Thank you for choosing Professional Service Industries, Inc. (PSI) as your geotechnical consultant for the proposed project.

Transcription

1 Geotechnical July 7, 2014 Attn: Mr. Gregory A. Kidder Chief Procurement Officer WVNET 837 Chestnut Ridge Road Morgantown, West Virginia Reference: Preliminary Subsurface Investigation and Geotechnical Evaluation Proposed WVNET Administration and Data Center Morgantown, Monongalia County, West Virginia PSI Project No: Dear Mr. Kidder: Thank you for choosing Professional Service Industries, Inc. (PSI) as your geotechnical consultant for the proposed project. As per your authorization, we have completed a preliminary subsurface exploration for this project. The findings of the exploration and our preliminary recommendations for the project are discussed in the accompanying report. As requested, the electronic draft of the report is being forwarded to you. Three paper copies will be delivered to the address above. The soil samples obtained during this exploration will be retained in our laboratory for sixty days. Should there be any questions, please do not hesitate to contact our office. PSI would be pleased to continue providing geotechnical services for the supplemental phases of this project, and we look forward to working with you and your organization on this and future projects. Respectfully submitted, PROFESSIONAL SERVICES INDUSTRIES, INC. Jeffrey E. Smith, EIT Geotechnical Department Manager Stephen M. Simonette, P.E. District Manager Professional Service Industries, Inc. 850 Poplar Street Pittsburgh, PA Phone 412/ Fax 412/

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3 TABLE OF CONTENTS 1 PROJECT INFORMATION PROPOSAL AND PROJECT AUTHORIZATION PROJECT DESCRIPTION PURPOSE AND SCOPE OF WORK SUBSURFACE EXPLORATION LABORATORY TESTING PRELIMINARY SITE AND SUBSURFACE CONDITIONS SITE LOCATION AND DESCRIPTION AREA GEOLOGY SUBSURFACE MINING PRELIMINARY SUBSURFACE CONDITIONS GROUNDWATER CONDITIONS PRELIMINARY GEOTECHNICAL EVALUATIONS SITE PREPARATION AND EARTHWORK DISCUSSION OF POTENTIAL ROCK EXCAVATION SEISMIC CONSIDERATIONS PRELIMINARY FOUNDATION DISCUSSIONS SLAB-ON-GRADE considerations CONSTRUCTION DEWATERING RECOMMENDATIONS FOR FINAL GEOTECHNICAL REPORT REPORT LIMITATIONS APPENDICES Vicinity Map and Boring Location Plan... Appendix A Boring Logs... Appendix B Laboratory Test Results... Appendix C i

4 1 PROJECT INFORMATION 1.1 PROPOSAL AND PROJECT AUTHORIZATION This report presents the findings and recommendations of the preliminary subsurface exploration and geotechnical evaluation performed by Professional Service Industries, Inc. (PSI) for the proposed WVNET Administration & Data Center project in Morgantown, West Virginia. These services were performed in general accordance with PSI s Proposal No , dated June 10, 2014 and were authorized by Mr. Greg Kidder representing WVNET. 1.2 PROJECT DESCRIPTION In accordance with Mr. Kidder s request, preliminary exploratory test borings were desired in advance of design and construction of the planned future WVNET Administration and Data building. PSI understands the new structure is planned for the northern portion of the site, and that the temporary structures for the construction phase are planned to be placed within the southern portion of the site. PSI understands plans detailing the locations of the planned new structure and temporary structures, structural dimensions, construction types, finished grades, and anticipated structural loads have not been prepared for this project at this time. Gradual slopes drop the grade approximately 40 feet from EL ± 1170 along the northern boundary of the site to EL ± 1130 at the southern boundary along Chestnut Ridge Road. The existing slopes are steepest in the northern portion of the site. If any of the noted information is incorrect or has changed, please inform PSI so that we may review the geotechnical data and amend the recommendations presented in this report, if appropriate. 1.3 PURPOSE AND SCOPE OF WORK The scope of services for this preliminary study included a site reconnaissance of the project area and the assessment of subsurface conditions through field exploration and laboratory testing. The current preliminary study included an evaluation of the site and subsurface conditions relative to the proposed construction and the preparation of a preliminary report of findings. The subsurface exploration was developed to provide the following: Review of readily available geologic references for the project site A discussion of subsurface conditions encountered including pertinent soil properties and groundwater conditions. 1

