The URL can be used to link to this page

Home My WebLink AboutCDP 15-20; FLORA RENOVATION; LIMITED GEOTECHNICAL INVESTIGATION 144 WALNUT AVENUE; DWG 496-8A; 2016-09-07EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. '---"'="'~",,"~-,.-,·, Bob & Monica Flora 2208 Eastbrook Road Fallbrook, California 92081 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 92071 (619) 258-7901 Fax 258..;7902 Subject: Limited Geotechnical Investigation Proposed Residential Renovation 155 Walnut Avenue City of Carlsbad, California 92008 Dear Mr. & 1vlrs. Flora: January 7, 2016 Project No. 15-1106E6 In accordance with your request, we have perfo1med a limited geotechnical investigation at the subject site to discuss the geotechnical aspects of the project and provide recommendations for the proposed residential improvement. Our investigation has found that the areas of the proposed improvement are underlain by topsoil to a depth of approximately 12 to 18 inches below existing grade. Dense terrace deposits were underlying the topsoil to the explored depth of 6 feet. It is our opinion that the proposed residential renovation is geotechnically feasible provided the recommendations herein are implemented in the design and construction. Should you have any questions with regard to the contents of this report, please do not hesitate to contact our office. Respectfully submitted, AUG 15 2016 BOB & MONICA FLORAi WALNUT AVENUE PROJECT NO. /5-l /06£6 TABLE OF CONTENTS IN'fRODUCTION .............................................................................................................................................. 3 SCOPE OF SERVICES ...................................................................................................................................... 3 SITE DESCRIPTION AND PROPOSED CONSTRUCTJON ................................ : ....................................... 3 FIELD INVESTIGiTION AND LABORATORY TESTJNG ....................................................................... .4 GEOLOGY ......................................................................................................................................................... 4 Geologic Setting .................................................................................................................................... 4 Site Stratigraphy .................................................................................................................................... 4 SEISMICITY ...................................................................................................................................................... 5 Regional Se.ismicity ............................................................................................................................... 5 Seisn1ic Analysis ................................................................................................................................... 5 2013 CBC Seis1nic Design Criteria ...................................................................................................... 6 Geologic Hazard Assessment. ............................................................................................................... 6 GEOTECHNJCAL EVALUATION .................................................................................................................. 7 Compressible Soils ................................................................................................................................ 7 Expansive Soils ...................................................................................................................................... 7 Groundwater .......................................................................................................................................... 7 CONCLUSIONS AND RECOMMEND A TIO NS ............................................................................................ 8 CLEARING AND GRUBBING ......................................................................................................................... 8 FOUNDATIONS AND SLABS ........................................................................................................................ 8 sE·rrLEMENT ................................................................................................................................................... 9 PRESATURAT1o·N OF SLAB SUBGRADE ................................................................................................... 9 TEMPORARY SLOPES .................................................................................................................................... 9 TRENCH BACKFILL ........................................................................................................................................ 