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HomeMy WebLinkAboutSW5130501_HISTORICAL FILE_20130507'k - ... STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW� DOC TYPE ❑CURRENT PERMIT ❑ APPROVED PLANS IQP HISTORICAL FILE l DOC DATE ,I ofol YYYYMMDD Report of Subsurface Investigation and Geotechnical Engineering Evaluation Siler City Kingdom Ball Siler City, North Carolina prepared for N.C. Regional Building Committee 94 TerraTech Engineers, Inc. (C-1356) 4905 Professional Court Raleigh, North Caroling 27609 Phone: 919-876-9799 Fax: 919-876-8291 TFRPATECH E N G I N E E R S- I N C C,eotechnlcaL Lngineering environmental CnnsuLting Construction tjateriaLn Tenting M M - 7 2013 September 20, 2011 N.C. Regional Building Committee #4 4509 Lawrence Daniel Drive Matthews, North Carolina 28104 "acek tcco.com ATTENTION: Mr. Jon Jacek Report of Subsurface Investigation and Geotechnical Engineering Evaluation Siler City Kingdom Hall Siler City, North Carolina Our Project Number 121-11-65510 Gentlemen: TFRPATECH E N G I N E E R S • I N C (�eotechnical Lngineering G nvironmental Con5ulting Construction Materials Testing TerraTech Engineers, Inc, has completed the authorized subsurface investigation and engineering evaluation for the planned construction of the Kingdom Hall in Siler City, North Carolina. The enclosed report describes our investigative procedures and presents the results of our testing and evaluation along with design and construction recommendations for this project. We appreciate the opportunity to work with you on this project, and look forward to providing the recommended construction testing services. If you have any questions concerning this report, please contact us. Sincerely, Te Tech Engineers, Inc. (C- 56) Glen A. Malpass, P.E. Erwin T. Williams III, P.E. Senior Geotechnical Engin r Principal Geotechnical Engineer GAM/sk 4905 Professional Court - Raleigh, North Carolina 27609 • (919) 876-9799 • Fax: (919) 876-9291 Page 1 SCOPE OF SERVICES TFRP4TECH E N G I N E E R$• I N C [eLItechnicalC-nyineenng Lnoronmental Cansulling Construction Materials Testing The scope of this subsurface investigation was outlined in our proposal #4910-N dated June 16, 2011. The primary objectives of this investigation were to evaluate the subsurface conditions within the area of proposed construction and to make recommendations regarding foundation design. More specifically, this investigation included the following objectives: (1) To evaluate the existing subsurface soil and ground water conditions within the area of proposed development. (2) To recommend foundation types which can safely and economically support the proposed construction. (3) To evaluate the allowable bearing pressure of the foundation subsoils encountered within the proposed building area for support of shallow foundations. (4) To make recommendations concerning site preparation and site grading, including a discussion of the excavation characteristics of the encountered materials. (5) To make design recommendations for concrete slabs -on -grade. (6) To make recommendations concerning control of ground water during construction and on a permanent basis, if necessary. (7) To make recommendations for material types and thicknesses for the planned pavement systems in the driveways and parking areas. (8) To make recommendations for achieving high density structural fill capable of satisfactorily supporting the proposed construction. (9) To make pertinent recommendations concerning quality control measures during construction. Page 2 INVESTIGATIVE PROCEDURES Field Investigation TORPATECH E N G I N E E R S - I N C C,eateehnlcal Lnglneer ng Cnvironmental Consulting Can5trucben Yaferial5 Testing The subsurface investigation consisted of five soil test borings advanced to a depth 15 feet below the existing ground surface elevation. The approximate test boring locations are shown on Figure 1 in the Appendix. The test borings were located in the field by representatives of TerraTech Engineers, Inc. by measuring distances and angles from existing site reference points. In general, the locations of the test borings should be considered approximate. Ground surface elevations were not known at the time of this report. Standard penetration testing, as provided for in ASTM D-1586, was performed at selected intervals in the soil test borings. The standard penetration resistance, in conjunction with soil classifications, provides some indication of a soil's engineering characteristics. Detailed descriptions of the soils encountered in the test borings are provided in the Test Boring Records included in the Appendix. Ground water conditions, penetration resistances, and other pertinent information are also included. Please note that the stratification lines on the Test Boring Records are approximate boundaries between soil types. The in -situ transitions are likely to be more gradual. Laboratory Investigation The laboratory investigation consisted of a physical examination and classification of all samples obtained from the drilling operation. Classification of the soil samples was performed in general accordance with ASTM D-2488 (Visual -Manual Procedure for Description of Soils). Soil classifications include the use of the Unified Soil Classification System described in ASTM D-2487 (Classification of Soils for Engineering Purposes). The soil classifications also include our evaluation of the geologic origin of the soils. Evaluations of geologic origin are based on our experience and interpretation and may be subject to some degree of error. Page 3 GENERAL SITE AND SUBSURFACE CONDMONS Site Location and Description TFRP4TECH ENGINEERS• INC (�eotechnical Lngineering Lmironmental Consulting Construction AAateriaLs Testing The site is located northeast of the intersection of Eden Hills Drive and Old U.S_ Highway 421 North in Siler City, North Carolina. At the time of our investigation, the site was clear of trees and the ground surface was generally covered with heavy underbrush and grass. Site topography generally slopes downward to the south. Maximum relief across