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Home My WebLink AboutSDP 2019-0012; RAF PACIFICA GROUP FUSION; SUPPLEMENTAL RECOMMENDATIONS; 2020-04-20GEOTECHNICAL MATERIALS SPECIAL INSPECTION RAF Pacifica Group-Real Estate Fund IV, LLC 315 South Coast Highway 101, Suite V-12 Encinitas, CA 92024 Attention: Subject: Mr. Jim Jacob, Director of Development Supplemental Recommendations Design for Flexible and Rigid Pavements fu·sion Site Improvements 1950 Camino Vida Roble, Carlsbad, California DVBE• SBE• SDVOSB• SLBE April 20, 2020 NOVA Project No. 2019195 r: ~ ..-., r---<\ :1 "'i-/ ·~,---: 1'f"'t.1 l~ "'L , ti, _,~ ~. V ,i k:, .... .JJ' References: NOVA 2019a. Report, Geotechnical Update, Mezzanine Addition, 1950 Camino Vida Roble, Carlsbad Airport Center, Carlsbad, California, NOVA Services, Inc., Project No. 2019195, September 20, 2019. NOVA 2019b. Report, Geotechnical Update, fu·sion Site Improvements, 1950 Camino Vida Roble, Carlsbad, California, NOVA Services, Inc., Project No. 2019195, November 5, 2019. SCA 2019. fu·sion, 1950 Camino Vida Roble, Carlsbad, California 92008, RAF Pacifica Group, SCA Architecture, Job No. 18034.S02, September 13, 2019. Dear Mr. Jacob: The intent of this letter is to provide recommendations for the design of flexible and rigid (PCC) pavements at the subject development. The recommendations utilize the results of laboratory testing recently completed by NOV A. These recommendations are provided by NOVA Services, Inc. (NOVA) for RAF Pacifica Group- Real Estate Fund IV, LLC (RAF Pacifica). NOVA is retained by RAF Pacifica as Geotechnical Engineer-of-Record (GEOR) for this project. PAVEMENT SUBGRADE PREPARATION The subgrade for areas to receive PCC or rigid pavements should be prepared in the stepwise described below. 1. Step 1, Moisture Conditioning and Densification. The upper 12 inches of soils exposed at subgrade for pavements should be moisture conditioned to at least 2% above optimum, then densified to at least 95% relative compaction after ASTM D1557 (the 'modified Proctor'). 2. Step 2, Proof Roll. The prepared subgrade should be proof-rolled under the observation of the GEOR using a loaded dump truck or similar. Any yielding, soft or unsuitable materials observed during this proof-rolling should be removed, replaced with an 4373 Viewridge Avenue, Suite B San Diego, CA 92123 P: 858.292.7575 www.usa-nova.com 944 Calle Amanecer, Suite F San Clemente, CA 92673 P: 949.388.7710 Supplemental Recommendations for Pavements fu·sion Site Improvements, Carlsbad, CA NOVA Project No. 2019195 April 20, 2020 approved backfill, and compacted. The GEOR can provide alternative options such as using geogrid and/or geotextile to stabilize the subgrade at the time of construction, if necessary. 3. Step 3, Timely Placement of the Base Course. Construction should be managed such that preparation of the subgrade immediately precedes placement of the base course. Proper drainage of the paved areas should be provided to reduce moisture infiltration to the subgrade. Construction should be managed such that preparation of the subgrade immediately precedes placement of the base course. NOVA approves the use of recycled base or Caltrans Class II base for pavement sections within the property. Proper drainage of the paved areas should be provided to reduce moisture infiltration to the subgrade FLEXIBLE PAVEMENTS R-Value testing by NOVA of a representative sample of subgrade soils after ASTM D2844 indicated R ~ 14. Design for pavements should anticipate R ~ 14. The structural design of flexible pavement depends primarily on anticipated traffic conditions, subgrade soils, and construction materials. Table 1 provides pavement sections for differing conditions of traffic. Table 1. Flexible Pavement Sections, R = 14 Asphalt Base Thickness Area Traffic Index Thickness {inches) (inches) Passenger Car 5.0 4 6 Driveways/Parking Fire Lane/Heavy 6.0 4 10 Duty Driveways RIGID (PCC) PAVEMENTS Pavement Section The Portland cement concrete (PCC) pavement section should consist of 7 inches of Portland cement concrete over 12 inches of properly prepared subgrade placed at a minimum relative compaction of 95%. NOVA expects that the exposed subgrade will be of relatively Low expansion potential. If the excavation exposes clayey subgrade soils with an Expansion Index El>50, the top 12 inches should be replaced with 'Select Fill' as defined in NOVA 2019b. 2 Concrete Properties Supplemental Recommendations for Pavements fu·sion Site Improvements, Carlsbad, CA NOVA Project No. 2019195 April 20, 2020 The concrete should be obtained from a mix design that conforms with the minimum properties shown on Table 2. Table 2. Recommendations for Concrete Pavements Property Recommended Requirement Compressive Strength @ 28 days 3,250 psi minimum Strength Requirements ASTM C94 Minimum Cement Content 5.5 sacks/cu. yd. Cement Type Type V Portland Concrete Aggregate ASTM C33 Aggregate Size 1-inch maximum Maximum Water Content 0.5 lb/lb of cement Maximum Allowable Slump 4 inches Jointing and Doweling Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation. Sawed joints should be cut within 24 hours of concrete placement, and should be a minimum of 25% of slab thickness plus ¼-inch. All joints should be sealed to prevent entry of foreign material and doweled where necessary for load transfer. Where dowels cannot be used at joints accessible to wheel loads, pavement thickness should be increased by 25% at the joints and tapered to regular thickness in 5 feet. CLOSURE NOVA appreciates the opportunity to be of continued service to RAF Pacifica. Should you have any questions regarding this letter or other matters, please do not hesitate to contact the undersigned at 858.292.7575. Sincerely, , Inc. Wail Mo~htar n . O'Brien, P.E, G.E. Senior Project Manager ri cipal Geotechnical Engineer ~ 3