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HomeMy WebLinkAbout; La Gran Via Storm Drain Repair; Geotechnical Evaluation; 2014-12-12 GEOTECHNICAL EVALUATION LA GRAN VIA STORM DRAIN REPAIR CARLSBAD, CALIFORNIA PREPARED FOR: City of Carlsbad 1635 Faraday Avenue Carlsbad, California 92008 PREPARED BY: Ninyo & Moore Geotechnical and Environmental Sciences Consultants 5710 Ruffin Road San Diego, California 92123 December 12, 2014 Project No. 107838001 La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc i TABLE OF CONTENTS Page 1. INTRODUCTION....................................................................................................................1 2. SCOPE OF SERVICES............................................................................................................1 3. SITE AND PROJECT DESCRIPTION ...................................................................................1 4. SUBSURFACE EXPLORATION AND LABORATORY TESTING....................................2 5. SUBSURFACE CONDITIONS...............................................................................................2 5.1. Fill.................................................................................................................................3 5.2. Santiago Formation.......................................................................................................3 5.3. Groundwater.................................................................................................................3 6. CONCLUSIONS ......................................................................................................................3 7. RECOMMENDATIONS..........................................................................................................4 7.1. Earthwork .....................................................................................................................4 7.1.1. Site Preparation...................................................................................................4 7.1.2. Excavation Characteristics..................................................................................5 7.1.3. Temporary Excavations and Shoring..................................................................5 7.1.4. Excavation Bottom Stability...............................................................................6 7.1.5. Slope Reconstruction ..........................................................................................6 7.1.6. Materials for Fill .................................................................................................8 7.1.7. Fill Placement and Compaction..........................................................................8 7.1.8. Pipe Zone Backfill ..............................................................................................9 7.1.9. Utility Trench Zone Backfill.............................................................................10 7.2. Shallow Foundations ..................................................................................................10 7.2.1. Bearing Capacity...............................................................................................10 7.2.2. Lateral Resistance.............................................................................................11 7.3. Corrosivity..................................................................................................................11 7.4. Pre-Construction Conference......................................................................................11 7.5. Plan Review and Construction Observation...............................................................12 8. LIMITATIONS.......................................................................................................................12 9. REFERENCES.......................................................................................................................14 Figures Figure 1 – Site Location Figure 2 – Boring Location Figure 3 – Lateral Earth Pressures for Braced Excavations Figure 4 – Energy Dissipater Subgrade Improvement | Appendices Appendix A – Boring Log Appendix B – Laboratory Testing La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 1 1. INTRODUCTION In accordance with your authorization and our scope and fee transmitted on October 8, 2014, we have performed a geotechnical evaluation for the La Gran Via Storm Drain Repair project lo- cated behind 2763 La Gran Via in Carlsbad, California (Figure 1). This report presents our findings and conclusions regarding the geotechnical conditions at the site and our recommenda- tions for the design and construction of the repair efforts for this project. 