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Home My WebLink AboutSW6081002_HISTORICAL FILE_20081002STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW� 0%�15 IIiD� DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS HISTORICAL FILE ❑ COMPLIANCE EVALUATION INSPECTION DOC DATE��D��, YYYYMMDD I ®�\S® ENGINEERS L$®®EI®M PLANNERS 0®11®$® ECONOMISTS N—W0® WilburSmith A 5 5 0 C I A T E 5 October 2, 2008 Mr. Mike Randall Stormwater and General Permits Unit 1617 Mail Service Center Raleigh, NC 27699-1617 RE: Harnett County Schools; Additions to Harnett Central High School Stormwater Management Permit Application Dear Mr. Randall: On behalf of the Harnett County Board of Education and SFL+A Architects, Wilbur Smith Associates is pleased to submit this application for storm water management associated with the proposed improvements for the above referenced project. The purpose of the project is to construct a new 21,460 sq. ft classroom addition, new 2250 sq. ft. cafeteria addition, and a new 14,360 sq. ft. band room and gymnasium addition along with a new parking lot to replace parking eliminated with the building addition. These improvements are being constructed to offset the portable classroom units and bathroom facilities that are to be removed upon completion of the project. A submittal has been made to NCDENR for erosion control review. Attached please find the following: a. 1 — original of Stormwater Management Permit Application b. 1 — copy of Stormwater Management Permit Application c. 1 — original of Bioretention Operation and Maintenance Agreement d. 1 — original of Supplemental Form e. 1 — copy of storm drainage specifications, calculations and geotechnical report f. 2 — copies of plans g. 1 — check Please review and if you have any questions or need any additional information, do not hesitate to call me. Sincerely, WILBUR SMITH ASSOCIATES 1 iui Q Merrick (Tregal, III, P.E. Project Manager Attachments WAfiamett County\Petmits\NCDWQ StormwaterLTR_100208.doc c: John Birath, SFL+A Architects Phil Ferrell, Harnett County Schools 421 Fayetteville Street, Suite 1303 Raleigh, NC 27601 919.755.0583 f919.832.8798 www.WilburSmith.com Harnett County Schools; Additions to Harnett Central High School Angier, North Carolina Stormwater Management October 2, 2008 ®Add®® ENGINEERS ® PLANNERS Ma®ff1f® ECONOMISTS ®077®® WilburSmith A 5 5 0 C I A T E 5 421 Fayetteville Street Suite 1303 Raleigh, NC 27601 Harnett County Schools; Additions to Harnett Central High School Angier, North Carolina Project Description The purpose of the project is to construct a new 21,460 sq. ft classroom addition, new 2250 sq. ft. cafeteria addition, and a new 14,360 sq. ft. band room and gymnasium addition. The project consists of clearing, grading and drainage, and paving work to construct the new building additions and associated sitework. The total disturbed area is anticipated to be up to 3.0 acres. Site Description The site consists of mostly grass lawn and existing paved areas. The general slope from the existing building averages 2.0% to 4.0%. According to FIRM maps, no floodplains exist within the project limits. Adjacent Property The adjacent property consists of Harnett Central Middle School to the west, residential area to the north, and the site is bounded by Neill's Creek Road to the east and Harnett Central Road to the south. Planned Stormwater Control Practices The new building additions will utilize closed roof drain systems to tie into closed stonn sewer systems. The new classroom addition which will result in the removal of the temporary mobile classrooms will discharge the eastern half of the roof into a bioretention pond which will also receive the discharge from the new parking lot. This bioretention pond will then discharge into a drop inlet and into an existing closed storm sewer system. Due to limited available space and grade limitations the bioretention pond cannot utilize a vegetative filter strip or level spreader for the overflow. The remaining runoff generated by the new classroom addition will then discharge into an existing closed storm sewer system. The new gymnasium/band room additions and the new cafeteria additions discharge directly into existing closed storm sewer systems that serve the locations of these sites. Calculations of the added and removed impervious areas are attached along with a map showing the drainage areas as calculated for the project. Specifications All storm drainage related specifications *are attached. WilburSmith SUBJECT WinTet-cy io Y� �uysd JOBNO. SH__LOF A S S O C I A T E 5 Q� h GTT GK I��TR BY T f{ DATE 5115109 CH. DATE 'TZ o O bA : 0.9 i A Added Z^�?✓vla S Chssi�o {addil;� S — Zz,$93 s�Z = 11,+1+7 P,W y 1_,� AddIk�on - = z 0,co9 -r = 7 Z Z :><. Q=CrAs 0,(P� (7,22) COI 1) = +.S 3ck cG�p�� c,rvin,��olcQc,C2✓ct�� . /vim �7/•1 /'IGr, Vcl �SC Ch 4n 7,3> . I RV = 0•os o,ti TA o, ss = 3630' 1,0'•S' o- 'I' 0,51 = 49,49 cF l;y,e_�-j Wume Z-O'J19 Pr TIzI Ci zs, 9sZ s� SUBJECT 14,n Gig l en I -6 JOB NO. SH _OF WilburSmith Fh'4� BY / f FQ DATE IS oS A 5 5 0 C I A T E 5 C� Pack T"re4o�,s T�til T, p ey ao� 32,310 sC 0.7'k PG �-�-�-. slur.,.= 6,1Z'i� Wiled �r,2 (VI !"chid%nlc re,✓Wal op Pvr�r,blL ClGurao,;� G= 0,915 (rook, sikL Jlr(, Pcrkil)) Rs')Co, Iz)(n,7`t) = 0.0b CF,S p/e Tw pP ril o,s G = 0.3.5'- ('Jvc.Sf lrw�) Ca = (0,3f)@, 12)(0.-7) = 0,03 cF� h-e, = 0, 0B - 0.03 = 0.05 Cfs Addition to Harnett Central High School SECTION 33 41 00 STORM DRAINAGE PART 1 — GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provision of the Contract, including the General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section. 1.2 SUMMARY A. This Section includes: 1. All storm drainage work including connecting foundation and roof drain down spouts to storm drainage inlets. Coordinate location of foundation and roof drains with Architectural Drawings. B. Related Sections: The following contain requirements that relate to this Section. 1. Section 31 23 17 for trenching and earthwork installation procedures. 2. Division 03 Cast -in -Place Concrete for cast -in -place concrete structures. 1.3 DEFINITIONS A. Drainage Piping: System of sewer pipe, fittings, and appurtenances for gravity flow of storm drainage including roof drains. 1.4 PERFORMANCE REQUIREMENTS A. Gravity -Flow, Non -pressure -Piping Pressure Ratings: At least equal to system test pressure. 1.5 SUBMITTALS A. General: Submit each item in this Article according to the Conditions of the Contract and Division 01 Specification Sections. B. Shop drawings for precast concrete manholes and other structures. Include frames, covers and grates. C. Shop drawings for cast -in -place concrete or field -erected masonry manholes and other structures. Include frames, covers and grates. D. Reports and calculations for design mixes for each class of cast -in -place concrete. E. Inspection and test reports specified in the "Field Quality Control' Article. 00807.000 Storm Drainage 33 41 00 - 1 Addition to Hamett Central High School 1.6 QUALITY ASSURANCE A. Environmental Agency Compliance: Comply with NCDOT for storm drainage systems. 