9 DRAINAGE ...................................................................................................................................................... JO FOUNDATION PLAN REVlEW .................................................................................................................... 10 LIMITATIONS OF INVESTIGATION .................................................................................................. : ...... 1 O ADDITIONAL SERVICES ............................................................................................................................ 1 i PLATES Plate J. Location of Exploratory Boreholes Plate 2 -Summary Sheet (Exploratory Borehole Logs) Plate 3 -USCS Soil Classification Chart PAGE L-1, LABORATORY TEST RES UL TS .............................................................................................. I 3 REFERENCES ...... , .......................................................................................................................................... 14 2 BOB & MONICA FLORAi WALNUT AVENUE PROJECT NO. l 5-l 106E6 INTRODUCTION This is to present the findings and conclusions of a limited geotechnical investigation for the proposed renovation of the existing single-family residence located at 155 Walnut Avenue, in the City of Carlsbad, California. The objectives of the investigation were to evaluate the existing soils conditions and provide recommendations for the proposed improvement. SCOPE OF SERVICES The following services were provided during this investigation: 0 Site reconnaissance and review of published geologic, seismological and geotechnical reports and maps pertinent to the project area 0 Subsurface exploration consisting of three (3) boreholes within the limits of the proposed areas of improvement. The boreholes were logged by our Staff Geologist. 0 Collection of representative soil samples at se]ected depths. The obtained samples were sealed in moisture-resistant containers and transported to the laboratory for subsequent analysis. 0 Laboratory testing of samples representative of the types of soils encountered during the field investigation 0 Geologic and engineering analysis of the field and laboratory data, which provided the basis for our conclusions and recommendations 0 Production of this report, which summarizes the results of the above analysis and presents our findings and recommendations for the proposed improvement SITE DESCRIPTION AND PROPOSED CONSTRUCTION The suqject site is a rectangular-shaped residential lot located on the south side of Walnut Avenue, in the City of Carlsbad, California. The property which encompasses an area of 4,375 square feet (87.5' X 50') includes a one-story residence with a detached parking canopy and a storage room. The building pad is relatively level with general drainage to the west. Vegetation consisted of grass, shrnb and a few trees. Site boundaries include Walnut Avenue to the north and similar residential developments to the remaining directions. The preliminary plans prepared_ by Wright Design of Carlsbad, California indicate that the proposed renovation will include a second-story and deck addition to the existing, one-story single- family residence and a detached garage with a living unit above, following demolition of the existing parking canopy and storage room. It is our understanding that the structures will be wood- framed and founded on continuous and/ or spread footings with a slab-on-grade floor. 3 BOB& l110NICA fl~ORAI WALNUT AVENUE PROJECT NO. 15-1106£6 FIELD INVESTIGATION AND LABORATORY TESTING On December 10, 2015, three (3) boreholes were excavated to a maximum depth of approximately 6 feet below existing grade with a hand auger. The approximate locations of the .boreholes are shown on the attached Plate No. 1, entitled "Location of Exploratory Boreholes". A continuous log of the soils encountered was recorded at the time of excavation and is shown on Plate No. 2 entitled "Summary Sheet". The soils were visually and texturally classified according to the filed identification procedures set forth on Plate No. 3 entitled "USCS Soil Classification". Following the field exploration, laboratory testing was perfonned to evaluate the pertinent engineering properties of the foundation materials. The laboratory-testing program included moisture and density, particle size analysis and expansion index tests. These tests were performed in general accordance with ASTM standards and other accepted methods. Page L-1 and Plate No. 2 provide a summary of the laboratory test results. GEOLOGY Geologic Setting The subject site is located within the southern portion of what is known as the Peninsular