Loading...
HomeMy WebLinkAboutCT 04-26; ROBERTSON RANCH EAST VILLAGE PA 16, 17, & 18; PAVEMENT DESIGN REPORT SUMMIT TRAIL; 2010-01-27Cl O4 -2, Geotechnical • Geologic' Coastal.En,,ronmental 5741 Palmer Way Carlsbad California 92010 (760) 438-3155 FAX (760) 931-0915 January27,2010 W.O.5981-E-SC, D.R.HoEtofl'; 1021 Costa Pacifica Way,.Suite 2107. Oceanside, California 92054. Attention Mr. Tom Lombardi Subject Pavement Design Report, Summit Trail (Stations 10+63 to 19+55 ), Portion of Planning .Area 21 of Robertson Ranch, Carlsbad, San Diego County, California Dear Mr. Lombardi:.. i -. •• • •,i In accordance with your request, GeoSoils, Inc (GSI) has prepared preliminary design and construction recommendations for asphalt concrete (AC) pavement at the subject site The scope of services provided in preparation of thi report included a review of the referenced reports and documents (see the Appendix), an evaluation of the pavement section for the subject area, and preparation of this report PAVEMENT DESIGN Pavement section evaluation was based on traffic index (TI) values provided by (O'Day Consultants, personal communications) Pavement sections were evaluated in general accordance with the California Department of Transportaon (Caltrans) Highway Design Manual of Instructions and the City of Carlsbad Standard Drawings (see the Appendix) R-value samples were collected in the field by this office and under the supervision/direction of the City..Pavement sections presented are based on the aforementioned criteria and resistance value (R-value) data (see table), evaluated from soils exposed at, or near, final subgrade elevations within the subject areas R-value testing was performed in general accordance withthe latest revisions to the Department of Transportation, State of California, Material & Research Test Method No 301 ASPHALT CONCRETE PAVEMENT Structural Section 4. .-- Traffic Indices (TI) were provided by the project civil engineer (O'Day Consultants, personal communication) as 5.0 for the subject traffic areas R-values (see attached Figures 1 through 4) ranging from 12 to 20 were obtained for representative subgrade soils onsite and used in pavement design The recommended pavement sections are provided in general accordance with the City guidelines (City of Carlsbad, 1993), and are presented iñthe following table:. Ac AGGREGATE APPROXIMATE TRAFFIC SUBGRADE THICKNESS BASE THICKNESS 2' TRAFFiC AREA INDEX11 R-VALUE (inches) (inches) 'Summit Trail, Stations 10to ' 5.0 .20W 4.0 13 (Sample obtained from . Station 12) Summit Trail Stations l 3+22 to 5.0 18 4.0 150 16(Sampie obtained from . Station 15) Summit Trail, Stations 16+22 to 5.0 12 4.0 18 (Samples obtained from . Station 18) I 0 Summit Trail, Stations 18+22 to 5.0 .13 4.0 19 (Sample obtained from . Station 19) . . C Per O'Day Consultants (2) Denotes Class 2 Aggregate Base R >78; SE >25) All pavement installation, including preparation and compaction of subgrade, compaction of base material, and placement and rolling of asphaltic concrete, shall be done in accordance with the City guidelines, and under the observation and testing of the project geotechnical engineer and/or the City. The recommended pavement sections are meant asminimums If thinner or highly variable pavement sections are constructed increased maintenance and repair may be needed The recommended pavement sections provided above are in only as a minimum guideline If thinner or highly variable pavement sections are constructed, increased maintenance and repair could be expected If the ADT (average daily traffic) or ADTT (average daily truck traffic) increases beyond that intended as reflected by the TI used for design, increased maintenance and repair could be required for the pavement section..Consideration should be given to the Increased potential for distress from overuse D.R.Horton . Wfl.5981-E-SC. Summit Trail Planning Area 21 Robertson Ranch January 27 2010 File e \wp9\5900\5981 e pdr Page 2 GeoSoils, Inc. of paved Street areas by heavy equipment and/or construction related heavy traffic (e.g., concrete trucks, loaded Supply trucks, etc.), particularly when the final section is not in place (i.e., topcoat). Best management construction practices should be followed at all times, especially during inclement weather. PAVEMENT GRADING RECOMMENDATIONS General All section changes shall be properly transitioned. If adverse conditions are encountered during the preparation of subgrade materials, special construction methods may need to be employed. A GSI representative shall be present for the preparation of subgrade, base rock, and asphalt concrete. Subgrade Within street and parking areas, all surficial deposits of loose soil material shall be removed and recompacted as recommended. After the loose soils are removed, the bottom is to be scarified.to a depth of atleast 12 inches, moisture conditioned as necessary, and compacted to 95 percent of the maximum laboratory density, as determined byASTM test designation D 1557. Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock fragments, and any other unsuitable materials encountered during grading shall be removed. The compacted fill material shall then be brought to the elevation of the proposed subgrade for the pavement. The subgrade shall be proof-rolled in order to ensure a uniform firm and unyielding surface. All grading and fill placement shall be observed by the project soil engineer and/or his representative. Base Rock Compaction tests are required for the recommended base section. Minimum relative compaction required will be 95 percent of the laboratory maximum density as determined by ASTM test designation D 1557. Base aggregate shall be in accordance with Section 26 of Caltrans Standard specifications (California Department of Transportation, 2006), for Caltrans Class 2 aggregate base. Paving Prime coat may be omitted if all of the following conditions are met: 1. The asphalt pavement layer is placed within two weeks of completion of base and/or subbase course. D.R. Horton W.O. 5981 -E-SC Summit Trail, Planning Area 21, Robertson Ranch January 27, 2010 Fi1e:e:\wp9\5900\5981e.pdr Page 3 GeoSOils, Inc. Traffic is not routed over completed base before paving. Construction is completed during the dry season of May through October. The base is kept free of debris prior to placement of asphaltic concrete. If construction is performed during the wet season of November through April, prime coat may be omitted if no rain occurs between completion of base course and paving and the time between completion of base and paving is reduced to three days, provided the base is free of loose soil or debris. Where prime coat has been omitted and rain occurs, traffic is routed over base course, or paving is delayed, measures shall be taken to restore base course and subgrade to conditions that will meet specifications as directed by the soil engineer. Drainage Positive drainage shall be provided for all surface water to drain toward the curb and gutter, or to an approved drainage channel. Positive site drainage shall be maintained at all times. Water shall not be allowed to pond or seep into the ground. Over-watering of landscape areas should be avoided. Due to the relatively low R-values, wet subgrade conditions could significantly reduce the life of the pavement. Therefore, it is imperative that subgrade materials are not allowed to become wet or saturated or allow water to flow into trenches or behind curbs. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer shall review the recommendations provided herein, incorporate those recommendations into their plans, and by explicit reference, make this report part of their project plans. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal 'changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is express or implied. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction, or D.R. Horton W.O. 5981 -E-SC Summit Trail, Planning Area 21, Robertson Ranch January 27, 2010 FiIe:e:\wp959OO\5981 e.pdr Page 4 GeoSoils, Inc. work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. The opportunity to be of service is greatly appreciated. If you have any questions, please do not hesitate to call our office. Respectfully subm G. OfQ' 0:10 cp a1" No 1934 I Certified I Engineering Geologist . 