5 Preliminary evaluation of the data as it relates to the proposed preliminary site development. Preliminary recommendations for site preparation, including placement and compaction of fill soils. Preliminary discussions concerning the geotechnical aspects associated with foundation support. Preliminary recommendations for concrete slab-on-grade design. Determination of the Seismic Site Class and seismic design parameters per IBC 2012 based on SPT N -values (within the practical limits of the proposed boring depths). Comments and recommendations relating to other observed geotechnical conditions that could impact development. Scope recommendation for a Final Geotechnical Report The scope of PSI s services did not include an environmental assessment. Statements made in this report or on the boring logs regarding odors, colors, unusual or suspicious items or conditions are strictly for the information of our client. 1.4 SUBSURFACE EXPLORATION Three test borings, designated B-1 through B-3, were drilled on June 19, 2014 at the site with an ATV-mounted CME 550 drill rig using hollow stem augers. Borings B-1 and B-2 were located north of the existing WVNET building structure and B-3 was performed south of the structure. A PSI representative established their locations in the field by measuring distances with a tape from available site features. The test boring locations referenced are accurate to the degree implied by the methodology used. Drilling and soil sampling were conducted with procedures generally recognized and accepted as standard methods for the exploration of subsurface conditions related to earthwork and foundation engineering projects. Representative soil samples were obtained by employing split-spoon sampling procedures in general accordance with ASTM D1586 test method. Soil samples obtained from the borings were identified according to boring number and depth, and a representative portion of each sample was placed in a moisture-tight glass container and transported to the PSI laboratory for visual classification and further evaluation. The approximate test boring locations are shown on the Boring Location Plan, in APPENDIX A. 2

6 1.5 LABORATORY TESTING The geotechnical engineering staff visually classified the recovered soil samples in the laboratory in accordance with the Unified Soil Classification System (USCS) (ASTM D2487 and D2488). Natural moisture content determinations (ASTM D2216), Atterberg limits tests (ASTM D4318) and grain size analyses (ASTM D6913 and ASTM D422) were conducted on some of the recovered samples. The laboratory test results are presented in APPENDIX C, and shown on the individual boring logs in Appendix B. A summary of the lab testing results are presented below: Boring Number B-1 B-2 Sample Number Depth (ft) Water Content (%) Liquid Limit Atterberg Limits Plastic Limit Plasticity Index Fines Content (%) USCS Classification S S Non - Plastic 90.7 ML S S S CH S CL 3

7 2 PRELIMINARY SITE AND SUBSURFACE CONDITIONS 2.1 SITE LOCATION AND DESCRIPTION The subject site is located at 837 Chestnut Ridge Road in Morgantown, Monongalia County, West Virginia. The location of the site is shown on the Vicinity Map attached as APPENDIX A. The site is bounded by Walgreens to the east, Chestnut Ridge Road to the south, by an un-named street to the west which extends from Chestnut Ridge Road to North Elementary School, and by the North Elementary School and undeveloped property to the north. The majority of the central and southern portions of the property are open and include grass covered terrain, the existing WVNET building, and bituminous concrete pavement for parking and vehicle access. Sparse trees and an isolated area of heavy brush exist south and east of the WVNET building structure. The approximate northern third of the property includes light to moderately wooded terrain. Surface topography is moderately to gently sloping north of the WVNET building structure and slightly sloping south of the structure. Terrain generally slopes downhill from north to south. North of the structure, there is an estimated 30 feet of elevational variation. South of the existing WVNET building structure, there is an estimated 8 feet of elevational variation. The age of the existing building is unknown at this time. However, based on a review of the available aerial photography on Google Earth, it appears that the existing WVNET building was constructed sometime prior to June AREA GEOLOGY The site is geologically located within the Western Appalachian Plateau Physiographic Province along the border with the Allegheny Mountains Province. A study of the area geology from the available literature 1 and field observation shows that the site is underlain by both the Quaternary Alluvium and the Conemaugh Group geologic units. The Quaternary Alluvium is a formation from the Quaternary Age and is comprised of thick alluvial deposits of sand, gravel, silt and clay. The Conemaugh Group is of the Pennsylvanian Age and is comprised of cyclic sequences of red and gray shale, siltstone and sandstone with thin layers limestone and coal. This formation is mostly non-marine. The Conemaugh Group extends from the base of the Pittsburgh Coal to the top of the Upper Freeport Coal, and includes the Elk Lick, Bakerstown, and Mahoning Coals along with the Ames and Brush Creek Limestones. 1 Simplified Geologic Map of Arlington County, Virginia, and Vicinity, William Frost and Timothy Ernest, Arlington County Mapping Center, Department of Public Works,

