Loading...
SS9301-PR 940623 reed engineering GEOTECHNICAL CONSULTANTS June 23, 1994 Proposal No. 6-23 city of Coppell Engineering Department P.O. Box 478 Coppell, Texas 75019 ATTN: Mr. Garreth Campbell SLOPE STABILITY ANALYSIS GRAPEVINE CREEK BELTLINE AT MOCKINGBIRD COPPELL, TEXAS Gentlemen: Submitted here is our proposal for providing necessary geotechnical engineering services for the referenced project. This proposal is based on a site visit of June 20, 1994 and our conversation of June 21, 1994. Project Description and Site Geology A relatively large rotational slide has occurred along Grapevine Creek northwest of the intersection of Beltline Road and Mockingbird Lane. The slope in which the failure occurred is a cut bank of the creek, and therefore subject to erosion and undercutting of the toe due to stream action. The slope had recently been regraded after completion of a tunneling project which required excavation of a temporary access road near the top of the slope. Site geology is anticipated to consist of fill and alluvial soils overlying weathered and unweathered shale of the Eagle Ford Formation. Unweathered shale does not appear to be exposed in the creek bottom. The lower portion of the slide mass is anticipated to be in weathered shale. 2424 STOTZ DRIVE · SUITE 4b~,, · ._.,,-.,~/:,.~ .... · · .~.,~ 350-00!9 City of Coppell Proposal No. 6-23 June 23, 1994 Page 2 Field Investigation Considering the type of failure and anticipated site geology, it is recommended that subsurface conditions be evaluated by four core borings. Two borings are proposed at the top of the slope. These borings will be advanced with truck-mounted drilling equipment and will be extended a minimum of five feet into unweathered shale. The remaining two borings will be drilled within the slope and slide areas, and will be advanced with hand-operated, portable drilling equipment. Ail borings will be sampled continuously to a depth of six feet, and at maximum five-foot intervals thereafter. Samples of cohesive soils will be obtained using three-inch diameter pushed tubes. Cohesionless soils (sands and gravels) will be sampled and evaluated in-situ by use of the Standard Penetration test. Unweathered shale in the two rig borings will be cored continuously using double-tube, NX-size core barrels. Borings will be bailed of drill fluids at the completion of field operations, and subsequent observations made in order to evaluate ground water conditions. Precautions will be taken during the field investigation to avoid damage to underground utilities and structures. However, Reed Engineering Group, Inc. will not be liable for damage to utilities or structures not identified on plans provided to us, or mislocated in the field by other parties. Laboratory Investigation Upon return to the laboratory, all samples will be visually classified by the project engineer or engineering geologist in accordance with the Unified Soil Classification System (USCS). Each sample of cohesive soil will be evaluated for consistency by use of a pocket penetrometer test. Selected samples will be subjected to classification and index property tests. Anticipated tests consist of Atterberg Limits, moisture content, and partial grain-size determinations. Shear strength characteristics of selected samples will be evaluated by unconfined compression, double-ring shear, and consolidated-drained direct shear tests. Both peak and residual shear will be evaluated. City of Coppell Proposal No. 6-23 June 23, 1994 Page 3 Engineering Services The results of the field and laboratory investigations will be evaluated and presented with our recommendations in a bound report. The report will address, but not necessarily be limited to, the following: 1. description of the soil and ground water conditions as they relate to the performance and construction of the project; 2. evaluation of cause(s) of existing slide and the potential for development of other slides in the future; 3. alternative remedial measures for stabilization/remediation of the existing slide including geotechnical design parameters associated with each alternative; and 4. general earthwork and testing recommendations. Four copies of the report will be provided. Additional copies may be obtained for a nominal fee. Budget Costs associated with the proposed scope of services are itemized on the attached cost breakdown. Based on the breakdown, we anticipate the total cost of our services to be on the order of $5,500.00 to $6,000.00. In the event unanticipated subsurface conditions are encountered, you will be notified prior to our exceeding the maximum of $6,000.00. Unless prior arrangements are agreed to in writing, payment for our services are due within 30 calender days of the invoice date. Payments not received within 40 calender days of the invoice date will be charged interest at a rate of 1.0 % per month. City of Coppell Proposal No. 6-23 June 23, 1994 Page 4 Authorization We appreciate the opportunity to present this proposal and look forward to working with you on the project. Authorization to proceed may be indicated by signing and returning one copy of this proposal to our office. If any questions arise, do not hesitate to call. Sincerely, F.~ Whi~e~ Smit~, P.G. Vice ~resident by FWS/aap copies submitted: (2) / ~ / Date City of Coppell Proposal No. 6-23 June 23, 1994 Page 5 COST ESTIMATE SLOPE STABILITY ANALYSIS GRAPEVINE CREEK BELTLINE AT MOCKINGBIRD COPPELL, TEXAS Field Investigation Mobilization $ 150.00 60 Linear Feet, Drilling and Sampling w/Truck- Mounted Rig 600.00 6 Hours, Drilling and Sampling w/Portable Drilling Equipment (three-man crew) 870.00 4 Hours, Field Reconnaissance - Project Engineering Geologist 260.00 Subtotal, Field $1,880.00 Laboratory Services 20 Moisture Content tests $ 80.00 4 Atterberg Limit tests 140.00 2 Partial Gradation Determinations 50.00 4 Direct Shear tests (w/residual) 600.00 2 Unconfined Compression tests 40.00 2 Double-Ring Shear tests 40.00 Subtotal, Laboratory $ 950.00 Engineering Services 2 Hours, Classification of Soil and Rock Samples - Project Engineer or Engineering Geologist $ 130.00 30 Hours, Analysis and Report Preparation - Project Engineer or Engineering Geologist 1,950.00 4 Hours, Analysis and Review - Principal Engineer 360.00 12 Hours, Typing and Drafting Support 360.00 Subtotal, Engineering $2,800.00 TOTAL ESTIMATED AMOUNT $5,630.00 Based on the above quantities, the total cost for our services is estimated to be $5,500.00 to $6,000.00. Reed Engineering Group, Inc. reserves the right to vary quantities and types of services as the project requires. The upper limit budget will not, however, be exceeded without prior written authorization.