The URL can be used to link to this page

Home My WebLink AboutPD 2019-0019; IONIS PHARMACEUTICALS CUL-DE-SAC; PAVEMENT RECOMMENDATIONS; 2019-08-09GEOCON INCORPORATED GEOTECHNICAL • ENVIRONMENTAL.. MATERIALS , )0,O ~ Project No. 06442-32-30B August 9, 2019 lonis Pharmaceuticals, Inc. 2855 Gazelle Court Carlsbad, California 92010 Attention: Mr. Wayne Sanders RECORD COPY - - RECEIVED SEP 16 2019 ID DEVELOPMENT ENGINEERING Subject: PAVEMENT RECOMMENDATIONS: CONCRETE PAVERS GAZALLE COURT STATION 15+55 TO 17+20 (END OF CUL-DE-SAC) IONIS CONFERENCE CENTER CARLSBAD, CALIFORNIA References: 1. Flexible Pavement Recommendations, Carlsbad Oaks North - Phase Two, Whiptail Loop Station 18+00 to 56+30 and Gazelle Court Station 10+00 to 17+30, Carlsbad, California, prepared by Geocon Incorporated, dated September 6, 2007 (Project No. 06442-32-14). 2. Improvement Plans for: lonis Pharmaceuticals Conference Center, Drawing No. 514-7A, Project No. MS 2018-0009, prepared by Pasco Laret Suiter & Associates, undated. Dear Mr. Sanders: In accordance with your request, we are providing concrete paver pavement recommendations for the existing paved subject street. We understand that the existing asphalt concrete pavement will be replaced with high strength concrete payers. We used information presented in Reference No. 1 to design the concrete paver section. The pavement recommendations presented herein need to be submitted to City of Carlsbad for review and approval prior to construction. As discussed in Reference No. 1, we collected the soil samples at subgrade elevations at the approximate locations presented in Table I. We performed laboratory resistance (R-Value) testing in accordance with ASTM D 2844. Table I summarizes the laboratory test results. The subgrade soils predominately consists of silty sands with gravel and typically exhibit moderate to high R-Value characteristics. Also, the subgrade materials possess an expansion potential (El) less than 20 and are defined as "non-expansive" by 2016 California Building Code (CBC) Section 1803.5.3. The subgrade soil is classified as "very low" expansive per ASTM D 4829. As indicated in Reference No. 1, we used a traffic index (TI) of 7.0 in pavement design for Gazelle Court. The pavement section presented herein is in accordance with City of Carlsbad Minimum Structural Standard GS-1 7. We used R-Values presented in Table I for soil and 78 for aggregate base in the pavement calculation. 6960 Flanders Drive U San Diego, California 92121-2974 U Telephone 858.558.6900 U Fox 858.558.6159 We calculated the concrete paver base section in general conformance with the Interlocking Concrete Pavement Institute Technical guidelines (ICPI) - Tech Spec Number 4, Structural Design of Interlocking Concrete Pavement for Roads and Parking Lots and Caltrans Highway Design Manual (Topic 633). Pavement calculations are presented at end of this report. As a minimum and in accordance with ICPI design standards, we recommend the payers be at least 3.15 inches (80 mm) thick and be placed on at least 1-inch-thick bedding sand. Table II presents the bedding sand and Class 2 aggregate base sections for support of the concrete payers. Provided below are recommendations for construction of the paver pavement section. Class 2 aggregate base materials should conform to Section 26-1.02B of the Standard Specifications of Caltrans with a 34-inch maximum size aggregate. Prior to placing aggregate base materials; the subgrade soil should be scarified, moisture conditioned as necessary, and compacted to a thy density of at least 95 percent of the laboratory maximum thy density near to slightly above optimum moisture content per ASTM D 1557. The depth of compaction should be at least 12 inches. Class 2 base materials should also be compacted to at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content per ASTM D 1557. 