DR9306-CN 951107 October 12, 1995
10555 Newkirk Slreet
S u i 1 e 530
Dallas, Texas. IS220
214.831.1111
FAX 214.831.0800
The City of Coppell
255 Parkway Blvd.
P. O. Box 478
Coppell, Texas 75019
Attn: Kenneth M. Griffin, P.E:
Assistant City Manager
City Engineer
Re: PROPOSAL FOR GEOTECHNICAL CONSULTING SERVICES
Channel Bank Stability
Stream G6/Bethel School Road
Coppeli, Texas
PBT Proposal No. 95-131
Dear Ken:
Patton, Burke & ThomPson (PBT) is pleased to submit this written proposal, in accordance with our earlier
conversations with you and Garreth Campbell, for performing certain geotechnical consulting services for the
referenced channel bank.
GENERAL
It is our Understanding, based on our discussion, a site visit on October 5, 1995, review of construction
plans and topo maps provided by you to date, and our past experience with the geological formations which exist
in the assignment area, that the following basic information is currently known about the area to be investigated:
· The channel bank to be investigated is a portion of the west bank (approximately between Station
8+50 and 11+00) of Stream G-6/Bethel School Road Drainage Improvement Project, in the
Northlake Woodlands section of the city.
· Overall construction for the drainage improvement project was started in late-1994 and primarily
involved (i.e., for the purposes of discussions for this specific assignment) excavating a new pilot
channel, construction of a new channel concrete bottom, and construction and backfilling behind
a new channel bank consisting of rock filled gabion baskets.
Pa,*on, Burke & Thompson
Engineering Consultants
City of Coppell
Stream G6
Page 2
. Alth°ugh there is considerable detail on the history of the construction of the subject new drainage
improvements, reportedly around the first week of May 1995 heavy rainfall and runoff was
experienced at the site. Shortly thereafter, reported as around May 10th, the project's general
contractor (M. A. 'Vinson out of Fort Worth) installed heavy steel sheet piling along a portion of
the subject bank a few feet behind the previously constructed gabion wall.
· The existing property immediately abutting the subject bank study area,'which involves a relatively
large home, swimming pool and concrete/brick patio areas, is owned by a Mr. Don Jones. Site
observations and discussions with Mr. Jones on October 5, 1995 indicated that since early May
1995 his pool and adjoining concrete deck has experienced both vertical and lateral movements.
In addition, southward of the Jones's pool area (but still on his property) several significant and
continuous ground cracks were noted approximately 8' to 10' behind the top of the subject bank
slope.
· Although the CitY has indicated that there is no geotechnical engineering or. subsurface boring data
currently available along this section of the channel, based upon available geological information and
our past experience in the general area, the subject study area is in all probability underlain by the
Eagle Ford Shale Formation and/or local areas of man-made fill, The Eagle Ford Shale typically
consists of highly plastic clays (i.e., residual soils) overlying weathered shale with depth. The
formation is quite variable, both the soils and shales are highly expansive, and it is not uncommon
for the highly plastic clays to occur in irregular distributions and for the depth of shale weathering
to extend for tens of feet.
The primary purpose of this investigation, as we understand it at this time, is to provide geotechnical
investigation and consulting services to assist the City in quantifying what caused the current movements and
alternatives on how to stabilize the current channel bank.
SCOPE OF WORK
Our proposed scope of work, based upon all of the above and our extensive past experience with slope
stability problems, will consist of' developing a technical approach, performing the necessary geotechnical
investi§ations and analysis, development of alternatives and recommendations for slide stabilization, and general
consultation with the City.
Thcfoilowing describes the general scope of' work we propose at this time for carryin§ out the necessary,
in our opinion, services for the study area:
1. Field Investigations -
a) Geotechnical - type borings will be drilled and sampled using a portable drill rig, due to site
accessibility. The magnitude of the envisioned field program would involve four (4) or five (5)
borings: two (2) taken on top of the bank (actually through the concrete deck slab) in the area
of the pool, one (1) on top of the bank in the grassy area south of the pool, and one (1) or two
(2) immediately behind the new gabion wall.
1
P~*on, Burke i Thompson ~
Engineering Consultants
City of Coppell
Stream G6
Page 3
b) Surface monitoring points will be installed at Selected p°ints alongboth the top of bank and
behind the new gabion wall, and an initial set of vertical elevation readings Will be established
for each point. At this time ten (10) to twelve (12) points are envisioned.
2. Laboratory Testing - The final laboratory testing program will depend on the actual subsurface
conditions encountered in the test borings for each of the areas, but in general will involve the
following:
· Moisture content, unit weight, Atterberg limits' and grain size analysis on selected soil samples
to eValuate classification and current consistency properties.
· Soil suction tests to assist in the evaluation of the depth of wetting of the slope materials.
· Q-triaxial shear on insitu natural and fill site soils fOr utilization in slope stability analysis.
· Other laboratory tests as deemed appropriate upon evaluating findings of borings.
3. Engineering Analysis/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:
· Site soil stratigraphy, Subsurface conditions and associated variability,
· Evaluation of physical, consistency, strength and soil suction potential characteristics of
subsurface soils, and/or weathered shale.
· Evaluation of findings and development of conclusions regarding probably mechanism and
causes of movements to date.
· Recommendations regarding technical and practical alternatives for the geotechnical
engineering design and construction of slide remediation.
4. Assumptions Regarding Site and Field Work
· · The borings will be located in the field based upon measurements from existing features or City
stationing along the channel, and surface elevations, if required, will be provided by the City.