1.7 DELIVERY, STORAGE, AND HANDLING A. Do not store plastic pipe or fittings in direct sunlight. B. Protect pipe, pipe fittings, and seals from dirt and damage. C. Handle precast concrete manholes and other structures according to manufacturer's rigging instructions. 1.8 PROJECT CONDITIONS A. Site Information: Perform site survey, research public utility records, and verify existing utility locations. B. Locate existing structures and piping to be closed and abandoned. C. Existing Utilities: Do not interrupt existing utilities serving facilities occupied by the Owner or others except when permitted under the following conditions and then only after arranging to provide acceptable temporary utility services. 1. Notify the Owner's Representative not less than 48 hours in advance of proposed utility interruptions. 2. Do not proceed with utility interruptions without receiving written permission from the Owner's Representative. 1.9 SEQUENCING AND SCHEDULING A. Coordinate sanitary sewerage system connections with the local public works department. PART 2 — PRODUCTS 2.1 PIPES AND FITTINGS A. Storm Drainage Pipe and Fittings 1. Reinforced -Concrete Pipe (RCP): NCDOT Section 1032-9, ASTM C76, Class III Wall B, for gasketed joints. a. Shall have section joints designed for cold applied sealing compound conforming to the latest Fed. Spec. SS-S-00210A. Sealing compound shall be RAM-NEK Flexible Plastic Gaskets as manufactured by K.T. Snyder Company, Inc. or approved equal. b. Minimum diameter is 15-inch, unless specifically noted otherwise on plans. 00807.000 Storm Drainage 3341 00 - 2 Addition to Harnett Central High School 2. Polyvinyl Chloride (PVC) Pipe: a. DR 35: ASTM D 3034. b. Gaskets: ASTM F 477, elastomeric seal. 3. Ductile Iron (DI) Pipe: a. See Section 33 3105. 2.2 SPECIAL PIPE COUPLINGS AND FITTINGS: - A. Sleeve -Type Pipe Couplings: Elastomeric sleeve and band assembly fabricated to match outside diameters of pipes to be joined, for non -pressure joints. 1. Sleeves for Cast -Iron Soil Pipe: ASTM F477, elastomeric seal. 2. Sleeves for Plastic Pipe: ASTM F 477, elastomeric seal. 3. Sleeves for Dissimilar Pipes: Compatible with pipe materials being joined. B. Gasket -Type Pipe Couplings: Elastomeric compression gasket, made to match outside diameter of smaller pipe and inside diameter or hub of adjoining larger pipe, for non - pressure joints. 1. Gaskets for Concrete Pipe: Preformed flexible plastic gasket. 2. Gaskets for Plastic Pipe: ASTM F 477, elastomeric seal. 3. Gaskets for Dissimilar Pipes: Compatible with pipe materials being joined. 2.3 MANHOLES A. Storm Drain Manholes: Conform to NCDOT, Section 840. B. Precast Concrete Manholes: ASTM C 478, precast, reinforced concrete, of depth indicated, with provision for rubber gasket joints. 1. Ballast: Increase thickness of precast concrete sections or add concrete to base section, as required to prevent floatation. 2. Base Section: 6-inch minimum thickness for floor slab and 5-inch minimum thickness for walls and base riser section, and having a separate base slab or base section with integral floor. 3. Riser Sections: a. 4-inch minimum thickness, 48-inch diameter, and lengths to provide depth indicated. b. 6-inch minimum thickness, 60-inch diameter, and lengths to provide depth indicated. C. 8-inch minimum thickness, 72-inch diameter, and lengths to provide depth indicated. d. Minimum manhole diameter is 48-inch. Minimum inside drop manhole diameter is 60-inch. Storm drain manhole diameters are determined by maximum diameter of pipe entering and angles between all pipes connected. 4. Top Section: Eccentric cone type, unless concentric cone or flat -slab -top type is indicated. Top of cone of size that matches grade rings. 5. Gaskets: ASTM C 443, rubber. 6. Grade Rings: Include 2 or 3 reinforced -concrete rings, of 6- to 9-inch total thickness, that match a 24-inch diameter frame and cover. 00807.000 Storm Drainage 33 41 00 - 3 Addition to Harnett Central High School 7. Steps: Individual steps of rubber or plastic encased steel reinforcing bar as manufactured by MA Industries (Model PSI-PF). Include a width that allows a worker to place both feet on one step and is designed to prevent lateral slippage off the step. Cast steps or anchor ladder into base, riser, and top section sidewalls at 12- to 16-inch intervals. Omit steps for manholes less than 60 inches deep. 8. Pipe Connectors: ASTM C 923, resilient, of size required, for each pipe connecting to base section. 9. Preformed flow channels shall not be acceptable. C. Manhole Frames and Covers: ASTM A 48-83, Class 30, heavy-duty cast iron. Include indented top design with lettering, equivalent to the following, cast into cover: I. Storm Drainage Piping Systems: Storm Sewer. 2.4 CATCH BASINS A. Precast Concrete Catch Basins: Conform to NCDOT Section 840. Dimensions shall be as indicated on the drawings. 1. Steps: Individual steps of rubber or plastic encased steel reinforcing bar as manufactured by MA Industries (Model PSI-PF). Include a width that allows a worker to place both feet on one step and is designed to prevent lateral slippage off the step. Cast steps or anchor ladder into base, riser, and top section sidewalls at 12 to 16 inches intervals. Omit steps for manholes less than 60 inches deep. 2. Pipe Connectors: ASTM C 923, resilient, of size required, for each pipe connecting to base section. B. Brick Catch Basins: Brick and mortar, of depth, shape, and dimensions indicated. 1. Base, Channel, and Bench: Concrete. 2. Wall: ASTM C 32, Grade MS, manhole brick; 8-inch minimum thickness with tapered top for a 24-inch frame and cover. a. Option: ASTM C 139, concrete masonry units may be used instead of brick. 3. Mortar: ASTM C 270, Type S, using ASTM C 150, Type II, portland cement. 4. Steps: Individual steps of rubber or plastic encased steel reinforcing bar as manufactured by MA Industries (Model PSI-PF). Include a width that allows a worker to place both feet on one step and is designed to prevent lateral slippage off the step. Cast steps or anchor ladder into base, riser, and top section sidewalls at 12-to 16-inch intervals. Omit steps for manholes less than 60 inches deep. C. Frames and Grates: ASTM A 48, Class 30 iron. Include 24-by-24-inch minimum flat grate with small square or short -slotted drainage openings as indicated. 00807.000 Storm Drainage 3341 00 - 4 Addition to Harnett Central Hieh School 2.5 DRAINS 1. Roof Drains: Provide PVC or DI pipe per size indicated on the plans. Refer to plumbing plans for location and invert of roof drains to be installed 5' from the building. 2. Bioretention Drains: Provide 4" PVC pipe with 3/8" holes drilled 6" oe in 4 rows around the diameter of the pipe. Provide filter fabric sock around pipe. 2.6 STORM -WATER INLETS A. Frames and Grates: Heavy-duty frames and grates according to NCDOT Roadway standards. 