8 2.3 SUBSURFACE MINING Based upon our review of the Interactive Coal Bed Mapping Project, presented on the West Virginia Geological & Economic Survey website, it appears that the project site has not been undermined by deep coal mining activities. Additional mining information for the site may be obtained from Steve McClelland of the West Virginia Geologic Survey, at (304) PRELIMINARY SUBSURFACE CONDITIONS A thin layer (3 to 4 inches) of topsoil was encountered in all of the preliminary borings performed at the site. Two primary soil strata were encountered at this site. The first stratum consisted of what appears to be fine-grained, Residual soils varying in thickness between 2 to 8 feet. Underlying the Residual soils, Weathered Rock was encountered in two of the preliminary borings. The Weathered Rock primarily consisted of weathered Clay-Shale and Shale, and was sampled to depths ranging from approximately 10 to 20 feet below existing grades. A more detailed breakdown of the soils encountered at this site is included below: RESIDUUM: Underlying the surficial soils at this site, Residual soils were encountered in all three of the preliminary borings to depths ranging from 2½ to 8½ feet below existing grades. The Residuum materials were generally comprised of Silt, Lean Clay, and high plasticity Fat Clay materials with varying amounts of sands and rock fragments. Standard Penetration Test (SPT) N-values for the Residual materials ranged from 7 to 19 blows per foot (bpf) across the site. Laboratory testing of samples from Boring B-2 showed the Clay materials in the Residuum to have a fines content of approximately 76 percent, Liquid Limits ranging from 26 to 52 and Plastic Limits ranging from 14 to 27. The Clay materials were classified as low plasticity, Lean CLAY (CL) and high plasticity, Fat CLAY (CH) using the Unified Soil Classification System (USCS). WEATHERED ROCK: Underlying the Residuum Stratum, Weathered Rock primarily consisting of weathered Clay-Shale and Shale was encountered in Borings B-1 and B-2. The Weathered Rock materials were sampled to depths ranging from approximately 10½ and 19½ feet before reaching auger refusal; Boring B-3 encountered Auger refusal at approximately 3½ feet below existing grades without encountering Weathered Rock. The samples of the weathered Clay-Shale were visually classified as very stiff to hard Silt; the samples of the weathered Shale were visually classified as either very dense Silty Sand or Silty Gravel. Typical SPT N-values for the weathered Clay-Shale ranged between 28 to over 50 blows per foot, whereas the N-values within the weathered Shale ranged from 41 to over 50 blows per foot. 5

9 Laboratory testing of a sample of the weathered Clay-Shale from Boring B-1 was found to be Non-Plastic and to have a fines content of approximately 91 percent. The sample was classified as a SILT (ML) in accordance with the Unified Soil classification System (USCS) More detailed descriptions of the subsurface conditions are presented on the soil boring logs included as APPENDIX B, and the laboratory test results located in APPENDIX C. The above subsurface description is of a generalized nature provided to highlight the major soil strata encountered. The boring logs included in the appendices should be reviewed for specific information as to individual test boring locations. The stratification lines shown on the test boring logs represent the conditions only at the actual test boring locations. The stratification lines represent the approximate boundaries between subsurface materials and the actual transition may be gradual. 2.5 GROUNDWATER CONDITIONS Groundwater was not encountered infiltrating into any of the preliminary borings drilled at the site. A review of the moisture contents of the samples tested in our laboratory show the fine grained Residuum soils to be saturated. It should be noted that discontinuous zones of perched water may exist within the overburden materials, over top of weathered rock or rock and the builder should anticipate surface and subsurface seepage into any subsurface excavations during high moisture periods of the year. The groundwater levels presented in this report are the levels that were measured at the time of our field activities. Fluctuation in groundwater levels should be anticipated. We recommend that the Contractor determine the actual groundwater levels at the time of construction to determine groundwater impact on the proposed construction procedure. 6