the site is approximately 30 feet. Reeional Geolo�v The subject site is located in the Piedmont Physiographic Province of North Carolina. Based on a review of geologic maps, it appears that the site is located within a geologic unit known as the Carolina Slate Belt. The site is generally underlain by massive metamorphic rocks consisting of biotite gneiss and schist, with some mica schist. Soils in this area have been formed by the in -place weathering of the underlying rock, which accounts for their classification as "residual" soils. Residual soils near the ground surface, which have experienced advanced weathering, frequently consist of clayey silt (ML) or silty clay (CL). The thickness of this surficial clayey zone may range up to roughly 6 feet. (For various reasons, such as erosion or local variation of mineralization, the upper clayey zone is not always present.) With increased depth, the soil becomes less weathered, coarser grained, and the structural character of the, underlying parent rock becomes more evident. These residual soils are typically classified as sandy micaceous silt (ML) or silty micaceous sand (SM). With a further increase in depth, the soils eventually become quite hard and take on an increasing resemblance to the underlying parent rock. When these materials have a standard penetration resistance of 100 blows per foot or greater, they are referred to as partially weathered rock. The transition from soil to partially weathered rock is usually a gradual one, and may occur at a wide range of depths. Lenses or layers of partially weathered rock are not unusual in the soil profile. Partially weathered rock represents the zone of transition between the soil and the indurated metamorphic rocks from which the soils are derived. The subsurface profile is, in fact, a history of the weathering process which the crystalline rock has undergone. The degree of weathering is most advanced at the ground surface, where fine grained soil may be present. The weathering process is in its early stages immediately above the surface of relatively sound rock, where partially weathered rock may be found. The thickness of the zone of partially weathered rock and the depth to the rock surface have both been found to vary considerably over relatively short distances. The depth to the rock surface may frequently range from the ground surface to 60 feet or more. The thickness of partially weathered rock, which overlies the rock surface, may vary from only a few inches to as much as 40 feet or more. Stream valleys in the Piedmont often contain alluvial (water deposited) soils, depending on ground surface topography, stream flow characteristics, and other factors. By nature, alluvial soils can be highly variable depending upon the energy regime at the time of deposition. Coarse materials such as sand or gravel are deposited in higher energy environments, while fine grained materials such as silt and Page 4 TFRPATECH E N G I N E E R S - I N C Geotechnical Engineer ng Lavironmentat Consulting Construction MateHats Testing clay are deposited in low energy environments. Alluvial soils may also contain significant amounts of organic materials, and are frequently in a loose, saturated condition. In many cases, fine grained alluvial soils will be highly compressible and have relatively low shear strength. General Subsurface Conditions From the ground surface, each of the test boring locations encountered topsoil. The thickness of the topsoil ranged from approximately 4 to 8 inches. The thickness of topsoil can be quite variable and could be significantly different at other locations on the site. The reported thickness of the topsoil should not, therefore, be used for detailed quantity estimates. Beneath the topsoil, residual materials were encountered in each test boring location. The residual soils generally consisted of sandy silts. Standard penetration resistances in the residual soils generally ranged from 14 to 52 blows per foot. Partially weathered rock was encountered in all of our test borings at depths ranging from approximately 3 to 8 feet below the existing ground surface. Partially weathered rock denotes residual material with a standard penetration resistance of 100 blows per foot or greater. Auger refusal was encountered in test borings B-3 and B4 at depths ranging from 11 to 12 feet below the existing ground surface. Auger refusal is the depth at which the boring cannot be further advanced using conventional soil drilling techniques. The material causing auger refusal may consist of a boulder, a lens or layer of rock, the upper surface of relatively massive rock, or other hard material. Ground water was not encountered in our test borings at the time of our investigation. It should be noted that ground water levels will fluctuate depending on seasonal variations of precipitation and other factors, and may occur at higher elevations at some time in the future. For more detailed descriptions of subsurface soil and ground water conditions, please refer to the Test Boring Records included in the Appendix. Page 5 PROPOSED CONSTRUCTION URPATECH E N G I N E E R S- I N C GeotechnicaL engineering LrvirannentaL CansuLting Construction MateriaL5 Testing Our understanding of the proposed construction is based on our conversations and e-mail correspondence with Mr. Jon Jacek and our testing services performed on similar Kingdom Hall buildings throughout central North Carolina. The building will most likely be a 1-story wood framed structure supported on shallow foundations and having a concrete slab -on -grade floor system. Site grading plans are not known at the time of this report. However, we estimate that site grading plans will include mass excavation and structural fill placement of about 8 to 10 feet. Structural loading conditions are currently unknown. However, based upon the type of construction, we anticipate maximum column loads of 30 kips and maximum wall loads of 3 kips per linear foot. If actual loading conditions are greater than these reported maximums, please contact us and we will review our recommendations