Loading...
HomeMy WebLinkAboutCT 02-13; FARBER CONDOMINIUMS; UPDATED SOILS REPORT; 2003-09-10I ENGINEERING DESIGN,GROUP GEOTECHNICAL, CIVIL, STRUCTURAL A ARCHITECTURAL CONSULTANTS . . . . . II .. FOR RESIDENTIAL & COMMERCIAL CONSTRUCTION 2121 Montiel Road San Marcos California 92069 (760)'839-7302 Fax (760) 480-7477 www designgroupca c 1 I T Date September 10, 2003 To Farber Family Partnership I I Attention Curtis Farber j. I 140 Marine View Avenue #220 I I Solana Beach, CA 92075 Re I Proposed Multi-family Development to Be Located at 1100 Las Flores Drive, I I City of Carlsbad, California I Subject Updated Soils Report Reference: "GEOTECHNICAL INVESTIGATION AND FOUNDATION RECOMMENDATIONS, FOR PROPOSED MULTI-FAMILY MULTI-FAMILY DEVELOPMENT, TO BE LOCATED AT 1100 LAS FLORES II ... . . . ..- . DRIVE 'CITY OF CARLSBAD CALIFORNIA.", Project No: 002486-1, dated December 22, -, I 2000 by Engineering Design Group I GENERAL 1 I I In accordance with your request, w have reviewed the above referenced Geotechnical I Investigation report and provided the following updated recommendations for the proposed development. Our update is based on our review of the above referenced report and site I. reconnaissances of the property. Based on our conversations with the project developer - it is anticipated that the proposed new improvements will consist of the following I I > Design and construction of new multi unit condominium complex I > Partially subterranean parking garage > Miscellaneous walkway and common area improvements I I UPDATE RECONNAISSANCE I Representatives of Engineering Design Group visited the subject property on September 9, 2003 and found the condition of the residential property to be generally similar to that described in our above referenced geotechnical report Based on our site reconnaissance, Page No. 1 of 8 I Project No. 002486-1 . . - - -- - - -. 1 E:\JOBS\1 JOBS\2000\002486.1, FARBER-MULTI-FAMILY DEV, F1100 LAS FLORES DRIVE, CARLSBAD - UPDATE.wpd I I4 I ENGINEERING - 60000CHNICAL, CIVIL, STRUCTURAL V ARCHITECTURAL CONSULTANTS - 1 DESIGN GROUP .•.. TOO RESIDENTIAL S COMMERCIAL CONSTRUCTION ,.2121 Montiel Road, San Marcos, California 92069. (760) 839-7302 Fax: (760) 480-7477 wwwesigngroupcacom I I Date September 10, 2003 I - To: . Farber Family Partnership. Attention:..Curtis Farber 140 Marine View Avenue #220 I Solana Beach, CA 92075 I Re: i Proposed Multi-family bevelopment to Be Located at 1100 Las Flores Drive, City of Carlsbad, California I Subject Updated Soils Report I Reference: "GEOTECHNICAL INVESTIGATION AND FOUNDATION RECOMMENDATIONS, FOR PROPOSED MULTI-FAMILY DEVELOPMENT, TO BE LOCATED AT 1100 LAS FLORES DRIVE, CITY OF CARLSBAD, CALIFORNIA.", Project No: 002486-1, dated December22, .2000, by Engineering Design Group. . . . . .. I GENERAL I . . In accordance with your request, we. have reviewed the above referenced Geôtechnical . Investigation report and provided the following updated recommendations for the proposed development. Our update is based on our review of.the above referenced report and site I •. reconnaissances of the property. Based on our conversations with the project developer .• it is anticipated that the proposed new Improvements will consist of the following I >.. Design and; construction of new multi unit condominium complex ... . . - Partially subterranean parking garage . . -. .. . . . . . . Miscellaneous walkway and common area improvements.- UPDATE RECONNAISSANCE I . Representatives of Engineering Design Group visited the.subject property on September 9, 2003 and found the condition of the residential pro perty be generally similar to, that described in ourabove referenced geotechnical report. Based on our site reconnaissance, . I I Page No. 1of8 Project No. 002486-1 f- E:\JOBS\1 JOBS\2000\002486-1, FARBER-MULTI-FAMILY DEV, F1100 LAS FLORES DRIVE, CARLSBAD - UPDATE.wpd I i : ! the recommendations of our above referenced report for the property remain pertinent and tw:applicable to the property, with the following amended updates The building Architect, or waterproofing subcontractor, shall design a retaining wall and slab waterproofing system to adequately prevent water intrusion into the . I subterranean garage per the design expectations of the developer. The