2.7 PVC DRAINAGE INLETS PVC surface drainage inlets shall be of the inline drain type. The ductile iron grates (12" and 15" frames are cast iron) for each of these fittings are to be considered an integral part of the surface drainage inlet and shall be furnished by the same manufacturer. The surface drainage inlets shall be as manufactured by Nyloplast America, Inc., or prior approved equal. The inline drain required for this contract shall be manufactured from PVC pipe stock, utilizing a thermo-molding process to reform the pipe stock to the furnished configuration. The drainage pipe connection stubs shall be manufactured from PVC pipe stock and formed to provide a watertight connection with the specified pipe system. This joint tightness shall conform to ASTM D3212 for joints for drain and sewer plastic pipe using flexible elastomeric seals. The pipe bell spigot shall be joined to the inline drain body by use of a swage mechanical joint. The pipe stock used to manufacture the inline drain body and pipe bell spigot of the surface drainage inlets shall meet the mechanical property requirements for fabricated fittings as described by ASTM D3034, Standard for Sewer PVC Pipe and Fittings; ASTM F1336, Standard for PVC Gasketed Sewer Fittings. 2.8 OUTFALLS A. Install flared end pipe sections to match pipe material. Adjust contours of grade surrounding end section to provide gradual, smooth tie to the surrounding grade. B. Riprap: Broken stone,- irregular size and shape, of NCDOT Class indicated in detail. Where no Class is indicated, use Class B. C. Velocity Dissipaters: Construct as indicated in detail. PART 3 — EXECUTION 3.1 EARTIIWORK A. Excavating, trenching, and backfilling are specified in Section 31 23 17. B. For Bioretention Pond see plans and detail sheets. 00807.000 Storm Drainage 3341 00 - 5 Addition to Harnett Central High School 3.2 IDENTIFICATION A. Materials and their installation are specified in Section 31 23 17 for installation of "detectable" tracer wire of minimum 12 gauge THHN buried along the pipe in accordance with local utility standards. 3.3 SPECIAL PIPE COUPLING AND FITTING APPLICATIONS A. Special Pipe Couplings: Use where indicated and where required to join piping and no other appropriate method is specified. Do not use instead of specified joining methods. 1. Use the following pipe couplings for non -pressure applications:: a. Strait -pattern, sleeve type to join piping, of same size, with small difference in outside diameters. b. Increase/reducer-pattern, sleeve type to join piping of different sizes. C. Gasket type to join piping of different sizes where annular space between smaller piping's outside diameter and larger piping's inside diameter permits installation. d. Internal -expansion type to join piping with same inside diameter. B. Special Pipe Fittings: Use where indicated. Include polyethylene (PE) encasement. 3.4 INSTALLATION, GENERAL A. Existing Conditions: Drawings indicate the general location and arrangement of existing underground utilities based upon best available data. Contractor shall be responsible for verifying all existing conditions, and shall notify the Owner's Representative of any discrepancies between field conditions and those indicated on the drawings. B. Install piping beginning at low point of systems, true to grades and alignment indicated with unbroken continuity of invert. Place bell ends of piping facing upstream. Install gaskets, seals, sleeves, and couplings according to manufacturer's recommendations for use of lubricants, cements, and other installation requirements. Maintain swab or drag in line and pull past each joint as it is completed. C. Use manholes for changes in direction, except where fittings are indicated. Use fittings for branch connections, except where direct tap into existing sewer is indicated. D. Use proper size increasers, reducers, and couplings, where different sizes or materials of pipes and fittings are connected. Reduction of the size of piping in the direction of flow is prohibited. E. Install gravity -flow -systems piping at constant slope between points and elevations indicated. 3.5 PIPE JOINT CONSTRUCTION AND INSTALLATION A. General: Join and install pipe and fittings according to the following. 00807.000 Storm Drainage 3341 00 - 6 Addition to Hamett Central High School B. Polyvinyl Chloride (PVC) Plastic Pipe and Fittings: As follows: 1. Join solvent -cement -joint pipe and fittings with solvent cement according to ASTM D 2855 and ASTM F 402. 2. Join pipe and gasketed fittings with elastomeric seals according to ASTM D 2321. C. Concrete Pipe and Fittings: Install according to ACPA "Concrete Pipe Handbook". Use the following seals. D. System Piping Joints: Make joints using system manufacturer's couplings, except where otherwise specified. E. Join piping made of different materials or dimensions with couplings made for this application. Use couplings that are compatible with and fit both system's materials and dimensions as approved by the Owner's Representative. 3.6 MANHOLE INSTALLATION A. General: Install manholes, complete with accessories, as indicated. B. Form continuous and smooth concrete channels and benches between inlets and outlet. Cut pipes to extend a maximum of 2 inches inside structure and grout openings. C. Set tops of frames and covers in suitable mortar surrounded by a concrete collar to a grade one-fourth inch (1/4") above finished surface where manholes occur in pavements. Set tops 3 inches above finished surface elsewhere, except where otherwise indicated. D. Place and install precast concrete manhole sections as indicated. 1. Provide rubberjoint gasket complying with ASTM C 443, at joints of sections. 2. Apply bituminous mastic coating at joints of sections. 3.7. CATCH BASIN INSTALLATION A:_ Construct catch basins to sizes and shapes indicated. Precast structures may be used if prior approval by the Owner's Representative is obtained. Install pipes and inverts as stated above. B. Set frames and grates to elevations indicated. 3.8 CONCRETE PLACEMENT A. Place cast -in -place concrete according to ACI 318, ACI 350R, and as indicated. 3.9 DRAIN INSTALLATION A. Install type drains in locations indicated. B. Embed drains in a 4-inch minimum depth of concrete around bottom and sides. 00807.000 Storm Drainage 3341 00 - 7 Addition to Harnett Central Hieh School C. Fasten grates to drains if indicated. D. . Set drain frames and covers with tops flush with surface of paving. 3.10 TAP CONNECTIONS A. Make connections to existing piping and underground structures so finished work conforms as nearly as practical to requirements specified for new work. B. Use commercially manufactured fittings for piping branch connections as indicated. C. Protect existing piping and structures to prevent concrete or debris from entering while making tap connections. Remove debris or other extraneous material that may accumulate. Use non -shrinking concrete grout around pipe openings as required. 3.11 FIELD QUALITY CONTROL A. Clear interior of piping and structures of dirt and superfluous material as the work progresses. Maintain swab or drag in piping and pull past each joint as it is completed. 1. In large, accessible piping, brushes and brooms may be used for cleaning. 2. Place plug in end of incomplete piping at end of day and whenever work stops. 3. Flush piping between manholes and other structures, if required by authorities having jurisdiction, to remove collected debris. B. Inspect interior of piping to determine whether line displacement or other damage has occurred. Inspect after approximately 24 inches of backftll is in place, and again at completion of the Project. Maximum pipe deflection (flattening) after backfilling shall not exceed five percent (5%) of the minimum average inside diameter of the pipe. 1. Submit separate reports for each system inspection. 