for applicability to the actual loading conditions. We have estimated that traffic volumes for the parking and driveway areas will not exceed 500 automobiles per day and 4 dumpster or delivery trucks per week. If actual traffic volumes are greater, please notify us and we will review our recommendations for applicability to the higher traffic volumes. Page 6 EVALUATIONS AND RECOMMENDATIONS TFRP.4TECH ENGINEE R S• INC (;&AechnicaL 6_ngiveering Environmental COn5P(tiny Contraction MateriaLs Testing The following recommendations are based on the information available on the proposed structure, the data obtained from our soil test borings, and our experience with soils and subsurface conditions similar to those encountered at this site. Because the test borings represent a very small statistical sampling of subsurface conditions, it is possible that conditions may be encountered during construction that are substantially different from those indicated by the test borings. In these instances, adjustments to the design and construction may be necessary depending on actual conditions. General Site Development Considerations Partially weathered rock and/or rock were encountered in the majority of our test borings. Mass excavation, as well as the excavation of foundation and utility trenches, will likely require ripping or blasting over a large portion of the site. A more detailed discussion of these items is provided in the following sections of this report. General Site>fregaration All topsoil, roots, and other deleterious materials should be removed from the proposed construction area. Site clearing, grubbing, and stripping should be performed only during dry weather conditions. Operation of heavy equipment on the site during wet conditions could result in excessive mixing of topsoil and organic debris with clean underlying soils. Based on our experience with similar soil conditions, some softening of the near surface and exposed soils should be expected during times of wet weather. The depth of soft soils caused by wet weather can be highly variable, and can be dependent on the slope of the ground surface, the presence of on -site or off -site sources of surface water, and other factors. Therefore, we recommend that site preparation operations be performed during times of dry weather. While wet weather can occur at any time during the year, the summer and early. fall are times when drier weather is generally prevalent. Scheduling site grading during this time frame would reduce the probability of softening of the near surface soils from inclement weather conditions. We recommend that areas to receive structural fill be proofrolled prior to placement of structural fill. Areas of proposed excavation should be proofrolled after rough finished subgrade is achieved. Proofrolling should be performed using a loaded dump truck weighing at least 15 tons. Proofrolling should be accomplished by performing at least 3 passes in each of two perpendicular directions within entire construction areas, and 10 feet beyond. Any unsuitable materials that may be present, and any low consistency soils that are encountered which cannot be adequately densified in place, should be removed and replaced with well compacted fill material placed in accordance with the Structural Fill section of this report. Proofrolling should be observed by our representative to determine if remedial measures are necessary. Proofrolling should facilitate the identification of soft surficial soils, but should not be expected to reveal soft conditions more than 2 feet below the ground surface at the time of proofrolling. Footing examinations will be required to evaluate the presence of deeper soft soils, which could adversely affect foundation support. Footing examinations will be discussed later in this report. Page 7 UPPATECH E N G I N E E A S- I N C C;eatechnical Engineering EnvironmentaL Consulting Construction MateriaLs Testing Based on our experience on similar sites, there may also be buried foundations, burn pits or trash pits located on the property. On sites located near developed areas this is not an unusual occurrence. Additionally, aerial photographs reviewed online indicate that a road may have previously been present on the site. Soft, wet soils are often present in the road -side ditches. All too frequently such buried material occurs in isolated areas which are not detected by the soil test borings. Any buried waste, construction debris, trash organics, or soft soils which are found during the construction operation should be thoroughly excavated, and the waste material should be removed from the site prior to placement of fill soils Excavation Characteristics For the purpose of discussing excavation characteristics, the subsurface materials encountered in our borings fall into one of three broad categories: (1) residual soils, (2) partially weathered rock, and (3) rock. The residual soils at the project site should generally be excavatable with conventional soil excavation equipment; such as scrapers, loaders, etc. However, residual soils having penetration resistances ranging from 50 to 100 blows per foot may prove to be difficult to excavate using scrapers. These very hard soils may require the use of heavy bulldozers, loaders, or track -mounted backhoes to effectively achieve excavation. It is possible that very hard soils may require ripping in some instances. Although materials identified as partially weathered rock may in some cases be excavatable with conventional soil excavation equipment, we believe that it is wise to assume that partially weathered rock.will require ripping to efficiently achieve excavation. The thickness and the continuity of partially weathered rock should be expected to vary widely, even over a relatively short distance. Additionally, it would not be unusual to find lenses of partially weathered rock within more weathered residual soils. Ripping can probably best be achieved with a single -tooth ripper mounted on a large tractor such as a Caterpillar D-8 or larger. In small area excavations, excavation of partially