10 3 PRELIMINARY GEOTECHNICAL EVALUATIONS The data developed during this preliminary study indicates that the subsurface conditions at the site are generally adaptable for the construction of the proposed new structures. A final supplementary investigation should be performed to document that the site is adequately characterized for the final design of the proposed structures. Final geotechnical recommendation should be prepared for each part of the planned improvements, once the design team has developed the final floor elevations and planned structural loads. The preliminary recommendations contained in this report should be used by the design team for the sole purpose of their planning purposes and should not be used for the development of final construction documents. Below is a brief list of geotechnical issues that may impact design and construction at this site. The encountered subsurface materials at the site include approximately 2 feet to 8 feet of fine grained Residuum soils, which included layers of high plasticity Fat CLAY. These soils will be difficult to work with and will degrade quickly in the presence of moisture and construction traffic. The residual soils were underlain by weathered clayshale or shale at depths beginning at depths of approximately 2½ to 8½ feet below site grades in our test borings. The materials of this stratum were typically classified as hard silt or dense sand/gravel. Two of three test borings met with auger refusal at 3½ and 10½ below site grade. Therefore, difficult or rock excavation may be required depending upon site grading and proposed cut excavations. Materials identified as Fill were not encountered in any of the preliminary borings performed at this site. Some amount of existing Fill and buried debris should be anticipated in the vicinity of the existing structures from previous construction activities which occurred at this site. The age of the existing building is unknown at this time. However, based on a review of the available aerial photography on Google Earth, it appears that the existing WVNET building was constructed sometime prior to June There is an inherent risk associated with construction on pre-developed sites. Particularly sites where undocumented fill was placed during the previous development. Performance of the proposed structures and the degree of acceptable risk need to be evaluated by the owner. Our preliminary recommendations are based on the assumption that some limited risk can be tolerated in pavement areas and all old fill within the building footprint will be removed and replaced to ensure satisfactory building performance. 7

11 PSI understands that further geotechnical exploration of this site is planned, however based on this preliminary investigation, if some modest risk can be assumed by the owner, the footings and slab can be planned to be supported by in-place soils that are evaluated during construction by procedures subsequently discussed. To further reduce the risk, a series of test pits could be performed to better quantify and identify buried debris, if present. 3.1 SITE PREPARATION AND EARTHWORK The following recommendations are intended to attain the planned grades within the footprint areas of the proposed building, infiltration facilities, and pavements. Areas to support slabs-on-grade and pavements should be stripped of pavement, construction debris, and topsoil. In addition, existing foundations, grade slabs and utilities should be removed and the site stripped to a consistent grade. The Geotechnical Engineer or qualified representative should observe the site for proper stripping and excavation and preparation. We would recommend further evaluation for the presence of deleterious materials within the old fill be performed at this time by probing, boring or observation pits. After stripping is complete and prior to beginning fill placement activities, we recommend that all areas receiving new fill be evaluated by a proof roll. The subgrade should be proofrolled in the presence of the Geotechnical Engineer of Record or qualified representative with at least two passes of a fully loaded dump truck weighing at least 18 kips per axle or similar equipment to identify soft/loose pockets. Based on the soil types encountered and the SPT N-values of the upper soils at the site, some of the near surface soils may not pass a proofroll and will require undercutting and removal. The contractor bids and project budget should include an allowance for the expected subgrade remedial earthwork. This should account for the possibility that the existing subgrade soils may not be suitable for re-use and that contamination may increase the cost of disposal. Soils that are observed to rut or deflect excessively under the moving load should be undercut and replaced with properly compacted fill. The contractor should replace excavated materials with soils satisfying the structural fill requirements detailed later in this report. The existing fill can be selectively reused if it has less than 3 percent debris and organics, with approval of the Geotechnical Engineer of Record or qualified representative at the time of construction; however the existing fill materials should be evaluated for contamination before reuse. 8