2. SCOPE OF SERVICES Ninyo & Moore’s scope of services for this project included review of pertinent background data, performance of a geologic reconnaissance and subsurface exploration, and engineering analyses with regard to the proposed project. Specifically, we performed the following tasks:  Reviewing background data listed in the References section of this report. The data reviewed included geotechnical geologic data, fault maps, and site plans prepared by Aecom.  Performing a geologic reconnaissance of the project site and nearby areas.  Performing a subsurface exploration that consisted of manually excavating, logging, and sam- pling of one boring to evaluate the subsurface conditions.  Performing geotechnical laboratory testing on representative soil samples to evaluate soil characteristics and geotechnical design parameters.  Compiling and analyzing the data obtained from our background research, subsurface explora- tion, and laboratory testing.  Preparing this report presenting our findings, conclusions, and recommendations regarding the geotechnical aspects of design and construction of the repair efforts for this project. 3. SITE AND PROJECT DESCRIPTION The site is located along and within the descending slope behind the residence located at 2763 La Gran Via in Carlsbad (Figure 2). The site descends downward from the adjacent property line at the top of the slope at an inclination of approximately 2:1 (horizontal to vertical) to the fresh wa- ter marsh down below in the open space easement. At the toe of the slope, a washout and erosion of the existing soils has occurred and portions of the corroded corrugated metal pipe (CMP) La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 2 storm drain has been exposed. There is also a manhole structure situated approximately mid- height of the slope. The elevation of the site ranges from approximately 202 feet above mean sea level (MSL) at the top of the slope to approximately 166 foot MSL near the base of the washout and the storm drain outlet. Vegetation consists of grass, weeds and brush. We understand that the project consists of the emergency repair of the corroded and partially ex- posed 24-inch diameter, CMP storm drain. The repair includes the removal of the existing CMP and manhole structure within the slope and installing approximately 32 feet of 24-inch diameter HDPE pipe. Along with the new HDPE piping, a new manhole structure will be installed at the top of the slope and an energy dissipator structure will be constructed at the base of the slope. In addition to the new storm drain system repair, the slope in the repair area will be reconstructed. 4. SUBSURFACE EXPLORATION AND LABORATORY TESTING Our field exploration at the project site included a geologic reconnaissance and a subsurface ex- ploration that were conducted on November 12, 2014. The subsurface exploration consisted of manually excavating one boring to a depth of approximately 5 feet. The boring location is pre- sented on Figure 2 and the boring log is presented in Appendix A. Prior to commencing the subsurface exploration, USA was notified for mark-out of the existing utilities. Geotechnical laboratory testing was performed on representative soil samples collected during our subsurface exploration. Testing included an evaluation of gradation (sieve) analysis, shear strength, and modified Proctor density relationships. Results of the laboratory tests performed are presented in Appendix B. 5. SUBSURFACE CONDITIONS Geologic units observed during our site reconnaissance and subsurface exploration of the project site included fill and materials of the Santiago Formation. Generalized descriptions of the units encountered are provided in the subsequent sections. Additional descriptions are provided on the boring log presented in Appendix A. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 3 5.1. Fill Fill materials were observed in the slope and encountered in our boring to a depth of approxi- mately 5 feet. As encountered, the fill materials generally consist of light brown, moist, medium dense, silty fine sand with scattered gravel, sandstone pieces, and iron oxide staining. 5.2. Santiago Formation Materials mapped as the Tertiary-age Santiago Formation (Kennedy and Tan, 2005) were observed beneath the fill in the eroded area at the base of the slope below an elevation of approximately 170 feet MSL. As observed, the Santiago Formation materials generally con- sist of light gray, moist to saturated, silty to clayey sandstone. 5.3. Groundwater Groundwater is anticipated to be at the approximate level of the adjacent fresh water marsh. Additionally, due to the presence of a corroded storm drain and residences situated upslope from the site, zones of seepage should be anticipated. Fluctuations in the groundwater level may occur due to variations in ground surface topography, subsurface geologic conditions and structure, tides, rainfall, irrigation, and other factors. 