2. Defects requiring correction include the following: a. Alignment: Less than full diameter of inside of pipe is visual between structures. b. Deflection: Flexible piping with deflection that prevents passage of a ball or cylinder of a size not less than 92.5 percent of piping diameter. C. Crushed, broken, cracked, or otherwise damaged piping. d. Infiltration: Water leakage into piping. e. Exftltration: Water leakage from or around piping. 3. Replace defective piping using new materials and repeat inspections until defects are within allowances specified. 4. Reinspect and repeat procedure until results are satisfactory. END OF SECTION 00807.000 Storm Drainage 3341 00 - 8 Tai and Associates, PLLC 5561 McNeely Dr., Suite 101 ❑ Raleigh, NC 27612 ❑ (919) 782-9525 ❑ (919) 782-9540 (FAX) August 6, 2008 Mr, Phil Ferrell Assistant Superintendent of Auxiliary Services Harnett County Schools PO Box 1029 Lillington, North Carolina 27546 Re: Subsurface Exploration Services Harnett Central High School Addition Angier; North Carolina Tai Job No. 08-175-1 Dear Mr. Ferrell: P[ECIEUU/ AUG 0 8 2GG8 9 In accordance with your authorization, we have completed a subsurface exploration and geotechnical engineering program for the referenced project. The work items performed include the drilling of twenty-two (22) soil borings, site visit, analyses of data, and the preparation of a report. This report presents the results of the subsurface exploration program. In summary, a shallow foundation is recommended to support the proposed school building addition after subgrade improvement. Undercut of some existing soft soil or compaction of loose sandy soils will be required to stabilize the building pad and foundation subgrade. FIELD EXPLORATION A total of twenty-two (22) soil borings (B-I thru B-22) were drilled for the project site. Borings were advanced to a maximum depth of ninety-eight (98.0) feet below the existing ground surface by a CME 75 and CME 450 drill rigs equipped with hollow stem augers to advance the boreholes. Standard Penetration Tests (ASTM D-1586) were performed at depths of 1.0, 3.5, 6.0, 8.5 feet, followed by one at every 5.0-foot interval. All borehole locations were located using existing surface features and are approximate. LABORATORY TESTING The laboratory testing program consisted of the visual classification of all soil samples recovered (ASTM D-2488). The descriptions of the subsurface materials as represented by the soil samples recovered are indicated in the "Boring Logs". All samples will be discarded 60 days later unless otherwise instructed. SUBSURFACE MATERIALS Based on the field and laboratory testing results, the subsurface materials at the project site consist of the following units starting from the existing ground surface: Mr. Phil Ferrell August 6, 2008 Re: Tai Job No. 08-175-1 Page 2 Surface Material: The existing ground surface is covered by a thin layer of topsoil 0.5 or organic matter to 3.0 inches thick. Asphalt and ABC base course exists in Borings B-1 I, 13, 15, 19 of an existing parking lot. Fill: Fill or backfill soil is encountered in Borings B13, 16 and 17 down to 5.5 feet deep. Some of the fill soil is loose (See Boring B-13): Natural Coastal Plains Deposits: The predominant subsurface materials at the project site consist of coastal plain sedimentary soils belonging to the Cretaceous Period (144 to 65 million years ago). The soils are mostly alternating layers of mostly fine sandy -silty clay and some fine to coarse sands. Some of the sands are extremely fine with thin layers of clay that when disturbed resemble silty soils or clayey soils. Some of the clay soil has low to moderate plasticity. The majority of the sandy soil has a consistency of firm to very firm to dense. A layer or pocket of loose silty clayey sand is encountered in thirteen (13) borings at an average depth of approximately 15 to 20 feet. Very hard blue clay with some thin layers of very dense, partially cemented sand is found in a deep seismic boring B.-6 at 54.0 to 98.0 feet below the ground surface. Auger Refusal is reached in B-6 at 98.0 feet deep. 4. Septic Field: In the general area of Borings B-1 and 2, there is a septic drainage field with potentially very wet septic field sandy soils at shallow depths and a septic tank near B-2. 5. Groundwater: Groundwater is measured in thirteen (13) borings at depths ranging from 9.0 to over 19.0 feet below the existing ground surface, indicating that the randomly present clay layers can trap and also retard or prevent the ground water from rising to the actual elevation. Therefore, we believe the actual groundwater elevation at the site may be at about 12.0 to 15.0 feet below the existing ground surface with pockets of trapped water at as high as 9.0 feet deep. PROJECT INFORMATION We understand that the project consists of the construction of a two (2) story" plus a large, one (1) story, masonry school building with mostly load bearing walls, about 3 to 8 kips per foot. The grading plan is not available. We assume a few feet of cut and fill will be required to grade the site. There will be some additional pavement in the general area of Borings B-20, 21 and 22. RECOMMENDATIONS The site subsurface soils are somewhat sensitive to surface water damage. Grading operations' performed in the winter months of November through March may difficult. Control of surface water is essential. Mr. Phil Ferrell August 6, 2008 Re: Tai Job No. 08-175-1 Page 3 Foundation Based on the above project and subsurface information, it appears that a shallow foundation system is best suited for the proposed project. The existing fill or backfill consisting of loose to very loose sands and soft clay located adjacent to the existing buildings to a depth of up to 5.5 feet below the ground surface will require some minor subgrade improvement. We recommend that the load bearing members of the proposed Harnett Central High School Building Additions in Angier be supported on a shallow foundation system such as spread, continuous, or combined footings. These footings should be supported on. either the firm or stiff natural soil or on new controlled fill. Any loose sands, soft fill, or soils disturbed by surface water must be undercut and replaced with lean concrete.. All footings should be designed at elevations such that no utility lines, utility line excavation, segmented or regular retaining basement wall backfill, and any other footings are located within a 1:1 zone of influence from the edge of the subject footing. The footings for the school building should be designed for a bearing capacity of 4,000 psf. The maximum total and differential post -construction *settlement of the footings will be about 1.0 and 0.5 inch respectively, most likely in the general area of Boring B-5. OTHER DESIGN RECOMMENDATIONS Cut and Fill: Any fill soil not confined by walls should have a final slope of two (2) horizontal on one (1) vertical and the top of fill should be at least ten (10) feet beyond the building limits and five (5) feet beyond the paved areas. All fill within the building pad any pavement system should be placed in 8.0 inch thick layers and compacted to 98% of the Standard Proctor Density (ASTM D-698). Most of the natural soil at the site except some high plasticity clay soil should be suitable for fill. 2. Utilities: All utility pipes should be supported on top of at least 6.0 inches of clean #57 washed stone or coarse clean sand. The backfill should consist of clean natural sandy soil and should be compacted to 95% of the Standard Proctor Density (ASTM D-698), except for the top 3.5 feet, which should be compacted to 98% of the Standard Proctor Density. Moisture content of controlled fill should be within 3% of the optimum moisture content. 