details i pro vi Jed in our referenced report are minimum guidelines only, intended to addrss hydrostatic buildup issues behind the retaining 'elements Upgraded 1 . .waterproofing elements' may include FirestoneEPMlinër in.:lieuof visqueen, pea gravl underlayment in lieu of sand, water retarding admixtures, slab underdrain systems, surface sealants, etc The design of the subterranean water proofing; ' I system for this development is beyond the scope of this report 1The fundation section of our report is updated as follows t . I I I FOUNDATIONS ""- 1- Footings bearing in competent formational materials or compacted and certified fill maybe designed utilizing maximum allowable soils pressure of 2,000 psf, I 2 Seismic Design Parameters I P'k. of Floors Supported M!niPnum Fo&tkig Width *Mjnj, Feoti/gepth Below Lowest Adjacent Grade 1. 18 inches 18 inches 2 18inch0s 18 inches 3 18incjjs 24inphe,, 4 ... ... . ............ All footings should be reinforced with a minimum of two #5 bars at the and two #5 bars at the bottom (3 inches above the ground). For footings over 30 inches in depth,, additional reinforcement, and possibly a stemwall , system will be necessary.,This detail should be reviewed on a case by case I basis by our office prior to construction ,. 5 All isolated spread footings should be "designed utilizing the above given 1 bearing values and footing depths, and be reinforced with a minimum of #5 1,.. . . . bars at 12 inches o c in each direction (3 inches above the ground) Isolated spread footings should have a minimum width of 24 inches I 6 For footings (including site\retaining wall footings) and all other cosmetically - sensitive improvements adjacent to slopes, a minimum 12 feet horizontal I " setback in formational or certified . fill material should be maintained. A setback measurement should be taken at the horizontal distance from the bottom of the footing or improvement to slope• daylight. Where . this. ,. . . . condition can not be met , it should be brought to the attention of the ;. Engineering Design Group for review. .. . '. I. ¼ 7. All excavations should be performed in general accordance with the content&L . . of this report, applicable codes, OSHA requirements and applicable city .and/or countystandards. . . . . . . . . . . . I 8. 1 Al! foundation sub grade soils and footings shall be pre-moistened aminimum . ..: • of 18 inches in depth prior to the pouring of concrete. I........ .. . • 9. Concrete for building foundations should have a minimum compressive It strength of 2,500 psi in 28 days. . . . . .. : ¼ I I I . . . . . . . .. Page No. 3 of 8 i . . I Project No. 002486-1 E:\JOBS\l .JOBS\2000\002486-1, FARBER-MULTI-FAMILY 0EV Fl 100 LAS FLORES DRIVE, CARLSBAD. UPDATE.wpd I 1' S . The concrete slabs ection of our report is updated as follows CONCRETE SLABS ON GRADE .. .. . 1. Concrete slabs on grade of the garage should have a minimum thickness of 5 inches (6 inches at garage and driveway locations) and should be reinforced with #4 bars at 18.inches o.c. placed at the midpointof the slab. All concrete shall be poured per the following: Slump: Between .3 and 4 inches maximum , Aggregate Size: 3/4 - 1 inch' " • j. ., Air Content: 5 to 8 percent . . Moisture retarding additive in concrete at moisture sensitive areas. Water to cement Ratio '- 0.5 maximum ,. All required fills used to support slabs, should be placed in accordance with the grading section of this. reptht and," the' attached Appendix B, and compacted to 90 percent Modified ProctdrDensity, ASTM D-1557.. ' . A uniform layer of 4 inches of clean sand is recommended under the slab in.• order to more uniformly support the slab, help distribute loads to the soils beneath the slab, and act as a capillary break. In addition, a vis queen layer (10 mil' should be placed mid-height in the sand bed to act as a vapor retarder. As an upgrade, an Firestone EPM liner may be used. instead of .' visqueen ".Adequate control joints should be installed to control the unavoidable , I cracking of concrete that takes place when undergoing.its natural shrinkage. during curing. The controljoints should be well located to direct unavoidable' slab cracking to areas that are desirable by the designer. . . . ., .;. : 'All sub grade soils'. to receive concrete flatwork are to be pre-soaked to. 2 percent over optimum moisture content to a depth of 18 inches. . . '. Brittle floor finishes placed, directly on slab .on grade floors may crack if concrete is not adequately cured prior, to installing the finish or if there is minor slab movement. To minimize potential damage to movement sensitive flooring, we recommend the use of slip sheeting techniques (linoleum type) which allows for foundation and slab movement without transmitting .this movement to the floor finishes. 