Ranges Geomorphic Province of California. The geologic map pertaining to the area (Reference No. 7) indicates that the site is underlain by Pleistocene terrace deposits (Qt). Site Stratigraphy The subsurface descriptions provided are interpreted from conditions exposed during the field investigation and/or inferred from the geologic literature. Detailed descriptions of the subsurface materials encountered during the field investigation are presented on the exploration logs provided on Plate No. 2. The following par<1graphs provide general descriptions of the encountered soil types. Topsoil Topsoil is the surficial soil material that mantles the ground, usually containing roots and other organic materials, which supports vegetation. Topsoil was observed in the boreholes with a thickness of approximately 12 to 18 inches. It consisted of dark brown, silty sand that was moist, loose and porous in consistency with some organics (roots and rootlets). Terrace Deposits (Qt) Terrace deposits were encountered below the topsoil layer. They generally consisted of reddish brown, silty sand that was moist and medium dense to dense in consistency. 4 BOB & MONICA FLORAi WALNUT A VENUE PROJECT NO. 15-1 l 06£6 SEISMICITY Regional Seismicity Generally, Seismicity within California can be attributed to the regional tectonic movement taking place along the San Andreas Fault Zone, which includes the San Andreas Fault and most parallel and subparallel faults within the state. The portion of southern California where the subject site is located is considered seismically active. Seismic hazards are attributed to groundshaking from earthquake events along nearby or more distant Quaternai-y faults. The primary factors in evaluating the effect an earthquake has on a site are the magnitude of the event, the distance from the epicenter to the site and the near surface soil profile. According to the Fault-Rupture Hazard Zones Act of 1994 (revised Alquist-Priolo Special Studies Zones Act), quaternary faults have been classified as "active" faults, which show apparent surface rupture during the last 1 I ,000 years (i.e., Holocene time). "Potentially-active" faults are those faults with evidence of displacing Quaternary sediments between 11,000 to 16,000 years old. Seismic Analysis Based on our evaluation, the closest kno\\-11 '"active" fault is the Newport-Inglewood Fault located approximately 7.4 kilometers (4.6 miles) to the west. The Newport-Inglewood Fault is the design fault of the project due to the predicted credible fault magnitude and ground acceleration. The Seismicity of the site was evaluated utilizing the 2008 National Hazard Maps from the USGS website and Seed and Idriss methods for active Quaternary faults within the regional vicinity. The site may be subjected to a Maximum Probable Earthquake of 7.2 Magnitude along the Newport- Inglewood Fault, with a corresponding Peak Ground Acceleration of 0.45g. 111e maximum Probable Earthquake is defined as the maximum earthquake that is considered likely to occur within a 100-year time period. The effective ground acceleration at the site is associated with the part of significant ground motion, which contains repetitive strong-energy shaking, and which may produce structural deformation. As such, the effective or '·free field" ground acceleration is referred to as the Repeatable High Ground Acceleration (RHGA). It has been determined by Ploessel and Slosson (1974) that the 'RHGA is approximately equal to 65 percent of the Peak Ground Acceleration for earthquakes occurring within 20 miles of a site. Based on the above, the calculated Credible RHGA at the site is 0.29g. 5 BOB & i\40NICA FLORAi WALNUT AVENUE PROJECT NO. I 5-1106£6 2013 CBC Seismic Design Criteria A review of the active fault maps pertaining to the site indicates the location of the Newport- Inglewood Fault Zone approximately 7.4 km to the west. Ground shaking from this fault or one of the m~ior active faults in the region is the most likely happening to affect the site. With respect to this hazard, the site is comparable to others in the general area. The proposed residential renovation should be designed in accordance with seismic design requirements of the 2013 California Building Code or the Structural Engineers Association of California using the following seismic design parameters: . r~i\tE,)iJJti:' < --··--.