6. CONCLUSIONS Based on our review of the referenced background data, geologic field reconnaissance, and sub- surface exploration, it is our opinion that construction of the proposed project is feasible from a geotechnical standpoint. Geotechnical considerations include the following:  The on-site materials are expected to be excavatable with conventional heavy-duty earth- moving equipment in good working condition.  The slope erosion and the repaired slope may be reconstructed as an engineered fill slope by removing the disturbed material to expose competent material and replacing the slope with compacted fill. Specific recommendations regarding slope reconstruction and benching are presented in following sections. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 4  Groundwater and seepage is expected to be a constraint during construction. Groundwater is anticipated to be at the approximate level of the adjacent fresh water marsh. Additionally, due to the presence of a corroded storm drain and residences situated upslope from the site, zones of seepage should be anticipated.  Due to the groundwater near the toe of the slope and the potential for seepage within the slope, the contractor should anticipate encountering wet soils that may need additional han- dling or stabilization efforts. Recommendations are presented herein for the removal of saturated material at the toe of the slope and replacement with gravel wrapped in filter fabric to aid in the construction of the energy dissipator.  On-site excavations may generate oversized materials and other debris. These materials should be removed from on-site soils prior to their reuse as engineered fill. 7. RECOMMENDATIONS Based on our understanding of the project, the following recommendations are provided for the design and construction of the project. 7.1. Earthwork In general, earthwork should be performed in accordance with the recommendations pre- sented in this report. Ninyo & Moore should be contacted for questions regarding the recommendations presented herein. 7.1.1. Site Preparation Site preparation should begin with the removal of vegetation, drainpipes, and other deleterious debris from areas to be graded. Roots should be removed to such a depth that organic material is generally not present. Clearing and grubbing should extend to the outside of the proposed excavation and fill areas. The debris and unsuitable material generated during clearing and grubbing should be removed from areas to be graded and disposed of at a legal dumpsite away from the project area. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 5 7.1.2. Excavation Characteristics Our evaluation of the excavation characteristics of the on-site materials is based on the results of our exploratory boring, our site observations, and our experience with similar materials. Fill materials may be in variable condition and, where loose or dry, will be subject to caving upon excavation. Debris may also be encountered within fill materials. Based on our evaluation the materials are expected to be rippable with heavy-duty earthmoving equipment. 7.1.3. Temporary Excavations and Shoring We recommend that trenches and excavations be designed and constructed in accor- dance with Occupational Safety and Health Administration (OSHA) regulations. For planning purposes, we recommend that OSHA soil classification Type B be used for site soils. For trench or other excavations, OSHA requirements regarding personnel safety should be met by using appropriate shoring (including trench boxes) or by laying back the slopes no steeper than 1:1 (horizontal to vertical). Loose materials in the slope faces should be removed prior to grading. Temporary excavations that encounter seepage may need shoring or may be stabilized by placing sandbags or gravel along the base of the seepage zone. Excavations encountering seepage should be evaluated on a case-by-case basis. On-site safety of personnel is the responsibility of the contractor. Due to site constraints, temporary excavations may need to be shored. Temporary earth retaining systems will be subjected to lateral loads resulting from earth pressures. Shor- ing systems for excavations may be designed using the lateral earth pressure parameters presented on Figure 3. These lateral earth pressures should be evaluated by a structural engineer for the design of the shoring systems. These design earth pressures assume that spoils from the excavations, or other surcharge loads, will not be placed above the ex- cavations within a 1:1 (horizontal to vertical) plane extending up and back from the base of the excavation. For bracing subjected to surcharge loads, such as soil stockpiles or construction materials/equipment, an additional horizontal uniform pressure of 0.40q may be applied to the full height of the excavation, where “q” is the surcharge pressure. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 6 7.1.4. Excavation Bottom Stability Based on our evaluation, due to the presence of the adjacent fresh water marsh, satu- rated and potentially yielding materials may be encountered at the toe of the slope repair and at the subgrade elevation for the dissipater structure. We recommend that the satu- rated material in the dissipater structure be removed to a depth of 2 feet below proposed subgrade elevation and replaced with a 1-foot thickness of open graded gravel wrapped in separation fabric (Figure 4). Following the removals, a woven fabric (such as HP 570 or an equivalent) should be rolled out over the excavation bottom. The fabric should ex- tend 2 feet or more up the sides of the excavation. Subsequent to the placement of the fabric, 12 inches of gravel may be placed over the fabric. Compaction effort should then be made in this layer to consolidate the gravel. A second layer of fabric should then be rolled out over the gravel. The filter fabric extending up the sides of the excavation should then be overlapped over the second layer of filter fabric. A 12-inch layer of com- pacted fill material should then be placed in two 6-inch lifts and compacted to 90 percent or greater relative compaction as evaluated by the ASTM International (ASTM) D 1557. Due to the saturated condition of the existing Santiago Formation ma- terials at the site, this material is not considered reusable in its present condition and the use of imported fill material may be needed. 7.1.5. Slope Reconstruction Based on our evaluation, we understand that the slope washout will be reconstructed to match the existing grades and the pre-existing configuration using imported fill soils. The sequence of excavation, stockpiling soil, and slope reconstruction should be evalu- ated by the contractor based on the site conditions and equipment capabilities. The slope work involves grading on a steep hillside and should be performed by a qualified con- tractor with experience in hillside grading techniques. The actual depth and extent of removals should be evaluated in the field at the time of construction by Ninyo & Moore. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 7 The slope should be stripped of vegetation and cleared of surface obstructions and de- bris. The slope may be reconstructed by excavating the loose surficial soils, benching the exposed slope face into competent material, and rebuilding the slope with com- pacted fill. The actual depth and extent of removal should be evaluated in the field at the time of construction by Ninyo & Moore. A key, inclined gently into the slope, should be constructed at the base of the recon- structed part of the slope. The keyway should extend to a depth of 3 feet below the toe of slope elevation, be 10 feet long as measured into slope, and extend the width of the reconstructed slope. Benches should be inclined slightly into slope and have a width of 4 feet or more. Lateral extents of the slope repair should extend a horizontal distance of 5 feet beyond the limits of the slope washout. However, the actual extent of removal should be evaluated in the field at the time of construction by Ninyo & Moore. Unless otherwise recommended by Ninyo & Moore and approved by the regulating agencies, fill and cut slopes should not be steeper than 2:1. Compaction of the face of fill slopes should be performed by backrolling at intervals of 4 feet or less in vertical slope height or as dictated by the capability of the available equipment, whichever is less. Fill slopes should be backrolled utilizing a sheepsfoot-type roller. Care should be taken in maintaining the desired moisture conditions and/or reestablishing them, as needed, prior to backrolling. Care should be taken to provide surficial soil stabilization such as an erosion control mat placed between the time the slope repair is made and landscaping is established. If the repair is made during the rainy season, plastic sheeting should be readily available to cover the slope in the event of rainfall. Site runoff should not be permitted to flow over the tops of slopes. Positive drainage should be established away from the slopes. This may be accomplished by incorporating brow ditches placed at the top of the slopes to divert surface runoff away from the slope face where drainage devices are not otherwise available. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 8 The on-site soils are likely to be susceptible to erosion; therefore, the project plans and specifications should contain design features and construction requirements to mitigate erosion of on-site soils during and after construction. Imported fill materials should be evaluated for suitability by Ninyo & Moore prior to their use in constructing fill slopes. 