4 • ,.,. 1' ... . Page No. 40f8 Project No. 002486-1 E:\JOBS\1 JOBS\2000\002486-1, FARBER-MULTI-FAMILY DEV, F1100 LAS FLORES DRIVE, CARLSBAD - UPDATE.wpd '.5- 5 ''' • I' I •. S 5,... Prior to placement of any moisture sensitive floor finishes, the flooring contractor shall conduct vapor emission testing, per ASTM standards, to 1 determine the suitability of the concrete for the proposed flooring type. Where emission rates exceed the. manufactures specifications, a concrete. I .. sealant product shall be utilized. . 7. Exterior concrete flatwork and driveway slabs, due to the nature of concrete I hydration and minor sub grade soil movement, are subject to normal minor concrete cracking. To minimize expected concrete cracking, the following may be implemented: . I 0 Concrete slump should not exceed 4 inOhes. : Concrete should be poured during "cool" (40 - 65, degrees) weather if possible. If concrete is poured in hotter weather, a set retarding.. I additive should be included in the mix, and the slump kept tb a minimum. Concrete sub grade should be pre-soaked prior to the pouring of concrete. The level of pre-soaking should be a minimum of 2% over optimum moisture to a depth of 18 inches. Concrete may be poured with a 10 inch deep thickened edge. I • Concrete should be constructed with tooled joints or sawcuts (1 inch deep) creating concrete sections no larger than 225 square feet. For sidewalks, the maximum run between joints should not exceed 5 feet. ' I . For rectangular shapes of concrete, the ratio of length to width should . generally not exceed 0.6 (i.e., 5 ft. long by 3 ft. wide). Joints should be cut at expected points of concrete shrinkage (such as male I corners), with diagonal reinforcement placed in accordance with industry standards. . Drainage adjacent to concrete flatwork should direct water away from I . the improvement. Concrete subgrade should be sloped and directed... . . : to the collective drainage system, such that water is not trapped below the flatwork. . . I . The recommendations set forth herein are intended to reduce cosmetic nuisance cracking but will not prevent concrete cracking. The owner should be aware all concrete, because of it's I cementitious nature, will to some degree shrink and crack. The amount, location and impact on the cosmetic finish, of cracking can be reduced by design philosophy and construction. The project , I concrete contractor is ultimately responsible for concrete quality and ' • .. performance, and should pursue a cost-benefit analysis of these recommendations with the owner & general contractor, and other 1 options available in the 'industry, prior to the 'pouring of concrete. I . • Page No. 5of8 Project No. 002486-1 E:UOBS\1 JOBS\2000\002486-1, FARBER-MULTI-FAMILY DEV, Fl 100 LAS FLORES DRIVE, CARLSBAD - UPDATE.wpd I I Additionally, the project owner should be made fully aware of expected performance of concrete. finishes, so as to avoid follow up calls regarding minor concrete cracking II) The retaining wall section of our report is updated as follows RETAINING WALLS: . •. .. . I Retaining walls up to 8 feet may be designed and constructed in accordance with the fdllowing recommendations and minimum design parameters 1 1. Retaining wall footings should be designed in'acóordañcè with.the allowable . bearing criteria given in the "Foundations" section of this report, and should maintain minimum footing depths outlined in "Foundation" section of this 1 I report . 2. Unrestrained cantilever retaining Walls should be designed using ana ctive' I . equivalent fluid pressure 0f35pcf This assumes that granular, free drainin: material will be used for backfill, and that the backfill surface will be level. For sloping backfill, the following parameters may be utilized: Backfill Sloping . 