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Home My WebLink AboutSDP 16-12; CARLSBAD VETERANS HOUSING; SUPPLEMENTAL RECOMMENDATIONS DESIGN FOR INTERLOCKING CONCRETE PAVERS; 2020-06-050A I GEOTECH kL MATERIALS Jlklk NOVA i SPECIAL INSPECTION DVBE • SBE • SDVOSB .SLBE Affirmed Housing Group CIO Marie Allen 13520 North Evening Creek Drive San Diego, CA 92128 Attention: Ms. Allen June 5, 2020 NOVA Project No. 3019097 (via email; marie@affirmedhousing.com) Subject: Supplemental Recommendations Design for Interlocking Concrete Payers Proposed Three-Story Apartment Building 3606, 3618 & 3630 Harding Street, Carlsbad, California Reference: KLE 2020. Grading Plans For: Harding Veterans Housing, 3606, 3618, 3630 Harding Street, Kettler Leweck Engineering, June 5, 2020. As requested by Kettler Leweck Engineering, this letter has been prepared to provide recommendations, for the installation of interlocking concrete payers at the subject property. These recommendations are provided by NOVA Services, Inc. (NOVA) for Affirmed Housing Group as NOVA is retained by Affirmed Housing Group as Geotechnical Engineer-of-Record (GEOR) for this project. The recommendations for interlocking concrete payers provided herein have been developed in general conformance with the Interlocking Concrete Pavement Institute (ICPI) guidelines, Technical Specification No. 4, dated May 2011 and with NOVA's familiarity of geotechnical matters of this nature. RECOMMENDATIONS Bedding and Joint Sand Gradation Table I summarizes bedding sand gradation recommendations and recommended joint sand gradation. The joint sand should comply with ASTM C144 with a maximum 100% passing the No. 16 sieves and no more than 5% passing the No. 200 sieve. Bedding sand may be used as joint sand; however, additional effort may be required due to its coarser gradation. 4373 Viewridge Avenue, Suite B www.usa-nova.com 944 Calle Amanecer, Suite F San Diego, CA 92123 Dana Point, CA 92673 P: 858.292.7575 P: 949.388.7710 A 1116, NOVA Supplemental Recommendations 3606, 3618 & 3630 Carlsbad, CA NOVA Project No. 3019097 June 5, 2020 Table 1. Gradation of Sand for Paver Systems Sieve Size Percent Passing Bedding Sand Joint Sand 3/8—inch 100 - No.4 95-100 100 No.8 80-100 95-100 No. 16 50 -85 70 -100 No. 30 25-60 40-75 No. 50 5-30 20-40 No. 100 0-10 10-25 No. 200 0-1 0-5 Base and Subgrade The bedding sand should be underlain with at least 6 inches of Class II base compacted to at least 95% of the maximum dry density at or slightly above optimum moisture content as determined by ASTM D1557. If wet or saturated conditions are anticipated, the excavation bottom may need additional stabilization effort using 3/4" rock or aggregate base and/or installation of geogrid. A NOVA representative should observe the surface soils prior to placement of any new fills. Isolated soft or loose areas may require deeper removals based on observations made in the field by a NOVA representative. The upper 12 inches of the subgrade soil should be scarified; moisture conditioned as necessary, and compacted to a dry density of at least 95% of the laboratory maximum dry density at or slightly above optimum moisture content as determined by ASTM D1557. Control of Infiltration An impermeable liner (e.g., 30-mil PVC or equivalent) should be placed surrounding the payers to prevent soil subgrade saturation and lateral water migration. The liner should extend up to the top of the aggregate base layer and adhered to the edge restraint. Water retained by the liner can be collected by a subdrain. The lined subgrade soils should be sloped at least one percent towards the subdrain. A 4-inch diameter, Schedule 40, perforated PVC pipe encapsulated with Caltrans Class II permeable base (or equivalent) should be suitable as a subdrain. This pping should connect to solid PVC pipe to convey the stormwater to a suitabe outlet structure, i.e. area drain or storm drain structure. Figure 3 depicts a design to control infiltrating surface water that reflects the above recommendations. 2 A Supplemental Recommendations 3606, 3618 & 3630 Carlsbad, CA NOVA Project No. 3019097 NOVA June 5, 2020 EDGE RESTRAINT, fiSAV ER AS RCOMMENDED BY r MANUFACTURER. I TYPICALLY 6' THICK 1" BEDDING SAND, PEI I CONCRETE BORDER MANUFACTURERS /SPECIFICATIONS 1'I :f 6' J . TTT. 0 0 0 0 10 0 4 0 I CLASS ii 0 4O .O d.PRMEBLE ii r 0 ---------- r P1 RMEABL f---01 LINER/30 MIL PVC OR 1 I APPROVED EQUIVALENT iIt (' II ft-ll J I - I II -' - SUOGRADE COMPACTED TO AT [ 2' MN I 1LEAST 95% RELATIVE COMPACTION T AT OR SLIGHTLY ABOVE OPTIMUM 4" DIA. PERFORATED MQISI,JREcONJLN1 LI i-I-j 'l SCHEDULE 40 PVC SUODRAIN L r1' r-I. 1 I1LzLL PIPE SURROUNDED BY ICU. L -Tn -' Li FT OF CLASS II PERMEABLE BASE. Figure 3. Design to Control Infiltration Installation Concrete paver units should be at least 80 millimeters (31/8 inches) thick for vehicular concrete payers. Interlocking concrete pavement can be constructed by placing the concrete paver units over a 1-inch bedding sand layer generally conforming to ASTM C-33 sand. Concrete paver installation should be performed in accordance with the manufacturer's and ICPI guidelines. Stable edge restraints such as concrete edge bands and curbs are essential to maintain horizontal interlock while the paver units are subjected to repeated vehicular loads. Edge Restraint The edge restraint may consist of a concrete pavement section. Other edge restraint recommendations can be found in the ICPI technical guidelines. A concrete edge restraint pavement section may be designed in general conformance with the procedure recommended by the American Concrete Institute report ACI 330R-08 Guide for Design and Construction of Concrete Parking Lots using the following parameters: Modulus of subgrade reaction, k = 100 pci Modulus of rupture for concrete, MR= 550 psi Traffic Category = B Average daily truck traffic, ADTT (assumed) = 25 Based on the criteria presented above, concrete pavement should consist of a minimum of 6 inches of PCC placed over subgrade soil compacted to a dry density of at least 95% of the laboratory maximum dry density near to slightly above optimum moisture content. This pavement section is based on a minimum concrete compressive strength of approximately 3,200 psi (pounds per square inch). No reinforcing steel will be necessary within the concrete for geotechnical purposes. 3 116, NOVA Supplemental Recommendations 3606, 3618 & 3630 Carlsbad, CA NOVA Project No. 3019097 June 5, 2020 Maintenance A maintenance schedule consisting of inspecting the pavement sections should be established. Periodic removal, replacement, and re-leveling of individual payers may be required. CLOSURE NOVA appreciates the opportunity to be of continued service to Affirmed Housing Group. Should you have any questions regarding this letter or other matters, please do not hesitate to contact the undersigned at (949) 388-7710. Sincerely, NOVA Services, Inc. (C843351 .i'e~se D. Baeld, RCE #84335 /* ênior Engineer 4 RETTTT) JUN 1 LAND U _NT