weathered rock may require the use of heavy track -mounted backhoes or pneumatic jackhammers. It should be noted that test borings B-1, B-3 and B-4 encountered zones of partially weathered rock which allowed little or no penetration of our sampling equipment. These zones are indicated on the test boring records by penetration resistances of 50 blows for zero inches, '/z inch, and 1 inch. It is likely that these zones of partially weathered rock cannot be efficiently pre -loosened by ripping. In such instances, blasting will be necessary. Rock was encountered in test borings B-3 and B-4 at depths ranging from approximately I 1 to 12 feet below the existing ground surface. Rock, as used in this report, is defined as auger refusal of our conventional soil drilling equipment. We believe it would be prudent to assume that blasting will be required for excavations below the depth at which rock was encountered in the area of these boring locations, and in other areas below the boring termination depths. We recommend that the project specifications include a clear definition of excavation types to prevent field discussions regarding excavation of hard materials. We have enclosed our standard Rock Excavation Specifications for your use. We recommend that these be incorporated into the project earthwork specifications. Page 8 TFRP4TECH E N G 1 N E E R S- I N C Ceatechnicat 6nyineering Lnvironmentat Comutting Construction Materials Testing It is important to note that the depth to rock or partially weathered rock may vary quite rapidly over relatively short distances. It would not be unusual for rock or partially weathered rock to occur at higher elevations between or around the soil test borings. Additionally, it is important to realize that ground water levels will fluctuate and could occur at significantly higher elevations at some time in the future. Earth Slopes Temporary construction slopes should be designed in strict compliance with the most recent OSHA regulations. The test borings indicate that most soils at the site are Type B as defined in the OSHA regulations. The Type B soils will require that temporary construction slopes be no steeper than 1 horizontal to I vertical for excavation depths of up to 20 feet. A competent person as defined by OSHA guidelines should be present to determine the type of material exposed during trench excavations. Temporary construction slopes should be closely observed for signs of mass movement: tension cracks near the crest, bulging at the toe of the slope, etc. If potential stability problems are observed, the geotechnical engineer should be immediately contacted. The responsibility for excavation safety and stability of construction slopes should lie solely with the contractor. We recommend that permanent cut or fill slopes be no steeper than 2.5 (H) to 1.0 (V) to maintain long term stability and to provide ease of maintenance. Slopes constructed steeper than 2.5 (H) to 1.0 (V) could be highly susceptible to erosion, will be difficult to maintain, and could experience large scale slope failure in some instances. The crest or toe of cut or fill slopes should be no closer than 15 feet to any building foundation. The crest or toe should be no closer than 5 feet to the edge of any pavements. Foundation DesiLwn After the above described site preparation and site grading are complete, it is our opinion that the proposed structure may be supported on conventional shallow foundations. Based on the test boring results, and our past experience, we recommend that the shallow foundations be designed using an allowable soil bearing pressure of 3,000 pounds per square foot (psf). This value assumes that soils similar to those encountered at the site will be utilized as structural fill materials, and that fill materials and floor subgrade soils will be compacted in accordance with the Structural Fill section of this report. We recommend a minimum width of 18 inches for continuous wall footings and 24 inches for isolated column footings to prevent localized shear failure. Footings should bear at a minimum depth of 18 inches below the prevailing exterior ground surface elevation to avoid potential problems due to frost heave. Detailed footing examinations should be performed in each footing excavation prior to placement of reinforcing steel. These examinations should be performed by our representative to confirm that the design allowable soil bearing pressure is available. The footing examinations should be performed using a combination of visual observation, hand rod probing, and dynamic cone penetrometer testing. Dynamic cone penetrometer testing, as described in ASTM STP-399, should be performed in each column footing location and at no greater than 15 foot intervals in continuous wall footings. Some of the foundations for this project may bear on new structural fill materials. For this reason, we must emphasize the importance of quality control during the placement of structural fill. Performance of building foundations which are supported by structural fill material will depend largely on achieving TFRP4TECH f N G 1 N F E R 5- I N C C,eatechnical C_ngincering Page 9 LnvironmentA Con:wLting Corstruction Materials Testing the recommended level of compaction on fill materials. Compacted soil densities less than the recommended percentage of the standard Proctor maximum dry density could result in excessive foundation settlement. Exposure to the environment may weaken the soils at the foundation bearing surface, if they are exposed for extended periods of time. If the foundation bearing surface becomes softened due to exposure, the soft soils should be removed prior to placement of concrete. Concrete Slabs -On -Grade Based on our test boring results, and the anticipated site grading operations, we recommend that a design modulus of subgrade reaction (k) value of 150 pounds per cubic inch (pci) be used for concrete slabs -on -grade. This recommended value assumes that the subgrade soils and fill soils will be compacted to a minimum of 98 percent of their standard Proctor (ASTM D-698) maximum dry density in the upper 12 inches_ Construction activities and exposure to the environment often cause deterioration of the prepared slab - on -grade subgrade. Therefore, we recommend that the subgrade soils be evaluated by our representative immediately prior to floor slab construction. This evaluation may include a combination of visual observations, proofrolling observations, and field density tests to verify that the subgrade has been properly prepared. If soft areas are encountered, we will provide recommendations for remedial measures. 