7.1.6. Materials for Fill Materials for fill may be obtained from on-site excavations or may be import materi- als. On-site or import soils with an organic content of less than approximately 3 percent by volume (or 1 percent by weight) and that meet the following recommen- dations are considered suitable for use as engineered fill material. Fill material should not contain rocks or lumps over approximately 3 inches in diameter and not more than approximately 30 percent larger than ¾ inch. On-site excavations may generate cob- bles larger than 3 inches in diameter. Oversize materials should be separated from material to be used as engineered fill and further processed and/or removed from the site. Moisture conditioning (including drying and/or mixing) of existing on-site mate- rials is anticipated if reused as engineered fill. Imported fill material, if needed, should generally be granular soils that are non-corrosive in accordance with the Caltrans (2012) corrosion guidelines and ACI 318. Materials for use as fill should be evaluated by Ninyo & Moore’s representative prior to filling or importing. 7.1.7. Fill Placement and Compaction Prior to placement of compacted fill, the contractor should request an evaluation of the exposed ground surface by Ninyo & Moore. Unless otherwise recommended, the ex- posed ground surface should then be scarified to a depth of approximately 8 inches and watered or dried, as needed, to achieve moisture contents generally above the optimum moisture content. The scarified materials should then be compacted to a relative com- paction of 90 percent as evaluated in accordance with ASTM D 1557. The evaluation of compaction by the geotechnical consultant should not be considered to preclude any re- quirements for observation or approval by governing agencies. It is the contractor's La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 9 responsibility to notify this office and the appropriate governing agency when project areas are ready for observation, and to provide reasonable time for that review. Fill materials should be moisture conditioned to generally above the laboratory opti- mum moisture content prior to placement. The optimum moisture content will vary with material type and other factors. Moisture conditioning of fill soils should be generally consistent within the soil mass. Prior to placement of additional compacted fill material following a delay in the grading operations, the exposed surface of previously compacted fill should be prepared to receive fill. Preparation may include scarification, moisture conditioning, and recompaction. Compacted fill should be placed in horizontal lifts of approximately 8 inches in loose thickness. Prior to compaction, each lift should be watered or dried as needed to achieve a moisture content generally above the laboratory optimum, mixed, and then compacted by mechanical methods, to a relative compaction of 90 percent as evaluated by ASTM D 1557. Successive lifts should be treated in a like manner until the desired fin- ished grades are achieved. 7.1.8. Pipe Zone Backfill The pipe zone backfill should from the top of the pipe bedding material and extend to 1 foot or more above the top of the pipe in accordance with the recent edition of the Standard Specifications for Public Works Construction (“Greenbook”). Pipe zone back- fill should have a Sand Equivalent (SE) of 30 or greater, and be placed around the sides and top of the pipe. Special care should be taken not to allow voids beneath and around the pipe. Compaction of the pipe zone backfill should proceed up both sides of the pipe. It has been our experience that the voids within a crushed rock material are sufficiently large to allow fines to migrate into the voids, thereby creating the potential for sinkholes and depressions to develop at the ground surface. If gravel is utilized as pipe zone back- fill, this material should be wrapped with a geosynthetic filter fabric. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 10 7.1.9. Utility Trench Zone Backfill On-site soils with an organic content of less than approximately 3 percent by volume (or 1 percent by weight) and that meet the following recommendations are generally considered suitable for reuse as trench zone backfill. Trench zone backfill material should be gener- ally free of trash, debris, roots, vegetation, or deleterious materials. Trench zone backfill should generally be free of rocks or hard lumps of material in excess of 3 inches in di- ameter. Rocks or hard lumps larger than about 3 inches in diameter should be broken into smaller pieces or should be removed from the site. On-site trench excavations may generate cobbles larger than 3 inches in diameter. Oversize materials should be separated from material to be used as trench backfill. Moisture conditioning (including drying and/or mixing) of existing on-site materials is anticipated if reused as trench zone backfill. Import material should also be non-corrosive in accordance with the Caltrans (2012) corrosion guidelines and ACI 318. Materials for use as fill should be evaluated by Ninyo & Moore’s representative prior to filling or importing. The contractor should be responsible for the uniformity of import material brought to the site. 7.2. Shallow Foundations Based on our understanding of the project, the proposed new manhole and energy dissipat- ing structures will be supported on shallow continuous and/or spread foundations. The following sections provide parameters for the design of shallow foundations bearing on compacted fill prepared in accordance with the earthwork recommendations presented in previous sections of this report. 