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Home My WebLink AboutCT 02-13; FARBER CONDOMINIUMS; CERTIFICATION LETTER; 2005-03-22N S 1 ENGINEERING . . .• S OEOOECHNICAL, CIVIL, STRUCTURAL A ARCHITECTURAL CONSULTANTS S S S S S DESIGN GROUP FOR RESIDENTIAL S COMMERCIAL CONSTRUCTION 2121 Montiel Road, San Marcos, California 92069 (760) 839-7302• Fax: (760) 480-7477 www.designg(oupca.com. S S S. 7RE.CE.IVED MAR 23 lOosj Date: March22, 2005 5 L S "cARLssAP ff S S S NG'EERING DEPARTMENT. To: Curtis Farber r 5 CM&1 DIVJSI0N S S do Farber Family Limited Partnership 991C Lomas. Santa Fe Drive #441 5 5 Solanà Beach, CA 02075 Proposed Multi-Family Development to be Located at 1100 Las Flores Drive, Cityofil S Carlsbad, California S S S Subject Certification Letter Ref: 1) "Updated Soils Report" Prepared by Engineering -Design Group Dated S S 5 September 10,. 2003. 2) "Geotechnical Investigation and Foundation Recommendations for theL . Proposed Multi-Family Development, to be Located at 1100 Las Flores Drive, S S City of Carlsbad, California." Prepared by Engineering Design Group, EDG I S Project No. 002486-1. 5 5 5 5 5 5 We have observed garage pad subgrade in areas of the proposed buildings. Competent formationall sandstone at subgrade is consistent with those identified in the project geotechnical. report . • . S .referenced above. Soils subgrade exposed are suitable to support foundation and improvements provided recommendations in the above referenced report are followed. S .1 Based upon our understanding of the building foundation plan-and observation of onsite conditions . S all new building foundations should extend to cOmpetent formational sandstone. material. This. . •. . requirement,may require localized deepening of foundations through retaining wall backfill wedges.: S Embedment bf footings into cut formational soil shall be confirmed during footing excavation,,,"'. S preferably while footings are. being excavated, so necessary deepening. may be accomplished ••. without re-mobilization of equipment. . 5 5 ..• 5 5 .• A local removal and recompaction of the upper 2L3 feet was conducted for support of the proposed . slab on grade floors beyond the basement retaining walls. Onsite soil was utilized as graded fill. • Prior to recompaction, fill soils were cleaned of vegetative and other *debris and moisture conditioned, where necessary. Onsite soil consisted of rustbrown slightly silty sands. Grading operations were conducted with the used of and placed utilizing a CAT D6 Dozer and a large wheel . roller. H • . S • S S • • • ••5 S AS-GRADED1 SUPPLEMENTAL RECOMMENDATIONS S • • 1: The dMailing of basement subgrade is critical, and can play an important role in controlling S S • S water;collection around the basement. Strong consideration should be given, to installing S • 5 5 5 5 S S • S • Project No. 002486-1 S • F:\LETTER\LETTER 42000\002486-1, FARBER DEV, 1100 LAS FLORES DR, CARLSBAD - CERT LTR & COMP RPT.WPd S I basement slab underdrains and sloping the formationàl soil subgrade, to collect subsurface, water. The basement slab underdrain system should flow (via gravity if possible) to a suitable outlet point on the rear slope. . 2. The concrete contractor should thoroughly review the Concrete Slabs section of the project, . soils. The recommendations call for use of concrete with a water to cement ratio of 0.5 or: less in all moisture sensitive areas. In addition an additive should be considered to minimize; the threat of water intrusion through the concrete. •The concrete mix design ultimately, chosen should be reviewed by Engineering Design Group prior to pouring. . Consideration should be given to utilizing cast in place concrete walls at lower basement areas. Our experience indicates cast in place walls generally less susceptible to water; intrusion than masonry wall systems. .. . . . . As stated in prior reports, subsurface french drain systems shall be independent of surface. area drain systems. These systems, in general, should not connect. All additional fill placement, including utility trenches, shall be tested by Engineering Design: Group per the recommendations of the project soils report and specification package. We anticipate compaction testing to include, but not limited to, fill placed behind. building retaining walls and utility trenches. . . . 6 All retaining wall backfill shall have expansion potential in the very low range (Ek20) FIELD AND LABORATORY TESTING . . Field density testswere performed in accordance with 02922-96 (Nuclear Gauge Method). Our test; . results indicate that .the fill placed, under our observation and testing, in the areas indicated has been compacted to at least 90 percent relative compaction, as determined by ASTM D1557-91, (Procedure A). The reported test results are representative of the soil conditions at the locations tested. Our observation and field density testing methods are in accordance with normally accepted, procedures. The accuracy of the relative compaction values are subject to the precision limitations of the ASTM test methods. The accuracy of the maximum-dry density determination (ASTM, .01557-91) is discussed.in the 1998 Annual Book of ASTM Standards, Section 4, Volume 04.08, entitled, Soil and Rock; Building Stones. Variations of relative compaction values should be expected, laterally and vertically, from the actual test locations. . SUMMARY . • . . . . . . . . . • . . . H. It is our opinion the soils graded onsite (as depicted herein) were compacted to a minimum Of 90 percent relative compaction and suitable for the support of proposed structures (based on ASTM 01557-91, Procedure A). • . . . .. • . . If you have any 0ns regarding the reco tions herein do not hesitate t call our office. . • •.. OFESS/Ô, . . • . . • . Sincer N No CO E NG DE ca 2590 STEVEN B. NORRIS rri Cie 12-31-05 CERTIFIED teve ENGINEERING SJSJ SJ RGE#2590; CEG #2263 CH 002486711 F:\LETTER\LETTER 4\2000\002486-1, FARBER DEV 1100 LAS FLORES DR CA I LTR & COMP RPT wpd id ?. SOIL SOIL TYPE MAXIMUM OPTIMUM U.S.C.S. TYPE: DENSITY (PCF) MOISTURE CLASSIFICATI ON 1 Rust Brown 130 SW • slightly Silty Sand TABLE NO. 2 • Field Test Results TEST DATE FINISHED SOIL DRY FIELD RELATIVE NO: • GRADE TYPE DENSITY MOISTURE COMPACTI MINUS (-) (#) (PCF) (PERCENT) ON • • • (PERCENT) 10-6-04 1 1 118 11 .2 90 CF-2 10-6-04 1 1 1192 10 91 CF-3 10-7-04 1 1 1171 c 90 CF-4 10-8-04 1 1 118.4 11 .5 . 91 CF-5 10-8-04 1 1 1196 : 108 92