The URL can be used to link to this page

Home My WebLink AboutCT 2019-0006; 2690 ROOSEVELT ST.; PERVIOUS PAVER RECOMMENDATION; 2025-08-046960 Flanders Drive ■ San Diego, California 92121-2974 ■ Telephone (858) 558-6900 ■ www.geoconinc.com Project No. G2245-52-02 August 4, 2025 Roosevelt Nine LLC 2033 San Elijo Avenue, Suite 423 Cardiff, California 92014 Attention: Mr. Randolf Cherewick Subject: PERVIOUS PAVER RECOMMENDATIONS THE ROOSEVELT 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01). 2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01). Dear Mr. Cherewick: In accordance with the request of Paul Nong with Civil Landworks, we prepared this letter to provide pervious paver recommendations for the Roosevelt project. We performed laboratory resistance values (R-Value) tests on samples of soil present near street subgrade elevations in general conformance with ASTM D 2844. Recommendations provided herein are based on the laboratory test results and Traffic Indexes of between 5.0 and 7.0. A review of the referenced report indicates that the subgrade soil at the site possesses a “low” expansion potential (expansion index of 50 or less). PAVER RECOMMENDATIONS Subgrade soil in the roadways is predominately silty to clayey sand with some gravel and cobbles exhibits relatively low to moderate R-Value characteristics. The following table presents the summary of R-Value laboratory test results for the subject roadway. SUMMARY OF LABORATORY R-VALUE TEST RESULTS ASTM D 2844 Sample No. Sample Location R-Value R-1 Proposed Drive Lanes (Between Buildings C4-2 and A5-2) 16 GEOCON INCORPORATED CAL ■ E NV I RONMENTA L ■ MA T ER I A L S G E OT E CHN I The Roosevelt Pervious Pavement Recommendations Project No. G2245-52-02 - 2 - August 4, 2025 We calculated the following paver sections in general conformance with the Caltrans Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) using an estimated Traffic Index (TI) of 5.0, 5.5, 6.0, and 7.0 for parking stalls, driveways, medium truck traffic areas, and heavy truck traffic areas, respectively. The following table presents the calculated pervious pavement section for the planned drive isles. We used an R-Value of 16 and 78 for the subgrade soil and base materials, respectively. We should be contacted to provide additional pavement sections if the project civil engineer evaluates a different traffic index for the planned roadways. PERMEABLE PAVER PAVEMENT SECTION Location Traffic Index (TI) Subgrade R-Value Equivalent Paver Asphalt Concrete Thickness (Inches) Option 1 Option 2 Estimated Sand Thickness (Inches) Base Materials (Inches) ASTM C 33 Aggregate Parking stalls for automobiles and light-duty vehicles 5.0 16 3 1 -1½ 8 3” Sand / 3” #8 / 5” #57 Driveways for automobiles and light-duty vehicles 5.5 16 3 1 -1½ 10 3” Sand / 3” #8 / 7” #57 Medium truck traffic areas 6.0 16 3 1 -1½ 12 3” Sand / 3” #8 / 9” #57 Driveways for heavy truck traffic 7.0 16 3 1 -1½ 15 3” Sand / 3” #8 / 12” #57 Based on the Interlocking Concrete Pavement Institute (ICPI), the pavers should possess a minimum thickness of 3⅛ inches overlying 1 to 1½ inch of sand. We used an equivalent asphalt concrete section equal to the thickness of the pavers of approximately 3 inches in accordance with Interlocking Concrete Pavement Institute (ICPI) Tech Spec Number 4. In addition, the pavers should be installed in a pattern appropriate for vehicular traffic. Class 2 permeable base should be placed below the pavers. The Class 2 permeable base can be replaced by aggregate in accordance with ASTM C 33 and the civil engineer/manufacturer’s recommendations. The aggregate presented in Option 2 should be in conformance with the following sieve requirements from ASTM C33. ~GEOCON The Roosevelt Pervious Pavement Recommendations Project No. G2245-52-02 - 3 - August 4, 2025 AGGREGATE GRADATION LIMITS PER ASTM C33 Sieve Size Percent Passing Sieves Choker Sand No. 8 No. 57 1.5 Inches -- -- 100 1 Inch -- -- 95-100 0.5 Inch -- 100 25-60 0.375 Inch 100 85-100 -- No. 4 95-100 10-30 0-10 No. 8 80-100 0-10 0-5 No. 16 50-85 0-5 -- No. 30 25-60 -- -- No. 50 5-30 -- -- No. 100 0-10 -- -- No. 200 0-3 -- -- The Class 2 permeable base/aggregate section can be thickened to increase the water capacity as required by the project civil engineer. Prior to placing base/aggregate materials, the subgrade soil should be scarified, moisture conditioned as