12 If soils are wet of optimum, lowering the moisture content by scarifying and aeration (discing and exposure to sun and wind) may be required. However, this method may not be feasible if construction occurs during wet seasonal conditions. Very moist to wet soils will pump under the operation of heavy equipment, resulting in deep rutting and perhaps rendering the operation of grading and paving equipment difficult or impossible. Therefore, other methods of subgrade modification may be required in areas of high moisture content. Modification may be achieved by undercutting and replacement with granular subbase (possibly in combination with a geotextile separation layer or geogrid reinforcement), mixing stone into the subgrade, or treating the subgrade with lime or cement. The appropriate method of subgrade modification should be determined at the time of construction. The first layer of fill should be placed in a relatively uniform horizontal lift and be adequately keyed into the stripped and scarified subgrade soils. Structural fill placement in the building pad should extend at least 5 feet laterally beyond the building limits on all the sides at the building pad subgrade elevation. The edge of the fill should be placed at a 1H:1V slope or flatter. The foundations should be installed after the building area has been properly prepared. Material satisfactory for structural fill should include clean soil or bankrun sand and gravel (SW, SP, SM, GW, and GM). Soils with USCS classifications of CL, ML, GC, and SC material can be used in engineered fills, subject to the following limitations: Maximum Dry Density (per AASHTO T-99) 110 pcf Liquid Limit 45 Plasticity Index 20 High plasticity soils (MH, CH) or organic soils (OL, OH, PT) should not be used in engineered fill. The fill materials should be free from topsoil, have less than 3 percent organics, debris and should not contain rock fragments having a major dimension greater than 3 inches. The use of the excavated fill soils for controlled structural fill will be subject to approval of the Geotechnical Engineer of Record and moisture adjustments at the time of construction, and the maximum dry density requirement specified in this section. Fill placement should be in loose horizontal lifts no greater than 8 inches thick compacted uniformly with the proper equipment. Fill required to support the footings and the slab-on-grade should be compacted to at least 95 percent of the maximum dry density as per ASTM D1557 (Modified Proctor) test method. The moisture content of the fill should be within plus or minus two (±2) percentage points of the optimum moisture content. 9

13 For proper site preparation, the earthwork should be performed under the observation of and to the satisfaction of the Geotechnical Engineer of Record or his authorized representative. It will be important to maintain positive site drainage during construction. Stormwater runoff should be diverted around the building areas. The site should be graded at all times such that water is not allowed to pond. If any surface soils become wet due to rains, they should be removed or dried prior to further site work operations and/or fill placement. Should there be a significant time lag or extended period of inclement weather between site grading and the fine grading of the slab prior to the placement of stone or concrete, the Geotechnical Engineer of Record or his authorized representative should assess the condition of the prepared subgrade. The subgrade may require scarification and recompaction or other remedial measures to provide a firm and unyielding subgrade prior to final slab construction. 3.2 DISCUSSION OF POTENTIAL ROCK EXCAVATION Based on our field exploration, most of the residual soils should generally be excavatable using conventional excavation equipment, such as scrapers, front end loaders, bulldozers, etc. However, the materials that appear to be excavatable or rippable were of limited thickness. Rock or weathered rock having SPT resistances greater than 60 blows per foot will require pre-loosening with heavy equipment in order to achieve excavation. Ripping should generally be performed using a Caterpillar D-8 or equivalent large bulldozer equipped with a single-tooth ripper blade; however, the rippability of the shale bedrock at this site is anticipated to be limited. At a minimum, trackhoes or pneumatic jackhammers may be needed to be employed in small area excavations, such as in foundation excavations or in utility trenches where rock is encountered above the design trench bottom. Contingency funds for difficult excavation should be set aside for these areas. For the purposes of this report, we recommend that subsurface materials causing auger refusal or having SPT N-values in excess of 50 blows per 3 inches penetration be considered unrippable rock. Disagreements often arise relative to excavatability of materials in the transition zone between soil and rock, and below. In addition, floaters or boulders also cause disagreements. Therefore, we recommend that the project specification stipulate that excavation materials are considered unclassified and provide contractors the information from the geotechnical borings to aid their estimates. If excavation materials will be classified, we suggest the contract documents include unit rock excavation prices. To reduce potential ambiguities, we suggest the contract documents define general rock excavation as: 10