3. Slabs: The floor slab should be founded on 4.0 inches of crushed stone or course sand over well -compacted soil. The top of the crushed stone or coarse sand should be lined with a layer of heavy-duty plastic to form a moist barrier. Slabs located in areas of soft or plastic clay soil should be supported on a minimum of 2.0-foot thick compacted crusher run rock or coarse sand replacing the plastic clay soil. Expansion joints should be Mr. Phil Ferrell August 6, 2008 Re: Tai Job No. 08-175-1 Page 4 installed in the floor slabs at every 15.0 feet or less in both directions. The modulus of subgrade reaction is 250 kips per cubic foot. 4. Liquefaction Investieation Sands were identified for a liquefaction investigation if they could be described as having all of the following properties: N-Value less than 11, with less than 11% passing the #200, and below the water table. Sand in the following borings met these criteria: Boring B-5 from 12.0 to 18.5 feet deep for this study, we assume the groundwater will rise to 12.0 feet below the ground surface (worst case). The potential for liquefaction was analyzed and the estimated liquefaction settlement was determined using the computer program SHAKE 2000, using the simplified cyclic stress ratio method of analysis. Detailed results are attached to this report for the boring identified for liquefaction investigation (B-5). Based on this analysis, this boring would encounter liquefaction settlement during a design earthquake due to thin, loose, clayey sand layers at elevations over 12.0 feet below ground surface. Based on the review of adjacent borings, it appears the loose sand lenses do not extend horizontally for great distances. However, other similar pockets probably exist on site between the borings. The loose sand lenses at the referenced depths can be described by an upper layer of soil of non liquefiable sand over a lower layer of liquefiable sand. Dr. Raymond Seed and Dr. Kenji Ishihara (See Attachment for references) reference the upper, non -liquefiable crust as Hi and the lower, liquefiable layer as H, and have developed a correlation be the ratio of Hi/Hz and liquefaction induced damage. The correlation is based on actual post -earthquake observations in Japan and California, and is referred to as the 1985 Criteria. Based on this research, it appears the loose sands in the above referenced boring B-S have little to no likelihood of causing damage during liquefaction induced settlement. Attached to this report is a chart indicating the likelihood of liquefaction -induced ground damage of layered systems, with the HIM2 values for the three borings plotted on the graphs. 5. Seismic Class: The project site subsoil belongs to Seismic Class D according to 2006 NC Building Code. 6. Pavement The pavement subgrade should consist of stiff natural soils or new controlled fill. The pavement system should consist of the following units of materials: Mr. Phil Ferrell August 6, 2008 Re: Tai Job No. 08-175-1 Page 5 ABC 1 19.013 S9.5B PAVEMENT TYPE (IN.) Ll IINN,) Heavy Duty, Service Area 12.0 2.5 1.5 Or 8" Reinforced Concrete Driveway 10.0 2.0 1.5 Parking Area 7.0 --- 2.0 The natural fine sandy soil is easily disturbed. Sometimes it is very difficult to repair the disturbed subgrade. If areas of disturbed soil, or soft fill is encountered at the pavement subgrade and it is impractical to replace, the poor subgrade should be undercut 8.0 inches and covered.with a layer of Mirafi 600X. A layer of Tensar SS-1 should also be placed in the middle of the thickened ABC stone. Positive drain must be maintained to promote release of surface water. CONSTRUCTION CONSIDERATIONS The project site should be cleared of all the existing surface features such as topsoil, old cultivated soil, septic Field soil, septic tank, asphalt, debris, etc. Most of the natural, non -plastic sandy soil excavated is suitable as structural fill. -All excavated plastic clay soil, septic field soil, and organics will not be suitable for re -use as structural fill, and should be hauled off site or wasted in a non-structural area. Surface water control measures such as diversion ditches with sump pumps must be placed prior to any grading and earthwork activity and should be installed as early as possible. The cleared site subgrade should then be proofrolled to identify soft or loose soil that requires removal. The remaining site should be compacted with eight passes of a dynamic 20-ton smooth drum roller. Areas undercut should be backfilled with suitable dry soil. The.actual volume of undercut will vary depending on the final floor elevation. The backfill should consist of clean, sandy, silty, natural soil, be placed in 8.0-inch layers and compacted to at least 98% of the maximum Standard Proctor Density (ASTM D-698). In -Place Density Tests should be performed on the fill and backfill at a rate of one test per lift, per day by the Sand Cone method (ASTM D-1556). Most of the clay soil may be too wet for suitable borrow soil. The foundation excavation not poured immediately should be covered by a 3-inch thick mud slab. The subgrade for the slabs will require a final inspection and some additional improvement including undercutting and backfilling of existing soft fill/backfill soil and any soil disturbed by surface water and construction traffic. Mr. Phil Ferrell August 6, 2008 Re: Tai Job No.08-175-1 Page 6 FIELD SERVICES All earthwork and foundation construction activities must be observed by a part-time field representative of this firm to ensure that the actual subsurface conditions and the intended design considerations are met in every phase of the earthwork and foundation construction. Some modification of the design recommendations presented in this report will very likely be required and any such changes must be verified by this firm. We cannot be held responsible for any of the conditions stated above and the post -construction performance of the foundation and the pavement systems unless we are authorized to perform the field services required. CLOSURE It has been a pleasure to have the opportunity to work with you on the design/development phase of this project. We would like to review the project site, grading, and structural plans when they are available to offer additional comments, including the location of temporary diversion ditches and permanent French drains if required, and an estimate of the amount of undercut required. Please call us if you have any questions or if you need any additional information or services. Very truly yours, Taii and Associates, PLLfCj Matthew T. Ryan, P.E. T. Danny Tai, Ph. D Attachments: I. Boring Location Plan 2. Boring Logs (22) 3. Seismic Classification '.