1i Robert G. Crisman O Engineering Geologist, CEG 934 RGC/ATG/J PF/jh GeoSoils, Inc. Attachments: Figures 1 through 4 - R-value Test Results Appendix - References Distribution: (4) Addressee (U.S. Mail) (1) Bausback Consulting, Attention: Mr. Kurt Bausback D.R. Horton W.O. 5981 -E-SC Summit Trail, Planning Area 21, Robertson Ranch January 27, 2010 File:e:\wp9\5900\5981 e.pdr Page 5 GeoSoils, Inc. TFT SPFCIMFN A B C D Compactor air pressure PSI 350 250 170 Water added % 2.7 3.7 4.7 Moisture at compaction 10.5 11.5 12.5 Height of sample IN 2.45 2.5 2.53 Dry density PCF 127.4 123.5 120.8 R-Value by exudation 38 25 13 R-Value by exudation, corrected 38 25 13 Exudation pressure PSI 553 368 229 Stability thickness I FT 1 0.7,91 0.961 1.11 Expansion pressure thickness FT 1 1.001 0.331 0.00 DESIGN CALCULATION DATA Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 0.83 R-Value by expansion 35 R-Value by exudation 20 1 P.-Value at equilibrium 20 Expansion, Stability Equilibrium 2.00 SAMPLE INFORMATION - IJuIJ MI a'flh111:1TTT Fk.], Li U, U, 1.00 0.00 " I I I I I I 0.00 0.50 1.00 1.50 2.00 Cover Thickness by Expansion Pressure (ft) GeoSoils, Inc. 5741 Palmer Way Carlsbad CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Project: DR HORTON Number: 5981-E-SC Date: Jan-10 Figure: 1 rr tf'IRM A R C D Compactor air pressure PSI 350 350 230 Water added % 2.7 3.4 4.5 Moisture at compaction % 11.3 12.0 13.1 Height of sample IN 2.49 2.49 2.53 Dry density PCF 124.4 123.6 122.8 R-Value by exudation 43 24 14 R-Value by exudation, corrected 43 24 14 Exudation pressure PSI 566 370 267 Stability thickness FT 0.73 0.97=.101 Expansion pressure thickness FT 0.671 0.131 0.00 flFRIN CAl CLJIATION DATA SAMPLE INFORMATION Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 0 R-Value by expansion NA R-Value by exudation 18 R-Value at equilibrium 18 Expansion, Stability Equilibrium 2.00 (I) U) 1.00 'Iø ICE 98.19,277so'lia so f..1' - . I ISiS_i 0.50 0.00 ' I I I ':' 0.00 0.50 1.00 1.50 2.00 Cover Thickness by Expansion Pressure (ft) GeoSoils, Inc. ç 5741 Palmer Way Carlsbad, CA 92008 \: Telephone: (760) 438-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Project: DR HORTON Number: 5981-E-SC Date: Jan-10 Figure: 2 TEST SPECIMEN A B C D Compactor air pressure PSI 350 170 110 Water added % 3.4 4.4 5.4 Moisture at compaction % 13.0 14.0 15.0 Height of sample IN 2.43 2.53 2.56 Dry density PCF 123.3 117.9 115.6 R-Value by exudation 38 13 10 R-Value by exudation, corrected 36 13 10 Exudation pressure PSI 763 324 227 Stability thickness I FT 0.791 1.111 1.15 Expansion pressure thickness I FT 1 2.831 0.771 0.33 DESIGN CALCULATION DATA Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 1.06 R-Value by expansion 17 R-Value by exudation 12 R-Value at equilibrium 12 Expansion, Stability Equilibrium 3.00 2.50 SAMPLE INFORMATION Sample Location: Summit Trail 18+10 Sample Description: Gray Sandy Clay Notes: PA 21 1% Retained on 3/4 inch sieve Test Method: Cal-Trans Test 301 R-Value By Exudation 80 70 60 50 a, 40 (I) w1.50 a, C U i-1.00 at 0050 000 l' 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Cover Thickness by Expansion Pressure (ft) GeoSoils, Inc. 5741 Palmer Way Carlsbad, CA 92008 '1 Telephone: (760) 438-3155 Fax: (760) 931-0915 R-VALUE TEST RESULTS Project: DR HORTON Number. 5981-E-SC Date: Jan-10 Figure: 3 GeoSoils, Inc. 5741 Palmer Way iiihk Carlsbad, CA 92008 43'Telephone: (760) 438-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Project: DR HORTON Number: 5981-E-SC Date: Jan-10 Figure: 4 iIfi h!ilI A B C D Compactor air pressure PSI 350 350 170 Water added % 3.0 4.0 5.0 Moisture at compaction % 11.0 12.0 13.0 Height of sample IN 2.47 2.51 2.55 Dry density. PCF 126.0 123.0 120.1 R-Value by exudation 44 22 10 R-Value by exudation, corrected 44 22 10 Exudation pressure PSI 591 3951 270 Stability thickness FT 0.72 1.00 1.15 Expansion pressure thickness I FT 1 1.33 0.721 0.10 DESIGN CALCULATION DATA Traffic index, assumed equivalent factor, assumed Expansion, stability equilibrium g5.O Gravel R-Value by expansion R-Value by exudation 13 R-Value at equilibrium 13 Expansion, Stability Equilibrium 3.00 2.50 c,i2.00 Cl) >. in 1.50 0 0 I-. 1.00 0 > 0 0.50 000 lI'I I I I I I I I I I I I I I I I I I I 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Cover Thickness by Expansion Pressure (ft) SAMPLE INFORMATION Of APPENDIX REFERENCES California Department of Transportation, 2006, Caltrans, Standard specifications, May printing. Carlsbad, City of, 1993, Standards for design and construction of public works improvements in the City of Carlsbad: NEWCON90, 1991 Computer program for the determination of asphalt pavement sections, version: April 30. State of California, Department of Transportation, 2008, Highway design manual of instructions, sixth edition, July 1.