·--•((/ ... __ ·-': _., --,·:· ·-·-y_ J· ";'.! JV$$,: fi11l,~J~1~;t~Qt:i;1U1gllQC12-s ·---•-. Site Class D Table 20.3-1/ ASCE 7, Chapter 20 Mapped Spectral Acceleration For Short Periods, 1.161g Figure 1613.3.1(1) Ss ,__...._.. Mapped Spectral Acceleration For a 1-Second 0.445g Figure 1613.3.1(2) Period, S1 -Site Coefficient, Fa 1.035 Table 1613.3.3(1) Site Coefficient, Fv l.555 Table 1613.3.3(2) Adjusted Max. Considered Earthquake Spectral I 1.203g Equation ]6-37 Response Acce.leration for Short Periods, SMs J I Adjust.ed Max. Considered Earth uake s ectral I 0.6920-E uation 16-38 I I q p ::, I q I I Response Acceleration for I-Second Period, SM1 -j 5 Percent Damped Design Spectral Response 0.802g Equation 16-39 -----1 ~IA~cc_·e_le __ ra_t_io_n_f._or_S_'h_o_n_P_e_ri_o_ds~,_S=os"'---~~~~-+-~~~+-~~~~~~-~~--~ 5 Percent Damped Design Spectral Response 0.461g Equation 16-40 Acceleration for 1-Second Period, Sm Geologic Hazard Assessment Ground Rupture Ground rupture due to active faulting is not considered likely due to the absence of known fault traces within the vicinity of the project; however, this possibility cannot be completely ruled out. The tmlikely hazard of !:,)found rupture should not preclude consideration of "flexible" design for on-site utility lines and connections. Liguefaction Liquefaction involves the substantial loss of shear strength in saturated soils, usually sandy soils with a loose consistency when subjected to earthquake shaking. Based on the absence of shallow groundwater and consistency of the underlying terrace deposits, it is our opinion that the potential for liquefaction is very low. ' Landsliding There is no indication that landslides or unstable slope conditions exist on or adjacent to the project site. There are no obvious geologic hazards related to landsliding to the proposed improvement or adjacent properties. 6 BOB & MONICA FLORAi WALNUT AVENUE PROJECT NO. 15-1106£6 Tsunamis and Seiches The site is not subject to inundation by tsunamis due to its elevation. The site is also not subject to seiches {waves in confined bodies of water). GEOTECHNICAL EVALUATION Based on our investigation and evaluation of the collected i.nfonnation, we conclude that the construction of the proposed additions is feasible from a geotechnical standpoint provided the recommendations herein will be properly implemented during construction. In order to provide a unifonn support for the proposed additions, footings should be embedded into the dense terrace deposits. However, for slab support for the proposed detached garage/ living unit, overexcavation and recompaction of the upper 18 inches of subgrade will be required. The foundations may consist of reinforced continuous or spread footings with reinforced slabs. Recommendations and criteria for foundation design are provided in the Foundation and Slab recommendations section of this report. Compressible Soils Our field observations and testing indicate low compressibility within the terrace deposits, which underlie the areas of the proposed additions. However, loose topsoil was encmmtered to a maximum depth of approximately 18 inches below surface grades. These soils are compressible, therefore not adequate for the support of the proposed additions. As a result, footings for the proposed additions should be extended to the dense terrace deposits. Following implementation of the recommendations presented herein, the potential for soil compression resulting from the new development has been estimated to be low. The low-settlement assessment assumes a well-planned and maintained site drainage system. Expansive Soils An expansion index test was performed on a representative sample of the terrace deposits to detennine volumetric change characteristics with change in moisture content. An expansion index of O was obtained which indicates a very low expansion potential for the foundation soils. Groundwater Static groundwater was not encountered to the depths of the boreholes. TI1e building pad is located at an elevation of approximately 50 feet above Mean Sea Level. We do not expect groundwater to affect the proposed construction. Recommendations to prevent or mitigate the effects of poor surface drainage are presented in the Drainage section of this report. 7 BOB & MONJCA FLORAi WALNUT AVENUE PROJECT NO. 15-J 106E6 CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon the analysis of the data and infonnation obtained from our soil investigation. This includes site reconnaissance; field investigation; laboratory testing and our general knowledge of the soils native to the site. The site is suitable for the proposed residential additions provided the recommendations set forth are implemented during construction. CLEARING AND GRUBBING The area of the proposed garage should be cleared of vegetation. Vegetation and debris from the clearing operation should be properly disposed of off-site. The area should be thoroughly inspected for any possible buried objects, which need to be rerouted or removed prior to construction. All holes, trenches, or pockets left by the removal of these objects should be properly backfilled with compacted fill