� i'i;`� +;j �s ,•`' 4. References 5. Liquefaction Analysis CC: Mr. John Birath, AIA; SfL+a Architects BORING LOCATION PLAN -I HARNETT CENTRAL HIGH SCHOOL ADDITIONS ANGIER, NORTH CAROLINA . ....... . B -2 B� .......... . ..... BF 4�' '4 .......... f I_ TAI JOB NO. 08-175-1 I' AUGUST, 2008 3 BORING LOCATION PLAN=II HARNETT CENTRAL HIGH SCHOOL ADDITIONS ANGIER, NORTH CAROLINA V s-'2 0 B-21 B-22 1B 1 8 y -1 / 19 YF ,� y r�n x oe B-1Al " if ,..... .3*a ...+.-tiCSs`•rf aim -.a'..- t.,�:-1::. _..;w.;: .. C{"'•a.Fvrer"�+.�+dwrs.' `�.«t�mrvxe^""' q....sFw.,�.::f�..t+K3fWHAw'�!i� � :•rc� f� � ytwq � ��+_ �Yd ,N1vN"'%t� tl� � � � epa AA@."�S.°' z:f,.— ....'.nr"..�:�..— . � �.,...>...✓.Nax+x...:�..�6.�......m..�:..5«b%,.r.«......+,w.�tn+w�' ' .. '+.4. [ L.:. T %h•_ B-15 -14' B-13 u -- 9 iamaxAzwa> �ww.hl: Ta B-12 Y �w---JY`.ont'a 13-11 t 1 t, f..... TAI JOB NO'. 08-175-1 UST,; 2008 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION Angier, North Carolina BORINGNO, B-1 PAGE I OF I CLIENT: Harnett County Schools DATE: August 2 , 2008 4.0 N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV 10 50 90 0.2 Topsoil Dry 6 0 2.9 Tan -brown, firm silty fine SAND 12.0 Tan -orange very stiff to hard fine sandy -silty CLAY 3 3 / 8 17.0 Grat, firm fine sandy-clavev SILT I 7 20.0 Tan -gray, loose silty fine SAND Boring Terminated at 20.0 Feet TAI JOB NO. 08-175-1 1A1 and ASSOCIA E; , PLLC 5561 MCNEELY-DRIVE, SUITE 101, RALEIGH, NC 27612, 919-782-9525 BORING LOG PROJECT. HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools n coTu neerDFDTinM cu, c,rW BORING NO. B-2 PAGE I OF 1 DATE: August 2 , 2008 4 N-VALUE (ASTM D-1586) 10 50 90 0.3 Topsoil 10 Brown, firm clayey fine SAND 3.9 1 Brown, firm silty fine SAND 6.6 10 Orange, stiff silty CLAY 8.8 9.5 1 Brown -gray, very stiff silty — 1.3 fine sandy CLAY Orange, stiff fine sandy clayey /1 SILT, wet / /5 6.5 Orange -gray, firm fine sandy SILT 21.9 \ Tan -gray, very stiff fine sandy CLAY 16 25.0 Boring Terminated at 25.0 Feet TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612,919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-3 LOCATIO14: Angier, North Carolina PAGE 1 OF I CLIENT: Harnett County Schools DATE: August 2 , 2008 0 N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV 10 50 90 0.3, To soil S T 23 2 3.2 Brown -gray, very firm clayey fine SAND. 0.5 Tan -brown, very stiff sandy - silty CLAY 26 3 10 7.1 Tan -gray, firm silty clayey fine SAND I17. 2.5 Tan, loose silty SAND, wet 16 5.0 Gray, very stiff .silty CLAY Boring Terminated at 25.0 Feet 1 Al and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 T61MCNLELY DRIVE. SUITE 101, RALEIGH, NC 27612.919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-4 LOCATION: Angier, North Carolina PAGE I OF CLIENT: Harnett County Schools DATE: August 2 , 2008 gI N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW . ELEV 10 50 90 0.3 Topsoil 1 Brown -gray, very firm clayey 4.0 fine SAND 27 Tan -orange very stiff to hard fine sandy -silty CLAY 31 7.8 41 Brown, stiff fine sandy clayey SILT 1.3, \ Tan -gray, very stiff fine sandy \ CLAY 1 / 6.5 17.— Tan -gray stiff silty CLAY 0.0 10 Boring Terminated at 20.0 Feet TAI JOB NO. 08-175-1 TAI and ASSOCIATES, PLLC 5561 McNEELY DRIVE, SUITE 101, RALEIGH, NC 27612, 919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-5 LOCATION: Angier, North Carolina CLIENT: Harnett County Schools uisaw� nccro m7lnwi PAGE I OF I DATE: August 2, 2008 a N-VALUE (ASTM D-1586) CIW FT FV In SO 90 0. —Topsoil Brown -gray, very firm clayey 3.6 fine SAND, some gravel 22 Tan=orange very stiff to hard fine sandy -silty CLAY 1 2 8.0 /j 14 Brown, stiff fine sandy clayey SILT 12-C Tan, loose clayey fine SAND, 4 wet 6. 18. 4 Tan -orange firm fine sandy CLAY 22. 2 Tan -gray stiff silty CLAY 5. Boring Terminated at 25.0 Feet , TAI JOB NO. 08-175-1 1'A1 and ASSOCIATES, PLLC 5561 McNEELY DRIVE, SUITE 101, RALEIGH, NC 27612, 919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools n¢, c, cv BORING NO. B-6 PAGE !.OF 2 DATE: August 3 , 2008 k N-VALUE (ASTM D-1586) 10 50 90 0.3 To soil 14 Tan, stiff sandy CLAY 3.2 \ 2 Tan -brown, very stiff sandy - silty CLAY 77. 81 8 20 Tan, firm silty CLAY 12.5 \ 16 Gray, very stiff fine sandy SILT, moist 17.4 19. r Tan -brown, firm silty fine 1 SAND 22.5 7 Tan -brown, loose silty fine SAND \ \ r 4 Gray hard sandy CLAY 2 31.0 Gray, hard silty plastic CLAY 7 TAI and ASSOCIAI ES, YLLt: TAI JOB NO. 08-175-1 - 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612, 919-782-9525 PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING140. B-6 LOCATION: Angier, North Carolina PAGE 2OF, 2 CLIENT: Harnett County Schools DATE: August 3 , 2008 a N-VALUE (ASTM D-1586) DEPTH DESCRIPTION G W ELEV 10 50 90 7.5 Gray, hard silty plastic CLAY 2 0 4.0 Blue gray very stiff fine sandy CLAY 56 6 8.0 Blue -gray, very hard fine sandy - silty CLAY Boring Terminated at 98.0 Feet Auger Refusal at 98.0 Feet 7 50 .3 50 .3 50 .3 50 .2 50 .2 50 .1 50 .0 TAI SOB N0. 08-175-1 1'A1 and ASSUCIA'IES, FLLC 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612, 919-792-9525 BORING LOG PROJECT: HARNET'T CENTRAL HIGH ADDITIONS BORING NO. B-7 LOCATION: Angier, North Carolina PAGE I OF CLIENT: Harnett County Schools DATE: August 2 , 2008 N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV 10 50 90 0.2 Tan fine SAND Dry 5 5.5 Orange -red, dense fine SAND and Gravel 2 16 2.0 Tan -brown, very stiff sandy - silty CLAY ' 1 6.7 Tan -gray, firm silty clayey fine SAND 20.0 Tan -brown, loose silty fine S AND Boring Terminated at 20.0 Feet 50 1.5 TAI and ASSOCIATES, PLLC TAI SOB NO. 08 -17 5.-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612, 919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-8 LOCATION: Angier, North Carolina PAGE 1 OF CLIENT: Harnett County Schools DATE: August 2 , 2008 N-VALUE (ASTM D-1586) DEPTH nccrainTinU .G w FLFV 10 50 90 0.3 Topsoil Dry 8 52 4.5 Orange red hard fine sandy CLAY 2.0 Tan -brown, very stiff sandy - silty CLAY 2 2 15 7.3 Brown, stiff fine sandy clayey SILT 1 20.0 Orange -gray, firm fine sandy SILT Boring Terminated at 20.0 Feet TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612, 919-782-9525 3ORMG LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORINGI40. B-9 LOCATION Angier, North Carolina PAGE I OF CLIENT: Harnett C6unty Schools DATE: August 2 2008 Vp N=VALUE (ASTM D-1586) DEPTH DESCRIPTION G W ELEV 10 50 90 0.3 Topsoil 17. 1 3 8.0 Tan -brown, very stiff sandy - silty CLAY 14 2 2.5 Tan -gray, firm silty clayey fine SAND I 116 7.0 Tan -gray, very stiff fine sandy CLAY / 9 0.0 Tan -gray, loose silty fine SAND I Boring Terminated at 20.0 Feet TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE, SUITE 101, RALEIGH,NC27612, 919-732-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING140. B-10 LOCATION: Angier, North Carolina PAGE.1 OF 1 CLIENT: Harnett County Schools DATE: August 2 , 2008 a N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV W 50 90 0.2 Topsoil 17. 