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Home My WebLink AboutCT 01-05; CALAVERA HILLS VILLAGE W; INTERIM REPORT OF ROUGH (MASS) GRADING; 2004-09-29SENT BY: 0E0S0ILS INC.; 7600810015; SEP-29-04 4:37PM; PAGE 2 Geotechnical Geologic • t1VfronmentflI 5741 lairner Way • Carlsbad, California 92008 (780) 438-3155 • FAX (760) 931-0915 September 29, 2004 W.O. 4254-13-SC Brookfield Homes 12865 Pointe Del Mar, Suite 200 Del Mar, California 91014 AttentiOn: Mr, Dale Gleed and Ms. Teri McHugh ___Lots-103thhii 3d Phae 3Lôts45 Through 7i Tfa~ ;7-W 9LW-- San Die -Co rityi-California go U References: 1. "California Building Code, Califoi'nia Code of Regulations.' TO 24, PM 2, Volume 2, Adopted November 1, 2002. by the California Building Sndards Commission. Update of Geotechnkal Report, Calavera Hills. Village W, City of carIbad, California,' W0. 2750--50, dated October 22, 1959, by GeoSoils, Inc.. "Uniform Building Code,' 1997 edition, by Intemalionel Conference of Building Officials. Dear Mr. Ueed and Ms. McHugh: In accordance with your request and authorization, GeoSoils. Inc. (GSI) is presenting this Interim report of rough grading. Grading and processing of original ground within the subject lots was observed and selectively tested by a representative 01 GSI during the earthwork phase of development for the subject property. The scope of our services Includes geotechnlcal observations during site grading, field density and laboratory testing and preparation of this summary letter. The Work performed to. date is In general conformance with the recommendations contained in our referenced report (QSI, 1599), and with the grading ordinance of the City of Carlsbad, California. Field testing indicates that IlUs placed under the purview of this report have been compacted to a minimum 90 percent relative compaction. Laboratory testing performed to date indicates that the subject lots have a very low expansion potential (Expansion Index (E.l.] less than 20), in accordance with Table 184B of the Uniform Building Code ([UBC], International Conference of Building Officials (ICBCI, 1997). Testing also Indicates that sulfate exposure is negligible for all of the subject lots, in accordance with Table 19-A'4 of the USC (ICBO, 1997). Based on our review of the as- built site conditions, the foundation categories for the subject lots are shown on the attached Lot Characteristics Table, based on Table 1 of Reference No. 2, using conventional foundation design and construction, or per Table 2 of Reference No, 2, using ei 02ON Sfl0HNWflS - sG wOH P1 31+100 J9 Lt:T t/6/60 SENT BY: 0050!L, INC.; 76010l5; SP-29-04 4:57PM; PAGE S post-tension slab design and construction. General site development critetia is attached in the Appendix. A final compaction report of rough grading and improvements construction, including observations and testing results for rough grading, utilities, and drivewaylparking areas, and final foundation design is forthcoming. The conclusions and recommendations presented herein are professional opinions. These opinions have been derived in accordance with current standards of practice and no warranty is expressed or Implied. Standards of practice are subject to change with time. (581 assumes no responsibility or liability for work, testing, or recommendations performed or provided by others, their inaction, or work performed without the benefit of geotechnical observation and testing services by GSI. The opportunity to be of service is greatly appreciated. If you have any questions, please do not hesitate to contact any of the undersigned. RespectMty si. GeoSolls, Inc. Robe .Crisf Engineering G iglk A ff .Rc 477I II E 2-05 * David W. Skelly Civil Engineer, RCE 478 RGC/DWS/JPFTjk Attachment Table 1 - Lot Characteristics - Village W Appendix - Development Criteria Distribution: (4) Addressee Brookfield Homes W.O. 4254-5-SC Village W, Calavera II1IIS II May 4. 2004 owp420(4254b1ro2 Page 2 GeoSoils, I,w.. 2006ØON 3snOHN3Wwns 4- Sa WOH PIH-)100 Lp:t /6/6 GENT Y: GE080IL5 INC.; 760931091E; aFP-29-04 4:G6PM; PAGE 9o$4. Geotechnical • Geologic • Environmental 5741 Palmer Way • Carlsbad, California 92008 • (760)438-3155 • FAX(760)931-0915 FAX TRANSMITTAL DATE: September 29, 2004 W.O. 4254-B-SC TO: Brookfield Homes ATFN: Ms, Ten McHugh FAX NO.: 858-793-2395 FROM: Robert Crismani/JK SUBJECT: Interim Report of Rough (Maas) Grading, Phase 2, Lots 59 through 68, and Lots 103 throughi 13, and Phase S. Lots 45 through 58, and 69 through 74, Calavera Hills ii, Village W, City of Carlsbad, San Diego County, California NUMBER OF PAGES INCLUDING COVER SHEET: 11 SENT BY: GEOSOILS, INC.; 703lO915; SEP-29-64 4:39PM; PA69 11111 When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed. A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGItPROFESSIONALSLCONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and design criteria specified herein. JJ4N REVIEW Any additional project plans should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/orfurther geotechnical studies may be warranted. UMITA1IONS The materials encountered on the project site and utilized for our analysis are behaved representative of the area; however, soil and bedrock materials vary in character between excavations and nalural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory. data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty Is expressed or implied. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when G$I is not requested to be onsite, to evaluate if our recommendations have been properly Implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place, In addition, this report may be subject to review by the controlling authorities. Brookfield Homes Appenthx G"8 01 Inc. IT06 0L20N SflOH61JNflS 4 sawoH P191+)I00JB, p: /6/E SENT BY: GEOSOILS, 780910915; EP-29-04 4:7PM; PAGE 4 TABLE I LOT CHARACTERISTICS - VILLAGE W Lot CI1ABACTER15T1CS -CALAV J.lHi5, VIUA0 W LOT EXPJUMON. por UBC EXPANSION :.. '30LUdW SW.FATE '.eIght%) . SULFAfE DEPTh OF aneinft) FILLFOUNDATiON . 45 <20 Very Low - <0.10 NelJgibe 4-8 I or I(FT) - 46 -. <20 Veiy Low - c 0.10 NegUge 9•19 I or I(P1) 47 <20 Vey Low <0.10 Nell 6-16 - I or I(Fr) 48 4C20 VoiyLow <0.10 - Nb 5-15 Iori(Pi) 49 - <20 Ve*ythw <0.10 togfle 8-14 IorI(PT) 30 <20 Very Low <0.10 Ne5lbl 4-12 I or lFT) 51 <20 Very Low <010 NebIe 3-9 Icr I(PT) 52 <20 Very Low c 0.10 NeUgible 3-4 I or I(PT) 53 -- <20 Very Low <0.10 Negligible 34 - I or IT) 54 <20 Very Low <0.10 Negligible 3-4 lot 65 <20 Vary Low <0.10 Negligible - -'4.4 IorWT) 58 <20 Very Low <0.10 MegT1Iblo 34 I or 57 - <20 Very Low 40.10 Negligible - 3-4 lot I1) 58 - <20 Very Low <0.10 NeQffoJblo - 3-4 1 o I(PT) 58 <20 Very Low <0.10 NegligIble 3.4 I or I(PT) <20 VeiyLow <0.10 Negligible 3-4 - IerlPi) - 61 <20 Very Low 40.10 Negllglble 34 1 o I(PT) 62 <20 Very Low <0.10 NegligIble 3-4 1 o I(PT) Very Low <0.10 Neg3glhle 34 1 orlPT) 64 <20 - Very Law C 0.10 NegJig1e 3-4 - lot lsPl) 65 <20 Very Low <0.10 Negligible - 3-4 IcrIl) 66 <20 Very Low <0.10 Negligible 4-8 I or t1) 67 <20 - Wry Low c 0110 Neg4blo let ll) - 68 <20 - Vary Low <010 NglIgIbte +-a - I or I(Pt) _69 <20 Very Low <0.10 Negligible 7-21 II or I1(F1J 70 <20 VcyLow <0.10 Negligible 16-21 Il0(WT) 71 <20 Very Low <0.10 NegUgibiD 13-16 Icr l(Pi) 72 <20 Very Low <0.10 NegligIble 12-15 lorI(1i) 73 <20 Yery Low <0.10 Negligible 3-8 I or I(PT) 74 <20 Very Low <0.10 Negligible 3.9 lot I(P'l) 103 <20 Very Low 1112 Modemle - 2-4 - I or UP1) 104 <20 -. Vary Low 0.12 Modereth - 3-4 - lot I(PT) GeeSoils, Inc. t0l26 @L..2DN - SflOH34WflS - SGWOH P!00.1E L':T /6/6 a SENT Y: CEOOILS, INC.; 7609G10915; EP-2-04 4:7PM; PAGE 5 -. LOCHARACTER1STCS. CALAVEBA HILLS VILLAGE W -- - EXPANSION MEK F SOUJELE IEPTh OF LOT (per Use 'Standard 18.2). EXPANSION SULFATE pJJ1 (Ight%) SULFATE EXPOSUREw FILL (Range In FL) FOUNDATION CATEGORY loS <20 Very Low 0.12 -- Moderate 2-4 Iorl(PI) 106 - <20 VeryLow 0.12 ModoraX. 3-4_- of 10M 107 <20 Vejy LOW 0.12 - Mie 3.4 I or I1) 109 <ao Very Low 0.12 Mqde'iIo S.0 I or I(P1) 109 - <20 - Very Low <010 Ne"ble 7.19 IorI(PT) 110 - <20 Very LOW - <0.10 Negulble +10 lorl(P1) 111 <o VoyLnw <0.10 —_NeglIØthlO - -__6.12 lorl(FI) 112 <20 - Very Low 0.10 - -_ c NegqibIo 7.11 - I or I1) - 113 <20 Very Low <0.10 NegligIble 4-11 IOrI(P1) "PorTable 184-0 of" LJnifom BuUdlng Coda (1997 ad.) PorTable 18-A4 of the Lkilform 8ulcling Code (1997 ad.) wFouidahIOrIe should becons"odinv=o(dancowkhr000mmandatiomforftspecificcaWgodes noted above and pratfled in the led of Un teport (PT reco nendaUons) and Table 3. V Bronkfeld Homes V - Table 1 Fle:eAwp4200434b.iro - Page 2 GeoSoils, Inc. SOOd ØLON 3snOHN3Wwns - SWO LP:T tø/6/60 11 GENT BY: GEOGOILG, INC.; ?6O21Ol5; GEP-2-04 4:28PM; PAGE 8 APPENDIX DEVELOPMENT CRITERIA Slope Deformation Compacted 1111 slops designed using customary factors of safety for gross or surficiai stability and constructed In general accordance withthe design specifications should be expected to undergo some differential vertical heave or settlement in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slopecreep, and lateral fill extension (LFE). Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (i.e., separations and/or cracking), placed now the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope. depending on the slope height This movement generally results in rotation and differential settlement of improvements located within the creep zone. LEE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. It is generally not practical to attempt to eliminate the effects of either slope creep or LIFE. Suitable mitigative rneasuresto reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the 1997 UBG and/or California Building Code), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. M of these measures are recommended for design of structures and improvements. The ramifications of the above conditions, and recommendations for mitigation, should be provided to each homeowner and/or any homeowners association. Slope Maintenance arid P.Lant1ng Water has been shown to weaken the inherent strength of all earth materials.. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements, and cause perched groundwater condItions. Graded. slopes constructed utilizing onsite materials would be eiosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction, Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment at a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, eta., to develop. A rodent control program to prevent burrowing should be implemented. GoSoUs, Inc.. 9006LON 3snOH83Wwns - s@ WOH PI 91.+100.lE LP:I t',sa WT BY: GFOOIL, INC.;786.1iO15; SEP-2-04 4:38PM; PAGE 7/11 Irrigation at natural (ungraded) slope areas is generally not recommended- These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construction activities and landscaping. Dralnq Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape, and slopes. Surface drainage should be sufficient to prevent ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 5 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation Will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Eroslon.ControI Cut and 1111 slopes will be subject to surfidal erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint Landscape Malnteance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 10 feet. As an alternative, closed- bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should Brookfield Homes - - Appendix' FIe:e:\42OO\4254bjr Page 2 GeoSoils, Inc.. eei OL'DN 3snOHN3wwns 4- SWO PI31100.l9 SENT Y: GEOSOILS, INC.; 750810915; EP-29-04 4:PM;. PAGE 5/11 be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade Provisions should be made to drain the excess irrigation water from The planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees Will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. lithe surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts As previously discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or non-erosive devices that will carry the water away from the house. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are Incorporated Into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precludedfrom occurring in thefuture dueto site Irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site lmproyernent Recommendations for exterior concrete flatwork design and construction can be provided upon request If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. This office should be notified in advance of any fill placement, grading of the site, or trench backfilllng after rough grading has been completed. This includes any grading, utility trench, and retaining wall backlllls. Brookfield Hones Appendix Rleo\42OO\4254b.iro2 Page 3 GcoSoils, .1"e- 8006 0L2ON SflOHWWflS- S9WOH P1 31 PI00.J9 LP:I t'OO/Br55 SENT Y: cEOOILS, INC.; 760930915; --04 4:9PM; PACE gill 'ills Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backflhllng after rough grading has been completed. This includes completion of grading In the greet and parking areas and utility trench and retaining wall backfllls. Footino Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and to concrete form and reinforcement placement. The purpose of the observations is to verify that the excavations are made into the recommended bearing matcnal and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended atthat time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction 0190 percent, if not removed from the site. Trenching Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls at the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Utility Trench Bac fill All Interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (124nch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater maybe utilized and jetted or flooded into place. Observation, probing and testing should be provided to verify the desired results. Brookfleld Homes Appendix Fra I 8:0,%v0\4,2100k4254b jro2 Page 4 GeoSoils, Inc. 6006 Ø2 ON 3snOHN3Wwns - S3WO PI!+lOolB p:I /6/60 SENT BY: OOIL5., INC.; 78O51O1S; --64 4: SOP M; PAGE 10111 2. Exterior trenches adjacent to, and within areas extending below a 1:1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. compaction testing and observations, along with probing, should be accomplished to verify the desired resutts. 3... All trench excavations should conform to CAL-OSHA and local safety codes. 4. Utities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF REqQMENDAT1QNSBEGARDlNG TCHN1CAL OBSERVATION-ANDJES We recommend that observation and/or testing be performed by OSI at each of the following construction stages: 1 During grading/recertif1cation = During significant excavation (i.e., higher than 4 feet). During placement of subdrains,toedrains, or, other subdrainage devices, prior to placing lw and/or backfill, After excavation of building footings, retaining Wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. • Prior to pouring arty stabs or flatwork, after presoaking/presaruration of building pads and other flatworic subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gavel, etc.), or vapor barriers (i.e., visqueen, etc.). •. During retaining wall subdrain installation, prior to backfill placement. •• During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. Hnokfle!d Homes -- Appendix RIe:1wp\4204254bJrQ2 Pace 5 .1. GeeSoils, Inc. 3SflOHNNns + S9WOH PI9!+oo5