7.2.1. Bearing Capacity Shallow, spread or continuous footings bearing on compacted fill prepared in accor- dance with the earthwork recommendations in previous sections, may be designed using a net allowable bearing capacity of 2,000 pounds per square foot (psf). These allowable bearing capacities may be increased by one-third when considering loads of short dura- tion such as wind or seismic forces. Shallow, spread or continuous footings should be La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 11 founded 15 inches or more below the lowest adjacent grade. Continuous footings should have a width of 15 inches or more and isolated footings should be 18 inches or more in width. The shallow, spread or continuous footings should be reinforced in accordance with the recommendations of the project structural engineer. 7.2.2. Lateral Resistance For resistance of footings to lateral loads, we recommend a passive pressure of 300 psf per foot of depth be used with a value of up to 3,000 psf. This value assumes that the ground is horizontal for a distance of 10 feet, or three times the height generating the passive pressure, whichever is greater. We recommend that the upper 1 foot of soil not protected by pavement or a concrete slab be neglected when calculating passive resistance. For frictional resistance to lateral loads, we recommend a coefficient of friction of 0.30 be used between soil and concrete. The allowable lateral resistance can be taken as the sum of the frictional resistance and passive resistance provided the passive resistance does not exceed one-half of the total allowable resistance. 7.3. Corrosivity As evidenced by the corroded nature of the existing CMP and the presence of a nearby marsh, the on-site soils should be considered corrosive. Therefore, we recommend that con- sideration should be given to using Type II/V cement for concrete structures in contact with soil. In addition, we recommend concrete have a 28-day compressive strength of 4,500 pounds per square inch (psi) and a water-to-cement ratio of no more than 0.45. 7.4. Pre-Construction Conference We recommend that a pre-construction meeting be held prior to commencement of construc- tion. The owner or his representative, the agency representatives, the civil engineer, Ninyo & Moore, and the contractor should be in attendance to discuss the plans, the project, and the proposed construction schedule. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 12 7.5. Plan Review and Construction Observation The conclusions and recommendations presented in this report are based on analysis of ob- served conditions in widely spaced exploratory borings. If conditions are found to vary from those described in this report, Ninyo & Moore should be notified, and additional recommenda- tions will be provided upon request. Ninyo & Moore should review the final project drawings and specifications prior to the commencement of construction. Ninyo & Moore should per- form the needed observation and testing services during construction operations. The recommendations provided in this report are based on the assumption that Ninyo & Moore will provide geotechnical observation and testing services during construction. In the event that it is decided not to utilize the services of Ninyo & Moore during construction, we request that the selected consultant provide the client with a letter (with a copy to Ninyo & Moore) indicat- ing that they fully understand Ninyo & Moore’s recommendations, and that they are in full agreement with the design parameters and recommendations contained in this report. Construc- tion of proposed improvements should be performed by qualified subcontractors utilizing appropriate techniques and construction materials. 8. LIMITATIONS The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical report have been conducted in general accordance with current practice and the standard of care exercised by geotechnical consultants performing similar tasks in the project area. No warranty, expressed or implied, is made regarding the conclusions, recommendations, and opinions pre- sented in this report. There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and conditions not observed or described in this report may be encountered during construction. Uncertainties relative to subsurface conditions can be reduced through addi- tional subsurface exploration. Additional subsurface evaluation will be performed upon request. Please also note that our evaluation was limited to assessment of the geotechnical aspects of the project, and did not include evaluation of structural issues, environmental concerns, or the pres- ence of hazardous materials. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 13 This document is intended to be used only in its entirety. No portion of the document, by itself, is designed to completely represent any aspect of the project described herein. Ninyo & Moore should be contacted if the reader requires additional information or has questions regarding the content, interpretations presented, or completeness of this document. This report is intended for design purposes only. It does not provide sufficient data to prepare an accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant per- form an independent evaluation of the subsurface conditions in the project areas. The independent evaluations may include, but not be limited to, review of other geotechnical reports prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory testing. Our conclusions, recommendations, and opinions are based on an analysis of the observed site conditions. If geotechnical conditions different from those described in this report are encountered, our office should be notified, and additional recommendations, if warranted, will be provided upon request. It should be understood that the conditions of a site could change with time as a result of natural processes or the activities of man at the subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to government ac- tion or the broadening of knowledge. The findings of this report may, therefore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore has no controls. This report is intended exclusively for use by the client. Any use or reuse of the findings, conclu- sions, and/or recommendations of this report by parties other than the client is undertaken at said parties’ sole risk. La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc 14 9. REFERENCES Aecom, Undated, Construction Plans For La Gran Via Storm Drain Pipeline Repair, Pages 1 through 4, Drawing No. 471-2C. American Concrete Institute, 2011, ACI 318 Building Code Requirements for Structural Con- crete (ACI 318) and Commentary (ACI 318R). California Building Standards Commission (CBSC), 2013, California Building Code (CBC), Ti- tle 24, Part 2, Volumes 1 and 2: dated June. Harden, D.R., 1998, California Geology: Prentice Hall, Inc. Kennedy, M.P., and Tan, S.S., 2005, Geologic Map of the Oceanside 30’ x 60’ Quadrangle, Califor- nia, Scale 1:100,000. Ninyo & Moore, In-House Proprietary Information. Norris, R. M. and Webb, R. W., 1990, Geology of California, Second Edition: John Wiley & Sons, Inc. Public Works Standards, Inc., 2012, “Greenbook,” Standard Specifications for Public Works Construction. United States Department of the Interior, Bureau of Reclamation, 1998, Engineering Geology Field Manual. AERIAL PHOTOGRAPHS Source Date Flight Numbers Scale United States Department of Agriculture 4-11-53 AXN-8M 17 and 18 1:20,000 SOURCE: 2008 THOMAS GUIDE FOR SAN DIEGO COUNTY, STREET GUIDE AND DIRECTORY; MAP © RAND MCNALLY, R.L.07-S-129 NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 1_107838001_SL.mxd AOB"SITE ! §¨¦8 §¨¦5 §¨¦15 §¨¦805 §¨¦215 MAP INDEX San DiegoCounty 0 2,400 4,8001,200 SCALE IN FEET LA GRAN VIA STORM DRAIN REPAIRCARLSBAD, CALIFORNIA SITE LOCATION FIGURE 1PROJECT NO.DATE 107838001 12/14 ± ± NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE LEGEND BORINGTD=TOTAL DEPTH IN FEET @A 0 50 10025 SCALE IN FEET BORING LOCATION FIGURE 2PROJECT NO.DATE 2_107838001_BL.mxd AOBSOURCE: 2012 SAN DIEGO IMAGERY ACQUISITION PARTNERSHIP (FLIGHT DATES: MAY 20 - JUNE 6, 2012) 107838001 B-1TD=5.0' @A B-1TD=5.0' LA GRAN VIA CALINA WAYLA GRAN VIA STORM DRAIN REPAIRCARLSBAD, CALIFORNIA12/14 pP D H CONSTRUCTION MATERIALS ARE NOT INCLUDED 5.SURCHARGES FROM EXCAVATED SOIL OR 4.ASSUMES GROUNDWATER IS NOT PRESENT 3.PASSIVE LATERAL EARTH PRESSURE, P P = 300 D psf 2. P = 120 psf CONSTRUCTION TRAFFIC INDUCED SURCHARGE PRESSURE, P 1. P = 28 H psf APPARENT LATERAL EARTH PRESSURE, P NOTES: Pa Ps a a s s p p 6.H AND D ARE IN FEET + FIGURE 3PROJECT NO. 107838001 LA GRAN VIA STORM DRAIN REPAIR CARLSBAD, CALIFORNIA DATE 12/14 LATERAL EARTH PRESSURES FOR BRACED EXCAVATIONS SHORING BRACES 3_107838001_d-lepgs.dwg FIGURE 4PROJECT NO. 107838001 LA GRAN VIA STORM DRAIN REPAIR CARLSBAD, CALIFORNIA DATE 12/144_107838001_d-edsi.dwgENERGY DISSIPATER SUBGRADE IMPROVEMENT MARSH ENERGY DISSIPATER SUBGRADE COMPACTED FILL TYPICAL BENCHING SEPARATION FABRIC (HP 570 OR EQUIVALENT) 1' 1' GRAVEL La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc APPENDIX A BORING LOG Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using the following method. Bulk Samples Bulk samples of representative earth materials were obtained from the exploratory boring. The samples were bagged and transported to the laboratory for testing. 0 5 10 15 20 XX/XX SM CL Bulk sample. Modified split-barrel drive sampler. 