18 3 2.1 Tan -brown, very stiff sandy - silty CLAY 3 2 1 6.9 Pink -gray, firm silty fine SAND 1.7 Orange -gray, firm fine sandy SILT 6 5.0 Gray hard CLAY Boring Terminated at 25.0 Feet . 1 Al and ASSOCIAI ES, YLLC; TAI JOB NO. 08-175-1 5561 McNEELY DRIVE, SUITE 101, RALEIGH, NC 27612, 919-752-9525 BORIING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools cw m vv BORING 1d0. B-11 PAGE 1 OF I DATE: August 2 , 2008 ij� N-VALUE (ASTM D-1586) 10 50 90 v0.5 Asphalt and Base Dry ® °Y1 3 16 5.5 Orange, stiff silty CLAY 8 1 8 1 Orange -gray, firm fine sandy SILT 16.8 Tan -brown, very stiff sandy- silty CLAY I 2 1 20.0 Tan, firm silty fine SAND Boring Terminated at 20.0 Feet 'I Al and ASSU( IAlhN, YLLL TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612, 919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORITIG NO. B-12 LOCATION: Angier, North Carolina PAGE I OF CLIENT: Harnett County Schools DATE: August 2 2008 * N-VALUE (ASTM D-1586) DEPTH iIF r-PIPTIC)N CiW FLEV 10 50 90 0.11 To soil 9 28 3. Brown -gray, very firm clayey fine n 5. Orange, stiff silty CLAY 23 28 16. Tan -brown, very stiff sandy - silty CLAY 29 6 Tan -gray, loose silty fine SAND Boring Terminated at 20.0 Feet TAI JOB No. 08-175-1 TAI and ASSOCIATES, FLLC 5561 McN EELY DRIVE. SUITE 101, RALEIG H. NC 27612, 919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION. Angier, North Carolina CLIENT: Harnett County Schools DEPTH nccrDIDTinnr r.w F1 FV 13ORING 1d0. B-13 PAGE I OF I DATE: August 2 , 2008 N-VALUE (ASTM D-1586) 10 50 90 0.6 Asphalt and Base.Course Dry 2 5.5 FILL--Tan-orange silty -clayey fine SAND 14 2 8.1 Brown, stiff fine sandy clayey SILT 0.0 Tan -brown, very stiff sandy - silty CLAY I 9 16 4 Boring Terminated at 20.0 Feet TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RA LEI GH. NC 27612. 919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools nCQr. (.-nnni 1w FI G\/ BORING NO. B-14 PAGE I OF 1 DATE: August 2 , 2008 N-VALUE (ASTM D-1586) 10 50 90 0.21 To soil 15. 15 3 3.1 Orange stiff fine sandy SILT 7.0. Tan -brown, very stiff sandy- silty CLAY 2 2 I 3 ` 0.0 Tan -gray, loose silty fine SAND Boring Terminated at 20.0 Feet TAI and ASSOCIA11 S, YLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612.919-782- 9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-15 LOCATION: Angier, North Carolina PAGE 1 OF 1 CLIENT: Harnett County Schools DATE: August 2 , 2008 a N-VALUE (ASTM D-1586) n 7:PTN nFSCRIPTInN GW ELEV 10 50 90 0. Asphalt and Base Course 9.0 1 2 2.3 Tan -brown, very stiff sandy- silty CLAY 2 2 / 9 0.0 Tan -brown, firm silty fine SAND ,1 Boring Terminated at 20..0 Feet TAI and ASSUCIAILS, FLLI; TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH. NC 27612,919-7S2-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools inv BORING NO, B-16 PAGE 1 OF I DATE: August 2 , 2008 #� N-VALUE (ASTM D-1586) 10 50 90 0.1 To soil Dry r 4 12 3.0 FILL --Brown silty SAND 5.5 Brown -gray, very firm clayey fine SAND 3 2 8.0 Orange, very firm clayey SAND 6.7 Tan -brown, very stiff sandy - silty CLAY I 8 / 4 20.0 Tan -gray stiff silty CLAY Boring Terminated at 20.0 Feet TAI and ASSOCIATES, PLLC TAI SOB NO. 08 -17 5 -1 5561 McNEELY DRIVE, SUITE 101, RALEIGH, NC 27612, 919-792-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-17 LOCATION: Angier, North Carolina PAGE 1 OF CLIENT: Harnett County Schools DATE: August 2 2008 4 N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV 10 50 90 0.2 Topsoil 14. 1 2 4.0 FILL --Orange silty fine SAND 6.0 Tan -brown, very stiff sandy- silty CLAY 1 16 . 6 / 0.0 Tan -gray, loose silty fine SAND Boring Terminated at 20.0 Feet I TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 - 5561 McNEELY DRIVE, SUITE 101, RALEIGH, NC 27612,919-78M525 BORING LOG PROJECT HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-18 LOCATION: Angier, North Carolina PAGE 1 OF CLIENT: Harnett County Schools DATE: August 2 2008 q) N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV 10 50 90 0.3 Topsoil 12.11/ 1 1 2.5 Tan -brown, very stiff sandy - silty CLAY 1 1 0.0 Tan, loose silty SAND, wet 1 9 Boring Terminated at 20.0 Feet 1 Al and ASSOCIATES, YLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC27612,919-782-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-19 LOCATION: Angier, North Carolina PAGE 1 OF CLIENT: Harnett County Schools DATE: August 2 , 2008 Q)r N-VALUE (ASTM D-1586) DEPTH DESCRIPTION GW ELEV 10 50 90 0,5i Asphalt and Base Course 9_0 13 27 Tan -brown, firm silty fine SAND 1.5 Tan -brown, very stiff sandy- silty CLAY 2 2 / 0.0 Tan, loose silty SAND, wet 1 1 8 Boring Terminated at 20.0. Feet r,' TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE IOL RALEIGH, NC 27612, 919-782-9525 BORING LOG PROJECT HARNETT CENTRAL HIGH ADDITIONS LOCATION Angier, North Carolina CLIENT: Harnett County Schools n FnTu nGcrDIDTinm nA3l Li GV/ BORING NO. B-20 PAGE i OF I DATE: August 2 , 2008 g N-VALUE (ASTM D-1586) in 90 0.2 Topsoil Dry 2 0 3.0 Brown -gray, very firm fine SAND clayey 5.5 Tan -brown, very stiff silty CLAY sandy- f ® 27 1 8.0 Brown -gray, very firm fine SAND clayey 0.0 Tan -brown, very stiff silty CLAY sandy- I Boring Terminated at 10.0 Feet TAI and ASSOCIATES, PLLC TAI JOB NO. 08-175-1 556.1 McNEELY DRIVE, SUITE 101, RALEIGH, NC27612,919-782- 9525 BORING LOG r1FPTH PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools DATE: August 2 , 2008 0 N-VALUE (ASTM D-1586) nw PI FV In cn nFICP IPTInN BORING NO. B-21 PAGE 1 OF I 0.3 Topsoil Dry 3 15 6.0 Brown, stiff fine sandy CLAY 3 9 8.0 Tan -brown, very stiff sandy- silty CLAY 0.0 Tan, firm clayey SAND Boring Terminated at 10.0 Feet 1 Al and AJJUUA I hJ, FLLI.: TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101, RALEIGH, NC 27612,919-7S2-9525 BORING LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS LOCATION: Angier, North Carolina CLIENT: Harnett County Schools nGnru nccro �nn nni BORINGNO. B-22 PAGE I OF 1 DATE: August 2 2008 ® N-VALUE (ASTM D-1586) 90. 0.3 Topsoil Dr 14. 19 4.0 Brown, stiff sandy CLAY 8.0 Tan -brown, very stiff sandy- silty CLAY 2 14 10-C Brown, tan, stiff silty CLAY Boring Terminated at 10.0 Feet lAlandASSUCIAILS,YLLC TAI JOB N0. 08 -17 S -1 5561 McNEELY DRIVE, SUITE 101, RALEIGH, NC 27612, 919-782-9525 SEISMIC SITE CLASS CALCULATION - BORING B-6 BASED ON N-VALUE PER EQUATION 16-42 OF THE 2006 NC BUILDING CODE JOHNSONVILLE ELEMENTARY SCHOOL ADDITION JOHNSONVILLE, NC DEPTH RANGE LAYER LAYER N-VALUE di / Ni CALCULATION THICKNESS 0 . 