materials. FOUNDATIONS AND SLABS a. Continuous and spread footings are suitable for use and should extend to a minimum depth of 18 inches for the proposed two-story structures into the dense terrace deposits. Continuous footings should be at least 15 inches in width and reinforced with a minimum of four #4 steel bars; two bars placed near the top of the footings and the other two bars placed near the bottom of the footings. Isolated or spread footings should have a minimum width of24 inches. Their reinforcement should consist of a minimum of #4 bars spaced 12 inches on center (each way) and placed horizontally near the bottom. New footings should be dowelled to existing footings in accordance with the structural engineer requirements. The minimum reinforcement recommended is based on soil characteristics and is not intended to supersede the structural engineer requirements. b. Interior concrete floor slabs should be a minimum 4 inches thick. Reinforcement should consist of #3 bars placed at 18 inches on center each way within the middle third of the slabs by supporting the steel on chairs or concrete blocks "dobies". The slabs should be underlain by 2 inches of clean sand over a 10-mil visqueen moisture ,barrier. The effect of concrete shrinkage will result in cracks in virtually all-concrete slabs. To reduce the extent of shrinkage, the concrete should be placed at a maximum of 4-foch slump. The minimum steel recommended is not intended to prevent shrinkage cracks. c. Where moisture sensitive floor coverings are anticipated over the slabs, the 10-mil plastic moisture barrier should be underlain by a capillary break at least 2 inches thick, consisting of coarse sand, gravel or crushed rock not exceeding 3/4 inch in size with no more than 5 percent passing the #200 sieve. 8 BOB & MONICA FLORAi WALNUT AVENUE PROJECT NO. 15-1106£6 d. An allowable soil bearing value of 2,000 pounds per square foot may be used for the design of continuous and spread footings at least 12 inches wide and founded a minimum of 12 inches into the dense terrace deposits as set forth in the 2013 California Building Code, Table 1804.2. This value may be increased by 400 psf for each additional foot of depth or width to a maximum value of 4,000 lb/ft2. e. Lateral resistance to horizontal movement may be provided by the soil passive pressure and the friction of concrete to soil. An allowable passive pressure of 300 pounds per square foot per foot of depth may be used. A coefficient of friction of 0.35 is recommended. The soils passive pressure as well as the bearing value may be increased by 1/3 for wind and seismic loading. SETTLEMENT Since the proposed footings are anticipated to be supported by the dense terrace deposits, the total and differential settlement should be within tolerable limits. PRESATURA TION OF SLAB SUBGRADE Because of the granular characteristics of on-site soils, presoaking of subgrade prior to concrete pour is not required. However, subgrade soils in areas receiving concrete should be watered prior to concrete placement to mitigate any drying shrinkage, which may occur following foundation excavation. · TEMPORARY SLOPES For the excavation of foundations and utility trenches, temporary vertical cuts to a maximum height of 4 feet may be constructed in fiH or natural soil. Any temporary cuts beyond the above height constraints should be shored or further laid back following a 1: 1 (horizontal to vertical) slope ratio. OSHA guidelines for trench excavation safety should be implemented during construction. TRENCH BACKFILL Excavations for utiJity lines, which extend under structural areas should be properly backfilled and compacted. Utilities should be bedded and backfilled with clean sand or approved granular soil to a depth of at least one foot over the pipe. This backfill should be uniformly watered and compacted to a finn condition for pipe support. The remainder of the backfill should be on-site soils or non-expansive imported soils, which should be placed in thin lifts, moisture-conditioned and compacted to at least 90% relative compaction. 