necessary, and recompacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content as determined by ASTM D 1557. The depth of compaction should be at least 12 inches. Similarly, the base materials should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. The subgrade of the pavers should be graded to allow water to flow to a subdrain or subdrain system. We understand the permeable pavement system will allow incidental infiltration at the base of the pavement section (i.e. not fully lined). However, a subdrain should be placed at the bottom of the base/aggregate section below the pavers and run the distance of the paver area to reduce the potential for water to build up within the paving section. The drain should be connected to an approved drainage device. The drain should consist of a 3-inch diameter perforated Schedule 40, PVC pipe and placed at the bottom of the base materials. Impermeable liners or concrete cutoff walls should be installed along the sides of the paver section to prevent water migration below and laterally outside the paver section. The liner should consist of a high-density polyethylene (HDPE) with a minimum thickness of 15 mil or equivalent. The liner should be sealed at the connections in accordance with manufacturer recommendations and should be properly waterproofed at the drain connection. ~GEOCON The Roosevelt Pervious Pavement Recommendations Project No. G2245-52-02 - 4 - August 4, 2025 The pavers should be installed and maintained in accordance with the manufacturer’s recommendations. The future owners should be made aware and responsible for the maintenance program. In addition, pavers tend to shift vertically and horizontally during the life of the pavement and should be expected. The pavers should be placed tightly adjacent to each other and the spacing between the paver units should be filled with appropriate filler. The pavers normally require a concrete border to prevent lateral movement from traffic. The concrete border surrounding the pavers should be embedded at least 6 inches below the pavement section into the subgrade to reduce the potential for water migration to the adjacent landscape areas and pavement areas. The side liners are not necessary if the concrete borders are installed as discussed herein. The performance of pavement is highly dependent on providing positive surface drainage away from the edge of the pavement. Ponding of water on or adjacent to the pavement will likely result in pavement distress and subgrade failure. Drainage from landscaped areas should be directed to controlled drainage structures. Landscape areas adjacent to the edge of pavements are not recommended due to the potential for surface or irrigation water to infiltrate the underlying permeable aggregate base and cause distress. Where such a condition cannot be avoided, consideration should be given to incorporating measures that will significantly reduce the potential for subsurface water migration into the aggregate base. If planter islands are planned, the perimeter curb should extend at least 6 inches below the level of the base materials. Should you have questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Dylan Thomas CEG 2784 Matt Love GE 3238 DT:ML:arm (e-mail) Addressee ~GEOCON GEOCON FIELD MEMO MEMONO: ---~1 __ WWW.GEOCONINC.COM PRorncTNAMEThe Roosevelt-2690 Roosevelt Street CORRESPONDING PROJECTNO. ___ G_2_24_5_-5_2_-Q_2 ___ FIELDREPORTNO: ____________ _ SUBJECT: field memo to re ort our field observations durin the construction of the residence. In eneral, in-lace densit test results indicate fill soil laced during grading for the roadway subgrade possesses a dry density of at least 95 percent of the laboratory maximum dry density near or slightly above optimum moisture content at the locations tested. We performed a site visit on 8/6/2025 to observed the current conditions of the paver sections. Two locations were pot holed to observe the installation of the subdrain and the paver section thickness. At the locations potholed, we observed the approx 6-inch subdrain wrapped in filter cloth, approx. 9-11" of rock (reported #57 aggregate), and approx. 3-4" of sand/ gravel (reported #8 aggregat aggregat ram pe tr ver sect10 on ir pans. DISTRIBUTION YES NO SUPERINTENDENT (CLIENT) Dylan Thomas-CEG 2784 FOREMAN (CONTRACTOR) GEOCON REPRESENTATIVE JOB TRAILER 8-6-2025 oTHER Randolf Cherewick ✓ DATE