series (LL & PL) ........................................ 155.00/ea
Unconfined Compression, peak stress only ......................... 35.00/ca
Unconfined Compression, with stress/strain curve ...................55.00lea
Triaxial Shear (UU), per point, peak stress only ..................... 85.00lea
Triaxial Shear (UU), pet point, w/stress-strain ..................... 110.00lea
Triaxial Shear (GU), per point, w/stress-strain ..................... 2$0.00/ea
Triaxial Shear (CU w/pore pressure), per point, w/stress-strain ........ 305.00lea
Direct Shear (UU), per point, w/stress-strain ....................... 120.00/ea
Direct Shear (CU), per point, w/stress-strain 140.00lea
Direct Shear (CD), per point, w/stress-strain ....................... 160.00/ca
Soil Suction (filter paper) ...................................... 20.00/ca
One-Dimensional Swell ........................................ 35.00/ea
One-Dimensional Swell with Load Back ........................... 5$.00lea
One Dimensional Swell with Load Back &Rebound .................. 75.001ca
Consolidation- w/o Time Plots ................................. 190.00/ea
Consolidation- with Time Plots ................................. 250.00/ca
Falling or Constant Head Permeability ............................ 175.00lea
Flexible Membrane Permeability ................................ 300.00/ea
Standard Compaction ........................................ 1 l$.00/ea
135.00/ea
Modifi~! Compaction ................................. .. ......
CBR (3-points, includes proctor) ................................ 325.00/ea
pH ..................................................... 20.00lea
Water Soluble Sulfates ......................................... 30.00/~a
Resistivity (natm~ moisture ,nd saturated) ........................ 40.00/ea
Concrete Mix design rcvicw .................................... 100.00/e~
Cylinder Compressive Strength .................................. 11.001ea
Compressive Strength of Concrete Cores .......................... 20.00I~a
Compressiv~ Strength & Density of Concrete Cores .................. 29.00lea
Splitting Tensile & Demity of Concrete Cores ...................... 29.00lea
Flexural Strength of Cast Beams ................................. l$.00/ea
Concrete or Asphalt Coring ..................................... $5.00/hr
Asphalt Mix Design Review ................................... 200.00lea
Hveem stability & density (w/Theoretical Maximum Density) ......... 200.00/ea
Extraction and gradation ...................................... 140.00/ea
Form (05/96/L)