9 BOB & MONICA FLORAi lt'ALNUT AVENUE PROJECT NO. 15-/ 106£6 DRAINAGE Adequate measures should be undertaken after the additions and other improvements are in place, such that the drainage water within the site and adjacent properties is directed away from the foundations, footings, floor slabs and the tops of slopes via rain gutters, downspouts, surface swales and subsurface drains towards the natural drainage for this area. A minimum gradient of 2 percent is recommended in hardscape areas; In earth areas, a minimum gradient of 5 percent away from the structures for a distance of at least 10 feet should be provided. Earth swales should have a minimum gradient of 2 percent. Drainage should be directed to approved drainage facilities. Proper surface and subsurface drainage wiil be required to minimize the potential of water seeking the level of the bearing soils under the foundations, footings and floor slabs, which may otherwise result in undermining and differential settlement of the structures and other improvements. FOUNDATION PLAN REVIEW Our firm should review the foundation plans during the design phase to assure confqrmance with the intent of this report. During construction, foundation excavations should be observed by our representative prior to the placement of forms, reinforcement or concrete for conformance with the plans and specifications. LJMJTAT10NS0F INVESTIGATION Our investigation was performed using the skill and degree of care ordinarily exercised, under similar circumstances, by reputable soils engineers and geologists practicing in this or similar localities. No other wruTanty, expressed or implied, is made as to the conclusions and professional advice included in this report. This report is prepared for the sole use of our client and may not be assigned to others without the written consent of the client and ECSC&E, Inc. The samples collected and used for testing, and the observations made, are believed representative of site conditions; however, soil and geologic conditions can vary significantly between exploration trenches, boreholes and surface exposures. As in most major projects, conditions revealed by construction excavations may vary with preliminary findings. If this occurs, the changed conditions must be evaluated by a representative of ECSC&E and designs adjusted as required or alternate designs recommended. This report is issued with the understanding that it is the responsibility of the O\.\'Uer, or of his representative to ensure that the information and recommendations contained herein are brought to the attention of the project architect and engineer. Appropriate recommendations should be incorporated into the structural plans. The necessary steps should be taken to see that the contractor and subcontractors carry out such recommendations in the field. 10 BOB & MONICA FLORA/ WALNUT AVENUE PROJECT NO. 15-1106£6 The findings of this report are valid as of this present date. However, changes in the conditions of a property can occur with the passage of time, whether they are due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside of our control. Therefore, this report is subject to review and should be updated after a period of two years. ADDITIONAL SERVICES The review of plans and specifications, field observations and testing under our direction are integral parts of the recommendations made in this report. If East County Soil Consultation and Engineering, Inc. is not retained for these services, the client agrees to assume our responsibility for any potential claims that may arise during construction. Observation and testing are additional services, which are provided by our finn, and should be budgeted within the cost of development. Plates No. 1 through 3, Page L-1 and References are parts of this report. 11 --....... -------~ .---~\:--------------'''--'_.,,:./." ----·----------,'\cc._ __ , ..... / I EAST COUNTY SOIL CONSULTATION & ENGINEERING, INC. 10925 HARTLEY RD .. SUITE I. SANTEE. CA 92071 (619) 258· 7901 Fax (619) 251! · 7902 DEPTH Surface l.O' 3.0' 4.0' 6.0' DEPTH Surface l.5' 3.0' 5.0' DEPTH Surface 1.0' 3.0' 4.0' BOB& MONICA FLORAi WALNUTAVENUE PROJECT NO.15-1106£6 PLATEN0.2 SUMMARY SHEET BOREHOLE NO. I SOIL DESCRIPTION TOPSOIL dark brown, moist, loose, porous, silty sand with rootlets TERRACE DEPOSITS (Qt) . reddish brown, moist, medium dense, silty sand " " " " becomes dense bottom of borehole, no caving, no groundwater borehole backfilled 12/l 0/l 5 BOREHOLE NO. 2 SOIL DESCRIPTION TOPSOIL dark brown, moist, loose, porous, silty sand with rootlets TERRACE DEPOSITS (Qt) reddish brown, moist, medium dense, silty sand becomes dense bottom of borehole, no caving, no groundwater borehole backfilled J2/l0115 BOREHOLE NO. 3 SOIL DESCRIPTION TOPSOIL dark brown, moist, loose, porous, silty sand with rootlets TERRACE DEPOSITS (Qt) reddish brown, moist, medium dense, silty sand becomes dense bottom of borehole, no caving, no groundwater borehole backfilled 12/10/15 y 1 I 1.7 109.4 y y Y = DRY DENSJTY IN PCF M == MOISTURE CONTENT IN% 12 M 7.3 7.9 7.5 6.7 M 8.3 M I l I l\tAJOR DIVISIONS SYMBOL DESCRIPTION GW WELL GRADED OR.A VELS OR GR.A VEL· SAND MIXTURES, Lrrn..E OR NO FINES GRAVELS GP POORLY GRADED ORA VELS OR GRAVEL-SAND (MORETHAN~ OF COARSE MIXTURES, LITTLE OR NO FfNES FRACTION GM SIL TY GR.A VELS, GR.A VEL-SAND-SILT MIXTURES >N0.4SIEVE SIZE) COARSE GC GRAINED SOILS CLAYEY GRAVELS, GR.A VEL-SAND-CLA Y MIXTURES (MORE THAN ~ OF SOIL SW > NO. 200 SIEVE SIZE) WELL GRADED SANDS OR GRAVELLY SANDS, Ll'ITLE OR NO FINES SANDS SP I (MORETHAN\'2 POORLY GRADED SANDS OR ORA VELL Y SANDS, OF COARSE UTILE OR. NO FINES FRACTION SM SILTY SANDS, SILT-SAND MIXTURES <N0.4SJEVE SIZE) SC CLAYEY SANDS, SAND-CLAY MIXTURES · J\IIL INORGANIC SILTS AND VERY FINE SANDS, ROCK SILTS & FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY CLAYS CL INORGAl"ilC CI.A YS OF LOW TO MEDIUM LIQUID LIMIT PLASTICITY, GR.A VELL Y CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLA VS < 50 FINE GRAINED OL I SOILS ORGANIC SILTS AND ORGANIC SILTY CLAYS Of LOW PLASTICITY (MORE THAN l4 OF SOIL MH < NO. 200 SIEVE SIZE) INORGANIC SILTS, MICACEOUS OR DIA.TOMACEOUS SILTS& FINE SANDY OR SILTY SOILS ELASTIC SILTS CLAYS CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT LIQUID LIMIT > 50 I CLAYS OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANfC SILTY CLAYS, ORGANIC SILTS HIGHL y ORGANIC son..s Pt PEAT AND OTHER HIGHLY ORGANIC SOILS CLASSIFICATION CHART (UNIFIED SOIL CLASSIFICATION SYSTEM) CLASSIFICATION RANGE OF GRAIN SIZES U.S. STANDARD GRAIN SIZE IN SIEVE SIZE MILLIMETERS BOULDERS Above 12 lnches Above 305 COBBLES 12 lnches To 3 Inches 30S To 76.2 GRAVEL 3 Inches to No. 4 76.2 to 4.76 Coarse 3 Inches to :Y. Inch 76.2 to 19.l Fine % Inch to No. 4 19.l to 4.76 SAND No. 4 to No. 200 4.76 to 0.074 Coarse No. 4 to No. JO 4.76 to 2.00 Medium No. 10 to No. 40 2.00 to 0.420 Fine No. 40 to No. 200 0.420 to 0.074 SILT AND CLAY Below No. 200 Below0.074 GRAIN SIZE CHART EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD, SUITE 4'1" SANTEE, CALIFORNIA 92071 U.S.C.S. SOIL· CLASSIFICATION .. .. l. 1~UU:I \, U,H T 11,,\,.J N\.f~O.-. PLASTICITY CHART INITIAL MOISTURE CONTENT(%) 9.1 1" 112" 3/8" #4 #8 #16 #30 #50 #100 #200 uses BOB& MONICA FLORAi WALNU7'AVENUE PROJECT NO. 15-1106£6 PAGE L-1 LABORATORY TEST RESULTS EXPANSION INDEX TEST (ASTM D4829) SATURATED MOISTURE CONTENT(%) 17.8 INITIAL DRY DENSITY EXPANSION (PCF) INDEX 109.6 0 PARTICLE SIZE ANALYSIS (ASTM D422) JO 99 98 96 JOO iOO 82 87 88 42 45 43 21 25 21 16 21 16 SM SM SM 13 LOCATION BH-2@ 1.5' JOO 90 40 18 12 SM ,~ f BOB & MONICA FLORAi WALNUT AVENUE PROJECT NO. 15-1106£6 REF.ERENCES I. "2013 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2", Published by International Code Council. 2. "Geologic Map of the San Diego 30' x 60' Quadrangle, California", by Michael P. Kennedy and Siang S. Tan, 2008. 3. ';EqfaultiEqsearch, Version 3.0", by Blake, T.f., 1995, Updated 2008. 4. "Geotechnical and Foundation Engineering: Design and Construction", by Robert W. Day, 1999. 5. "1997 Unifonn Building Code_, VoJume 2, Structural Engineering Design Provisions", Published by lntemational Conference of Building Officials. 6. "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada to be used with 1997 Uniform Building Code", Published by International Conference of Building Officials. 7. "Geologic Maps of the Northwestern Part of San Diego County, California", Department of Conservation, Division of Mines and Geology, by Siang S. Tan and Michael P. Kennedy, 1996. 8. "Bearing Capacity of Soils, Technical Engineering and Design Guides as Adapted from the US Army Corps of Engineers, No. 7", Published by ASCE Press, 1994. 9. ''Foundations and Earth Structures, Design Manual 7.2", by Department of Navy Naval Facilities Engineering Command, May 1982, Revaiidated by Change I September 1986. 10. "Ground Motions and Soil Liquefaction during Earthquakes", by H.B. Seed and J.M. Idriss, 1982. 14 EAST COUNTY SOIL CONSULTATION AND ENGINEERINGr INC. Bob & Monica Flora. 2208 Eastbrook Road Fallbrook, California 92081 10925 HARTLEY ROAD, SUITE "':P' S-4N'IEE, CALIFORNIA 92071 (619) 258-7901 Fax (619) 258-7902 Subject: Addendum to Limited Geotechnical Investigation Proposed Residential Renovation 15 5 Walnut Avenue City of Carlsbad, California 92008 October 14, 2016 Project No. 15-1106E6 Reference: · "'Limited Geotecbnical Investigation Proposed Residential Renovation, 155 Walnut Avenue, City of Carlsbad, California 92008, Project No. 15-1106E6, Prepared by East County Soil Consultation.and Engineering, Inc .• Dated January 7) 2016. Dear 'Nir. & :Mrs. Flora:- 1n accordance 'With your request, we have reviewed the grading plans. prepared by Bob Sukop of Carlsbad, California to address the proposed su..-rface drainage adjacent to the east and south properi"f lines.at the subject site. A minimum gradient of l percent in hardscape areas around the proposed foundation for at least 3 feet and a minimum of 1 percent i11 the drainage swales may be used provided the swales are lined with gu.,tiite or ooncrete. If we can be of any further assistance, please do not hesitate to contact our office. Respectfully submitted,