'eIn order to provide a stable base for construction activity, and to protect the prepared slab subgrade soils 17. from inclement weather and construction traffic, we recommend that all slab -on -grade construction be I— underlaiiv by a minimum 4 inch thickness of aggregate base course (ABC) stone meeting the NCDOT Specification. Flexible Pavement Desien Based on the above described site preparation recommendations, we anticipate that the pavement area subgrade soils will generally consist of sandy silts. These materials may reasonably have a California Bearing Ratio (CBR) ranging from approximately 3 to 8, if compacted to at least 100% of the standard Proctor maximum dry density. For purposes of pavement design, we have used a California Bearing Ratio of 6 for the pavement subgrade soils and the loading condition described previously in this report. Based on the AASHTO -design method, a. 20 year design life, and our past experience, we suggest the following design pavement section: Driveways: 2 inches Asphaltic Concrete Surface Course 8 inches Aggregate Base Course Parking Areas: 2 inches Asphaltic Concrete Surface Course 6 inches Aggregate Base Course The asphaltic concrete surface course should be a type SF9.5A bituminous concrete mixture in accordance with Section 645 of the NCDOT Standard Specifications (2006). Aggregate base course Page 10 TFRP4TECH E N G I N E E Ps. INC �,eotechnicaL Lngineering 6nvironmentaL Consulting Construction NiateHats Testing stone should be in accordance with Section 520 of the NCDOT Standard Specifications. Proper subgrade compaction, adherence to the NCDOT specifications, and compliance with project plans and specifications are critical to the performance of the constructed pavement. Based on our past experience, we recommend that a Portland cement concrete pavement be used in dumpster areas, and in other areas where heavy trucks are turning while traveling at slow speeds. We suggest the use of a 6 inch thick section of Portland cement concrete having a 28 day design compressive strength of 4,500 psi above a 4 inch thick section of compacted ABC stone. The concrete pavement may be designed as a "plain concrete pavement" with no reinforcing steel, or reinforcing steel may be used at joints. Construction joints and other design details should be in accordance with guidelines provided by the Portland Cement Association and the American Concrete Institute. Suitabilitv of Excavated Materials for Reuse as Structural Fill Based on the results of our soil classifications, the residual soils at the site appear to be suitable for reuse as structural fill material. Routine adjustment of moisture content will be necessary to allow compaction in accordance with project specifications. Partially weathered rock will be suitable for use as structural fill, if it can be adequately broken down into pieces smaller than 3 inches in any dimension. Based on our experience, the majority of the partially weathered rock encountered at this site will break down to a size adequate for use as structural fill. Blasted rock should be considered unsuitable for use as structural fill. Structural Fill In order to achieve high density structural fill, the following recommendations are offered: (1) Materials selected for use as structural fill should be free of vegetable matter, waste construction debris, and other deleterious materials. The material should not contain rocks having a diameter over 3 inches. It is our opinion that the following soils represented by their USCS group symbols will typically be suitable for use as structural fill and are usually found in abundance in the Piedmont Region: (SM), (SC), (ML), and (CL). The following soil types are not recommended as fill on this site since they could create a perched water condition: (SW), (SP), (SP-SM), and (SP-SC). The following soil types are considered unsuitable: (MH), (CH), (OL), (ON), and (Pt). (2) Laboratory Proctor compaction tests and classification tests should be performed on representative samples obtained from the proposed borrow material to provide data necessary to determine acceptability and for quality control. The moisture content of suitable borrow soils should generally not be more than 4 percentage points above or more than 4 percentage points below optimum at the time of compaction. Tighter moisture limits may be necessary with certain soils. (3) Suitable fill material should be placed in thin lifts (lift thickness depends on type of compaction equipment, but in general, lifts of 8 inches loose measurement are recommended). The soil should be compacted by mechanical means such as steel drum rollers or sheepsfoot rollers. Proofrolling with rubber tired, heavily loaded vehicles may be desirable at approximately every third lift to bind the lifts together and to seal the surface of the compacted area thus reducing potential for absorption of surface water following a rain. This sealing operation is particularly important at the end of the work day and at the end of the week. Page i I TFRP4TECH E N G I N E E R S- I N C <eatechnicaL C_noineering C_nviranmental Censlflno Conshruc{ian Makerdah Teatinq Within small excavations such as behind retaining walls or in footing excavations, we recommend the use of "wacker packers" or diesel sled tamps to achieve the specified compaction. Loose lift thicknesses of 4 to 6 inches are recommended in small area fills. (4) We recommend that structural fill be compacted to a minimum of 95% of the standard Proctor maximum dry density (ASTM Specification D-698). The upper 12 inches in building pad areas should be compacted to at least 98 percent of the same standard. Additionally, the in -place maximum dry density of structural fill should be no less than 90 pcf. Pavement area fill should be placed in accordance with the NCDOT Standard Specifications. (5) An experienced soil engineering technician should take adequate density tests throughout the fill placement operation to verify that the specified compaction is achieved. It is particularly important that this be accomplished during the initial stages of the compaction operation to enable adjustments to the compaction operation, if necessary. Page 12 ADDITIONAL SERVICES RECOMMENDED TFRPaTECH E N G I N E E R S- INC CeotechnicaL engineering LnVironmental Can>olting Construction Materials 1 e56ng Additional foundation engineering, testing, and consulting services recommended for this project are summarized below: (1) Proofrollina Observation: Proofrolling should be observed by a representative of the Geotechnical Engineer to determine if remedial measures are necessary in certain instances. (2) Quality Control of Fill Placement and Compaction: We recommend that an experienced engineering technician witness all required filling operations and take sufficient in -place density tests to verify that the specified degree of compaction has been achieved. Soil engineering judgments will be involved and should be made by our project geotechnical engineer with information provided by our engineering technician, (3) Footing and Slab Evaluation : Footing and -slab areas for this project should be evaluated by our representative. The purpose of these evaluations will be to verify that the design soil bearing pressure is available and that subgrade areas are properly prepared. (4) Pavement Components Testing and Inspection: Pavement components should be tested and inspected during and following construction to verify compliance with project plans and specifications. The attached Appendix completes this report. Sincerely, Engineers, Inc. (�-1356) Glen A. Malpass, P.E. Senior Geotechnical E GAMIsk 6111 BAR `'". �'E'st �id'�.'li�'•; : 4Z 30M z .r + �HGINE.��•' Gjy �•` A • Erwi T. Williams Principal Geotechnical Engineer TERRATECH E NGINEERS • I N C APPENDIX TERRATECH £ N G i K E E R S- V N C Rock Excavation Specifications Excavation Classifications: The classifications of excavation below will be made when rock excavation is encountered in work. Do not perform such work until material to be excavated has been cross -sectioned and classified by the Geotechnical Engineer. Such excavation will be paid on basis of contract conditions relative to changes in work. 1. Earth excavation includes removal and disposal of pavements and other obstructions visible on surface; underground structures and utilities indicated to be demolished and removed; along with earth and other materials encountered that are not classified as rock excavation or unauthorized excavation. 2. Mass rock excavation consists of the removal and disposal of a formation that cannot be excavated with a Caterpillar D-8 bulldozer or equivalent, mounted with a single tooth ripper. Trenches in excess of 10 feet in width and pits in excess of 30 feet high in either length or width are classified as mass rock excavation. 3. In trench excavations for footings and utilities, trench rock excavation shall be the removal and disposal of a formation that cannot be excavated with a Caterpillar 322 track mounted excavator or equivalent, equipped with'/< cubic yard bucket equipped with rock teeth. 4. The owner's testing agency or architect shall be the final judge as to what is to be classified as rock excavation. The contractor shall provide the specified equipment at the site to confirm_ rock excavation. 5. Intermittent ripping or drilling and blasting to increase production and not necessary to permit excavation will be classified as earth excavation. 6. Rock payment lines are as follows: A. Two feet outside of concrete work for which forms are required, except footings. B. One foot outside perimeter of footings. C. In pipe trenches, 6 inches below invert elevation of pipe and two feet wider than inside diameter of pipe, but not less than 3 feet minimum trench width. D. For drainage structures, 18 inches outside ofstructure dimension, and 6 inches below bottom of structure. E. Neat outside dimensions of concrete work where no forms are required. F. Under slabs -on -grade, 6 inches below bottom of concrete slab. G. Under pavements, 6 inches below planned subgrade elevation. 7. Field verification of rock quantities shall be performed by the owner's testing agency or a registered land surveyor. 8. Remove all excavated material classified as rock from the site. 9. Unauthorized excavation consists of removal of materials beyond indicated subgrade elevations or dimensions without specific direction of the architect. Unauthorized excavation, as well as remedial work associated with unauthorized excavation, shall be at Contractor's expense. �Vlil 2. ui I = Symbols and Nomenclature I Undisturbed Sample (UD) Standard penetration resistance (ASTM D-1586) iow, Number of blows (100) to drive the spoon a number of inches (2) w-O-H, R Weight of Hammer, Weight of Rods Ax, ex, NX Core barrel sizes for rock cores 65% ROD Z Z A C Gs z P 18 Percentage of rock core recovered Rock quality designation - % of core 4 or more inches long Water table at least 24 hours after drilling Water table one hour or less after drilling Loss of drilling water Atterberg Limits test performed Consolidation test performed Grain size test performed Triaxial shear test performed Proctor compaction test performed Natural moisture content (percent) Penetration Resistance Results Sands Silts and Clays Number of Blows, N 0-4 5-10 l 1-20 21-30 31-50 over 50 Number of Blows, N 0-1 24 5-8 9-15 16-30 31-50 over 50 Drilling Procedures Relative Density very loose loose firm very firm dense very dense Approx. Consistency very soft soil firm stiff very stiff hard very hard TERRATECH ENGINE E K 5- INC Soil sampling and standard penetration testing performed in accordance with ASTM D-1586. The standard penetration resistance is the number of blows of a 140 pound hammer falling 30 inches to drive a 2 inch O.D., 1.4 inch I.D. split spoon sampler one foot. Core drilling performed in accordance with ASTM D-2113. Undisturbed sampling performed in accordance with ASTM D-1587. TEST BORING RECORD TERRATECH ENGINEERS • 1 NC Depth Description Elev. Water Level Blow Counts Standard Penetration Test blows/ft 40 60 80 -20 Topsoil (Approximately 6 inches) -0.5 1 2 7-10-13 • 3 Very stiff fine sandy silt (ML) (RESIDUUM) 4- 5— 12-9-8 • 6 -- — 7 50 3" 8 9 10 Partially weathered rock sampled as brown and tan fine sandy silt (ML) 50 S. 1l 12 13 14 15 -15 50 W BORING TERMINATED 16 17 18 19 20 Water Level 24 hr.: Boring Backfilled Upon Completion TerraTech Engineers, Inc. Boring Number. B-1 Water Level I hr.: Not Encountered 4905 Professional Court project plumber. 