2-inch inner diameter split-barrel drive sampler. No recovery with modified split-barrel drive sampler, or 2-inch inner diameter split-barrel drive sampler. Sample retained by others. Standard Penetration Test (SPT). No recovery with a SPT. Shelby tube sample. Distance pushed in inches/length of sample recovered in inches. No recovery with Shelby tube sampler. Continuous Push Sample. Seepage. Groundwater encountered during drilling. Groundwater measured after drilling. MAJOR MATERIAL TYPE (SOIL):Solid line denotes unit change. Dashed line denotes material change. Attitudes: Strike/Dip b: Bedding c: Contact j: Joint f: Fracture F: Fault cs: Clay Seam s: Shear bss: Basal Slide Surface sf: Shear Fracture sz: Shear Zone sbs: Shear Bedding Surface The total depth line is a solid line that is drawn at the bottom of the boring. BORING LOG Explanation of Boring Log Symbols PROJECT NO. DATE FIGUREDEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.BORING LOG EXPLANATION SHEET TYPICAL NAMES GW Well graded gravels or gravel-sand mixtures, little or no fines GP Poorly graded gravels or gravel-sand mixtures, little or no fines GM Silty gravels, gravel-sand-silt mixtures GC Clayey gravels, gravel-sand-clay mixtures SW Well graded sands or gravelly sands, little or no fines SP Poorly graded sands or gravelly sands, little or no fines SM Silty sands, sand-silt mixtures SC Clayey sands, sand-clay mixtures ML Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with slight plasticity CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays OL Organic silts and organic silty clays of low plasticity MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts CH Inorganic clays of high plasticity, fat clays OH Organic clays of medium to high plasticity, organic silty clays, organic silts Pt Peat and other highly organic soils U.S. Standard Sieve Size Grain Size in Millimeters BOULDERS Above 12" Above 305 COBBLES 12" to 3" 306 to 76.2 GRAVEL 3" to No. 4 76.2 to 4.76 Coarse 3" to 3/4" 76.2 to 19.1 Fine 3/4" to No. 4 19.1 to 4.76 SAND No. 4 to No. 200 4.76 to 0.075 Coarse No. 4 to No. 10 4.76 to 2.00 Medium No. 10 to No. 40 2.00 to 0.420 Fine No. 40 to No. 200 0.420 to 0.075 SILT & CLAY Below No. 200 Below 0.075 SYMBOL U.S.C.S. METHOD OF SOIL CLASSIFICATION FINE-GRAINED SOILS(More than 1/2 of soil < No. 200 sieve size)U.S.C.S. METHOD OF SOIL CLASSIFICATIONCOARSE-GRAINED SOILS(More than 1/2 of soil > No. 200 Sieve Size)MAJOR DIVISIONS HIGHLY ORGANIC SOILS GRAVELS (More than 1/2 of coarse fraction > No. 4 sieve size SANDS (More than 1/2 of coarse fraction < No. 4 sieve size SILTS & CLAYS Liquid Limit <50 SILTS & CLAYS Liquid Limit >50 GRAIN SIZE CHART RANGE OF GRAIN CLASSIFICATION PLASTICITY CHART CH CL MH & OH ML & OLCL - ML 0 10 20 30 40 50 60 70 0 102030405060708090100 LIQUID LIMIT (LL), %PLASTICITY INDEX (PI), %Updated Nov. 2011 0 5 10 15 20 SM FILL:Light brown, moist, medium dense, silty fine SAND; scattered organics (roots, leaves); scattered gravel. Scattered fine-grained sandstone pieces; scattered iron-oxide staining. Moist. Total Depth = 5 feet. Groundwater not encountered. Backfilled on 11/12/14. Note: Groundwater, though not encountered at the time of excavation, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report. The ground elevation shown above is an estimation only. It is based on our interpretations of published maps and other documents reviewed for the purposes of this evaluation. It is not sufficiently accurate for preparing construction bids and design documents. BORING LOG LA GRAN VIA STORM DRAIN REPAIR CARLSBAD, CALIFORNIA PROJECT NO. 107838001 DATE 12/14 FIGURE A-1DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION DATE DRILLED 11/12/14 BORING NO.B-1 GROUND ELEVATION 190'  (MSL)SHEET 1 OF METHOD OF DRILLING Hand Tools DRIVE WEIGHT N/A DROP N/A SAMPLED BY AQP LOGGED BY AQP REVIEWED BY FOM 1 La Gran Via Storm Drain Repair December 12, 2014 Carlsbad, California Project No. 107838001 107838001 R.doc APPENDIX B LABORATORY TESTING Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D 2488. Soil classifications are indicated on the log of the exploratory boring in Appendix A. Gradation Analysis A gradation analysis test was performed on a selected representative soil sample in general ac- cordance with ASTM D 422. The grain-size distribution curve is shown on Figure B-1. The test results were utilized in evaluating the soil classifications in accordance with the USCS. Proctor Density Test The maximum dry density and optimum moisture content of a selected representative soil sample was evaluated using the Modified Proctor method in general accordance with ASTM D 1557. The results of the test are summarized on Figure B-2. Direct Shear Tests A direct shear test was performed on a remolded sample in general accordance with ASTM D 3080 to evaluate the shear strength characteristics of the selected material. The sample was inundated during shearing to represent adverse field conditions. The results are shown on Figure B-3.