3.25 layer 1 3.25 14 0.23 Sum of di 100 3.25 5.75 layer 2 2.5 23 0.11 Sum of di/Ni 3.62 5.75 8.25 layer 3 2.5 20 0.13 8.25 12 layer 4 3.75 8 0.47 Nbar 28 12 17 layer 5 5 16 0.31 17 22 layer 6 5 11 0.45 ISITE CLASS: D 22 27 layer 7 5 7 0.71 27 32 layer 8 5 34 0.15 32 37 layer 9 5 25 0.20 37 42 layer10 5 37 0.14 42 47 layerll 5 33 0.15 47 52 layer 12 5 60 0.08 52 57 layer 13 5 88 0.06 57 62 layer 14 5 100 0.05 62 67 layer 15 5 100 0.05 67 72 layer 16 5 100 0.05 72 77 layer 17 5 100 0.05 77 82 layer 18 5 100 0.05 82 87 layer 19 5 100 0.05 87 92 layer 20 5 100 0.05 92 97 layer 21 5 100 0.05 97 100 layer 22 3 100 0.03 This is used after verification that the Site Class is not E, F,.A, or B The notations presented apply to the upper 100 feet of the site profile. Profiles containing distinctly different soil and/or rock layers shall be subdivided into those layers designated by a number that ranges from I to n at the bottom where there is a total of n distinct layers in the upper 100 feet. i = Refers to any one layer of the layers between 1 and n di = The thickness of any layer between 0 and 100 feet N, = The Standard Penetration Resistance (ASTM D-1586) not to exceed 100 blows/foot as directly measured in the field without corrections. When refusal is met for a rock layer, Ni shall be taken as 100 blows/foot TAI JOB NO. 08-174-1 August 4, 2008 BORING. LOG PROJECT: HARNETT CENTRAL HIGH ADDITIONS BORING NO. B-5 LOCATION: Angier, North Carolina PAGE I OF CLIENT: Harnett County Schools DATE: August 2, 2008 ¢P N-VALUE (ASTM D-I535) DEPTH DESCRIPTION GW ELEV 10 50. gn 0.3 Topsoil Brown -gray, very firm clayey 3.6 fine SAND, some gravel 22 Tan -orange very stiff to hard fine sandy -silty CLAY 2 8.0 14 Brown, stiff fine sandy clayey SILT 12.0 4 Tan, loose clayey fine SAND, wet 6. 18. 4 Tan -orange firm fine sandy CLAY 22. 2 Tan -gray stiff silty CLAY 5. Boring Terminated at 25.0 Feet ATTACHMENT 4 LIQUEFACTION ANALYSIS Assuming the groundwater rises to 12.0 feet and that the entire layer of loose clayey sand from 12.0 to 18.5 feet will liquefy. Results are plotted on next page. 1 Al and ASSOCIATES, YLLC TAI JOB NO. 08-175-1 5561 McNEELY DRIVE. SUITE 101. RALEIGH, NC 27612.919-782-9525 REFERENCES FOR LIQUEFACTION THORY Liquefaction consists of the loss of strength, movement and consolidation of soil particles during an earthquake. It typically occurs in loose, uniformly graded sands located below the water table. Since liquefaction is not a phenomenon that takes place often, it is very difficult to predict and to analyze with certainty. Most of the research on liquefaction theory in the United States has taken place in California. Professor Raymond B. Seed, Ph.D., at the University of California -Berkeley is considered to be at the forefront of this research. While there is no official industry standard for liquefaction analysis, the work performed by Dr. Seed is probably the most commonly accepted. With the North Carolina adoption of the International Building Code, analysis of liquefaction has become a requirement in the state of North Carolina. This analysis affects the seismic Site Class, and requires that engineers consider liquefaction in foundation design. The building code does not provide specific instructions on how to analyze liquefaction, so it is up to geotechnical engineers to choose an analysis method. For this analysis, we have relied on the following four sources for analysis:. 1. 4-30-03 Publication: 'Recent Advances in Soil Liquefaction Engineering: A Unified and Consistent Framework", by R. B. Seed, et. al. 2. 03-99 Publication: 'Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and Mitigating Liquefaction in California" 3. 1985 Publication: "Proceedings of the eleventh international conference on soil mechanics and foundation engineering", Page 321, "Stability of natural deposits during earthquakes", K.Ishihara 4. Software: Shake 2000. Fob EkPLArJ "toN'. C'AO't,�)c-f- required to avoid ,damage due to liquefaction is surprisingly large. This fact may need to be interpreted in the light of the extremely strong shaking occurring in this area during the Tangshan earthquake. Since this area is located within 30 Km from the epicenter of the magnitude 7.8 earth- quake, the intensity of shaking is believed to have been of the order of 8 to 9 on the Chinese intensity scale. The corresponding ground accel- eration is supposed to have been as great as 400 to 500 gal. In order to compare the results of the two inde- pendent studies described above, the boundary curve obtained by Gao at al. (1983) was re -plotted using the same type of presentation as for the diagram in Fig. 85. The two boundary curves thus superimposed are shown in Fig.. 87. One of the peculiar features of the curve by Gao at al. (1983) is that, for increasing thickness of lique- fiable sand layer, .the thickness of surface layer 12 11 10 NIMnYaI-chuEu Ea. 9 Motaac.4 200 gat B iE:v $ 1). Turw Eq. F v 'hon coo tat (19aa) 6 Mos, acc. M o P aco-scs t s. a l'q:IrMuceE grow,E aongge .% q 2 0 1 2 9 a 6 6 2 4 9 m Fig. 87 Comparison of two boundary curves differentiating between conditions of damage and no damage due to liquefaction F-S-S utTS 1- of L t Q0EV7-?._C_" a aJ — Ln�O. I C�'> OA n �� [ac tVE,N (�4@ l2I required to prevent liquefaction damage tends to decrease when it is smaller than about 5 m. This contradiction appears to result from Gao's defini- tion of surface layer being different from that illustrated in Fig. 84. In their data arrange- ments,the surface layer thickness appears to be taken simply as the thickness of the sandy clay deposit near the ground surface. However, in cases where the ground water table is located below the bottom of the surface layer as illustrated in. Fig. WE), the thickness of the unliquefiable surface layer should have been taken as being equal to the depth of the elevation of the ground water table. If such a modification is incorporated in Gas 'a data interpretation, the boundary curve would probably be corrected as indicated in Fig. 88. Also plotted in Fig. 88 is the boundary curve established in Fig. B5. Comparison of these two curves appears to indicate that the difference emerges mainly from the difference in the intensity of shaking incurred in the investigatedareas 362 W zsy $T C A"Sf_ is �RSe- w _ $ 43l ::1 �a - a 2 2 t Thickness of surface Byer H, (m) Fig. 88 Proposed boundary curves for site identification of liquefaction - induced damage during these two earthquakes. Considering the great difference in the intensity of shaking and hence the large gap between the two proposed curves, it might well be possible to draw another boundary curve between them as shown in Fig. 88 for an intermediate level of shaking intensity with a ground acceleration on the order of 300 gal. The three boundary curves thus established and shown in Fig. 88 may be useful for identifying sites from the viewpoint of whether or not the ground sustains damage due to liquefaction during a given intensity of earthquake shaking. SEISMIC STABILITY OF NATURAL SLOPES XI EVALUATION OF SOIL PROPERTIES IN SEISMIC LOADING 11.1 General Failure of natural slopes during earthquakes is governed in many cases.by details of geological and hydrological conditions. However, careful scrutiny of the site conditions in many slide areas during past earthquakes has indicated that there always seems to exist a well-defined slip plane in the slide area and that this plane runs through a zone of weakness near the surface of the slope -forming soil deposits. The weak zone is often created by water infiltration into sur- face layers of residual or weathered soils but there are also many cases where planes of weakness coincide with tectonically disturbed zones such as fault surfaces and contact surfaces between beds or sequences of rock. Evaluation of seismic stability of natural slopes should, therefore, be made by identifying the potential slip plane and by investigating the properties of the soils constituting the zone of weakness. Since the mode of stress applications