4. Concrete paver installation should be performed in accordance with ICPI Tech Spec 2, Construction of Interlocking Concrete Pavement. Stable edge restraints such as concrete bands and curbs are essential to maintain horizontal interlock while the paver units are subjected to repeated vehicular loads. Edge restraints should be incorporated into the concrete paver pavement sections and designed in accordance with ICPI guidelines. The concrete bands should be at least 8 inches wide and extend at least 12 inches below pavement surface. The payers should be placed on at least 1-inch of bedding sand the meets ASTM C33 gradation as indicated in ICPI Tech 17 (see paver manufacture specifications for actual bedding sand gradation). Interlocking payers should be placed directly adjacent to one another to minimize areas where water can percolate down into the base and subgrade. In addition, a sealant to bind the sand between the payers should be used. A maintenance schedule consisting of inspecting the paver pavement sections needs to be established and, periodic removal and replacement of individual payers will be required. Consideration should be given to placing Mirafi HP570 or equivalent subgrade stabilizing materials on the compacted subgrade soil prior to placing the aggregate base and installing the payers. The use of subgrade stabilizing materials reduces the potential for paver movement due to saturated subgrade soils that typically result with time. Also, the frequency of removing and replacing individual payers may be reduced potentially resulting in lower maintenance costs. The performance of pavement, aggregate base, and subgrade materials are highly dependent on providing positive surface drainage. Ponding of water on or adjacent to the structural surface may result in saturation of the aggregate base and subgrade materials, and subsequent distress. In addition, saturation of the bedding sand may result in pumping and bedding material loss beneath payers causing differential settlement. To reduce the occurrence for such Project No. 06442-32-30B - 2 - August 9, 2019 situations, a surface drainage gradient should be maintained across the pavement surface. Drainage from landscaped areas should be directed to controlled drainage structures. 10. Where landscaping or landscape planters are planned adjacent to pavements supporting vehicular loading, an impermeable liner should be placed at the edges to prevent landscape irrigation from migrating into the adjacent pavement base and subgrade soils. The liner should extend at least 6 inches below the bottom of the aggregate base. In-lieu of providing an impermeable liner, edge restraints (band and/or concrete curbs) may be extended at least 6 inches below the bottom of the base section. Should you have questions regarding this letter, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED AL Emilio Alvarado (0 Mo. 660915 us RCE 66915 EA:dmc Attachments: Tables I and II Pavement Calculation (e-mail) Addressee Project No. 06442-32-30B - 3 - August 9, 2019 TABLE I SUMMARY OF RESISTANCE VALUE (R-VALUE) TEST RESULTS ASTM D 2844 Sample No. Street —Sampled Location (Representative Street Sections) RValue* R-14 Gazelle Court -Station 10+00 to 13+00 70 R-15 Gazelle Court - Station 13+00 to 16+00 54 R-16 Gazelle Court - Station 16+00 to 17+30 55 *R..Values from Reference No. I (report dated September 6, 2007). TABLE II PAVER PAVEMENT RECOMMENDATIONS* Street (Representative Street Traffic Paver Bedding Sand Class 2 Sections) Index Thickness** (inches) Aggregate Base (inches) (inches) Gazelle Court Station 15+55 to 7.0 17+20 (End of Cul-De-Sac) 3.15 1.0 8.0 *pavement sections should be reviewed and approved by City of Carlsbad prior to construction. **paver of thickness 3.15 inches is approximately equivalent to 3.0 inches of asphalt concrete. *** The pavement section provided is equivalent to existing pavement section consisting of 4.0 inches AC over 6.0 inches of AB. Project No. 06442-32-30B August 9, 2019 PAVEMENT CALCULATION (Reference: Caltrans Hwy Design Manual, May 7, 2012: Topic 633) Project Name: lonis CC Project No.: 06442-32-30B Date: 08/09/19 Enter Values: Sample No. R-Vulue: TI: Gr(AC) Gr(Class 11 Base): Ex. AC Section (City mm.), tAC (in.): Ex. AB Section (City mm.), tcrB (in.): t (ft)=GE/G, GE (ft)=tGt=tG,/(12 in./ft) R-15 54 7 2.14 Gf= 2.5(5.14/TI)'0.5 1.1 <Use 1.0 for Subbase, 1.1 for Aggregate Base, 1.7 for CTB 4.0 6.0 <per Caltrans GE of Existinv Pavement Section Cnnistin of 4"AC/6"AR GE=0.0032(TI)(100-R),(feet) 1.03 GE, 4"AC=tACGfAc (feet) 0.71 GE, 6"ABtisGf,8, (feet) 0.55 GE of Existing Pavement Section, (feet) 1.26 Paver Pavement Section Calculation: Paver ti in thick ann2le. tO inehec of AC GE, 3.15" Paver=tAc*Gf.kc, (feet) 0.54 GE, AB Required=GE Ex. Pavement-GE of 3.15" Paver, (feet) 0.73 GE, Paver Section (feet) 1.26 t, AB (in.)=GE/G, 7.95 Recommended Paver Section: Paver (in) 3.15 AB (in) 1 8.00 Project No. 06442-32-308 August 9, 2019