121-11.65510 Raleigh, NC 27609 Date Drilled: 9/13111 Sheet: 1 of I TEST BORING RECORD TERRATECH ENGINEE R$' INC Depth Description Elev. Water Level Blow Counts Standard Penetration Test blows/ft 20 60 80 - _40 -Topsoil tApproNimateIX 4 inches 1 2 Stiff to very stiff tan fine sandy silt (ML) 6-6-9 • 3 (RESIDUUM) 5 6-8-13 10 6- Partially weathered rock sampled as brown and 7 tan fine sandy silt (ML) 50 8 -8 5., 9 L0 Very hard tan fine sandy silt (ML) 8-15-37 11 12 12 13 Partially weathered rock sampled as brown fine sandy silt (ML) 14 1S BORING TERMINATED -15 50 2" 16 17 18 I 19 20 Water Level 24 hr.: Boring Backf fled Upon Completion TerraTeeh Engineers, Inc. Boring Number. B-2 Water Love! 1 hr.: Not Encountered 4905 Professional Court Project Number. 121-11-65510 Raleigh, NC 27609 Date Drilled: 9113111 Sheet: 1 of 1 TEST BORING RECORD TERRATECH E N G I N E E R S • I N C Depth Description Elev. Water Level Blow Counts Standard Penetration Test blows/ft 20 40 60 80 Topsoil (Approximately b inches) -0.5 1 10-11-14 • 3 4 Very stiff to hard tan and brown fine sandy silt - - (ML) (RESIDUUM) 5 10-12-12 • 6 -- 7 8-11-20 • 8 -8 9 10 Partially Feathered rock sampled as grey fine sandy silt (ML) S0 1+ —_ 11 12 -12 AUGER REFUSAL 13 14 15 16 17 18 19 20 Water Level 24 hr.: Boring Backfilled Upon Completion TerraTeeh Engineers, Inc. Boring Number: B-1 Water Level i hr.: Not Encountered 4905 Professional Court project Number: 121-11-65510 Raleigh, NC 27609 Date Drilled: 9/13111 Sheet: 1 of t TEST BORING RECORD TERRATECH E N G I N E f R 5• INC Depth Description Elev. Water Level Blow Counts Standard Penetration Test blows/ft 20 40 60 80 'topsoil (Approximately 6 inches) _0.5 1 Very stiff tan fine sandy silt (ML) (RESIDUUM) 2 9-8-10 • 3 -3 4 5 50 2" 6 — Partially weathered rock sampled as tan and gray fine sandy silt (ML) 50 2" 8 — 9 10 25 0" 11 -11 AUGER REFUSAL 12 13 14 15 16 17 18 19 20 Wattr Level 24 hr.: Boring Backfilled Upon Completion TermTech Engineers, Inc. Boring Number. B4 Water Level l hr.- Not Encountered 4905 Professional Court Project Number: 121-11-65510 Raleigh, NC 27609 Date Drilled: 9/13111 Sheet: 1 of I. TEST BORING RECORD TERRATECH E N G I N -f E A S- t N C Depth Description Elev. Water Level Blow Counts Standard Penetration Test blows/ft 20 40 60 80 Topsoil (Approximately 8 inches) -0.7 1 2 Stiff tan fine sandy silt (ML) (RESIDUUM) {-- — 6-5-9 • 3 -3 4- 5- Ward to very hard tan and gray fine sandy silt 12-14-27 11 (ML) 6 _. 7 8 -8 18-22-29 • 9 10 50 2" _-- 11 Partially weathered rock sampled as gray fine sandy silt (Mu 12 13 14 15 -15 50 3" BORING TERMINATED 16 -- 17 18 19 20 Water Ltvel 24 hr.: Boring Backfilled Upon Completion TerraTech Englneers, InC. Boring Number. B-5 Water Ltvel i hr..- Not E mtrrnered 4905 Professional Court Project Number. 121-11-65510 1i81eighr NC 27609 Date Drilled: 9/13111 Sheet: t of 1 Wet Pond Calculations Confirm Permitting Authority Latitude: 35.7525 Long: 79.4929 General Requirements • Sizing shall take into account all runoff at ultimate buildout, including off -site drainage • Vegetated slopes shall be no steeper than 3:1. • BMP shall be located in a recorded drainage easement with access to a public ROW. • Basin discharge shall be evenly distributed across a minimum 30 feet long vegetative filter strip unless it is designed to remove 90% TSS. (A 50-ft filter is required in some locations.) • The design storage shall be above the permanent pool. • Discharge rate of the treatment volume shall completely draw down between 2 and 5 days. • The average depth of the permanent pool shall be a minimum of 3 feet. The average depth shall be calculated as described in Figure 10-2b. • Permanent pool surface area shall be determined using Tables 10-1, 10-2, 10-3, and 10-4. • The flow within the pond shall not short circuit the pond. • BMP shall be designed with a forebay. • BMP shall not be located to produce adverse impacts on water levels in adjacent wetlands. • A minimum 10-foot wide vegetated shelf shall be installed around the perimeter. The inside edge of the shelf shall be 6" below the permanent pool elevation; the outside edge of the shelf shall be 6" above the permanent pool elevation. • The forebay volume should be about 20% of the total permanent pool volume, leaving about 80% of the design volume in the main pool. • Freeboard shall be a minimum of 1 foot above the maximum stage of the basin. SHWT: The permanent pool elevation shall be within 6 inches (plus or minus) of the SHWT elevation. e-mailed design engineer advising him that the soils report indicated that the SHWT was not determined. While the soil report indicated they were clay with poor infiltration rates, good engineering practice calls for the proposed permanent pool elevation to be at approximately the same elevation as the SHWT, i.e., six inches above or below the SHWT. Determining infiltration rates and SHWT is not an exact science. If the permanent pool elevation cannot be maintained, then DWQ looks to the design professional to apply the appropriate method for their specific site to ensure the proposed design will not adversely affect wetlands, surface waters, buffers and that the water level is maintained