· No special permit or permission will be required of PBT to enter any portion of the site, that
will result in a delay or additional cost.
· Selected boring locations are free of either overhead or underground obstructions, and all
underground utilities, if any, will be identified by the City.
· Field standby time (outside PBT's control) will not exceed 1-hour.
Burke & Thompson
Engineering Consultants
City of Coppell
Stream G6
page 4
· 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.
· The City will' assist PBT in developing elevation control at the study area and true scale X-
sections of the existing groundline through the slide area.
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 $6,500. Furthermore, we
propose to provide all services in accordance with PBT's General Terms & Conditions (Form 1-95A), 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 9-95/B and 9/95L).
SCHEDULING OF WORK
Patton, Burke & Thompson will develop a final schedule for the field investigation program immediately
upon your authorization to proceed. The field program, barring any access problems or severe weather, can be
completed within 1-1/2 to 2-working days after mobilization to the site, and the laboratory testing program, for
selected soil samples retained from the borings, will be completed within eight (8) working days after field program
completion.
Following the collection °fall field investigation and laboratory testing data, preliminary verbal findings will
be presented, within four (4) working days. The final written report will be submitted within five (5) working days
after the preliminary verbal findings.
Patton, Burke & Thompson is pleased to have the' opportunity to submit this geotechnical investigation
services proposal to you, and we look forward to being of continued professional service. If you have any question
in regard to the content of this proposal, or if additional input is desired, please feel free to contact the undersigned.
To authorize this work, please sign and return one c6py of this agreement to us.
Very truly yours,
PATTON, BURKE & THOMPSON.
ck W Burke, P.E."'-~
Enc: Assignment Authorization
General Terms and Conditions
Schedule o£ Charges (2)
JWB:jp
95-131 .pr(~
Pa*boa, Burke & Thompson l
Engineerlng Consultants
A "" City of Coppell
Stream G6
Page 5
ASSIGNMENT AUTHORIZATION
The City of Coppell 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 9-95/B and 9/95L).
Proposal accepted by:
The City o~f Coppe, ll*
[ ~~ City of Coppel.1
Name /- Company
City Manager November 7, 1995
Title Date
* Individual with financial authority to commit to this Assignment Authorization.
Pu~*on, Burke & Thompson
E~beerbg ('of~s~r6wrs
Pa ton, Burke & Thompson
General Terms and Conditions
1.0 General
Patton, Burke & Thompson (PBT) by the performance of services covered hereunder, does not in any way assume any of
those duties 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 characteristics 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.
2.0 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 performed, 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 those services are rendered. No other warranty or representation, either expressed or implied, is included
or intended in PBT's proposals, contracts, or 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 the 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 injury 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 injury or loss arising from comprehensive general and automobile exposures shall not exceed $100,000.
The client agrees to defend, indenmify, 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 caused 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 Ihe 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 governed by the laws of the State of Texas.
I:on'a(1-95/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:
A. GEOTECHNICAL ENGINEERING SERVICES
Principal $ 95/hr
Senior Engineer ............................................. 75/hr
Project Engineer .............................................. 55/hr
Geologist ................................................... 50/hr
Staff Engineer ............................................... 45/hr
Word Processor/Secretary ..................................... 30/hr
B. CONSTRUCTION MATERIALS ENGINEERING & TESTING SERVICES
Project Manager ........................................... $ 85/hr
Sr. Project Engineer .......................................... 70/hr
Project Engineer ............................................. 55~hr
Field Engineer · 40/lu'
CWI/Structural Steel Inspector ................................. 40/hr
Field Technician ............................................. 31/hr
Word Processing/Draf~g ..................................... 30/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 pubic carrier 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 10 percent includes shipping charges, subsistence, transportation, outside printing and
reproduction, long distance communication, special supplies and rentals.
Cost plus 15 percent includes surveying services, land drilling equipment, construction equipment
and testing laboratories.
Cost plus 20 percent includes aircraft, watercrat~, and marine drilling equipment,
FORM (9-95/B)
PAT'~ ON, BURKE & THOMPSON
SCHEDULE OF LABORATORY TESTING CHARGES
Visual Unified Classification, sample .............................. $ 2/ea
Natural Moisture Content .......................................... 5/ea
Unit Weight ................................................... 10/ca
Specific Gravity ' 40/ea
A~g Limits ................................................ 35/ca
Lime Series (LL & PL) .......................................... 155/ea
Grain Size Analysis, l-inch to #200 sieve ............................30/ea
Grain Size Analysis, #200 sicvc only ............................... 20/ea
Hydromeler Analysis ............................................ 70lea
Unconfined Compressi6n, peak stress only ........................... 32/ea
Unconfined Compression, with stress/strain curve ..................... 50/ea
One-Dimensional Swell .......................................... 30lea
One-Dimensional Swell with Load Back ............................. 55lea
Soil Suction (filter paper) ' ' 16/ea
Consolidation ................................................. 190/ea
Standard Compaction (D 698) .................................... 115/ea
Modified Compaction (D 1557) ................................... 135/ea
CBR (3-points, includes proctor) .................................. 325/ea
Water Soluble Sulfates ........................................... 30/ea
pH ....................................................... 20/ea
Concret~ Mix design review ....................................... g5/ea
Cylinder Compressive Strength (including untested cylinders) ............ 1 l/ea
Cylinder Compressive Strength, cast by others ........................ 16/ea
Asphalt'mix design review ....................................... 200/ea
Hveem stability and density ...................................... 200/ea
Extraction and gradation ........................................ 140/ea
Form (9/95/L)