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Coppell Cross L2-CS 990524 2146540122 ' e5/24/1999 02:03 21485~P='~ DUNAWAY ASSOC~S PAGE 0i D~te; From: To: Project: 512419g Chris Lam Michael Msrtln. p,E.-City c~ Goppel! Coppell Crossing 98566 Dunaway AssocJates, Inc. Engineers ~ Plannem ~ 'Landscape Architects * .Surveyors Dallas, TX · F~W~ · R~e, TX MEMORANDUM SUBJECT: Request for Pavement Variance Dear Mr. Martin. The purpose of this letter is to request for a pavement variance to the City of Goppetl'$ subdivision ordinanCe. We are requesting to. increase the proposed pa~ing and firelane pavement with subgrade compacted to 95% standard proctor density in lue of lime stablized subgrade. Attached is a copy of the Ge°tach recommendation to support our request. If you have any questions or comments regarding the above subject, please contact our office at (214)654-0123. ~/7~,/~~ Thanks Chris Lam Attachment: Geotech report (2 pages) CC: File i~t98566 2351 W. NOrthwest Hwy,, Suite 3280 '~ D~$. Texas· ?$220- ~ (~.~,S4-0~2~ ~ FAX (2~4)fi~'O f50t Merrimac, Suite 100 ~ Fort Worth, Texas T6107 ~ (017)-335-1121 ~ FAX (817)-335-7437 2~5 N. Oak Street, Suite B ~ Roanoke, Texas ?6262 ~ ($17)-491-0~29 ~ FAX (8t?)~491-0640 05/2~/1999 02:03 21~65~0122 999 i4:~-3 214618240'3 DUNAWAY ASSOCIATES [~VID c~Ht'.lON 8, ~SSOC PAGE 82 ALPHA TESTING, INC. 2209 WlscoP~ St., Suite ~lla~, Texos 75229 ~72/620-8~1 ! - 972/263.4937 (Metro) FAX: ~72/406.8023 June.2, 't997 MAVEX COPPELL CROSSING, LTD. P.O. Box 29.305'3 Lewisville, Texas 75029-3053 Attention: Mr, Mitch Vexler Re; Geotechnical ExplOration COPPELL CROSSING Beltline at MacArthur Coppell, Texas ALPHA Report No, 97332-I Attached is the report of the 9eotechnical exploration performed for the project referenced above. This study has been authorized by Mr. Mitch Vexler On May 14, 1997 and performed in accordance.with ALPHA Proposal No. GT 4029 dated May t.4, 1997. This report contains results' of field, explorations and iaboratory testing and an engineering interpretation of these with respect to available project characteristics. The results and analyses have been used to develop recommendations to aid design and construction of foundations and pavement. ALPHA TESTING, INC. appreciates the'opportunity to be of service on 'this project. If we can be 'of further assistance, such as providing materials testing services during construction, please contact our office, ~.-- ...,.'..%~. -.- ·..; .~;.? .~. ~ncere~y yours, .~'~/."' ,~,~q-.:~-",';~2.'I, ALPHA TESTING, INC. ~l,t'.,/'.:"'::':¢~?=-;~?::.~,=' David A. Lewis, P.E. . "~(~2,,z'~ M.,anager of Engineering  President DAL/JLH/pc Copies: (3) Client (1) Kurtz * Bedford, inc. 05/24/1999 82:83 21455~0i22 '1999 14:83 2146182403 DUNAWAY ASSOCIATES pAVID CANHOI"I .~, /~$SOC PAGE 03 PAGE 15 .: ALPHA Report'No. 97332-1 1. The pavement section in parking areas can consist of at least 5 inches of aSPhaltic concrete composed of 3.5 inches of binder under 1.5 inches of surface course overlying a mechanically lime stabilized clay subgrade. 2. In drive areaS, 6 inches of asphaltic concrete (4.5 inches of binder under 1.5 inches of surface course) overlying a mechanically lime stabilized clay subgrede should be adequate.. 3..The coarse aggregate in the surface course should be COmPosed of angular crushed limestone raffler than smooth gravel, 6.3.2 Portland Cement Pavement If concrete pavement is utilized, the above recommended procedure for mechanical time stabilization (see Section 6.3.1) would be required.. Pavement can then consist of 5 inches of adequately reinforced concrete in both parking and drive traffic areas. Theoretically, a thinner pavement section is possible-in 13arl(ing areas; however, to provide adequate concrete cover for bar reinforcing steel, a 5- inch thick pavement section is required. Joints in concrete paving should not exceed 15 ff. Alternately, mechanical lime stal:)illzation, could be ehmlnated by ~nc easing the ~k,,,xconcrete thickness as follows: ' ' ~ 1. 'In parking and drive areas, the concrete thickness should be increased ~../ / by 1 inch ~o a total of 6 inches if mechanical lime stabilization °f'.the clay .~ % subg.rade ooil is deleted, ' . / / 2. Prior t° construction of pavement on untreated clay subgrade soil, the / exposed subgrade should be Scarified to a depth of at least 6'inches and ! compacted to at least 95 % of standard. Proctor maximum dry denSity ~, (ASTM D 698) and withi,n, the range of 1 percent below to 2 Percentage · ~ points above the material s optimum moisture content, 6.3.3 Pavement Specifications Pavement should be specified, constructed and tested to meet the following requirements: Hot Mix Asphaltic Concrete: Texas SDHPT item 340; Type B Base Course (.binder), Type D Surface Course. 13