at the design permanent pool elevation. Should you need to line the basin or convert it to an infiltration system, the modifications can be addressed when the BMP is certified. MAY - 7 2013 Water Quality Treatment Volume Volume = 3630 * Rd * Rv * Ac Where Rd = Design Storm = 1 inch I = Impervious Portion / Drainage Area = 33,647 / 43754 % = 76.9 % = 0.7690 Rv = 0.05 + 0.9 * I = 0.05 + 0.9 * 0.7690 = 0.73055 Volume = 3630 * 1.0 * 0.7355 * 1.0 Acres = 2,651 cf Q: Discharge Rate (cfs) for 2 to 5 days Q = CdA [2 g Ho] ^ 0.5 For a 1 inch diameter orifice r = 0.5 inches/12 inches/ft = 0.04 ft A = 3.14 rz = 3.14 (0.04) 2 = 0.005 sf Cd = 0.6 g = 32.2 Ho = (Temporary Pool Elevation -Permanent Pool Elevation) / 3 = (867-866)/3 = 0.333 Q = 0.6 (0.005) [(64.4) (0.333)] ^ 0.5 = 0.014 cfs' Note: Q must be between Discharge Rate for 2 days and 5 days Discharge Rate (2-5 days) = Water Quality Treatment Volume/(seconds/day)/(number of days) Q-Discharge Rate (2 days) = 2651 cf / (86,200 seconds per day) / 2 = 0.015 cfs' Q-Discharge Rate (5 days) = 2651 cf / (86,200 seconds per day) / 5 = 0.006 cfs Note: 0.015 cfs > 0.014 cfs > 0.006 cfs Surface Area (SA) SA = DA/100 * Ratio Average Depth:3.0 BUA1 = 76.9 % DA = Drainage Area = 43754 sf Ratio= 4.0 to 4.5 (from Table 10-1, 10-2, 10-3 or 10-4 is based on BUA, average depth, TSS and removal ) SA = DA/100 * Ratio = 43754 /100 * 4.25 = 1857 sf ' Rough approximation that does not consider head LETTER OF TRANSMITTAL v STEWART TO FROM NCDENR - DWQ Adam Pike, PE NCDENR Civil Project Engineer 512 North Salisbury St (919) 380-8750 x (205) Raleigh, NC 27601 DATE SENT VIA 4/30/13 Hand Delivery PROJECT NUMBER PROJECT NAME C12031 Kingdom Hall - Siler City COPIES DATE DESCRIPTION 2 4 25 13 Plan Set 1 4 25 13 Stormwater SIA 1 4 25 13 Check O&M Agreement, Deed For approval For review & comment Returned for corrections For your use Approved as submitted Returned after review As requested Approved as noted Resubmit copies for approval COMMENTS Please find included the necessary documents for state stormwater submittal for Kingdom ball - Siler City. Please feel free to contact me if you have any questions. Thanks Adam Pike 7 2413 SIGNED Adam Pike, PE - Civil Project Engineer [APR 2013 - YATEi4 OUALI �!!'affands e z,-- . N COPIED TO file STRONGER BY DESIGN 421 FAYETTEVILLE ST. RALEIGH, NC T 919.380.8750 SUITE 400 27601 F 919.380.8752 r i 1247 0945 BOOK 124 r PAGE 945 Prepared by W. Ben Atwater, Jr., Attorney P. O. Box 629, Siler City, NC 27344 Mail to: Kingdom Hall of Jehovah's Witnesses Siler City Congregation 3670 Alston Bridge Road, Siler City, NC 27344 NORTH CAROLINA } } CHATHAM COUNTY ) No title search performed FILED CHATHAM COUNTY REBA G. THOMAS REGISTER OF DEEDS FILED Mar 30, 2006 AT 12:27:00 pm BOOK 01247 START PAGE 0945 END PAGE 0946 INSTRUMENT # 04079 WARRANTY DEED Chatham county o3-30-2ow NORTH CAROLINA Real Estate Excise Tax $60.00 1Q910. 440 d THIS DEED, made and entered into this 7th day of March, 2006, by and between FRANKLIN-WOOD PROPERTIES, LLC, of Chatham County, North Carolina, Grantor, AND LYLE WESTBROOK, LEROY CHEEK and CHARLES WESTBROOK, the duly elected Board of Trustees of KINGDOM HALL OF JEHOVAH'S WITNESSES, SILER CITY CONGREGATION, and their successors in office, of 3670 Alston Bridge Road, Siler City, NC 27344, Grantee, WITNESETH: THAT the Grantor, for a valuable consideration paid by the Grantee, the receipt of which is hereby acknowledged, have and by these presents do grant, bargain, sell and convey unto the Grantee in fee simple, all that certain lot or parcel of land situated in Matthews Township, Chatham County, North Carolina, and more particularly described as follows: Being all of Lot 01, containing 1.81 acres more or less, as shown on a Plat entitled "Survey for Jerry B. Wood, III", dated April 10, 1966, prepared by rufus L_ Johnson, RLS, and recorded in Plat Slide 96-138, Chatham County Registry, to which plat reference is hereby madae for a more accurate description. For chain of title see Deed Book 690, Page 285, Chatham County, North Carolina. (1) The above described property is subject to any restrictive or protective covenants of record, (2) The above described property is subject to any recorded or unrecorded rights -of -way in favor of the North Carolina Department of Transportation and Town of Siler City and any other easements of record. (3) The above described property is subject to any easements which might now exist in favor of any Public Utility Company. (4) The above described property is subject to a Water and Sewer Easement in favor of the Town of Siler City. , ti . 'w T247 0946 BOOK124i PAGE 946 (5) The above described property is subject to any zoning ordinances of the county or the Town of Siler City. (5) Grantors and Grantee shall pro -rate the 2006 Chatham County ad valorem taxes. (6) The above described property is subject to any matters which a recent and accurate survey might disclose. TO HAVE AND TO HOLD the aforesaid lot or parcel of land and all privileges and appurtenances thereto belonging to the Grantee in fee simple. AND the Grantor covenants with the Grantee, that Grantor is seized of the premises in fee simple, and has the right to convey the same in fee simple, that title is marketable and free and clear of all encumbrances, and that Grantor will warrant and defend the title against the lawful claims of all persons whomsoever. IN WITNESS WHEREOF, the Grantor has duly executed the foregoing instrument, as of the day and year first above written. FRANKLIN-WOOD PROPMUIES. LLC, Y NORTH CAROLINA, CHATHAM COUNTY: WOOD,111f Member -Manager Member -Manager I, a notary public of said county and state, do hereby certify that Jerry B. Wood, III and Betty F. Wood, member managers of Franklin -Wood Properties, LLC, a limited liability company, and by authority duly given and as an act of the entity, have signed the foregoing instrument in its name and on its behalf as its act and deed. WITNESS my hand and notarial seal this the - 12 day of March, 2006. ZTAAY PUBLIC 1 j ,0Q(A 0, 1 k erJA.) My commission expires: r O v Iq /aa a Z Z7 = /QJ� GO 2