2:1 Slope , ' 1.5:1 Slope Condition ' .'. . .. .. .. Active Fluid 50 pcf ' ' 65 pcf Pressure I , Any other surcharge loadings shall be analyzed in addition to the above values. I 3 If the tops of retaining walls are restrained from movement, they should be designed for a uniform soil pressure of 65 psf. I . 4. Passive soil resistance maybe calculated using an equivalent fluid pressure of 300 pcf.. This value assumes that the soil being utilized to resist passive ' I • . . pressures, extends horizontally 2.5 times the height of the passive pressure wedge of the soil. Where the horizontal distance of the. available passive L pressure wedge is less than 2.5 times the height, of .the soil, the passive pressure value must be reduced by the percent reduction in available I ' '. • horizontal length.. . . . • ' 5. A coefficient of friction of 0.35 betWeen the soil and concrete footings may I •, ":-.be 'utilized to resist lateral loads in addition to the passive earth pressures above. . , .' •• ' . I . . • . ' Page No. 60f8 . Project No. 002486-1 . E:\JOBS\1 JOBS\2000\002486-1, FARBER-MULTI-FAMILY DEV, Fl 100 LAS FLORES DRIVE, CARLSBAD - UPDATE.WPd I ' • , • •'. . S , •. It I I I 6. Retaining walls should be braced and.monitored during compaction. If this cannot be accomplished, the compà'ótive' effort should be included as a . surcharge load when designing the wall. 7. . Al/walls shall be provided with adequate back drainage to relieve hydrostatic 'pressure, and be designed in accordance with the minimum standards I contained in the "Retaining Wall Drainage Detail", Appendix D Area drains -i: should not be connected to French Drain System behind retaining wall. Wall ' waterproofing systems shall be designed by the building Architect. 1 8 Retaining wall backfill should be placed and compacted in accordance with the "Earthwork" section• of this, report. Backfill shall consist of a non-c' I expansive granular, free draining material IV) The construction observation and testing section of our report is updated as follows: , CONSTRUCTION OBSERVATION AND TESTING . .. The recommendations provided in this report are based on subsurface conditions, our review of the site, and knowledge of the area. Interpolated subsurface conditions must be verified in the field during construction; The following items shall be conducted.prior/during construction by a representative of Engineering Design Group (under separate contract) in order to verify compliance, with the geotechnical and civil engineering recommendations provided herein, as applicable.. S Review of final project grading and foundation plans prior to construction. f Attendance of a pre-grade/pre-construction meeting prior to the . .start of: construction. . . . . 3.' . Observation of removal bottom.'park!ng garage subgrade,. .• ' 4 ..' Observation and testing, of any fill placement, including utility trenches and . '.retaining wall backfill. • . I ... 5. Final review of onsite drainage systems.'. • . . ... The 'project soils engineer may at their discretion deepen footings or 'locally: recommend additional steel reinforcement to upgrade any condition as deemed 'necessary during site observations. . . The field inspection protocol, as outlined above, is a requirement of this report. Engineering Design Group assumes no liability for structures constructed utilizing this report not 'meeting.this protocol. In the event field inspection work is conducted by others, they shall assume sole responsibility for work conducted and certilfy the suitability of soils for building support. • . .' • S • .......... . "' • ' . . Page No. 7 of 8 S , ' Project No. 002486-1 E:\JOBS\1 JOBS\2000\002486-1, FARBER-MULTI-FAMILY DEV, Fl 100 LAS FLORES DRIVE, CARLSBAD - UPDATE.wpd -. - - I . If you have any questions, regarding this report, or.ifwe can be of further service, please do not hesitate to 'co ntactus. We hope the report provides you with necessary information to continue with the development of the project. <0 263 6) CERTIFIED co C 7672 ca 2590 7- EERING California RCE #47672 r Sincer GE I I: I P I I I Page No. 8 of 8 1 - Project No. 002486-1 E:\JOBS\1 JOBS2000\002486-1, FARBER-MULTI-FAMILY 0EV, Fl 100 LAS FLORES DRIVE, CARLSBAD - UPDATEwpd I: