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HomeMy WebLinkAboutCT 02-07; EMERALD POINTE ESTATES; UPDATE REPORT OF GEOTECHNICAL INV; 2002-04-30UPDATE REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Emerald Pointe Estates BGS Property APN 212-040-50 Carlsbad, California JOB NO. 97-7189 30 April 2002 Prepared for: Mr. Tony Hummel BCS NATURAL RESOURCES RECEIVED DEPARTMENT GEOTECHNICAL EXPLORATION, INC. SOIL & FOUNDATION ENGINEERING • GROUNDWATER HAZARDOUS MATERIALS MANAGEIVIENT • ENGINEERING GEOLOGY 30 April 2002 Mr. Tony Hummel BCS NATURAL RESOURCES CORPORATION 1303 Avocado Avenue, Suite 245 Newport Beach, CA 92660 Job No. 97-7189 Subject: Update Reoort of Preliminary Geotechnical Investigation Proposed Emerald Pointe Estates BCS Property, APN 212-040-50 Carlsbad, California Dear Mr. Hummel: In accordance with your request and per our proposal dated April 4, 2002, Geotechnical Exploration, Inc. has prepared this update report of geotechnical investigation and geologic reconnaissance of the soil and geologic conditions at the subject site. The geologic reconnaissance of the site was performed per the requirements of the City of Carlsbad. This firm previously issued a report titled ''Report of Preliminary Geotechnical Investigation," 6ate6 March 25, 1998. The original field work was performed on January 23, 1998. Present conditions at the site remain as they were at the time of our initial investigation in 1998. It is our understanding that the site is being developed to receive a residential project with adjacent streets and associated Improvements. The proposed development is anticipated to include 17 residentiai lots on approximately 18 acres at the northwest corner of Cobblestone Road and Sapphire Drive. Grading is anticipated to involve cuts up to 18 feet and fills up to 23 feet to create level building pads and streets. The structures are to be a maximum of two stories in height and will be constructed of standard-type building materials utilizing a conventional concrete slab-on-grade foundation system. The purpose of this update report and prior subsurface investigation was to evaluate the soil conditions In the proposed building areas, recommend any necessary site preparation procedures, assess the allowable bearing capacity of the on-site soils, and to provide slab and foundation design recommendations. The accompanying report presents the results of our review of available geologic reports and maps, fieid investigation and laboratory analysis, as well as our conclusions and recommendations for the proposed development. 7420 TRADE STREET • SAN DIEGO, CA 92121 • (858) 549-7222 • FAX: (858) 549-1604 • E-MAIL: geotecti@ixpres.com The woric performed and recommendations presented in this report are the result of an investigation and analysis that meet the contemporary standard of care in our profession within the County of San Diego. This opportunity to be of service is sincerely appreciated. Should you have any questions concerning the following report, please do not hesitate to contact us. Reference to our lob No. 97-7189 will expedite a response to your inquiries. Respectfully submitted. GEOTECHNICAL EXPLORATION, INC. Jaime A. Cerros, P.E. Senior Geotechnical Engineer R.C.E. 34422/G.E. 2007 te'^ne-d.'ReedrPres'^ent C.E.G. 999[exp. 3-31-03J/R.G. 3391 JKH/JAC/LDR/pj CERTIFIED j Of cf-^-- TABLE OF CONTENTS II. IV. SCOPE OF WORK SITE DESCRIPTION III. FIELD INVESTIGATION LABORATORY TESTS V. GENERAL GEOLOGIC DESCRIPTION VI. SITE-SPECIFIC GEOLOGIC DESCRIPTION VII. GEOLOGIC HAZARDS VIII. EARTHQUAKE RISK EVALUATION IX. CONCLUSION AND RECOMMENDATIONS X. LIMITATIONS REFERENCES PAGE 1 2 3 4 6 7 9 15 17 36 FIGURES la. Vicinity Map Ib. Plot Plan and Geologic f4ap Ila-k. Trench Logs Illa-c. Laboratory Test Results IV. Foundation Requirements Near Slopes V. Regional Fault Map VI. Bench and Key Requirements APPENDICES A. Unified Soil Classification System B. Seismic Data - EQFault C. Seismic Data - EQSearch D. Modified Mercalli Intensity Index E. General Earthwork Specifications UPDATE REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Emerald Pointe Estates BCS Property APN 212-040-50 Carlsbad, California JOB NO. 97-7189 The following report presents the findings and recommendations of Geotechnical Exploration, Inc. for the subject property (refer to Figure No. I for Vicinity Map and Site Plan). I. SCOPE OF WORK It is our understanding, based on communications with Mr. Jack Henthorn and Associates, and review of a Revised Tentative Map prepared by Hunsaker and Associates, dated February 5, 2002, that the site is being developed to receive a residential project with adjacent streets and associated improvements. The proposed development is anticipated to include 17 residential lots on approximately 18 acres located 1/4-mile south of Palomar Airport Road, and east of Laurel Tree Road. Grading is anticipated to involve cuts up to 18 feet and fills up to 23 feet to create level building pads and streets. As part of this update report preparation, we reviewed our previous report prepared for this site, dated March 25, 1998. With the above in mind, the Scope of Work is briefly outlined as follows: 1. Identify and classify the surface and subsurface soils in the area of the proposed construction, in conformance with the Unified Soil Classification System (refer to Figure Nos. II and III, and Appendix A). Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 2 2. Make note of any faults or significant geologic features that may affect the site (see Figure No. V, and Appendices B, C and D). 3. Recommend site preparation procedures, including recommendations for the proposed grading operation and slope construction. 4. Recommend preliminary allowable bearing capacity for the on-site formational soils or properly compacted fill soils. 5. Evaluate the settlement potential of the bearing soils under the proposed structural loads. 6. Recommend preliminary foundation design information and provide active and passive earth pressures to be utilized in design of any proposed retaining walls and foundation structures. In addition, as part of our investigation, we reviewed the preliminary grading plans and City of Carlsbad Zone 20 Local Facilities Management Plan. II. SITE DESCRIPTION The property is known as: Assessor's Parcel No. 212-040-50, in the City of Carlsbad, County of San Diego, State of California. The site, consisting of approximately 18 acres, is located approximately 1/4-mile south of Paiomar Airport Road at Cobblestone Road and Sapphire Drive, in the City of Carlsbad. The property is bordered on the north by undeveloped land; on the south by the Greystone/Cobblestone residential development; on the east by similar undeveloped land and Sapphire Drive; and on the west by Cobblestone Road. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 3 The site is presently undeveloped, and was previously cultivated for agricultural purposes. Access to the site is provided from the Greystone/Cobblestone residential development on Sapphire Drive. High tension power transmission lines extend approximately north to south through the extreme northwest portion of the site. A large depression exists in the northwest portion of the site that may have been a former water storage reservoir. The depression is approximately 140 feet long by 60 feet wide and 10 feet deep. A cut was made on the uphill side and a fill slope constructed on the downhill side. Vegetation on the site consists primarily of wild grasses on flat areas, with some thick shrubbery and chaparral on the slope areas. The property slopes moderately to steeply down to the north and west from a gently sloping ridge top in the southern portion of the property. Approximate elevations across the site range from a high of 262 feet above mean sea level (MSL) to a low of 100 feet MSL. Survey information concerning elevations across the investigated portion of the site was obtained from topographic maps and preliminary grading plans by BHA, Inc., dated November 18, 1997, and a Revised Tentative Map prepared by Hunsaker and Associates, dated February 5, 2002. III. FIELD INVESTIGATION Our field investigation, conducted on January 23, 1998, consisted of a geologic reconnaissance of the site and surrounding terrain, plus the excavation of 11 tractor-mounted backhoe trenches. The excavations were located in the field by referring to a preliminary grading plan prepared by BHA, Inc., dated November 18, 1997. The trenches were observed and logged by our Engineering Geologist, and samples were taken of the predominant soils throughout the field operation. Trench logs have been prepared on the basis of our observations and the results have been Proposed Emerald Pointe Estates Carlsbad, California Job No. 97-7189 Page 4 summarized on Figure No. II. The predominant soils have been classified in conformance with the Unified Soil Classification System (referto Appendix A). IV. FIELD AND LABORATORY TESTS Field and laboratory tests were performed on the soils in order to evaluate their physical and mechanical properties and their ability to support the proposed residential structures, streets and improvements. The following tests were conducted on the sampled soils. 1. Moisture/Density Relations (ASTM Dl557-91, Method A) 2. Moisture Content (ASTM D2216-92) 3. Mechanical Analysis (ASTM D422-90) 4. Expansion Test (UBC Method 29-2) 5. Density Measurement (ASTM Dl 188-84 and D2937-83) 6. Consolidation Tests (ASTM D2435-90) The relationship between the moisture and density of the soil gives qualitative information regarding the soil strength characteristics and soil conditions to be anticipated during the proposed grading operation. The mechanical analysis and Atterberg Limit tests were used to aid in the classification of the soils according to the Unified Soil Classification System and for the liquefaction potential analysis. The expansion potential of the on-site soils was evaluated utilizing the Uniform Building Code Test Method for Expansion Soils (UBC Standard No. 29-2). In accordance with the UBC (Table 18-1-B), expansive soils are classified as follows: Proposed Emerald Pointe Estates Carlsbad, California Job No. 97-7189 Page 5 EXPANSION INDEX POTENTIAL EXPANSION 0 to 20 Very low 21 to 50 Low 51 to 90 Medium 91 to 130 Hiqh Above 130 Very high Based on our laboratory analysis, the on-site soils tested can be classified as having a very high expansion potential, with a maximum tested expansion index of 198. It should be noted that the expansion potential at existing soil moisture contents is medium, with tested expansion potential ranging from 6.5 to 9.0 percent of the sample height, which would roughly correspond to an Expansion Index between 51 and 90. The expansive soils will require proper moisture conditioning and compaction to help reduce expansion potential. Consolidation tests were performed on relatively undisturbed samples of the existing natural-ground soils. The consolidation test aids in evaluating whether there is significant settlement potential of the existing soils under the anticipated loads and proposed surcharge loads. Results of laboratory testirtg can be found on Figure No. III. Based on the above laboratory test data, observations of the primary soil types on the project, and our previous experience with laboratory testing of similar soils, our Geotechnical Engineer has assigned values for friction angle, coefficient of friction, and cohesion to those soils which will have significant lateral support or bearing functions on the project. These values are presented in Figure No. Ill and have been utilized in the assigning the allowable bearing values, as well as active and passive earth pressure design criteria for wall and footing designs in competent native soils or properiy compacted fills. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 6 V. GENERAL GEOLOGIC DESCRIPTION The Carlsbad area is part of a seismically active region of California. It is on the eastern boundary of the Southern California Continental Borderland, part of the Peninsular Ranges Geomorphic Province. This region is part of a broad tectonic boundary between the North American and Pacific Plates. The actual plate boundary is characterized by a complex system of active, major, right-lateral strike- slip faults, trending northwest/southeast. This fault system extends eastward to the San Andreas Fault (approximately 81 miles from Carlsbad) and westward to the San Clemente Fault (approximately 54 miles off-shore from Carlsbad) (Berger and Schug, 1991). During recent history, the San Diego County area has been relatively quiet seismically. No fault ruptures or major earthquakes have been experienced in historic time within the San Diego area. Since earthquakes have been recorded by instruments (since the 1930s), the San Diego area has experienced scattered seismic events with Richter magnitudes generally less than 4.0. During June 1985, a series of small earthquakes occurred beneath San Diego Bay; three of these earthquakes had recorded magnitudes of 4.0 to 4.2. In addition, the Oceanside earthquake of July 13, 1986, located approximately 26 miles offshore ofthe City of Oceanside, resulted in a magnitude of 5.3 (Hauksson, 1988). In California, major earthquakes can generally be correlated with movement on active faults. As defined by the California Division of Mines and Geology (Hart, E.W., 1980), an "active" fault is one that has had ground surface displacement within Holocene time (about the last 11,000 years). Additionally, faults along which major historical earthquakes have occurred (about the last 210 years in California) are also considered to be active (Association of Engineering Geologist, 1973). The California Division of Mines and Geology defines a "potentially active" fault as one Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 7 that has had ground surface displacement during Quaternary time, that is, during the past 11,000 to 1.6 million years (Hart, E.W., 1980). VI. SITE-SPECIFIC GEOLOGIC DESCRIPTION A geologic investigation of the site was conducted to evaluate the on-site geology and potential of geologic hazards that might affect the site. Our investigation drew upon information gathered from published and unpublished geologic maps and reports, as well as the results of our exploratory trench excavations. A. Stratigraphy The subject site is located within a residential area approximately 1/4-mile south of Palomar Airport Road at Cobblestone Road and Sapphire Drive, in the City of Carlsbad. A review of avaiiabie geologic maps and reports, as well as our field investigation, indicates that the subject property is located in an area underlain by surficial topsoils and dense formational materials of the Eocene-age Del Mar/Friars Formation (undifferentiated) and the Santiago Formation. A description of these units, from youngest to oldest, is included herein. Refer to Figure Nos. II and III for details. ToDsoils: Topsoils were found overlying the formational materials on most of the site and consist of soft to firm, moist, dark brown, silty clay with some sand and abundant roots. The topsoils are approximately VA to IVz feet in depth and are considered to be very highly expansive. The topsoils have been previously disturbed by agricultural cultivation and are unsuitable to support structural loads and compacted fill. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 8 Santiaqo Formation (Tsa): The majority of the site is underlain by the Eocene-age Santiago Formation, which consists of light brown and tan-gray, silty, fine to medium sandstone with interbeds of darker-colored sandy siltstones. The sandstones are by far the most common and typically they are moderately well- indurated. The siltstones ofthe Santiago Formation may exist with some moderate to high expansion characteristics. Del Mar/Friars Formation rundifferentiated - Td/Tf): The site is mapped showing Santiago Formation being underlain by the Eocene-age Del Mar/Friars Formation (Eisenberg, 1983). At the site, we found this formation to be comprised of several lithologic (material type) units. Our trenches advanced at the site revealed the Del Mar/Friars Formation to be primarily massive, tan-gray and dark gray-green and orange, silty sandstone,, siltstone and claystone that is dense but poorly to moderately well-indurated. Along the perimeter of the steep slopes we encountered approximately 2 to 4 feet of highly fractured and weathered formation. These materials consist of medium dense to dense, dry to damp, tan-gray and light brown, silty sandstone with some shells and caliche beds. Some ofthe caliche beds ranged from 1 to 4 inches thick and are thought to be related to topsoil chemical weathering processes. B. Structure Adjacent slopes and nearby road cuts allowed observation of bedding and geologic structural features of the Santiago and Del Mar/Friars Formation in the vicinity of the subject site. The observed Del Mar/ Friars formational material appears to be massively bedded (as exposed in the relatively shallow depth exploratory excavations). In the vicinity of the subject site, the formational materials strike approximately N80°E and dip 2 to 3 degrees to the south (Eisenberg, 1983). Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 9 VII. GEOLOGIC HAZARDS A. Local and Regional Faults Reference to a geologic map for the area (Eisenberg, 1983) indicates the presence of a northeast-trending fault less than 300 feet west of the site. The published projection suggests that the fault displaces the Eocene-age formation but not the Pleistocene-age terrace material and Holocene-age sediments. This fault is considered minor and does not impact the site. It is our opinion that a known "active" fault presents the greatest seismic risk to the subject site during the lifetime of the proposed structures. To date, the nearest known "active" faults to the subject site are the northwest-trending Rose Canyon Fault, Coronado Bank Fault and the Elsinore Fault. Rose Canvon Fault: The Rose Canyon Fault Zone (Mount Soledad and Rose Canyon Faults), located approximately 5 miles west of the subject site, is mapped trending north-south from Oceanside to downtown San Diego, from where it appears to head southward into San Diego Bay, through Coronado and offshore. The Rose Canyon Fault Zone is considered to be a complex zone of onshore and offshore, en echelon strike slip, oblique reverse, and oblique normal faults. The Rose Canyon Fault is considered to be capable of causing a 7.5-magnitude earthquake and considered microseismically active, although no significant recent earthquake is known to have occurred on the fault. Investigative work on faults (believed to be part of the Rose Canyon Fault Zone) at the Police Administration and Technical Center in downtown San Diego and at the SDG&E facility in Rose Canyon, has encountered offsets in Holocene (geologically recent) sediments. These findings have been accepted as confirmed Holocene displacement on the Rose Canyon Fault and this previously classified "potentially active" fault has now been upgraded to an "active" fault as of Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 10 November 1991 (California Division of Mines and Geology - Fault Rupture Hazapd Zones in California, 1994). Coronado Bank Fault: The Coronado Bank Fault is located approximately 21 miles southwest of the site. Evidence for this fault is based upon geophysical data (acoustic profiles) and the general alignment of epicenters of recorded seismic activity (Greene, 1979). An earthquake of 5.3 magnitude, recorded July 13, 1986, is known to have been centered on the fault or within the Coronado Bank Fault Zone. Although this fault is considered active, due to the seismicity within the fault zone, it is significantly less active seismically than the Elsinore Fault (Hileman, 1973). It is postulated that the Coronado Bank Fault is capable of generating a 7.0- magnitude earthquake and is of great interest due to its close proximity to the greater San Diego metropolitan area. Elsinore Fault: The Elsinore Fault is located approximately 25 miles northwest of the site. The Elsinore Fault extends approximately 200 km (125 miles) from the Mexican border to the northern end of the Santa Ana Mountains. The Elsinore Fault zone is a 1- to 4-mile-wide, northwest-southeast-trending zone of discontinuous and en echelon faults extending through portions of Orange, Riverside, San Diego, and Imperial Counties. Individual faults within the Elsinore Fault Zone range from less than 1 mile to 16 miles in length. The trend, length and geomorphic expression ofthe Elsinore Fault Zone identified it as being a part ofthe highly active San Andreas Fault system. Like the other faults in the San Andreas system, the Elsinore Fault is a transverse fault showing predominantly right-lateral movement. According to Hart, et al. {1979), this movement averages less than 1 centimeter per year. Along most of its length, the Elsinore Fault Zone is marked by a bold topographic expression consisting of linearly aligned ridges, swales and hallows. Faulted Holocene alluvial Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 11 deposits (believed to be less than 11,000 years old) found along several segments of the fault zone suggest that at least part of the zone is currently active. Although the Elsinore Fault Zone belongs to the San Andreas set of active, northwest-trending, right-slip faults in the southern California area (Crowell, 1962), it has not been the site of a major earthquake in historic time, other than a 6.0- magnitude quake near the town of Elsinore in 1910 (Richter, 1958; Toppozada and Parke, 1982). However, based on length and evidence of late-Pleistocene or Holocene displacement, Greensfelder (1974) has estimated that the Elsinore Fault Zone is reasonably capable of generating an earthquake with a magnitude as large as 7.5. Recent study and logging of exposures in trenches in Glen Ivy Marsh across the Glen Ivy North Fault (a strand of the Elsinore Fault Zone between Corona and Lake Elsinore), suggest a maximum earthquake recurrence interval of 300 years, and when combined with previous estimates of the long-term horizontal slip rate of 0.8 to 7.0 mm/year, suggest typical earthquake magnitudes of 6 to 7 (Rockwell, 1985). B. Other Geologic Hazards Ground Rupture: Ground rupture is characterized by bedrock slippage along an established fault and may result in displacement of the ground surface. For ground rupture to occur along a fault, an earthquake usually exceeds magnitude 5.0. If a 5.0-magnitude earthquake were to take place on a local fault, an estimated surface- rupture length 1 mile long could be expected (Greensfelder, 1974). Since a fault does not cross the subject site, the risk of ground rupture at the site is considered remote. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 12 Ground Shaking: Structural damage caused by seismically induced ground shaking is a detrimental effect directly related to faulting and earthquake activity. Ground shaking is considered to be the greatest seismic hazard in San Dlego County. The intensity of ground shaking is dependent on the magnitude of the earthquake, the distance and orientation from the earthquake, and the soil and geologic structure beneath the site. Earthquakes of magnitude 5.5 Richter scale or greater are generally associated with significant damage. It is our opinion that the most serious damage to the site would be caused by a large earthquake originating on a nearby strand of the Rose Canyon Fault Zone or one of the major regional active faults. Although the chance of such an event is low, it could occur within the proposed development. The ground accelerations that could be reasonably expected to occur during a major earthquake, on a fault within 100 miles of the site, are provided in Appendix B. Landslides: According to our geologic reconnaissance and a review of the geologic maps (Weber 1982, and Eisenberg 1983) and aerial photographs (4-11-53, AXN- 8M-71 and 72), there are no known or suspected ancient landslides located on the site. However, we encountered some highly fractured and weathered caliche beds within the dense. Eocene-age formational sandstone materials in exploratory trenches. The 1- to 4-inch-thick caliche beds were encountered along the perimeter of the steep west-facing slopes. The beds were present within the massive formational sandstone, but found to be moderately compressible due to the dry condition and void space present. Due to potential slope instability, we have recommended deeper removal and recompaction in the areas where highly weathered formational materials exist. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 13 Slope Stability: The proposed cut and fill slopes should remain stable for the proposed elevations and/or configurations shown in the preliminary plans for the project. The slopes possess a factor of safety against deep shear failure of at least 1.5. The fill slope toe in the area along the western subdivision boundary shall be cut below the weathered formation approximately 5 to 6 feet below existing grade. Geological observations and further slope stability evaluations shall be provided during grading of cut and fill slopes, as needed. Liquefaction: The liquefaction of saturated sands during earthquakes can result in major damage to buildings. Liquefaction is the process in which soils are transformed into a dense fiuid, which will flow as a liquid when unconfined. It occurs principally in loose, saturated sands and silts when they are sufficiently shaken by an earthquake. Although there is a potential for experiencing a seismic event that could produce the required ground acceleration to induce liquefaction, the earthquake necessary to cause this magnitude of acceleration has not occurred in the San Diego County area since the year 1800 (see Appendix C). Since no submerged loose sand or silt conditions exist at the site, the probability of occurrence of soil liquefaction is negligible. Flooding: Due to the site's elevation and the proposed grading, there is little risk of flooding on the proposed site building pads. However, the natural drainage canyon along the western portion of the site could be subject to occasional flooding. Although the drainage of the area, in general, appears to be adequately controlled within the existing channel and the drainage basin is relatively small, the project civil engineer should evaluate the potential for flooding in this area. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 14 With the construction of an adequate on-site drainage system and proper finish surface grades, the risk of flooding should be minimal within the proposed building areas. Groundwater: Groundwater was not encountered during our field investigation and we do not expect significant groundwater problems to develop in the future — if the property is developed as presently proposed and proper drainage is provided and maintained. It should be kept in mind that the proposed construction and grading on the site may change surface drainage patterns. Such changes, plus irrigation of landscaping or significant increases in rainfall, may result in appearance of surface or near- surface perched water at locations where non existed previously. The damage from such water is expected to be localized and cosmetic in nature if good positive drainage is implemented, as recommended in this report, during and at the completion of construction. It must be understood, however, that unless discovered during initial site exploration or encountered during site grading operations, it is extremely difficult to predict if or where perched or true groundwater conditions may appear in the future. When site fill or formational soils are fine-grained and of low permeability, water problems may not become apparent for extended periods of time. Whereas water conditions encountered during grading operations should be evaluated and remedied by the project civil and geotechnical consultants, the project developer and eventual homeowners must realize that post-construction appearances of groundwater may have to be dealt with on a site-specific basis. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 15 The alternative to the possible post-construction, site-specific appearance and resolution of subsurface water problems is the design and construction of extensive subdrain dewatering systems during the initial site development process. This option is usually selected when there is sufficient evidence during initial exploration or site grading to indicate such efforts are warranted. C. Summary The seismic hazard most likely to impact the site is ground shaking, probably resulting from an earthquake on the nearby Rose Canyon Fault or more distant Coronado Bank Fault or Elsinore Fault. In the event that severe earth shaking does occur from major faulting within the area, compliance with UBC and City of Carlsbad Building Code requirements, and the accompanying recommendations for construction, should help to minimize structural damage. No soil liquefaction is anticipated to occur in the buildable areas of the site and no loss of strength or stability is anticipated in the soils ofthe same buildable area due to seismic activity. From a geotechnical standpoint, our investigation Indicates that the site is favorable for the proposed development, provided the recommendations in this report are followed. VIII. EARTHOUAKE RISK EVALUATION Evaluation of earthquake risk requires that the effect of faulting on, and the mass stability of, a site be evaluated utilizing the Mio seismic design event, i.e., an earthquake event on an active fault with less than a 10 percent probability of being exceeded in 50 years. Further, sites are classified by UBC 1997 Edition Into "soil profile types SA through Sp." Soil profile types are defined by their shear velocities where shear velocity is the speed at which shear waves move through the upper 30 meters (approximately 100 feet) ofthe ground. These are: Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 16 SA => Greater than 1500 m/s SB => 760 to 1500 m/s Sc => 360 m/s to 760 m/s SD => 180 to 360 m/s SE => Less than 180 m/s SF => Soil requiring spedfic soil evaluation By utilizing an earthquake magnitude Mio for a seismic event on an active fault, knowing the site class and ground type, a prediction of anticipated site ground acceleration, g, from these events can be estimated. The subject site has been assigned Classification "Sc." An estimation of the peak ground acceleration and the repeatable high ground acceleration (RHGA) likely to occur at the project site by the known significant local and regional faults within 100 miles of the site is included in Appendix C. Also, a listing of the known historic seismic events that have occurred within 100 miles of the site at a magnitude of 5.0 or greater since the year 1800, and the probability of exceeding the experienced ground accelerations in the future based upon the historical record, is provided in Appendix C. Both tables generated from computer programs EQ Fault and EQ Search by Thomas F. Blake (1989) utilizing a digitized file of late-Quaternary California faults (EQ Fault) and a file listing of recorded earthquakes (EQSearch). Estimations of site intensity are also provided as in these listings as Modified Mercalli Index values. The Modified Mercalli Intensity Index is attached as Appendix D. Proposed Emerald Pointe Estates Job No. 97-7189 Carisbad, California Page 17 IX. CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon our report and plan reviews, the limited field investigation conducted by our flrm, and resulting laboratory tests, in conjunction with our knowledge and experience with the soils in this area ofthe City of Carlsbad. Based on a review of a Revised Tentative Map for the site prepared by Hunsaker and Associates, it is our understanding that the site is to be developed to receive a 17-lot residential development with adjacent streets and associated improvements. Fourteen lots will be developed and three will be designated open-space areas. The site is to be graded into relatively level building pads, resulting in cuts up to approximately 18 feet and fills up to approximately 23 feet in depth. Final plans should be submitted for our review as soon as they become available, so that more specific design recommendations or needed alterations can be provided, if required. In general, we found that the site is underlain by dense, sandy and silty formational material of good bearing strength for support of the proposed development. However, some soft to firm topsoil and weathered formation was found on the ridge top and slope edges. As such, we recommend that in order to provide a more firm, uniform soil base, the loose topsoils and weathered formation be removed and properly compacted (to at least 90 percent per ASTM D1557-98) prior to any addition of new fill. In cut areas, any remaining underlying loose soils should be removed and properly compacted. In addition, on all cut/fill transition lots, where the proposed structure is underlain by both cut and fill, the cut portion of the building site (and up to at least 10 feet beyond the perimeter thereof), should be undercut to at least 3 feet at the farthest shallow end and gently transition to the deep end and replaced as compacted fill, so as to reduce the potential for differential settlement under the proposed structures. The moisture content for the Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 18 upper 10 feet of fill shall be at least 5 percent over their Optimum Moisture Content. If medium to highly expansive formational soils are encountered, they shall be moisture conditioned and recompacted in a similar manner in the upper 2 feet (as a minimum). A. Site Grading 1. The proposed grading operations shall be performed in accordance with the General Earthwork Specifications (Appendix E) and the requirements of the City of Carlsbad Grading Ordinance. Geotechnical Exploration, Inc. recommends that our firm verify the actual soil conditions revealed during the grading to be as anticipated in this "Update Report of Preliminary Geotechnical Investigation." In addition, the compaction of any fill soils placed during the grading must be tested by the soil engineer. It is the responsibility of the grading contractor to comply with the requirements of the grading plans and the local grading ordinance. Any fill soils that are observed to be loose or that have been placed without control or sufficient testing shall be removed and recompacted to comply with the grading specifications. It is recommended that our firm review the flnal grading plans and project soil-related speciflcations prior to the start of construction. Also, we recommend that a pre-construction conference be held at the site with the owner/developer, architect, civil engineer, contractor, grader, and geotechnical engineer in attendance. Special soil handling procedures and the grading plan requirements can be discussed at that time. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 19 We recommend that the entire property be cleared of all vegetation and any other debris or rubble. The unsuitable material generated should be disposed of off-site prior to the placing of any new fill. Our investigation revealed that the eastern (investigated) portion of the site is underlain by dense formational materials, with some loose (soft to firm) topsoil and weathered formational materials ranging from IVi to 51/2 feet deep overlying the site. Since a portion of the site is to be lowered to achieve the finish grade, it is anticipated that dense formational materials will be exposed over the majority of the eastern portion of the site. Some removal and recompaction of the loose surface soils and weathered formation will be required in the proposed fill areas and also in cut areas when the soils are not at the adequate moisture content (as discussed previously). We estimate that the deepest removal of loose topsoil and weathered formation will be in the northern and western portions of the site and along the edges of the slopes where thicker topsoils and weathered formational materials were encountered. Also, any areas with unfavorable geologic conditions may require special grading and drainage recommendations. The excavated, low- expansive soils to be used as fill shall be watered to approximately optimum moisture content and compacted to at least 90 percent of Maximum Dry Density ASTM D1557-98. Any soils possessing an expansion potential equal to or higher than 50 shall be compacted with a moisture content at or higher than 5 percent over the optimum moisture content. The relative compaction of such compacted soils shall be at least 90 percent of the maximum obtained per ASTM D1557-98. - Highly expansive soils shall not be overcompacted higher than 93 percent of Maximum Dry Density. Proposed Emerald Pointe Estates Carlsbad, California Job No. 97-7189 Page 20 4. In addition, a deeper key will be required at the toe of the proposed fill slope along the western subdivision boundary. Caliche beds were encountered within the exploratory trench excavations placed in this area. Any backfill soils placed in utility trenches or behind retaining walls, which support structures, and other improvements (such as patios, sidewalks, driveways, pavements, etc.) shall be compacted to at least 90 percent of Maximum Dry Density. 5. No uncontrolled fill soils shall remain on the site after completion of site grading. In the event that temporary ramps or pads are constructed of uncontrolled fill soils, the loose flil soils shall be removed and/or recompacted priorto completion ofthe grading operation. B. Preliminarv Design Parameters 6. For preliminary foundation design of new footings, based on the assumption that new footings will be placed on low expansive to medium expansive soils at least 18 inches as measured from the adjacent ground surface into medium dense to dense natural (formational) soils or properly compacted on- site soils, we provide a preliminary allowable soil bearing capacity equal to 2,000 pounds per square foot (psf) for properly compacted flil and 3,000 pounds per square foot for dense formation. Footings resting on compacted fill or formational soils with high to very high expansion potential shall be embedded at least 24 inches in depth. Footing width, in all cases, shall be at least 12 inches. For wider and/or deeper footings, the allowable soil bearing •capacity may be calculated based on the following equation: Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Pagg 21 Qa = 1000D-F500W for footings in compacted fill Qa = 1500D-F750W for footings in formation where "Qa" is the allowable soil bearing capacity (in psf); "D" is the depth of the footing (in feet) as measured from the lowest adjacent grade; and "W" Is the width of the footing (in feet). The allowable soil bearing capacity may be increased one-third for analysis including wind or earthquake loads. The maximum total allowable soil bearing capacity for dense flIls or natural formation is 6,000 psf. We recommend that all footings be founded either entirely in dense formation or entirely in compacted fill. The final foundation embedment will depend on expansion index test results obtained from representative soils obtained from the upper 4 feet of building pads. If imported soils are required to bring the site to grade, the imported soils should be low expansive (EI lower than 50) and be obtained from an approved oft^-site borrow area. Should soils with an expansion index higher than 90 be left: at subgrade elevation in the building areas, the footing excavations shall be deepened to at least 24 inches. 7. The passive earth pressure of the encountered dense natural-ground soils and any properly compacted fill soils (to be used for design of shallow foundation and footings to resist the lateral forces) shall be based on an Equivalent Fluid Weight of 275 pounds per cubic foot. This passive earth pressure shall only be considered valid for design if the ground adjacent to Proposed Emerald Pointe Estates Carlsbad, California Job No. 97-7189 Page 22 the foundations structure is essentially level for a distance of at least three times the total depth ofthe foundation. 8. A Coefflcient of Friction of 0.35 times the dead load may be used to calculate friction force between the bearing soils and concrete wall foundations or structure foundations and fioor slabs. The following table summarizes site-specific seismic design criteria to calculate the base shear needed for the design of the residential structure. The design criteria was obtained from the Uniform Building Code (1997 edition). Parameter Value Reference Seismic Zone Factor, Z 0.40 Table 16-1 Soil Profile Type Sc Table 16-J Seismic Coefficient, C^ 0.40Na Table 16-Q Seismic Coefflcient, Cv 0.56Nv Table 16-R Near-Source Factor, Na 1.0 Table 16-S Near-Source Factor, Nv 1.1 Table 16-T Seismic Source Type B Table 16-U 10. Our experience indicates that, for various reasons, footings and slabs occasionally crack, causing ceramic tiles and brittle surfaces to become damaged. Therefore, we recommend that all conventional shallow footings and slabs-on-grade contain at least a minimum amount of reinforcing steel to reduce the separation of cracks, should they occur. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 23 10.1 A minimum of steel for continuous footings should include at least four No. 5 steel bars continuous, with two bars near the bottom of the footing and two bars near the top. A minimum clearance of 3 inches shall be maintained between steel reinforcement and the top, bottom or sides of the footing. 10.2 Isolated square footings should contain, as a minimum, a grid of No. 4 steel bars on 12-inch centers, both ways, with no less than two bars each way. 10.3 Interior fioor slabs should be a minimum of 5 inches actual thickness and be reinforced with at least No. 3 steel bars on 18-inch centers, both ways, placed at midheight in the slab (or 6x6-W2.9xW2.9 welded- wire mesh mats). Slabs shall be underlain by a 2-inch-thick layer of clean sand (S.E. = 30 or greater) overlying a moisture retardant membrane over 2 inches of sand. Slab subgrade soil shall be verified by a Geotechnical Exploration, Inc. representative to have the proper moisture content within 48 hours prior to placement of the vapor barrier and pouring of concrete. Slab thickness may be reduced to 4 inches if the expansion index of the soils in the upper 4 feet is 50 or lower. As an option, post-tensioned slabs on-grade may be used in lieu of a conventionally reinforced slab. However, the perimeter footing shall be embedded at least 18 inches for soils with an expansion index below 90, and 24 inches for soils with an expansion index over 90. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 24 We recommend the project Civil/Structural Engineer incorporate isolation joints and sawcuts to at least one-fourth the thickness of the slab in any fioor designs. Control joints should not be spaced farther than every 25 feet for slabs reinforced with rebars, and 15 feet for slabs reinforced with welded wire fabric. The joints and cuts, if properly placed, should reduce the potential for and help control floor slab cracking. However, due to a number of reasons (such as base preparation, construction techniques, curing procedures, and normal shrinkage of concrete), some cracking of slabs can be expected. Control joints shall be placed within 12 hours after concrete placement and shall penetrate at least one-quarter the slab thickness. Following placement of any concrete floor slabs, sufflcient drying time must be allowed prior to placement of floor coverings. Premature placement of floor coverings may result in degradation of adhesive materials and loosening ofthe finish floor materials. Tiled floors shall be provided with an approved isolation sheet to prevent reflective shrinkage and/or control joint cracking. NOTE: The project Civil/Structural Engineer shall review all reinforcing schedules. The reinforcing minimums recommended herein are not to be construed as structural designs, but merely as minimum safeguards to reduce possible crack separations. Actual reinforcing requirements should be provided by the project Structural Engineer for the design loads and anticipated deflections. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 25 Based on our laboratory test results and our experience with the soil types on the subject site, the dense natural soils and properly compacted fill soils should experience differential angular rotation of less than 1/240 under the allowable loads. The maximum differential settlement across the structure and footings when founded on properly compacted fill or dense natural formation shall be on the order of 1 inch. 11. As a minimum for protection of on-site improvements, it is recommended that all nonstructural concrete slabs (such as patios, sidewalks, etc.), be founded on properly compacted, moisture-conditioned and tested fill or dense native formation and underlain by at least 12 inches of low expansive potential, properly compacted soils, with 6x6-6/6 welded wire mesh at the center of the slab, and contain adequate isolation and control joints. The performance of on-site improvements can be greatly affected by soil base preparation and the quality of construction. It is therefore important that all Improvements are properly designed and constructed for the existing soil conditions. The improvements should not be built on loose soils or fills placed without our observations and testing. Any rigid improvements founded on the existing loose surface soils can be expected to undergo movement and possible damage and is therefore not recommended. Geotechnical Exploration, Inc. takes no responsibility for the performance of the improvements built on loose or inadequately compacted fills. Any exterior area to receive concrete improvements shall be verified for compaction and moisture within 48 hours prior to concrete placement. -For exterior slabs with the minimum shrinkage reinforcement, control joints shall be placed at spaces no farther than 15 feet apart or the width of the slab, whichever is less, and also at re-entrant corners. Control joints in Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 26 exterior slabs shall be sealed with elastomeric joint sealant. The sealant shall be inspected every 6 months and be properly maintained. Control joints shall penetrate at least one-quarter the thickness ofthe slab. 12. Driveway pavement, consisting of Portland cement concrete at least SVi inches in thickness, may be placed on properly compacted and moisture conditioned subgrade soils. The concrete shall be at least 3,500 psi compressive strength, with control joints no farther than 15 feet apart or the width of the slab, whichever is less, and also at re-entrant corners. Pavement joints shall be properly sealed with pavement joint sealant, as required in sections 201.3.6 through 201.3.8 of the Standard Specifications for Public Work Construction, 2000 Edition. Depending upon the lateral slab support of the drive, restraining steel dowels may be required in areas that are not sufficiently restrained. C. Floor Slab Vaoor Transmission 13. Vapor moisture can cause some problems on moisture sensitive floors, some fioor sealers, or sensitive equipment in direct contact with the floor, in addition to mildew and staining on slabs, walls and carpets. 14. The common practice in Southern California is to place vapor retarders made of PVC, or of polyethylene. PVC retarders are made in thickness ranging from 10- to 60-mil. Polyethylene retarders, called visqueen, range from 5- to 10-mil in thickness. The thicker the plastic, the stronger the resistance will be against puncturing. Proposed Emerald Pointe Estates Job No. 97-7189 Carisbad, California Page 27 15. Although polyethylene (visqueen) products are most commonly used, products such as Vaporshield possess much higher tensile strength and are more specifically designed for and intended to retard moisture transmission into concrete slabs. The use of Vaporshield or equivalent is highly recommended when a structure is intended for moisture-sensitive fioor coverings or uses. 16. The vapor retarders need to have joints lapped and sealed with mastic or manufacturer's recommended tape for additional protection. To provide some protection to the moisture retarder, a layer of at least 2 inches of clean sand on top and 2 inches at the bottom shall also be provided. No heavy equipment, stakes or other puncturing instruments shall be used on top of the liner before or during concrete placement. In actual practice, stakes are often driven through the retarder material, equipment is dragged or rolled across the retarder, overlapping or jointing is not properly implemented, etc. All these construction deficiencies reduce the retarder's effectiveness. The vapor retarders are not waterproof. They are intended to help prevent or reduce capillary migration of vapor through the soil into the pores of concrete slabs. Other waterproofing systems must supplement vapor retarders if full waterproofing is desired. The owner should be consulted to determine the specific level of protection required. D. Retainina Wails 17. The active earth pressure (to be utilized in the design of cantilever retaining walls utilizing a mixture of on-site or imported, low expansive soils as backfill) shall be based on an Equivalent Fluid Weight of 45 pounds per cubic foot (for level backflll and properly drained retaining wall backfill only). The Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 28 designer of the retaining walls shall specify in the retaining wall plans that the wall backflll shall consist of soils with an expansion index less than 50. The "wall backfill" shall be all retained material within a distance equal to its height. In the event that a retaining wall is surcharged by sloping backfill (of the same soil type), the design active earth pressure shall be based on the appropriate Equivalent Fluid Weight presented in the following table: Height of Slope/Height of Wall* Slope Ratio 0.25 0.50 0.75 1.0Q(+) 2.0:1.0 52 58 62 63 •Utilization of other than clean sandy soils as backfill or any encountered adverse geologic conditions in the cut slopes behind walls will require the use of higher equivalent fluid weights. In the event that a retaining wall Is to be designed for a restrained condition, a uniform pressure equal to lOxH (ten times the total height of retained wall, considered in pounds per square foot) shall be considered as acting everywhere on the back of the wall in addition to the design Equivalent Fluid Weight. Any additional load or surcharge located within a horizontal distance equal to the height ofthe wall shall be included as extra pressure. Any loads placed on the active wedge behind a cantilever retaining wall shall be included in the design by multiplying the load weight by a factor of 0.45, and 0.62 for restrained retaining walls. The temporary cuts and bottom of Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 29 excavation soils during retaining wall construction shall be maintained with proper moisture until just prior to backfilling. 18. Due to possible buildup of groundwater (derived primarily from rainfall and irrigation), excess moisture is a common problem in below-grade structures or behind retaining walls that may be proposed. These problems are generally in the form of water seepage through walls, mineral staining, mold growth and high humidity. Even without the presence of free water, the capillary draw characteristics, especially of flne grained soils, can result in excessive transmission of water vapor through walls and floor slabs. In order to reduce the potential for moisture-related problems to develop at the site, proper and sufficient ventilation and waterproofing shall be provided for below-ground areas and the backfill side of all structure retaining walls should be properly waterproofed and drained. 19. Proper subdrains and free-draining backwall material or geofabric drainage shall be installed behind all retaining walls (in addition to proper waterproofing) on the subject project. Geotechnical Exploration, Inc. will assume no liability for damage to structures or improvements that is attributable to poor drainage. The architectural plans shall clearly indicate that the subdrains for any lower-level walls shall be placed at an elevation at least 1 foot below the bottom of the lower-level slabs. At least 0.5-percent fall shall be provided for the subdrain. The subdrain shall be placed in an envelope of crushed rock gravel up to 1 inch in maximum diameter, and be -wrapped with Mirafi 140N filter or equivalent (see Figure No. VI). Proposed Emerald Pointe Estates Carlsbad, California Job No. 97-7189 Page 30 In general, guidelines and requirements of Chapter 18 and its Appendix (UBC 1997 Edition) shall be followed for wall and fioor basement waterproofing. Proper ventilation (per UBC requirements) shall be provided to the crawl space areas. E. Slopes 20. The preliminary grading plan (Revised Tentative Map, Emerald Pointe Estates) calls for maximum cut and fill slopes up to approximately 30 feet high, both at an inclination of 2:1 (horizontal to vertical). Review of the slope stability analyses, for both surfidal and deep-seated stability, indicate that the proposed grading slopes have factors of safety of 1.5 or greater. These analyses assume no weak clay seams, no groundwater, and no other adverse geologic conditions exist In the cut slopes or within the foundation of fill slopes. In addition, the weakest soil on the slope shall possess at least one ofthe following combinations of shear strength parameters: Friction Angle f degrees) Cohesion fpsf) 28 300 29 260 30 225 31 185 30 150 Soil shear strength parameters shall be evaluated using representative samples of soil composing the slopes. Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 31 We recommend that a geologist from our firm observe all cut slopes during grading for possible adverse conditions. Additional investigation and analyses may be required if adverse geologic conditions such as groundwater seepage, adversely oriented bedding, relatively weak or sheared daystone beds, or adverse jointing or faulting are encountered. Although buttress fill slopes are not anticipated, out-of-slope bedding or highly weathered formational materials encountered during the grading may require the construction of stability and/or buttress fills if needed. 21. We recommend that all faces of fill slopes be backrolled at maximum 4-foot fill height intervals during the grading operation. Additionally, we recommend that all faces of fill slopes be track-walked at the completion of the rough grading operation so that a dozer track covers all surfaces at least twice. All cut and fill slopes should be properly drained, planted, and maintained to control erosion and surface sloughing. No pad runoff water shall drain over the tops of slopes. All building pads shall drain toward the front street. 22. If unshored temporary slopes are to be constructed on the site or along the property lines, design engineers and/or excavation contractors must take into account any adjacent utility lines or subsurface structures. Geotechnical Exploration, Inc. has no knowledge as to the location or condition of any such utility lines, or as to whether any such lines can tolerate slight vibration-induced by earth movements associated with excavation and/or shoring of temporary slopes in close proximity to any such lines. 23. -We anticipate that steep temporary slopes may be required on portions of the site during grading. Based on the results of our fleld investigation and laboratory tests, it is our opinion that steep temporary slopes may be Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 32 considered in areas where the slope top will be at least 10 feet away from any existing improvements. The existing soils may be cut to temporary slope ratios of 1.0 horizontal to 0.75 vertical (for an unsupported period not to exceed four weeks) for slope heights up to 18 feet. A representative of Geotechnical Exploration, Inc. should be called to observe all steep temporary slopes during construction. In the event that soils and formational material comprising a slope are not as anticipated, any required slope design changes would be presented at that time. 24. Where not superseded by spedfic recommendations presented in this report, trenches, excavations, and temporary slopes at the subject site shall be constructed in accordance with subparagraph (1) paragraph (f), of section 1541 of Title 8, Construction Safety Orders, issued by OSHA. 25. The soils that occur within the proximity of the rim or face of even properly compacted fill or dense natural ground cut slopes often possess poor lateral stability. The degree of lateral and vertical deformation depends on the inherent expansion and strength characteristics of the soil types comprising the slope, slope steepness and height, loosening of slope face soils by burrowing rodents, and irrigation and vegetation maintenance practices, as well as the quality of compaction of fill soils. Structures and other improvements could suffer damage due to these soil movement factors if not properly designed to accommodate or withstand such movement. Foundations and footings of proposed structures, walls, etc., when founded 5 -feet and farther away from the top of compacted fill slopes, may be of standard design. However, if the proposed foundations and footings are located closer than 5 feet (or H/3 for slopes 15 feet high or greater) from the Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 33 top of compacted fill slopes (where H=height of the slope), they should be deepened to at least Vh feet below a line beginning at a point 5 feet horizontally and to provide a daylight distance of at least H/3 inside the fill slopes (for slopes with heights of 15 feet or higher) and projected outward and downward, parallel to the face of the fill slope (see Figure No. IV). Special reinforcement and design considerations should be provided by the Structural Engineer for all improvements within 5 feet of the top of fill slopes, due to the anticipated "creeping" movement of the underlying fill soils. As a general rule, the recommended setback from the slope face is a minimum of 5 feet and a maximum of H/3 for slopes 15 feet in height or higher. 26. Rigid improvements such as top-of-slope walls, columns, decorative planters, concrete fiatwork, swimming pools and other similar types of improvements can be expected to display varying degrees of separation typical of improvements constructed at the top of a slope. The separations result primarily from slope top lateral and vertical soil deformation processes. These separations often occur regardless of being underlain by cut or fill slope material. Proximity to a slope top is oft:en the primary factor afl^ecting the degree of separations occurring. Typical and to-be-expected separations can range from minimal to up to 1 inch or greater in width. In order to minimize the effect of slope-top lateral soil deformation, we recommend that the top-of-slope improvements be designed with fiexible connections and joints in rigid structures so that the separations do not result in visually apparent cracking damage and/or can be cosmetically dressed as part of the ongoing property maintenance. These •fiexible connections may indude "slip joints" In wrought iron fendng, evenly spaced vertical joints in block walls or fences, control joints with flexible caulking in exterior flatwork improvements, etc. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 34 In addition, use of planters to provide separation between top-of-slope hardscape such as patio slabs and pool decking from top-of-slope walls can aid greatly in redudng cosmetic cracking and separations in exterior Improvements. Actual materials and techniques would need to be determined by the project architect or the landscape architect for individual properties. Steel dowels placed in flatwork may prevent noticeable vertical dlfl^erentlals, but if provided with a slip-end they may still allow some lateral displacement. 27. It Is recommended that all compacted fill slopes and natural cut slopes be planted with an erosion resistant plant, in conformance with the requirements of the City of Carlsbad. F. Site Drainage Considerations 28. Subdrains shall be Installed under any canyon fills. The subdrains shall be placed in an envelope of gravel and wrapped with filter doth. If stabilization fills or buttresses are required during grading, subdrains shall also be required where recommended by our firm. 29. Groundwater was not encountered during the course of our field investigation, and we do not expect groundwater to cause significant problems if the property is developed as presently designed. It should be kept in mind, however, that any required additional grading operations may change surface drainage patterns and/or reduce permeabilities due to the densification of compacted soils. Such changes of surface and subsurface •hydrologic conditions, plus irrigation of landscaping or significant increases in rainfall, may result in the appearance of minor amounts of surface or near- surface water at locations where none existed previously. The damage from Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, California Page 35 such water is expected to be minor and cosmetic in nature. If good positive drainage is implemented at the completion of construction. Corrective action should be taken on a site-specific basis if and when it becomes necessary. Any significant seepage observed during grading will be reported to the contractor for corrective work. Additional recommendations will be provided as warranted. 30. Adequate measures shall be taken to properly finish-grade the site to prevent ponding or erosion, specifically of the slopes. Drainage waters from this site and adjacent properties are to be directed away from building pads and slopes, onto the natural drainage direction for this area or into properly designed and approved drainage facilities. Roof gutters and downspouts should be installed on all structures, with runoff directed away from the foundations via closed drainage lines. Proper subsurface and surface drainage will help minimize the potential for waters to seek the level of the bearing soils under the building pads. Failure to observe this recommendation could result in excessive uplift or undermining and differential settlement of the future structures and improvements on the site. We recommend that the minimum gradient around the structures be not less than 5 percent in the nearest 5 feet to structures. 31. Appropriate erosion-control measures shall be taken at all times during construction to prevent surface runoff waters from entering footing excavations and ponding on finished building pads or running uncontrolled over the tops of newly constructed cut or fill slopes. Particular care should be taken to prevent saturation of any temporary construction slopes. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 36 32. Sediment accumulation and standing water along street curbs is a common occurrence after construction of a residence or subdivision, most often as a result of excess irrigation and/or relatively level street grades. Continual slow water fiow from yard drainage systems into street swales oftien results In curb areas that remain wet, muddy or support moss growth and algae. During high water flow conditions (such as during a heavy rainfall), the velocity of the water will most likely carry the sediments and dear the curb area. However, during low water flow (such as continual slow draining of yard area drains Into the curb outlets), the slow velocity allows silts and fine sands to deposit and accumulate. Heavily landscaped yards, the presence of cut ground lots that create near-surface perched water conditions, and relatively level streets with shallow gradients to storm drain inlets all contribute to wet and muddy curb conditions. It is the responsibility of the project Civil Engineer to design adequate street/curb surface drainage. It is recommended that the future homeowners be advised as to the irrigation-related cause(s) of persistent water and sedimentation in the street curb areas. If street curb flow from yard area drains is not considered acceptable, we may be contacted by the project Civil Engineer to discuss the design ofa yard area discharge collection system. 33. Planter areas, flower beds, and planter boxes shall be sloped to drain away from the foundations, footings, and floor slabs at a gradient of at least 5 percent within 5 feet from the perimeter walls. Any planter areas adjacent to the building or surrounded by concrete improvements shall be provided with suffident area drains to help with rapid runoff disposal. No water shall be -allowed to pond adjacent to the building or other improvements. Closed planter boxes shall be constructed with a sealed bottom and a subsurface drain, installed in gravel, with the direction of subsurface and surface flow Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 37 away from structures, to an adequate drainage fadlity. Suffident area drains shall be placed In landscape areas to provide a fast runoff disposal. The landscape surface shall be provided with effective flow lines and gradients to reduce water ponding throughout the project. Roof gutter and downspouts shall be tied to storm drain lines. G. General Recommendations 34. In order to minimize any work delays at the subject site during site development, this flrm should be contacted at least 24 hours prior to any need for observation of slopes or fleld density testing. 35. Design of the street pavement sections was not induded within the scope of this report. Pavement sections will depend largely on the street subgrade soil conditions exposed aflier grading and the expected traffic load, and should be based on R-value test results. These tests should be performed aflier completion of the rough grading operation. X. LIMITATIONS It should be noted that all recommendations are of a preliminary nature and subject to change, based upon review of your flnal grading and building plans, and our observations during grading. Our preliminary condusions and recommendations have been based on the available data obtained from our report reviews, fleld investigation and laboratory analysis, as well as our experience with the soils and formation materials in this area of the City of Carlsbad. Proposed Emerald Pointe Estates job No. 97-7189 Carlsbad, California Page 38 Of necessity, we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is, therefore, necessary that all obsen/ations, conclusions, and recommendations be verified at the time grading operations begin. In the event discrepancies are noted, additionai recommendations may be issued, if required. This report has been prepared for design purposes only, and may not be sufficient to prepare an accurate bid for the grading work. The work performed and recommendations presented herein are the result of an Investigation and analysis that meet the contemporary standard of care in our profession within the County of San Diego. No warranty is provided. This report should be considered valid for a period of two (2) years, and is subject to review by our firm following that time. If significant modifications are made to the grading plans, espedally with respect to the height and location of any proposed cuts and fills, this report should be presented to us for immediate review and possible revision. The firm of Geotechnical Exploration, Inc. shall not be held responsible for changes to the physical condition of the property, such as addition of fill soils or changing drainage patterns, which occur subsequent to Issuance of this report. This firm does not practice or consult in the fleld of safety engineering. We do not direct the contractor's operations, and we cannot be responsible for the safety of- personnel other than our own on the site; the safety of others is the responsibility of the contractor. The contractor should notify the owner If he considers any of the recommended actions presented herein to be unsafe. Proposed Emerald Pointe Estates Carlsbad, California Job No. 97-7189 Page 39 It is the responsibility of the owner and/or developer to ensure that the recommendations summarized in the report are carried out in the field operations and that our recommendations for design of the project are incorporated in the building and grading plans. Our firm should review the grading and the building plans when they become available and before grading starts. This opportunity to be of service is sincerely appredated. Should you have any questions regarding this matter, please contact the undersigned. Reference to our Job No. 97-7189 will help to expedite a response to your inquiries. Respectfully submitted, GEOTECHNICAL EXPLORATION, INC. Jay*^. Falser Senior Project Geologist Jaime A. Cerros, P.E. R.C.E. 34422/G.E. 2007 Senior Geotechnical Engineer C.E.G. 999i:exp. 3-3i-03i/R.G. 3391 JKH/JAC/LDR/pj REFERENCES JOB NO. 97-7189 April 2002 Association of Engineering Geologists, 1973, Geology and Earthquake Hazards, Planners Guide to the Seismic D u Southern Califomia Section, Association of Engineering Geologists, Special Publication, rublisned July 1973, p. 44. Berger & Schug, 1991, Probabilistic Evaluation of Seismic Hazard in the San Diego-Tijuana Metropolitan Region, Environmental Perils, San Diego Region, San Diego Association of Geologists. Bryant, W.A. and E.W. Hart, 1973 (10* Revision 1997), Fault-Rupture Hazard Zones in Califomia, Calif. Div. of Mines and Geology, Special Publication 42. California Division of Mines and Geology - Alquist-Priolo Special Studies Zones Map, November 1, 1991. City of San Diego Seismic Safety Element, revised 1995, Map Sheet 29. Clarke, S.H., H.G. Greene, M.P. Kennedy and J.G. Vedder, 1987, Geologic Map of the Inner-Southem California Continental Margin in H.G. Greene and M.P. Kennedy (editors),.Calif ornia Continental Margin Map Senes, Map IA, Calif. Div. of Mines and Geology, scale 1:250,000. Crowell, J.C, 1962, Displacement along the San Andreas Fault, Califomia; Geologic Society of America Special Paper 71, 61 p. Gray, C.H Jr., M.P. Kennedy and P.K. Morton, 1971, Petroleum Potential of Southem Coastal and Mountain Area, California, American Petroleum Geologists, Memoir 15, p. 372-383. Greene, H.G., 1979, Implication of Fault Pattems in the Inner Califomia Continental Borderland between San Pedro and San Diego, in "Earthquakes and Other Perils, San Diego Region," P.L. Abbott and W.J Elliott editors. ' Greensfelder, R.W., 1974, Maximum Credible Rock Acceleration fmm Earthquakes in Califomia; Califomia Division of Mines and Geology, Map Sheet 23. Hart, E.W., D.P. Smith and R.B. Saul, 1979, Summary Report: Fault Evaluation Program, 1978 Area (Peninsular Ranges-Salton Trough Region), Calif. Div. of Mines and Geology, OFR 79-10 SF, 10. Hauksson, E. and L. Jones, 1988, The July 1988 Oceanside (M, = 5.3) Earthquake Sequence in the Contenental Borderland, Southern California Bulletin of the Seismological Society of America, v. 78, p. 1885- Hileman, J.A., CR. Allen and J.M. Nordquist, 1973, Seismicity of the Southem Califomia Region, January 1 1932 to December 31, 1972; Seismological Laboratory, Cal-Tech, Pasadena, Calif. Kennedy, M.P., 1975, Geology of the San Diego Metropolitan Area, California; Bulletin 200, Calif Div of Mines and Geology. Kerinedy, M.P., and S.H. Clarke, 2001, Late Quatemary Faulting in San Diego Bay and Hazard to the Coronado Bndge, California Geology, July/August 2001. Kennedy, M.P. and S.H. Clarke, 1997A, Analysis of Late Quatemary Faulting in San Diego Bay and Hazard to the Coronado Bridge, Calif. Div. of Mines and Geology Open-file Report 97-1 OA. Page 2 Kennedy, M.P. and S.H. Clarke, 1997B, Age of Faulting in San Diego Bay in the Vicinity of the Coronado Bridge, an addendum to Analysis of Late Quaternary Faulting in San Diego Bay and Hazard to the Coronado Bridge, Calif. Div. of Mines and Geology Open-file Report 97-1 OB. Kennedy, M.P., S.H. Clarke, H.G. Greene, R.C. Jachens, V.E. Langenheim, J.J. More and D.M. Bums, 1994, A Digital (GIS) Geological/Geophysical/Seismological Data Base for the San Diego 30-x60' Quadrangle, California ~ A New Generation, Geological Society of America Abstracts with Programs, v. 26, p. 63. Kennedy, M.P. and G.W. Moore, 1971, Stratigraphic Relations of Upper Cretaceous and Eocene Formations, San Diego Coastal Area, California, American Association of Petroleum Geologists Bulletin, v. 55, p. 709-722. Kennedy, M.P., S.S. Tan, R.H. Chapman and G.W. Chase, 1975, Character and Recency of Faulting, San Diego Metropolitan Area, California, Calif. Div. of Mines and Geology Special Report 123, 33 pp. Kennedy, M.P. and E.E. Welday, 1980, Character and Recency of Faulting Offshore, metropolitan San Diego California, Calif. Div. of Mines and Geology Map Sheet 40, 1:50,000. Kem, J.P. and T.K. Rockwell, 1992, Chronology and Deformation of Quaternary Marine Shorelines, San Diego County, Califomia in Heath, E, and L. Lewis (editors). The Regressive Pleistocene Shoreline, Coastal Southern California, pp. 1-8. Lindvall, S.C. and T.K. Rockwell, 1995, Holocene Activity of the Rose Canyon Fault Zone in San Diego, California, Journal of Geophysical Research, v. 100, no. B-12, p. 24121-24132. McEuen, R.B. and CJ. Pinckney, 1972, Seismic Risk In San Diego; Transactions of the San Diego Society of Natural History, Vol. 17, No. 4, 19 July 1972. Moore, G.W. and M.P. Kennedy, 1975, Quaternary Faults in San Diego Bay, Caiifornia, U.S.Geological Survey Journal of Research, v. 3, p. 589-595. Richter, C.G., 1958, Elementary Seismology, W.H. Freeman and Company, San Francisco, Calif. Rockwell, T.K., D.E. Millman, R.S. McElwain, and D.L. Lamar, 1985, Study of Seismic Activity by Trenching Along the Glen Ivy North Fault, Elsinore Fault Zone, Southern California: Lamar-Merifield Technical Report 85- 1, U.S.G.S. Contract 14-08-0001-21376, 19 p. Simons, R.S., 1977, Seismicity of San Diego, 1934-1974, Seismological Society of America Bulletin, v. 67, p. 809-826. Tan, S.S., 1995, Landslide Hazards in Southern Part of San Diego Metropolitan Area, San Diego County, Calif. Div. of Mines and Geology Open-file Report 95-03. Toppozada, T.R. and D.L. Parke, 1982, Areas Damaged by California Earthquakes, 1900-1949; Calif. Div. of Mines and Geology, Open-file Report 82-17, Sacramento, Calif. Treiman, J.A., 1993, The Rose Canyon Fault Zone, Southern California, Calif. Div. of Mines and Geology Open- file Report 93-02, 45 pp, 3 plates. U.S. Dept. of Agriculture, 1953, Aerial Photographs AXN-8M-71 and 72. SITE MAP «y fiOCKi FELLER , - -" a ; I5f Proposed Ennerald Pointe Estates APN-212-040-50 Carlsbad, CA. Figure No. la Job No. 97-7189 LEGEND T-11 ASSUMED SUBDIVISION BOUNDARY APPROXIMATE EXISTING TOPOGRAPHY (feet) APPROXIMATE LOCATION OF EXPLORATORY TRENCH / T-l Geologic Legend Fuvem-mw ' SanfitegoFomiaton Eocma-a^ TH /T{ OBlMarandFrkuv 1/ -%;T-11 T-4 SCALE: r = loa ^^^^^ T-e . y 7 \ \ /V T-3 Xj(Assumed Ceologic\fonfacf) 1 30 97-7189-P2 LAtmL Tim REFERENCE: This Plot Pian luafi prepared from an existing CAD dratufng file provided by Hunsaker 4 Assocfates SP, Inc. and from on-sfte ffeld reconnafssance performed by CiEI. NOTE; This Plot Plon is not to be used for legoi purposes. Locations and dimensions are approxi- mate. Actual property dimensions ond locations of utilities may lie obtained from tlie Approved Building Plans or thie "As-Built" Groding Plons. PL Of PLAN and GEOLOGIC MAP l^n^posBd ErrmeJd Pt^nto EstBtas APN-212-040-S0 Carlsbad, CA. Figure No. I Job No. 97-7189 GootccfinlMl Exploratton, Inc. Apnl 2002 I I EQUIPMENT Case Backhoe DIMENSION & TYPE OF EXCAVATION 2' X 10' X 6' Trench DATE LOGGED 1-23-98 SURFACE ELEVATION ± 205' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH HELD DESCRIPTION AND CUSSIFICATtON DESCRIPTION AND REMARKS (Grain size. Density, Moisture, Color) Ms O 3 a s. d CO Sf Wo i5 8 m o o o 30 2 - SILTY CLAY with some sand and root Stiff to firm. Moist. Dark brown TOPSOIL CL/ CH 3 - 7 - 18 - SILTY SANDSTONE, highly fractured and weathered. Medium dense to dense. Damp. Tan-gray and 1ight brown. WEATHERED FORMATION SANDSTONE, well cemented wiTh same concretions. Very dense. Damp. Tan-gray. FORMATION ML SM Bottom of hole @ 6 I I y WATER TABLE 13 LOOSE BAG SAMPLE ED IN-PUCE SAMPLE • DRIVE SAMPLE SAND CONE/F.D.T. CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa & North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-71.89 RGURE NUMBER I la REVIEWED BY OD LOG No. T*1 EQUIPMENT Case Backhoe DIMENSION 4 TlTPE OF EXCAVATION 2' X 10' X 7' Trench OATE LOGGED 1-23-98 SURFACE ELEVATION ± 214' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH nELD DESCRIPTION ANO CUSSinCATION DESCRIPTION AND REMARKS (Grain size, Densiiy. Moisture, Color) CO u CO UJ Ul a.. " o MS LU oat o a. to ' a Sf + r CO oa o o UJ?0' COv SILTY CLAY with some sand and roots Soft to firm. Moist. Dark brown. TOPSOIL CL/ CH 16.6 112 -198 2 - k - 5 - 6 - 0 _ SILTY FINE SAND/SANDY SILT with some roots and abundant caliche beds, iron oxide staining, very punky and porous. Medium dense. IDry to damp. Dark gray-brown and jwfu te. SILTY SANDSTONE, more massive and well indurated with 3"-4" thick caliche beds. Medium dense. Damp. Tan-brown and white. WEATHERED FORMATION SM/ ML 18.9 92.3 19.5 107 86 SM SILTY SANDSTONE, well cemented, Dense. Damp. Tan-gray. FORMATION SM Bottom of hole @ 7' UBC EXPANSION INDEX i y WATER TABLE 13 LOOSE BAG SAMPLE [2 IN-PUCE SAMPLE • DRIVE SAMPLE SAND CONE/F.D.T. CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa & North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-7189 RGURE NUMBER I Ib REVIEWED BY OD LOG No. T-2 EQUIPMENT Case Backhoe SURFACE ELEVATION ± 236' Mean Sea Level DIMENSION & TYPE OF EXCAVATION 2' x 20' x 7.5' Trench GROUNDWATER DEPTH Not encountered OATE LOGGED 1-23-98 LOGGED BY JKH HELD DESCRIPTION AND CLASSIFICATION DESCRIPTION AND REMARKS (Grain size. Density, Moisture. Color) CO o vi CL. ^ si SLiQ '2 So Ul ii o is = CO o a MS S 8 ^ o m o o tlJf>) SILTY CLAY with some sand and roots Soft to firm. Moist. Dark brown. TOPSOIL CL/ CH 1 SILTY SANDSTONE, moderately well cemented with some shell and caliche beds (pockets). Medium dense to dense. Damp. Tan-gray and 1ight brown. WEATHERED FORMATION - becomes more dense, but caliche beds still prsent at 5-5' SM 6.6 84.0 8 - •9 - SILTY SANDSTONE, well cemented Dense. Damp. Tan-gray and 1i ght brown. FORMATION SM Bottom of hole @ 7.5 y WATER TABLE ^ LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE S SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 y WATER TABLE ^ LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE S SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE SITE LOCATION East of Laurel Tree Roaa 6 North of Cobblestone Road, Carlsbad, CA y WATER TABLE ^ LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE S SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE JOB NUMBER 97-71-89 REVIEWED BY LOG No. T-3 y WATER TABLE ^ LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE S SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE RGURE NUMBER 1 Ic REVIEWED BY LOG No. T-3 I I I I I EQUIPMENT DIMENSION k TYPE OF EXCAVATION DATE LOGGED Case Backhoe 2' X 10' x 6' Trench 1-23-98 SURFACE ELEVATION GROUNDWATER DEPTH LOGGED BY ± 230' Mean Sea Level Not encountered JKH 1 HELD DESCRIPTION AMD CLASSIRCATION DESCRIPTION ANO REMARKS (Grain size. Density, Moisture, Color) to ci CO UJUJ Q. „ " o Ms o'ln So . UJ 03 o a. S CO 3| O sr SM -I- I S 8 O.D. 0.3: au CO 0 1 - SILTY CLAY with some sand and root Soft to firm. Moist. Dark brown. TOPSOIL CL/I CH J — SILTSTONE with some clay, slightly weathered. Firm. Moist. Dark gray-green and orange. SILTSTONE/CLAYSTONE, moderately undurated. Stiff. Damp to moist, Dark gray-green and orange. FORMATION ML ML/ MC Bottom of hole @ 6' UBC EXPANSION INDEX 24.4 99.9 9.5 107 93 A65 I I I y WATER TABLE ^ LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE SAND CONE/F.D.T. CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa & North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-7T89 RGURE NUMBER I Id REVIEWED BY JO LOG No. T-4 I I ^ EQUIPMENT ' Case Backhoe DIMENSION 4 TYPE OF EXCAVATION 2' X 20' c 7' Trench DATE LOGGED ^ 1-23-98 SURFACE ELEVATION ± 245' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH HELD DESCRIPTION AND CLASSinCATIOM DESCRIPTION AND REMARKS (Groin size. Density, Moisture, Color) Ul UJ r I o 1 §s So lae ss Sf + I I §8 a ci Q.X a<-9 SILTY CLAY with some sand and roots Soft. Moist. Dark brown. TOPSOIL Cl/ CH -m^:^ 1 SILTY SANDSTONE with caliche beds, moderately well cemented. Medium dense to dense. Dry to damp. Tan-gray and light brown. 3" to 4" thick caliche beds with dense Sandstone layers between. WEATHERED FORMATION SM 14.4 111.3 SILTY SANDSTONE, moderately well cemented. Dense. Damp. Tan-gray and orange. FORMATION 8 - '9 - 0 J Bottom of hole @ 7 b y WATER TABLE ' m LOOSE BAG SAMPLE 1 Q] IN-PUCE SAMPLE " • DRIVE SAMPLE • dl SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE JOB NAMEg^g Property - APN 212-040-50 b y WATER TABLE ' m LOOSE BAG SAMPLE 1 Q] IN-PUCE SAMPLE " • DRIVE SAMPLE • dl SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE SITE LOCATION East of Laurel Tree Roaa & North of Cobblestone Road, Carlsbad, CA b y WATER TABLE ' m LOOSE BAG SAMPLE 1 Q] IN-PUCE SAMPLE " • DRIVE SAMPLE • dl SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE JOB NUMBER 97-7189 REVIEWED BY LOG No. T-5 b y WATER TABLE ' m LOOSE BAG SAMPLE 1 Q] IN-PUCE SAMPLE " • DRIVE SAMPLE • dl SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE RGURE NUMBER 1 le REVIEWED BY LOG No. T-5 EQUIPMENT Case Backhoe SURFACE ELEVATION ± 252' Mean Sea Level DIMENSION 4 TITPE OF EXCAVATION 2' X 10' X 6' Trench GROUNDWATER DEPTH Not encountered DATE LOGGED 1-23-98 LOGGED BY JKH HELD DESCRIPTION ANO CLASSIHCATIOH ^1 S. DESCRIPTION AND REMARKS (Grain size. Density, Moisture, Color) CO ci I CO I I KM Ms si M UJ O 3 s^ is = CO gs ,D.D.^ + 1 Sf Sf S 8 Q O BLOW COUNTS. SAMPLE (INCHES] 1 -/> SILTY CLAY, with some sand and roots. Soft to firm. Moist. Dark brown. - some caliche (pockets) TOPSOIL CL/"A" I Horizo^ CH cu11 i vated 'B" HorizoJ SILTSTONE with some clay, slightly weathered and fractured. Firm. Moist. Dark gray-green and orange ML 19.4 92.0 wi tj 19.5 cal ic 107 86 Ago SILTSTONE/CLAYSTONE, moderately indurated. Stiff. Damp. Dark gray-green and orange. \ FORMATION ML/ 18.3 100.9 94 *70 Bottom of hole @ 6' UBC EXPANSION INDEX y WATER TABLE S LOOSE BAG SAMPLE D] IN-PUCE SAMPLE • DRIVE SAMPLE SAND CONE/F.D.T. CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa & North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-7189 RGURE NUMBER I if REVIEWED BY LOG No. T-6 EQUIPMENT Case Backhoe DIMENSION 4 TYPE OF EXCAVATION 2' X 10' X 6' Trench OATE LOGGED 1-23-98 SURFACE ELEVATION ± 256' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH RELD DESCRIPTION ANO CUSSinCATION DESCRIPTION AND REMARKS (Grain size. Density, Moisture, Color) c/1 ci ui Q. CO f uj"—' MS S.CO IS UJ i i o s t a Sf c/1 s SM S 8 m8 o o UJVJ SILTY CLAY with some sand and roots. Soft to firm. Moist. Dark brown. - some caliche pockets TOPSOIL CL SILTSTONE with some clay, slightly weathered and fractured. Firm. Moist. Dark gray-green and orange SILTSTONE/CLAYSTONE, moderately indurated. Stiff. Damp. Dark gray-green and orange. FORMATION Bottom of hole 0 6' ML ML/ CL 22.2 y WATER TABLE S LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE [s] SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa 6 North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-71«9 RGURE NUMBER Ilg REVIEWED BY LOG No. T-7 EQUIPMENT Case Backhoe DIMENSION 4 TYPE OF EXCAVATION 2' X 10' X 6' Trench QATE LOGGED 1-23-98 SURFACE ELEVATION ± 258' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH P Q- nELD DESCRIPTION AND CLASSinCATION DESCRIPTION AND REMARKS (Grain size. Density, Moisture, Color) to ci if Ul UJ M^ Q. . I O E3 o — Sc u a a. is S CO gs a o Sf M o Q. • Z3 O CD U O o 0.x ac3 1 - 2 - -t: _1 15 - .6 km Mm SILTY CLAY with some sand. Soft to firm. Moist. Dark brown. TOPSOIL CL/ CH SILTY SANDSTONE with slight calich fractured and weathered. Dense. Damp. Tan-gray and light brown. SM WEATHERED FORMATION f SILTY SANDSTONE, well cemented. Dense. Damp. Tan-gray. FORMATION SM 7 - 8 - Bottom of hole @ 6' • y WATER TABLE • 13 LOOSE BAG SAMPLE I Q] IN-PUCE SAMPLE ' • DRIVE SAMPLE • S SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE JOB NAME „ BCS Property - APN 212-040-50 • y WATER TABLE • 13 LOOSE BAG SAMPLE I Q] IN-PUCE SAMPLE ' • DRIVE SAMPLE • S SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE SITE LOCATION East of Laurel Tree Koaa & North of Cobblestone Road, Carlsbad, CA • y WATER TABLE • 13 LOOSE BAG SAMPLE I Q] IN-PUCE SAMPLE ' • DRIVE SAMPLE • S SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE JOB NUMBER 97-71^9 REVIEWED BY LOG No. T-8 • y WATER TABLE • 13 LOOSE BAG SAMPLE I Q] IN-PUCE SAMPLE ' • DRIVE SAMPLE • S SAND CONE/F.D.T. • ^ CONTINUOUS CORE SAMPLE RGURE NUMBER 1 Ih REVIEWED BY LOG No. T-8 EQUIPMENT Case Backhoe DIMENSION 4 TYPE OF EXCAVATION 2' X 10' X 6' Trench DATE LOGGED 1-23-98 SURFACE ELEVATION ± 262' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH OELD DESCRIPTION AND CLASSIRCATION DESCRIPTION AND REMARKS ^ (Groin size. Density, Moisture. Color) to ^ I 3 Sa MS a. to I S IS S CO Sf CO o 2 8 2 O CQ O a UlCO" Q.X au SILTY CLAY with some sand and roots. Soft to firm. Moist. Dark brown. TOPSOIL CL/ CH »9 - SILTSTONE with some clay, slightly weathered and fractured. Firm. Moist. Dark gray-green and orange MC 10.8 SILTSTONE/CLAYSTONE, moderately indurated. Stiff. Damp. Dark gray-green and orange. FORMAT I ON MLy CL Bottom of hole @ 6' I I I y WATER TABLE K LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • ORIVE SAMPLE SAND CONE/F.D.T CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa s North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-71-89 RGURE NUMBER I I i REVIEWED BY LOG No. T-9 I ^EQUIPMENT Case Backhoe DIMENSION 4 TYPE OF EXCAVATION 2' X 10' X 6' Trench DATE LOGGED > 1-23-98 SURFACE ELEVATION ±242' Mean Sea Level GROUNDWATER DEPTH Not encountered LOGGED BY JKH 1 00 m RELD DESCRIPTION AND CLASSIRCATION DESCRIPTION AND REMARKS (Groin size, Density. Moisture, Color) ^1 .a <^ I Mil MS Ui-S 4.S =3 I Sa l So 41 , UJ i.OC o a :-0 ! CO ; z UJ o Sf 1/5 O £ s 2 8 2 o CQ o d Q.X SO 2 - 4 5 6 ^ 7 - '8 "9 - 0 _: SILTY CLAY with some sand and root Soft to firm. Moist. Dark brown. some caliche pockets TOPSOU CL, CHi SILTSTONE with some clay, slightly weatheTed and fractured. Firm. Moist. Dark gray-green and orange ML SILTSTONE/CLAYSTONE, moderately indurated. Stiff. Damp. Dark gray-green and orange. FORMATION ML/ MC Bottom of hole @ 6' i I I y WATER TABLE ^ LOOSE BAG SAMPLE D] IN-PUCE SAMPLE • DRIVE SAMPLE [E SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE JOB NAME BCS Property - APN 212-040-50 SITE LOCATION East of Laurel Tree Koaa & North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-71-89 RGURE NUMBER I I J REVIEWED BY DD LOG No. T-10 f EQUIPMENT DIMENSION 4 TYPE OF EXCAVATION DATE LOGGED ^ 1 Case Backhoe 2' X 10' X 6' Trench 1-23-98 1 SURFACE ELEVATION GROUNDWATER DEPTH LOGGED BY 1 ± 225' Mean Sea Level Not encountered JKH RELD DESCRIPTION ANO CLASSIRCATION DESCRIPTION AND REMARKS (Grain size. Density, Moisture, Color) CO o t/i 2 1 s a So CO s SM o d ~cj 1 - SILTY CLAY with some sand and root Soft to firm. Moist. Dark brown TOPSOIL CL CH l-» — t 6 _ SILTSTONE with some clay, slightly weathered and fractured. Firm. Moist. Dark gray-green and orange ML SILTSTONE/CLAYSTONE, moderately indurated. Stiff. Damp. Dark gray-green and orange. FORMATION ML/ MC Bottom of hole @ 6' y WATER TABLE 13 LOOSE BAG SAMPLE Q] IN-PUCE SAMPLE • DRIVE SAMPLE [f] SAND CONE/F.D.T. ^ CONTINUOUS CORE SAMPLE JOB NAME „ BCS Property - APN 212-040-50 STTE LOCATION East of Laurel free Koaa & North of Cobblestone Road, Carlsbad, CA JOB NUMBER 97-71^9 REVIEWED BY LOG No. T-11 RGURE NUMBER 1 Ik REVIEWED BY LOG No. T-11 REGIONAL FAULT MAP PACIFIC ocEm COMPILED FROM CDMG AND UCSD MAPS Fault Map of southem California. 0 10 20 30 40 50 60 miles 1 \itim itmii iiiiMji i^imi^v mm 30 60 km 140 LABORATORY SOIL DATA SUMMARY DIRECT SHEAR TEST DATA 1 * 2* 3 APPARENT COHESION (psf) 260 300 APPARENT FRICTION ANGLE 29° 28' 100 SPECIFIC GRAVITY ZERO AIR VOIDS CURVES 10 20 30 LABORATORY COMPACTION TEST SOIL TYPE SOIL CLASSIFICATION BORING No. TRENCH No. DEPTH 1 SILTY CLAY.with some sand. Dark brown. T-2 1.5' 2 SILTSTONE with some clay. Dark gray-green. T-6 4' 3 SWELL TEST DATA 1 2a 2b INITIAL DRY DENSITY (pcf) 98.2 92.8 100.0 INITIAL HATER CONTENT {%) 15.5 19.6 24.2 LOAD (psf) 144 144 144 UBC EXPANSION INDEX 198 90 65 FIGURE NUMBER I I la JOB NUMBER 97-7189 4D 10 ATTERBERG LIMIT DETERMINATIONS (ASTM D423 AND D424) No. DESCRIPTION Liquid Limit;LL Plastic Limit,PL Plastic Index; PI 1 SILTY CLAY with some sand. Dark brown. 61.0 26.4 34.6 2 SILTSTONE with some clay. Dark gray-green. 42.0 31.0 12.0 PLASTICITY INDEX; PI=:LL-PL 50 40 30 H 20 CO 10 7 4 0 CN *-1 CL r,;" MHor OH 1 VLU> mL 1 _IMI1_ 10 20 30 40 50 60 70 80 90 100 LIQUID LIMIT, LL FIGURE NUMBER lllb JOB NUMBER 97-7189 10 CONSOLIDATION - PRESSURE CURVE V 10 NORMAL PRESSURE - LBS./SQ.FT. 100 1000 10.000 100.000 Trench Number 3, Depth: 5 Feet Carved from Undisturbed Sample RING DIAMETER 2.375 (inches) FIGURE NUMBER MIc JOB NUMBER 97-7189 emi FOUNDATION REQUIREMENTS NEAR SLOPES PROPOSED STRUCTURE CONCRETE FLOOR SLAB SETBACK . .1 I , n-— ^\ \ \ REINFORCEMENT OF \ FOUNDATIONS AND FLOOR SLABS FOLLOWING THE RECONCNDATIONS OF THE ARCHITECT OR STRUCTURAL ENGINEER CONCRETE FOUNDATION 18- MINIMUM OR AS DEEP AS REQUIRED FOR LATERAL STABILITY TOP OF COMPACTED FILL SLOPE (Any loose soils on the slope surface shall not be considered to provide lateral or vertical strength for the footing or for slope stability. Needed depth of labedKnt shall be measured froB coapetent soil.) COMPACTED FILL SLOPE UITH MAXIMUM INaiNATION AS PER SOILS REPORT. TOTAL DEPTH OF FOOTING MEASURED FROM FINISH SOIL SUB-GRADE OUTER MOST OF FOOTING TYPICAL SECTION (SHOWING PROPOSED FOUNDATION LOCATED WITHIN 5 FEET OF TOP OF SLOPE) 18' FOOTING/ 5'SETBACK TOTAL DEPTH OF FOOTING 1.5:1.0 SLOPE 2.0:1.0 SLOPE U IL z o 1° r 0 58" 48" 1* 51" 42" 2' 42" 36" 3' 34" 30" 4' 26" 24" I 5" 18" 18" # when applicable FIGURE NUMBER IV JOB NUMBER 97-7189 APPENDIX BENCH AND KEY REQUIREMENTS REMOVE ALL TOPSOIL, STRIP AS SPECIFIED ORIGINAL GROUND SURFACE SLOPE RATIO = VERTICAL NOTES 1. = HORIZONTAL = 2.0 : 1.0 (OR AS PER SOILS ENGINEER/ ENGINEERINQ GEOLOGIST) SLOPED SUCH THAT SLOUGHING OR SLIDING DOES NOT OCCUR DRAINS (IF REOUIRED SPECIFIC DESIGN CRITERIA WILL BE ISSUED) BOTTOM DRAIN 4. The minimum width "B* of key shall be a minimum of 1.5 times the width of the compaction equipment. Minimum width of benches shall be not less than three feet (or as per Soils Engineer/Engineering Geologist). Key and benches shall be excavated to firm dense, natural-ground and verified by a Soils Engineer/Engineering Geologist. ' The outside edge of bottom key shall be below topsoil or loose surface material: Minimum one foot embedment Into dense material (or as per Soils Engineer/Engineering Geologist). Key and benching required where the natural slope Is steeper than 5.0 horizontal to 1.0 vertical (5.0:1,0), or as per Soils Engineer/Engineering Geologist. Minimum 10% fall (10.0:1.0 slope ratio) Into slope (or as per Soils Engineer/Engineering Geologist). SEE MOTE t SEE NOTE 2 5. Compaction test required every two (2) vertical feet from lowest fill area. 10/84 Figure No. VI dD 10 APPENDIX A QD 10 APPENDIX A UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION COARSE-GRAINED More than half of material is larger than a No. 200 sieve GRAVELS, CLEAN GRAVELS More than half of coarse fraction is larger than GW Well-graded gravels, gravel and sand mix- No. 4 sieve size, but smaller than 3" tures, little or no fines. GP Poorly graded gravels, gravel and sand mix- tures, little or no fines. GRAVELS WITH FINES GM Silty gravels, poorly graded gravel-sand-siit (appreciable amount) mixtures. GC Clay gravels, poorly graded gravel-sand-siit mixtures. SANDS, CLEAN SANDS SW Well-graded sand, gravelly sands, little or no More than half of coarse fraction is smaller than a no fines. No. 4 sieve. SP Poorly graded sands, gravelly sands, little or no fines. SANDS WITH FINES SM Silty sands, poorly graded sand and silty (appreciable amount) mixtures. SC Clayey sands, poorly graded sand and clay mixtures. FINE-GRAINED More than half of material is smaller than a No. 200 sieve SILTS AND CLAYS ML Inorganic silts and very fine sands, rock flour, sandy silt and clayey-silt sand mixtures with a slight plasticity. Liquid Limit Less Than 50 CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, clean clays. OL Organic silts and organic silty clays of low plasticity. MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Liquid Limit Greater Than 50 CH Inorganic clays of high plasticity, fat clays, OH Organic clays of medium to high plasticity, HIGHLY ORGANIC SOILS PT Peat and other highly organic soils. APPENDiX B dD ID APPENDIX B GENERAL EARTHWORK SPECIFICATIONS General The objective of these specifications is to properly establish procedures for the clearing and preparation of the existing natural ground or properly compacted fill to receive new fill; for the selection of the fill material; and for the fill compaction and testing methods to be used. Scope of Work The earthwork includes all the activities and resources provided by the contractor to construct in a good workmanlike manner ali the grades of the filled areas shown in the plans. The major items of work covered in this section include ail clearing and grubbing, removing and disposing of materials, preparing areas to be filled, compacting of fill, compacting of backfills, subdrain installations, and all other work necessary to complete the grading of the filled areas. Site Visit and Site Investigation 1. The contractor shall visit the site and carefully study it, and make all inspections necessary in order to determine the full extent of the work required to complete ail grading in conformance with the drawings and specifications. The contractor shall satisfy himself as to the nature, location, and extent of the work conditions, the conformation and condition of the existing ground surface; and the type of equipment, labor, and faciiities needed prior to and during prosecution of the work! The contractor shall satisfy himself as to the character, quality, and quantity of surface and subsurface materials or obstacles to be encountered. Any inaccuracies or discrepancies between the actual fieid conditions and the drawings, or between the drawings and specifications, must be brought to the engineer's attention in order to clarify the exact nature of the work to be performed. 2. A soils investigation report has been prepared for this project by GEI. It is available for review and should be used as a reference to the surface and subsurface soil and bedrock conditions on this project. Any OD ]0 B2 recommendations made in the report of the soil investigation or subsequent reports shall become an addendum to these specifications. Authority of the Soils Engineer and Engineering Geologist The soils engineer shall be the owner's representative to observe and test the construction of fills. Excavation and the placing of fill shall be under the observation of the soils engineer and his/her representative, and he/she shall give a written opinion regarding conformance with the specifications upon completion of grading. The soiis engineer shall have the authority to cause the removal and replacement of porous topsoils, uncompacted or improperiy compacted fills, disturbed bedrock materials, and soft alluvium, and shall have the authonty to approve or reject materials proposed for use in the compacted fill areas. The soils engineer shall have, in conjunction with the engineering geologist, the authority to approve the preparation of natural ground and toe-of-fill benches to receive fill material. The engineering geologist shall have the authority to evaluate the stability of the existing or proposed slopes, and to evaluate the necessity of remedial measures. If any unstable condition is being created by cutting or filling, the engineering geologist and/or soils engineer shall advise the contractor and owner immediately, and prohibit grading in the affected area until such time as corrective measures are taken. The owner shall decide all questions regarding: (1) the interpretation of the drawings and specifications, (2) the acceptable fulfillment of the contract on the part of the contractor, and (3) the matter of compensation. Clearing and Grubbing 1. Clearing and grubbing shall consist of the removal from all areas to be graded of all surface trash, abandoned improvements, paving, culverts, pipe, and vegetation (including ~ but not limited to - heavy weed growth! trees, stumps, logs and roots larger than 1-inch in diameter). 2. All organic and inorganic materiais resulting from the clearing and grubbing operations shall be collected, piled, and disposed of by the contractor to give the cleared areas a neat and finished appearance. Burning of combustible materials on-site shall not be permitted unless allowed by local regulations, and at such times and in such a manner to OD 10 83 prevent the fire from spreading to areas adjoining the property or cleared area. It is understood that minor amounts of organic materials may remain in the fill soils due to the near impossibility of complete removal. The amount remaining, however, must be considered negligible, and in no case can be allowed to occur in concentrations or total quantities sufficient to contribute to settlement upon decomposition. Preparation of Areas to be Filled 1. After clearing and grubbing, ail uncompacted or improperly compacted fills, soft or loose soils, or unsuitable materials, shall be removed to expose competent natural ground, undisturbed bedrock, or properly compacted fill as indicated in the soiis investigation report or by our field representative. Where the unsuitable materials are exposed in final graded areas, they shall be removed and replaced as compacted fill. 2. The ground surface exposed after removai of unsuitable soils shall be scarified to a depth of at least 6 inches, brought to the specified moisture content, and then the scarified ground compacted to at least the specified density. Where undisturbed bedrock is exposed at the surface, scarification and recompaction shall not be required. 3. All areas to receive compacted fill, including ail removai areas and toe-of- fiil benches, shall be observed and approved by the soiis engineer and/or engineering geologist prior to placing compacted fill. 4. Where fills are made on hillsides or exposed slope areas with gradients greater than 20 percent, horizontal benches shall be cut into firm, undisturbed, natural ground in order to provide both lateral and vertical stability. This is to provide a horizontal base so that each layer is placed and compacted on a horizontal plane. The initial bench at the toe of the fill shall be at least 10 feet in width on firm, undisturbed, natural ground at the elevation of the toe stake placed at the bottom of the design siope. The engineer shall determine the width and frequency of all succeeding benches, which will vary with the soil conditions and the steepness of the slope. Ground slopes flatter than 20 percent (5.0:1.0) shall be benched when considered necessary by the soils engineer. OD ID 84 Fill and Backfill Material Unless otherwise specified, the on-site material obtained from the project excavations may be used as fill or backfill, provided that all organic material, rubbish, debris, and other objectionable material contained therein is first removed. In the event that expansive materiais are encountered during foundation excavations within 3 feet of finished grade and they have not been properly processed, they shall be entirely removed or thoroughly mixed with good, granular material before incorporating them in fills. No footing shall be allowed to bear on soiis which, in the opinion of the soils engineer, are detrimentally expansive ~ unless designed for this clayey condition. However, rocks, boulders, broken Portland cement concrete, and bituminous- type pavement obtained from the project excavations may be permitted in the backfill or fill with the following limitations: 1. The maximum dimension of any piece used in the top 10 feet shall be no larger than 6 inches. 2 Clods or hard lumps of earth of 6 inches in greatest dimension shall be broken up before compacting the material in fill. 3. If the fill material originating from the project excavation contains large rocks, boulders, or hard lumps that cannot be broken readily, pieces ranging from 6 inches in diameter to 2 feet in maximum dimension may be used in fills below final subgrade if ail pieces are placed in such a manner (such as windrows) as to eliminate nesting or voids between them. No rocks over 4 feet wiil be allowed in the fili. 4. Pieces larger than 6 inches shall not be placed within 12 inches of any structure. 5. Pieces larger than 3 inches shall not be placed within 12 inches of the subgrade for paving. 6. Rockfills containing less than 40 percent of soil passing 3/4-inch sieve may be permitted in designated areas. Specific recommendations shall be made by the soils engineer and be subject to approvai by the city engineer. 7. Continuous observation by the soiis engineer is required during rock piacement. OD ID 85 8. Special and/or additional recommendations may be provided in writing by the soils engineer to modify, clarify, or amplify these specifications. 9. During grading operations, soil types other than those analyzed in the soil investigation report may be encountered by the contractor. The soils engineer shall be consulted to evaluate the suitability of these soils as fill materials. Placing and Compacting Fill Material 1. After preparing the areas to be filled, the approved fill material shall be placed in approximately horizontal layers, with lift thickness compatible to the material being placed and the type of equipment being used. Uniess otherwise approved by the soils engineer, each layer spread for compaction shall not exceed 8 inches of loose thickness. Adequate drainage of the fill shall be provided at all times during the construction period. 2. When the moisture content of the fill material is below that specified by the engineer, water shall be added to it until the moisture content is as specified. 3. When the moisture content of the fill material is above that specified by the engineer, resulting in inadequate compaction or unstable fill, the fill material shall be aerated by blading and scarifying or other satisfactory methods until the moisture content is as specified. 4. After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted to not iess than the density set forth in the specifications. Compaction shall be accomplished with sheepsfoot rollers, multiple-wheei pneumatic-tired rollers, or other approved types of acceptable compaction equipment. Equipment shall be of such design that it will be able to compact the fill to the specified relative compaction. Compaction shall cover the entire fill area, and the equipment shall make sufficient trips to ensure that the desired density has been obtained throughout the entire fill. At locations where it would be impractical due to inaccessibility of rolling compacting equipment, fill layers shall be compacted to the specified requirements by hand-directed compaction equipment. 5. When soii types or combination of soil types are encountered which tend to develop densely packed surfaces as a result of spreading or OD ID 86 compacting operations, the surface of each layer of fill shali be sufficientiy roughened after compaction to ensure bond to the succeeding layer. 6. Unless otherwise specified, fill slopes shall not be steeper than 2.0 horizontal to 1.0 vertical. In general, fill slopes shall be finished in conformance with the lines and grades shown on the plans. The surface of fill slopes shall be overfilled to a distance from finished slopes such that it will ailow compaction equipment to operate freely within the zone of the finished slope, and then cut back to the finished grade to expose the compacted core. Alternate compaction procedures inciude the backrolling of slopes with sheepsfoot rollers in increments of 3 to 5 feet in elevation gain. Alternate methods may be used by the contractor, but they shall be evaluated for approvai by the soils engineer. 7. Unless otherwise specified, ail allowed expansive fill material shall be compacted to a moisture content of approximately 2 to 4 percent above the optimum moisture content. Nonexpansive fill shali be compacted at near-optimum moisture content. All fili shall be compacted, unless otherwise specified, to a relative compaction not less than 95 percent for fill in the upper 12 inches of subgrades under areas to be paved with asphait concrete or Portland concrete, and not less than 90 percent for other fill. The relative compaction is the ratio of the dry unit weight of the compacted fill to the laboratory maximum dry unit weight of a sample of the same soii, obtained in accordance with A.S.T.M. D-1557 test method. 8. The observation and periodic testing by the soiis engineer are intended to provide the contractor with an ongoing measure of the quality of the fill compaction operation. It is the responsibility of the grading contractor to utilize this information to establish the degrees of compactive effort required on the project. More importantly, it is the responsibility of the grading contractor to ensure that proper compactive effort is applied at all times during the grading operation, including during the absence of soiis engineering representatives. Trench Backfill 1. Trench excavations which extend under graded lots, paved areas, areas under the influence of structural loading, in slopes or close to slope areas, shall be backfilled under the observations and testing of the soils engineer. All trenches not failing within the aforementioned locations OD 3D 87 shall be backfilled in accordance with the City or County regulating agency specifications. 2. Unless otherwise specified, the minimum degree of compaction shall be 90 percent of the laboratory maximum dry density. 3. Any soft, spongy, unstable, or other similar material encountered in the trench excavation upon which the bedding material or pipe is to be placed, shall be removed to a depth recommended by the soiis engineer and replaced with bedding materiais suitably densified. Bedding material shaii first be placed so that the pipe is supported for the full length of the barrel with full bearing on the bottom segment. After the needed testing of the pipe is accomplished, the bedding shall be completed to at least 1 foot on top of the pipe. The bedding shall be properly densified before backfill is placed. Bedding shall consist of granular material with a sand equivalent not less than 30, or other material approved by the engineer. 4. No rocks greater than 6 inches in diameter will be allowed in the backfill placed between 1 foot above the pipe and 1 foot beiow finished subgrade. Rocks greater than 2.5 inches in any dimension wiil not be allowed in the backfill placed within 1 foot of pavement subgrade. 5. Material for mechanically compacted backfill shall be placed in lifts of horizontai layers and properly moistened prior to compaction. In addition, the layers shall have a thickness compatibie with the material being placed and the type of equipment being used. Each layer shall be evenly spread, moistened or dried, and then tamped or rolled until the specified relative compaction has been attained. 6. Backfill shall be mechanically compacted by means of tamping rollers, sheepsfoot rollers, pneumatic tire rollers, vibratory rollers, or other mechanical tampers. Impact-type pavement breakers (stompers) will not be permitted over ciay, asbestos cement, plastic, cast iron, or nonreinforced concrete pipe. Permission to use specific compaction equipment shall not be construed as guaranteeing or implying that the use of such equipment will not result in damage to adjacent ground, existing improvements, or improvements installed under the contract. The contractor shall make his/her own determination in this regard. 7. Jetting shall not be permitted as a compaction method unless the soils engineer allows it in writing. OD ID 88 8. Clean granular material shali not be used as backfill or bedding in trenches located in slope areas or within a distance of 10 feet of the top of slopes unless provisions are made for a drainage system to mitigate the potential buildup of seepage forces into the siope mass. Observations and Testing 1. The soils engineers or their representatives shall sufficiently observe and test the grading operations so that they can state their opinion as to whether or not the fill was constructed in accordance with the specifications. 2. The soiis engineers or their representatives shall take sufficient density tests during the piacement of compacted fill. The contractor should assist the soils engineer and/or his/her representative by digging test pits for removai determinations and/or for testing compacted fill. In addition, the contractor shouid cooperate with the soils engineer by removing or shutting down equipment from the area being tested. 3. Fill shall be tested for compliance with the recommended relative compaction and moisture conditions. Field density testing should be performed by using approved methods by A.S.T.M., such as A.S.T.M. D1556, D2922, and/or D2937. Tests to evaluate density of compacted fill shouid be provided on the basis of not less than one test for each 2- foot vertical iift of the fill, but not less than one test for each 1,000 cubic yards of fill placed. Actual test intervals may vary as field conditions dictate. In fill slopes, approximately half of the tests shall be made at the fill siope, except that not more than one test needs to be made for each 50 horizontai feet of slope in each 2-foot vertical lift. Actual test intervals may vary as field conditions dictate. 4. Fill found not to be in conformance with the grading recommendations should be removed or otherwise handled as recommended by the soiis engineer. Site Protection It shall be the grading contractor's obligation to take all measures deemed necessary during grading to maintain adequate safety measures and working conditions, and to provide erosion-control devices for the protection of OD ID 89 excavated areas, slope areas, finished work on the site and adjoining properties, from storm damage and flood hazard originating on the project. It shall be the contractor's responsibiiity to maintain slopes in their as-graded form until ail slopes are in satisfactory compiiance with the job specifications, ail berms and benches have been properly constructed, and ail associated drainage devices have been instaiied and meet the requirements of the specifications. All observations, testing services, and approvals given by the soiis engineer and/or geologist shall not relieve the contractor of his/her responsibilities of performing the work in accordance with these specifications. After grading is completed and the soils engineer has finished his/her observations and/or testing of the work, no further excavation or filling shall be done except under his/her observations. Adverse Weather Conditions 1. Precautions, shall be taken by the contractor during the performance of site clearing, excavations, and grading to protect the worksite from flooding, ponding, or inundation by poor or improper surface drainage. Temporary provisions shall be made during the rainy season to adequately direct surface drainage away from and off the worksite. Where low areas cannot be avoided, pumps should be kept on hand to continually remove water during periods of rainfall. 2. During periods of rainfall, plastic sheeting shall be kept reasonably accessible to prevent unprotected slopes from becoming saturated. Where necessary during periods of rainfall, the contractor shall install checkdams, desilting basins, rip-rap, sandbags, or other devices or methods necessary to controi erosion and provide safe conditions. 3. During periods of rainfall, the soiis engineer should be kept informed by the contractor as to the nature of remedial or preventative work being performed (e.g. pumping, placement of sandbags or plastic sheeting, other labor, dozing, etc.). 4. Following periods of rainfall, the contractor shall contact the soils engineer and arrange a walk-over of the site in order to visually assess rain-related damage. The soils engineer may also recommend excavations and testing in order to aid in his/her assessments. At the request of the soils engineer, the contractor shall make excavations in order to evaluate the extent of rain-reiated damage. OD 1 810 5. Rain-related damage shall be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress, and other adverse conditions identified by the soiis engineer. Soil adversely affected shaii be classified as Unsuitable Materiais, and shall be subject to overexcavation and replacement with compacted fill or other remedial grading, as recommended by the soiis engineer. 6. Relatively level areas, where saturated soils and/or erosion gullies exist to depths of greater than 1.0 foot, shall be overexcavated to unaffected, competent material. Where less than 1.0 foot in depth, unsuitable materials may be processed in place to achieve near-optimum moisture conditions, then thoroughly recompacted in accordance with the applicable specifications. If the desired results are not achieved, the affected materials shall be over-excavated, then replaced in accordance with the appiicable specifications. 7. In slope areas, where saturated soiis and/or erosion gullies exist to depths of greater than 1.0 foot, they shall be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where affected materials exist to depths of 1.0 foot or less beiow proposed finished grade, remedial grading by moisture-conditioning in place, followed by thorough recompaction in accordance with the appiicable grading guideiines herein presented may be attempted, if materials shall be overexcavated and replaced as compacted fill, it shaii be done in accordance with the slope-repair recommendations herein. As field conditions dictate, other slope-repair procedures may be recommended by the soils engineer. OD ID APPENDIX C OD ID TABLE 1 DATE: Thursday, March 26, 1998 * * * EQFAULT * * * * Ver. 2.00 * * * * * (Estimation of Peak Horizontal Acceleration From Digitized California Faults) SEARCH PERFORMED FOR: JAY JOB NUMBER: 97-7189 JOB NAME: BCS PROPERTY SITE COORDINATES: LATITUDE: 33.12 N LONGITUDE: 117.3 W SEARCH RADIUS: 100 mi ATTENUATION RELATION: 1) Campbell (1991) Horiz. - Deep Soil & Soft Rock UNCERTAINTY (M=Mean, S=Mean+l-Sigma): M SCOND: 0 COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: CALIFLT.DAT SOURCE OF DEPTH VALUES (A=Attenuation File, F=Fault Data File): A I I I II I ll DETERMINISTIC SITE PARAMETERS ABBREVIATED FAULT NAME APPROX. DISTANCE mi (km) MAX, MAX. CRED. MAG. CREDIBLE EVENT!I MAX. I I SITE i i MAX PROBABLE EVENT PEAK SITE ACC. g INTENSIIPROB. MM Ij MAG. PEAK SITE ACC. g SITE INTENS MM I I i 'BLUE CUT 81 131) 7.00 0.011 III III 6.25 0.006 II IBORREGO MTN. (San Jacinto) 65 104) 6.50 0.012 I r ' 6.25 0.010 III I CAMP ROCK - EMERSON 100 160) 7.50 0.010 III V I I t I I I 6.00 0.003 ICASA LOMA-CLARK (S.Jacin.) ^CHINO 48 77) 7.50 0.039 I I II 7.00 0.028 V II 49 79) 7.00 0.032 V II I I r I I I 4.75 0.007 i I i i 1 r TT • CLEGHORN CORONADO BANK 80 128) 6.50 0.008 I I j 6.25 0.007 II VI 21 34) 7.00 0.090 VII V i I I I I I 6.50 0.066 COYOTE CREEK (San Jacinto) 51 81) 7.50 0.036 I I I I 6.00 0.013 III III CUCAMONGA 73 118) 7.00 7.50 0.016 IV VII I I I I i I 6.75 0.013 ELSINORE 25 40) 0.100 I I I I 6.75 0.063 VI V GLN.HELEN-LYTLE CR-CLREMNT 51 82) 7.50 7.50 0.035 V IV I I I I I I 7.00 0.025 HELENDALE 85 137) 0.014 I I I I I i 6.25 0.006 II IV I OT S-BUCK RDG.(S.Jacinto) 51 82) 7.50 7.25 0.036 V III I I I I 6.25 0.015 fLENWOOD JMALIBU COAST 94 152) 0.009 6.00 0.004 96 154) 7.50 7.00 0.013 III III 5.00 0.002 !MOJAVE RIVER (Ord Mtn.) NEWPORT - INGLEWOOD 82 132) 0.013 ii 6.25 0.007 II 42 68) 7.50 7.50 0.048 VI IX ii 6.50 0.025 V VII I III II I IX Tb: FFSHORE ZONE OF DEFORM. 15) 0.274 I I I I I I 6.00 0.121 LD WOMAN SPRINGS 92 148) 7.00 7.00 0.008 III V I I I I I I 5.75 0.003 jj^ALOS VERDES HILLS I PINTO MOUNTAIN - MORONGO 41 67) 0.035 I I I I I I 5.50 0.013 74 RAYMOND j KOSE CANYON . AN ANDREAS (Mojave) 119) 7.50 7.50 0.019 IV IV I I I I I I 6.00 0.006 82 132) 0.018 I I ! 5.50 0.004 8) 7.50 8.50 0.422 X V I 6.25 0.250 81 131) 0.0321 Ii 8.25! n 097! SAN ANDREAS (Southern) 69 (111) 8.00 0.030 7.25 0.018 IV DETERMINISTIC SITE PARAMETERS Page j! i APPROX. 1 DISTANCE 1 mi (km) IMAX. CREDIBLE EVENT! !MAX. PROBABLE EVENT 1 ABBREVIATED FAULT NAME i APPROX. 1 DISTANCE 1 mi (km) ! MAX. ICRED. 1 MAG. PEAK ! SITE i ACC. g! SITE ! INTENS i MM ! i MAX. !PROB. ! MAG. ! PEAK ! ! SITE ! |ACC. g! SITE INTENS MM iSAND HILLS 1 94 (151) ! 8.00 0.017! IV 1 ! 7.00 ! 0.008! III ISAN CLEMENTE 1 54 ( 87) 7.50! 0.032! V 1 ! 6.25 1 0.014! III jjSAN GABRIEL 86 (139) 7.501 0.014! IV ! ! 6.25 i 0.0051 II ISAN GORGONIO - BANNING 62 (100) 8.001 0.036! V 1 ! 7.00 ! 0.018! IV || SANTA MONICA - HOLLYWOOD 87 (141) 7.501 0.0161 IV 1 i 6.00 1 0.005! II 1 1 SIERRA MADRE-SAN FERNANDO 76 (123)! 7,501 0.021! IV 1 1 6.50 I 0.010! III 1 [SUPERSTITION HLS.(S.Jacin) 84 (136)1 7.00! 0.010! III ! I 5.75 0.004! I 1 JSUPERSTITION MTN.(S.Jacin) 79 (127)i 7.00! 0.011! Ill ! 6.00 0.006! II 1 !VERDUGO 1 84 (136)i 7.00! 0.012! Ill i 4.50 0.002! 1 WHITTIER - NORTH ELSINORE | 47 ( 76)! 7.50! 0.040! V i 6.25 0.017! IV ! END OF SEARCH- 35 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS, HE ROSE CANYON FAULT IS CLOSEST TO THE SITE. T IS ABOUT 5.1 MILES AWAY. LARGEST MAXIMUM-CREDIBLE SITE ACCELERATION: 0.422 g IARGEST MAXIMUM-PROBABLE SITE ACCELERATION: 0.250 g TABLE 2 DATE: Thursday, March 26, 1998 ********** * * * EQFAULT * * * * Ver. 2.00 * * * * * ***********************:t,i^t:^^^:t,^it'***** (Estimation of RHGA Horizontal Acceleration From Digitized California Faults) SEARCH PERFORMED FOR: JAY JOB NUMBER: 97-7189 JOB NAME: BCS PROPERTY SITE COORDINATES: LATITUDE: 33.12 N LONGITUDE: 117.3 W SEARCH RADIUS: 100 mi ATTENUATION RELATION: 1) Campbell (1991) Horiz. - Deep Soil & Soft Rock UNCERTAINTY (M=Mean, S=Mean+l-Sigma): M SCOND: 0 COMPUTE RHGA HORIZ. ACCEL. (FACTOR: 0.650 DISTANCE: 20.0 mi) FAULT-DATA FILE USED: CALIFLT.DAT SOURCE OF DEPTH VALUES (A=Attenuation File, F=Fault Data File): A I I I i ll i I i I I I I I DETERMINISTIC SITE PARAMETERS ABBREVIATED FAULT NAME APPROX. DISTANCE mi (km) MAX. CREDIBLE EVENT!IMAX. PROBABLE EVENT I I MAX CRED MAG RHGA SITE ACC. g SITE I! MAX INTENSIIPROB MM I I MAG RHGA SITE ACC. g SITE INTENS MM BLUE CUT 81 (131) 7.00 0.011 III III I I I I I I 6.25 0.006 II BORREGO MTN. (San Jacinto) 65 (104) 6.50 0.012 I I I I I I 6.25 0.010 III I CAMP ROCK - EMERSON 100 (160) 7.50 0.010 III V I I I I I I 6.00 0.003 [CASA LOMA-CLARK (S.Jacin.) 48 ( 77) 7.50 0.039 I I I! 7.00 0.028 V II CHINO 49 ( 79) 7.00 0.032 V II I I I 1 I I 4.75 0.007 CLEGHORN 80 (128) 21 ( 34) 6.50 0.008 6.25 0.007 II VI CORONADO BANK 7.00 0.090 VII V I 6.50 0.066 COYOTE CREEK (San Jacinto) 51 ( 81) 73 (118) 7.50 0.036 I I I I I i 6.00 0.013 III III CUCAMONGA 7.00 0.016 IV VII I I 6.75 0.013 ELSINORE 25 ( 40) 51 ( 82) 7.50 0.100 I I I I 6.75 0.063 VI V GLN.HELEN-LYTLE CR-CLREMNT f 7.50 0.035 V IV I! 7.00 0.025 LENDALE 85 (137) 51 ( 82) 7.50 7.50 0.014 I I I I I I 6.25 0.006 II IV I OT S-BUCK RDG.(S.Jacinto) ENWOOD 0.036 V III I I 6.25 0.015 94 (152) 96 (154) 7.25 7.50 0.009 I I I I 6.00 0.004 ^LIBU COAST !MOJAVE RIVER (Ord Mtn.) 0.013 III III I I I I 5.00 0.002 82 (132) 42 ( 68) 7.00 7.50 0.013 I! 6.25 0.007 II EWPORT - INGLEWOOD FFSHORE ZONE OF DEFORM. 0.048 VI VIII I I I! 6.50 0.025 V VII I I _ 9 ( 15) 92 (148) 7.50 7.00 0.178 ii 6.00 0.079 LD WOMAN SPRINGS 0.008 III V 5.75 0.003 I III ALOS VERDES HILLS 41 ( 67) 74 (119) 7.00 7.50 0.035 I I I I i I 5.50 0.013 !PINTO MOUNTAIN - MORONGO 0.019 IV IV t r I I 6.00 0.006 II I YMOND 82 (132) 5 ( 8) 81 (131) 7.50 7.50 8.50 0.018 i i 5.50 0.004 I OSE CANYON AN ANDREAS (Mojave) 0.274 IX V i i 6.25 0.162 VIII 0.032 1 I! 8.2.=;! n n971 SAN ANDREAS (Southern) 69 (111) 8,00 0.030 7.25 0.018 IV DETERMINISTIC SITE PARAMETERS Page i APPROX. !DISTANCE ! mi (km) !MAX. CREDIBLE EVENT! IMAX. PROBABLE EVENT ! ABBREVIATED 1 FAULT NAME i APPROX. !DISTANCE ! mi (km) 1 MAX, ICRED, 1 MAG. 1 RHGA ! 1 SITE 1 !ACC. g! SITE ! INTENS! MM ! ! MAX, !PROB. ! MAG. ! RHGA ! ! SITE ! !ACC, g! SITE INTENS MM ISAND HILLS 1 94 (151) 1 8.00 ! 0,017! IV ! ! 7,00 ! 0.008! III !SAN CLEMENTE 1 54 ( 87) 7,50 ! 0.032! V ! ! 6,25 ! 0,014! III ISAN GABRIEL 1 86 (139) 7.50 ! 0.014! IV ! ! 6.25 ! 0,005! II ISAN GORGONIO - BANNING 62 (100) 8.00 ! 0,036! V ! ! 7.00 i 0,018! IV SANTA MONICA - HOLLYWOOD 87 (141) 7,50 ! 0.016! IV ! 1 6.00 ! 0,005| II SIERRA MADRE-SAN FERNANDO 76 (123) 7,50 ! 0.021! IV ! ! 6,50 1 0,0101 III SUPERSTITION HLS.(S.Jacin) 84 (136) 7,00 1 0.010! Ill 1 ! 5,75 1 0,004! I SUPERSTITION MTN.(S.Jacin) 79 (127) 7,00 1 0.011! III 1 ! 6.00 0,006! II 1 VERDUGO 84 (136)1 7,00 1 0,012! III ! 1 4,50 0.002! 1 WHITTIER - NORTH ELSINORE 47 ( 76)1 7.50 1 0.040! V ! 1 6,25 0.017! IV ! ***********************************************^i^^iiliititti^ilf4fiiil,ili^1tJtfiti^it:il!^i^i^4ii^^idl,it.itii^i. END OF SEARCH- 35 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS, HE ROSE CANYON FAULT IS CLOSEST TO THE SITE, T IS ABOUT 5.1 MILES AWAY. LARGEST MAXIMUM-CREDIBLE SITE ACCELERATION: 0,274 g ARGEST MAXIMUM-PROBABLE SITE ACCELERATION: 0.162 g TABLE 3 DATE: Thursday, March 26, 1998 *************************4iitit^i^^t:t:^it,^^^^ * * * EQSEARCH * * * Ver. 2.00 * * * * * ***********************4i;^*4,it:i^it:i:^,^:^,^.i^^^,^ (Estimation of Peak Horizontal Acceleration From California Earthquake Catalogs) pEARCH PERFORMED FOR: JAY JOB NUMBER: 97-7189 LOB NAME: BCS PROPERTY ITE COORDINATES: LATITUDE: 33.12 N LONGITUDE: 117.3 W HYPE OF SEARCH: RADIUS SEARCH RADIUS: 100 mi JiEARCH MAGNITUDES: 5.0 TO 9.0 SEARCH DATES: 1800 TO 1997 ATTENUATION RELATION: D Campbell (1991) Horiz. - Deep Soil & Soft Rock I UNCERTAINTY (M=Mean, S=Mean+l-Sigma): M SCOND: 0 I FAULT TYPE ASSUMED (DS=Reverse, SS=Strike-Slip): DS COMPUTE PEAK HORIZONTAL ACCELERATION IARTHQUAKE-DATA FILE USED: ALLQUAKE.DAT (IME PERIOD OF EXPOSURE FOR STATISTICAL COMPARISON: 25 years OURCE OF DEPTH VALUES (A=Attenuation File. E=Earthquake Catalog): A I I I *age :ODE LAT. NORTH LONG. WEST 1 DATE ! TIME ! 1 (GMT) I 1 H M See! DEPTH (km) QUAKE MAG. i SITE i ACC. i g iSITE ! MM i INT. i 11/22/1800 !2130 0 .01 3 .0 6 .50 i 0 .219 i IX 5/25/1803 ! 0 0 0 .0! 3 .0 5 .00 i 0 .024 i IV 12/ 8/1812 !15 0 0 .0! 3 .0 7 .00 i 0 .011 i III 9/23/1827 ! 0 0 0 .01 3 ,0 5 .00 1 0 ,003 ! I 7/11/1855 1 415 0 ,0! 3 .0 6 .30 ! 0 ,008 ! II 1/10/1856 10 0 0 ,0! 3 .01 5 .00 i 0 ,003 i I 9/21/1856 1 730 0 .0! 3 .0 5 .00 i 0 .034 i V 12/ 0/1856 I 0 0 0 .01 3 ,0| 5 .00 I 0 .017 i IV 1 12/16/1858 110 0 0 .0 1 3 .01 7 .00 1 0 .022 i IV ! 3/26/1860 ! 0 0 0 • 0! 3 ,0| 5 .00 i 0 .003 ! I 1 5/27/1862 120 0 0 .0! 3 ,0! 5 ,90 i 0 .034 1 V 1 10/21/1862 1 0 0 0 .0! 3 .0! 5 .00 ! 0 ,017 i IV i 5/24/1865 ! 0 0 0 .0! 3 ,0! 5 .00 ! 0 .017 i IV i 5/ 0/1868 ! 0 0 0 .01 3 ,0! 6 ,30 i 0 .006 1 II i 1/13/1877 120 0 0 .0! 3 ,0| 5 .00 i 0 .005 i II i 12/19/1880 ! 0 0 0 .0! 3 ,0| 6 .00 1 0 .014 i III! 2/ 7/1889 1 520 0 .0! 3 .0! 5 .30 i 0 -004 i I i 8/28/1889 I 215 0 .0! 3 .0! 5 .50 i 0 .004 1 I i 2/ 9/1890 !12 6 0 .0! 3 ,0! 6 .30 1 0 ,014 ! III! 2/24/1892 ! 720 0 .0! 3 .0! 6 .70 I 0 ,016 IV ! 5/28/1892 ! 1115 0 .0! 3 • 0! 6 .30 i 0 .012 III! 7/30/1894 ! 512 0 .0! 3 •0| 6 .00 0 .006 II i 10/23/1894 !23 3 0 •0| 3 .0! 5 .70 0 ,022 IV ! 7/22/1899 ! 046 0 0! 3 0! 5 50 0 .005 II i 7/22/1899 12032 0 0! 3 .01 6 .50 0 .009 III! 12/25/1899 i 1225 0 0! 3 0| 6. 40 0 021 IV i 12/25/1903 ! 1745 0 0! 3 Oi 5 00 0 .004 I i 7/15/1905 12041 0. 0| 3, 0! 5, 30 0, 005 1 II i 9/ 3/1905 1 540 0. Oj 3. 0| 5 30 0 003 I i 9/20/1907 ! 154 0, 0! 3. 0! 6. 00 i 0. 007 1 II 1 4/11/1910 ! 757 0. Oj 3. 0| 5. 00 i 0. 012 1 III i 5/13/1910 ! 620 0, 0! 3. 0! 5. 00 ! 0. 012 1 III! 5/15/1910 ! 1547 0. 0! 3. 0! 6. 00 1 0. 022 1 IV ! 9/30/1916 ! 211 0, 0! 3. Oi 5. 00 ! 0. 007 i II ! 4/21/1918 122322 •5. 0! 3, Oi 6. 80 ! 0. 030 1 V 1 4/22/1918 [2115 0. 0! 3, 0! 5. 00 ! 0. 008 i III! 6/ 6/1918 12232 0, 0! 3. 0! 5, 00 i 0. 009 ! III! 11/19/1918 2018 0, 0| 3, Oi 5. 00 ! 0. 002 ! 1/ 1/1920 ! 235 0. 0| 3. 0! 5. 00 ! 0. 014 ! IV i 7/16/1920 18 8 0, 0| 3. Oi 5, 00 i 0. 003 ! 10/12/1920 1748 0. 0| 3. Oi 5, 30 i 0, 014 ! IV i 7/23/1923 73026. 0| 3. 0! 6. 25 ! 0, 013 i III! 4/ 3/1926 20 8 0. Oj 3. Oi 5. 50 i 0, 003 i I i 8/ 4/1927 1224 0, 0! 3. 0! 5, 00 1 0, 002 ! _ 1 9/ 5/1928 1442 0. Oj 3. Oi 5. 00 ! 0. 002 ! _ 1 10/ 2/1928 19 1 0, 0! 3, Oi 5, 00 ! 0. 002 i — 1 1/16/1930 02433. 0! 3. Oi 5, 20 i 0. 004 i I i 1/16/1930 1 034 3, 6! 3. Oi 5. 10 i 0. 004 ! I ! 8/31/1930 04036. 0| 3. Oi 5. 20 ! 0. 002 ! — 1 3/11/1933 1 154 7, 8! 3. 01 6. 30 ! 0. 018 ! IV i 3/11/1933 i 2 9 0, Oj 3. Oi 5. 00 ! 0, 005 i II i 3/11/1933 1 230 0, 0| 3. Oi 5. 10 ! 0. 006 i II i 3/11/1933 1 323 0. 0! 3. 0! 5. 00 ! 0. 005 ! II ! APPROX. DISTANCE mi [km] 33.000 32.800 34,370 34.000 34.100 34.000 33.000 32.670 34.000 34.000 32.700 32.670 32.670 33,500 32,250 33.900 34.100 34.200 33.400 32,700 33.200 34.300 32.800 34.200 34,300 33,800 34,000 34.100 34.000 34,200 33.700 33,700 33.700 33.500 33.750 33.800 33.750 34.000 33.200 34,080 33,200 34.000 34.000 34.000 34,000 32.900 34.180 34,180 33,950 33.617 33.750 33.750 33.750 117.300 117.100 117 118 118 118, 117 117, 117, 118. 117. 117. 117. 115, 117. 117. 116. 117. 116. ,650 ,250 ,100 250 000 170 500 250 200 170 170 820 500 200 700 900 300 116,300 116.200 117.600 116,800 117,400 117 117 118 117 118 117, 117, 117, 117, 116. 117. 117. 117. 118, 116. 118. 116. 117. 116. 118, 500 000 000 300 300 100 400 400 400 500 000 600 000 500 700 260 600 250 000 500 116,000 115.700 116, 116, 118. 117. 118. 118. 118. 920 920 632 967 083 083 083 8 25 89 82 82 82 19 32 62 82 30 32 32 89 61 54 76 82 61 65 64 83 36 75 82 50 73 68 84 75 40 40 40 53 47 50 47 92 35 86 41 61 96 92 96 94 76 76 96 52 63 63 fi.? r 13] 40] 143] 132] 132] 132] 31] 51] 100] 132] 48] 51] 51] 144] 98] 87] 122] 132] 98] 104] 103] 134] 59] 120] 132] 81] 117] 109] 135] 121] 65] 65] 65] 85] 75] 81] 75] 148] 57] 139] 66] 98] 155] 148] 155] 151] 123] 123] 154] 83] 101] 101] 1 ni 1 IDMG DMG DMG IDMG DMG 33.700 33.575 33.683 33.700 33.750 118.0671 3/11/1933 117.983! 3/11/1933 118.050! 3/11/1933 118.067! 3/11/1933 118.083! 3/11/1933 51022.0! 518 4.0! 658 3.0i 85457.0! 910 0,01 3,0 3.0 3,0 3.0 3.0 5.10 5.20 5.50 5.10 5.10 0.006 0,009 0,009 0.006 0,006 II III III II II 60 50 58 60 63 96] 81] 94] 96] 101] iPage 'ILE :ODE LAT. NORTH LONG, WEST I TIME i SITE ISITE ! DATE ! (GMT) DEPTH 1 QUAKE i ACC. i MM ! H M Sec (km) i MAG, i g ilNT. 1 3/11/1933 11425 0.0! 3,0 5,00 ! 0.004 i I I 3/13/1933 1131828.0 3,0 5.30 ! 0.006 i II 3/14/1933 il9 150.01 3.0 5.10 i 0.007 i II 10/ 2/1933 i 91017.61 3.0 5,40 i 0.006 i II 11/25/1934 ! 818 O.OI 3.0 5,00 i 0.003 ! I 10/24/1935 11448 7.6] 3.0 5,10 ! 0.004 i I 2/27/1937 i 12918.4! 3.0 5,00 ! 0.002 3/25/1937 !1649 1.8! 3.0 6.00 i 0.010 i III 5/31/1938 ! 83455,4! 3.01 5,50 i 0.015 i IV 5/ 1/1939 i2353 0,0! 3.0] 5,00 ! 0.003 ! I 6/24/1939 11627 0.0! 3.01 5.00 i 0.003 ! I 5/18/1940 ! 5 358.5! 3.0| 5.40 ! 0.003 i I 5/18/1940 i 55120.2! 3.0! 5.20 i 0,003 ! I 5/18/1940 i 72132.7! 3.0! 5.00 ! 0.003 6/ 4/1940 il035 8.3! 3.0! 5.10 1 0,008 i III 11/14/1941 i 84136.3! 3,0! 5.40 1 0,005 i II 5/23/1942 !154729,0! 3,0! 5.00 0.003 1 I 10/21/1942 il62213.0! 3.0! 6.50 \ 0.010 1 III 10/21/1942 !162519,0! 3.0! 5.00 0.003 I ; 10/21/1942 il62654.0! 3.0! 5.00 0.003 I I 10/22/1942 ! 15038,0! 3.0| 5. 50 0.003 I 1 10/22/1942 !181326,0! 3,0! 5.00 0.003 I 1 8/29/1943 1 34513,0! 3,0i 5,50 0.004 I i 6/12/1944 1104534,7! 3.0! 5,10 0.005 II i 6/12/1944 !111636.0! 3.0! 5,30 j 0.005 II i 8/15/1945 !175624.0i 3,0! 5.70 0.007 II i 1/ 8/1946 i185418.0! 3,0! 5.40 1 0.004 1 I ! 9/28/1946 ! 719 9.0! 3,0! 5.00 ! 0.005 i II i 7/24/1947 1221046,0! 3.0! 5.50 1 0.005 1 II i 7/25/1947 i 04631,0! 3.0! 5.00 1 0.003 1 I i 7/25/1947 i 61949.0! 3,0! 5.20 i 0,004 1 I i 7/26/1947 i 24941.0! 3,0! 5.10 i 0.004 ! I I 2/24/1948 i 81510,0! 3,0! 5.30 ! 0.003 i I i 12/ 4/1948 1234317,0! 3.0! 6.50 i 0.010 i III i 11/ 4/1949 I 204238,Oi 3.0! 5.70 ! 0.006 i II i 11/ 5/1949 I 43524.0! 3.01 5,10 ! 0.004 i I ! 1/24/1951 717 2.6! 3.0! 5,60 ! 0.004 ! I i 12/26/1951 04654.0! 3.0! 5,90 ! 0.009 ! III! 6/14/1953 41729.9! 3.0! 5,50 1 0.003 ! I i 3/19/1954 95429.0! 3.01 6.20 ! 0.011 ! III! 3/19/1954 95556,0! 3,01 5,00 ! 0.005 i II i 3/19/1954 102117.0! 3.0! 5,50 i 0.007 ! II i 3/23/1954 41450.0! 3.0! 5,10 ! 0.005 i II i 4/25/1957 215738.7! 3.0! 5.20 i 0.003 ! I ! 4/25/1957 1 222412.0! 3.0! 5,10 i 0.003 ! I i 5/26/1957 i 155933.6! 3.0! 5.00 ! 0.004 i I ! 9/23/1963 1 144152.6! 3.0! 5.00 i 0.009 i Ill! 12/22/1964 1 205433.2! 3.0! 5.60 ! 0.004 ! I ! 4/ 9/1968 1 22859.1! 3.0! 6.40 ! 0.012 i III! 4/ 9/1968 ! 3 353.5! 3,01 5.20 1 0.004 1 I ! APPROX. DISTANCE mi [km] 33.850 33.750 33,617 33.783 32,083 34.100 31,867 33,408 33.699 32,000 32,000 34.083 34,067 34,067 33.000 33,783 32,983 32.967 32.967 32.967 33,233 32,967 34.267 33.976 33,994 33,217 33.000 33,950 34,017 34.017 34,017 34.017 32,500 33.933 32.200 32.200 32.983 32.817 32.950 33,283 33,283 33,283 33.283 33.216 33.183 33.231 33.710 31.811 33.190 33.113 118,267 118,083 118,017 118.133 116.667 116 116, 116, 117, 800 571 261 511 117.500 117.500 116,300 116.333 116.333 116,433 118,250 115,983 116.000 116.000 116.000 115.717 116,000 116,967 116,721 116,712 116.133 115,833 116.850 116 116 116 116 118, 116, 116. 116, 115. 118. 115, 116. 116. 500 500 500 500 550 383 550 550 733 350 717 183 183 116.183 116.183 115,808 115,850 116.004 116,925 117,131 116,129 116,037 75 63 54 66 81 74 96 63 42 78 78 88 86 86 51 71 77 76 76 76 92 76 81 68 69 68 85 63 77 77 77 77 84 77 77 77 91 64 92 66 66 66 66 86 84 75 46 91 68 73 r 121] 101] 86] 107] 130] 118] 155] 102] 67] 126] 126] 141] 138] 138] 82] 115] 124] 122] 122] 122] 148] 122] 131] 109] 111] 109] 137] 101] 124] 124] 124] 124] 136] 124] 124] 124] 147] 104] 149] 105] 105] 105] 105] 139] 135] 121] 74] 146] 109] lift! I DMG DMG DMG •PAS •PAS ^AS _PAS •PAS 33,343 34.270 33.033 33.944 34,327 33,501 33.098 33.998 116.346 117.540 115.821 118.681 116.445 116,513 115,632 116,606 4/28/1969 9/12/1970 9/30/1971 1/ 1/1979 3/15/1979 2/25/1980 4/26/1981 7/ 8/1986 232042 143053, 224611 231438, 21 716, 104738. 12 928. 92044. 3.0 3.0 3.0 3,0 3.0 3,0 3.0 3.0 5 5, 5 5. 5 5. 5, 5, 80 40 10 00 20 50 70 60 0.011 0.004 0.003 0.002 0.002 0.010 0.003 0.006 III I I III I II 57 [ 92] 81 [ 130] 86 [ 138] 98 [ 157] 97 [ 156] 52 [ 84] 96 [ 155] 73 [ 117] E age ! i TIME i SITE ISITE! APPROX. f ILE LAT. LONG. ! DATE ! (GMT) DEPTH QUAKE ACC. ! MM i DISTANCE pODE NORTH WEST i ! H M Sec (km) MAG. g ilNT.i mi [km] PAS ft>AS ft'AS PAS P>AS B>AS GSP (SP SP SN GSP ftSP KSP GSN tfSP BSP "sp XSP KSP IJSP GSP BSP •SP GSP ISP **** -END 32.971 34.061 34.073 33,082 33.013 33.919 34.140 34,262 33.961 34.201 34.139 34.341 34.163 34.203 34,108 33.876 34.332 34.239 33,902 34,195 34.064 34,340 34.369 34,029 34.268 117.870 118,079 118,098 115,775 115.839 118,627 117.700 118,002 116.318 116.436 116,431 116,529 116,855 116,827 116,404 116.267 116,462 116.837 116.284 116.862 116,361 116.900 116.897 116.321 116.402 OF SEARCH- 14 7/13/1986 11347 8.2 10/ 1/1987 i144220.0 10/ 4/1987 1105938.2 11/24/1987 i 15414.5 11/24/1987 1131556.5 1/19/1989 i 65328.8 2/28/1990 i234336,6 6/28/1991 i144354.5 4/23/1992 i045023.0 6/28/1992 i115734.1 6/28/1992 !123640.6 6/28/1992 1124053.5 6/28/1992 i144321.0 6/28/1992 i150530.7 6/29/1992 {141338.8 6/29/1992 i160142.8 7/ 1/1992 1074029.9 7/ 9/1992 1014357.6 7/24/1992 1181436,2 8/17/1992 !204152,1 9/15/1992 1084711,3 11/27/1992 !160057.5 12/ 4/1992 i020857.5 8/21/1993 1014638,4 6/16/1994 1162427,5 ********ilf1f*^i*4!t******* 1 RECORDS FOUND 3.0! 5.30 i 0.018 i IV 3.0! 5.90 ! 0.006 ! II 3.0! 5,30 ! 0.004 i I 3.0! 5.80 ! 0,004 ! I 3.0! 6.00 i 0,006 ! II 3.0! 5.00 ! 0,002 i - 3.0! 5.20 ! 0.004 i I 3.0! 5.40 ! 0.003 ! I 3.0! 6.10 i 0.007 i II 3,0! 7.60 ! 0,016 ! IV 3.0! 5.10 i 0.003 i I 3.0! 5.20 ! 0.002 i - 3.01 5.30 i 0.004 ! I 3,0! 6,70 ! 0,011 ! Ill 3.0! 5.40 i 0.004 I I 3.0! 5.20 ! 0.004 ! I 3.0i 5.40 i 0.003 i I 3.0! 5.30 ! 0,004 ! I 3.0i 5.00 i 0.003 ! I 3,0! 5.30 ! 0,004 ! I 3.0i 5,20 I 0,003 ! I 3,0! 5.30 ! 0.003 i I 3.0| 5,30 i 0,003 i I 3,0! 5,00 ! 0,003 i I 3.0! 5.00 i 0.002 ! - *******nm*iti*)ti*1f4t*****i^*iH^H:* 35 79 80 88 85 94 74 89 81 90 86 95 76 80 85 79 97 82 80 78 85 87 89 84 95 ****** 56] 127] 129] 142] 137] 152] 119] 143] 130] 144] 139] 153] 123] 128] 138] 127] 155] 132] 128] 126] 136] 141] 144] 136] 152] **** JOMPUTER TIME REQUIRED FOR EARTHQUAKE SEARCH: 0,4 minutes MAXIMUM SITE ACCELERATION DURING TIME PERIOD 1800 TO 1997: 0.219g IAXIMUM SITE INTENSITY (MM) DURING TIME PERIOD 1800 TO 1997: IX :IMUM MAGNITUDE ENCOUNTERED IN SEARCH: 7.60 lEST HISTORICAL EARTHQUAKE WAS ABOUT 8 MILES AWAY FROM SITE, JUMBER OF YEARS REPRESENTED BY SEARCH: 198 years gAXI> IEARI I I RESULTS OF PROBABILITY ANALYSES IriME PERIOD OF SEARCH: 1800 TO 1997 TLENGTH OF SEARCH TIME: 198 years ATTENUATION RELATION: 1) Campbell (1991) Horiz. •*** TIME PERIOD OF EXPOSURE FOR PROBABILITY: 25 PROBABILITY OF EXCEEDANCE FOR ACCELERATION - Deep Soil years & Soft Rock ^CC NO.OF TIMES EXCED AVE. OCCUR. #/yr RECURR. INTERV. years COMPUTED PROBABILITY OF EXCEEDANCE in 0.5 yr in 1 yr m 10 yr m 50 yr in 75 yr in 100 yr in *** yr 0.01 B.02 m.03 0.04 K .05 ,06 0,07 (,08 ,09 ,10 0,11 1 ,12 .13 0,14 t ,15 .16 ,17 (,18 .19 .20 0,21 33 9 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0, 0. 0, 0. 0. 0, 0. 0. 0. 0. 0. 0. 0. 0, 0. 0, 0. 0. 0. 0. 0. ,167 045 ,020 005 005 005 005 005 005 005 005 005 005 005 005 005 005 005 005 005 005 6.000 22.000 49.500 198.000 198,000 198,000 198.000 198.000 198.000 198.000 198,000 198.000 198,000 198,000 198,000 198.000 198.000 198,000 198,000 198.000 198.000 0,0800 0.0225 0,0101 0,0025 0.0025 0.0025 0.0025 0.0025 0.0025 0.0025 0,0025 0.0025 0,0025 0,0025 0,0025 0.0025 0.0025 0,0025 0.0025 0.0025 0.0025 0.1535 0.0444 0,0200 0.0050 0,0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0.0050 0,0050 0,0050 0.8111 0,3653 0,1829 0.0493 0.0493 0.0493 0,0493 0,0493 0,0493 0,0493 0.0493 0.0493 0.0493 0.0493 0.0493 0,0493 0.0493 0,0493 0.0493 0.0493 0.0493 0.9998 0.8970 0.6358 0.2232 0.2232 0.2232 0,2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0.2232 0,2232 1.0000 0.9669 0.7802 0.3153 0.3153 0.3153 0.3153 0.3153 0,3153 0,3153 0.3153 0.3153 0,3153 0,3153 0.3153 0,3153 0.3153 0.3153 0.3153 0.3153 0.3153 1.0000 0.9894 0.8674 0,3965 0.3965 0.3965 0,3965 0,3965 0,3965 0,3965 0,3965 0.3965 0.3965 0.3965 0.3965 3965 3965 3965 3965 0.3965 0.3965 0 0 0 0, 0. 0. 0, 0, 0. 0, 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 9845 6790 3965 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 1186 I I I PROBABILITY OF EXCEEDANCE FOR MAGNITUDE ! NO. OF AVE. iRECURR. MAG. TIMES OCCUR. INTERV. in EXCED #/yr ! years 0. 5 yr '5,00 141, 0.712 1.404 !0. 2996 5.50 49 1 0.247 4.041 0. 1164 |6.00 26! 0.131 7.615 0. 0635 l6,50! 10| 0.051 19.800 0. 02491 7.00! 3| 0.015 66.000 0. 0075 |7.50| 1! 0.005j 198.000 0. 0025! COMPUTED PROBABILITY OF EXCEEDANCE in in in in I in in 1 yr 10 yr 50 yr 75 yr iioo yr !*** yr io. 5094 0 ,9992 1 ,0000 1 .0000 1.0000 1. OOOO 0. 2192 0 ,9158 1 .0000 1 .0000 1.0000 0. 9979 0. 1231 0 .7310 0 .9986 0 .9999 1.0000 0. 9625 0. 0493 0 ,3965 0 .9200 0 .9774 0.9936 0, 7171 0. 0150 0 .1406 0 .5312 0 .6790 0,7802 0. 3153 0. 0050! 0 .04931 0 .22321 0 .3153! 0,3965! 0. 1186 GUTENBERG & RICHTER RECURRENCE RELATIONSHIP: a-value= 3.493 b-value= 0.734 beta-value= 1,691 05/22/22105 12:10 8585491B04 PAGE 02 ^IH^I GEOTECHNICAL EXPLORATION, INC. SOIL & FOUNDATION ENGINEERING • GROUNDVtfATER HAZARDOUS MATERIALS MANAGEMENT • ENGINEERING GEOLOGY 23 May 2005 RWR HOMES, INC. 2710 Loker Avenue West, Suite 350 Carlsbad, CA 92008 Attn: Mr. Klaus Mendenhall RECEIVED JUN 2 3 2005 ENGINEERJNiG DEr'Ari.TiVichT Job No. 97-7189 Subject: Gradinq Plan Review and Response to City Report Review Proposed Emerald Pointe Estates Subdivision APN 212-040-50 Northwest of Cobblestone Drive, East of Laurel Tree Road Carlsbad, California Dear Mr. Mendenhall: As requested, we have reviewed the latest version of the grading pians for the project. The reviewed plans (6 sheets) were prepared by Hunsaker and /Associates, are print dated April 15, 2005. The plans have been reviewed from a geotechnical engineering viewpoint to verify their adequate compliance with the intent of our recommendations presented in our "Updated Report of Preliminary Geotechnical Investigation, Proposed Emerald Pointe Estates, BCS Property, APN 212-040-50, Carlsbad, Calffornia," Job No. 97-7189, dated April 30, 2002. In addition, we herein respond to red-lined comments made by the City of Carlsbad's reviewer of an updated report dated April 30, 2005. COINMENTS ON THE GRADING PLAN The reviewed grading plans. In our opinion, are in general compiiance with the recommendations presented in our updated report dated April 30, 2002. However, we emphasize that due to fractured formational soils, and the expansive nature of the encountered on-site soils, the soils be prepared with the proper moisture 7420 TRADE STREET • SAN DIEGO, CA 92121 • (858)549-7222 • FAX: (868) 549-1604 • E-MAIL: geotech@lxpres.com 05/22/2005 12:10 8585491604 GEI PAGE 03 Proposed Emerald Pointe Estates Job No. 97-7189 Carlsbad, Caiifornia Page 2 content and under continued observations and soil testing. In addition, a geologist from our firm shouid provide observations of the exposed cut bottoms before any fill or additional grading Is performed on the formational soils. Because of the fill thickness anticipated in the western end lots, we aiso recommend that a subdrain be instaiied in the keyway of the fiir embankment, and an intermediate subdrain placed in a bench located at approximately midheight of the fill depth. Other recommendations may be issued, as warranted, during the grading observations of the subdivision. Proposed retaining walls should be backfilled with imported low expansive soils. On site soils are typically classified as medium to highly expansive, and may not be used as wall backfill material. All other recommendations presented in our previous reports on the project remain applicable unless superseded in writing by our firm. RESPONSE TO CITY COMMENTS ON REPORT REVIEW A red-line comment by the City of Carisbad's reviewer of our updated report dated April 30, 2002, refers to our comment in the report's transmittal letter indicating that the proposed development Includes 17 residential iots. In fact, the number of lots where homes wiil be built is only 14, as shown In the current grading plan. Other comments by the City's reviewer Is a highlighted copy of a folded Plot Pian (incomplete copy), Rgure No. I. Attached herewith, we include a complete copy of Rgure No. I for the April 30, 2002, report. 05/22/2005 12:10 8585491504 Proposed Emerald Pointe Estates Carlsbad, California GEI PAGE 04 Job No. 97-7189 Page 3 If you have any questions regarding this letter, please contact our office. Reference to our Job No. 97-7189 will help expedite a response to your inquiry. Respectfully submitted, GEOTECHNICAL EXPLORATION, INC. Jaime A. Cerros, P.E. R.C.E. 34422/G.E.2007 Senior Geotechnical Engineer