14 Material that cannot be dislodged and excavated with a single-tooth ripper drawn by a crawler tractor having a draw bar pull rated at not less than 56,000 pounds (Caterpillar D8T or equivalent) and occupying an original volume of at least one cubic yard. Additionally, trench rock excavation should be defined as material that cannot be excavated with a backhoe having a bucket curling force rated at not less than 45,000 pounds (Caterpillar 330D L or equivalent) and occupying an original volume of at least ½ cubic yard. If the Contractor elects to use equipment with power ratings that exceed the minimum power ratings described in this section, then rock should be defined based on the actual equipment used. Excavation of weathered rock or bedrock is typically much more difficult within confined excavations such as, footings, utility trenches, etc. Jackhammering or blasting is generally required for removing these materials at or below the level that auger refusal is encountered. If blasting is required, we recommend conducting a pre-blast condition survey by a registered land surveyor of the surrounding structures that may be impacted by the blasting and the performance of vibration monitoring during blasting. A pre-blast survey will help to establish the existing condition and integrity of the surrounding structures prior to commencement of construction activities. Collecting the actual preexisting and post-construction conditions will help reduce the possibility of future damage claims. If blasting is required, care should be taken to avoid over-blasting, as this may damage adjacent structures and the underlying rock, thereby reducing the load bearing capability of the rock. If blasting is utilized, all loose rock and rock fragments should be cleaned out of the excavations prior to placement of structural fill, reinforcement steel, or concrete, particularly within foundation excavations or other load bearing areas. Also, if blasting is utilized, the excavation of the rock should be done in accordance with 29 CFR Part 1926 Subpart U, Blasting and the Use of Explosives, prepared by the United States Department of Labor, Occupational Safety and Health Administration (OSHA). 3.3 SEISMIC CONSIDERATIONS The project site is located within a municipality that employs the International Building Code (IBC), 2012 edition. As part of this code, the design of structures must consider dynamic forces resulting from seismic events. These forces are dependent upon the magnitude of the earthquake event as well as the properties of the soils that underlie the site. Part of the IBC code procedure to evaluate seismic forces requires the evaluation of the Seismic Site Class, which categorizes the site based upon the characteristics of the subsurface profile within the upper 100 feet of the ground surface. 11

15 To define the Seismic Site Class for this project, and in accordance with your requested level of assessment, we have interpreted the results of our soil test borings drilled within the project site per Section 1613 of the code. The estimated soil properties are based upon data available in published geologic reports as well as our experience with subsurface conditions in the general site area. Based upon our preliminary assessment, it is our opinion that the subsurface conditions within the areas of the site planned for building construction are consistent with the characteristics of Site Class C as defined in Table of 2010 ASCE-7 Standard. As per Section of the building code, this classification was used for this assessment. The associated IBC 2012 probabilistic ground acceleration values for latitude o and longitude o obtained from the U.S. Seismic Design Maps Web Application web page ( are as follows: Period (seconds) Mapped MCE Spectral Response Acceleration** (g) Table 1 Seismic Design Parameters* Site Coefficients Adjusted MCE Spectral Response Acceleration (g) Design Spectral Response Acceleration (g) 0.2 S s F a 1.2 SM S SD S S F v 1.7 SM SD PGA (%g) * 2% Probability of exceedance in 50 years. ** At B-C interface (i.e. top of bedrock). MCE= Maximum Considered Earthquake The Site Coefficients, F a and F v presented in the above table were also obtained from the same USGS application but can be interpolated from IBC Tables (1) and (2) as a function of the site classification and mapped spectral response acceleration at the short (S s ) and 1 second (S 1 ) periods. Since the N-value evaluation of the site class has resulted in a Site Class C, geophysical testing to measure and evaluate the shear wave velocity (V s ) profile of subsurface materials at the site may be beneficial, but is not recommended at this time. For buildings with a Seismic Design Category of C, D, E, or F the code requires an assessment of slope stability, liquefaction potential, and surface rupture due to faulting or lateral spreading. Detailed assessments of these factors were beyond the scope of this study. However, the following presents a qualitative assessment of these issues considering the site class, the subsurface soil properties, the groundwater elevation, and probabilistic ground motions: 12

16 Table 2 Seismic Hazards Hazard Relative Risk Comments Liquefaction Low No groundwater was encountered at the depths explored in our test borings and the soils contained sufficient fines to limit liquefaction. The seismic hazard at the site is relatively low Slope Stability Low Probabilistic ground accelerations are very low and should not significantly affect the stability of anticipated cut and fill slopes at this site Surface Rupture Low The site is not underlain by a mapped Holocene-aged fault 3.4 PRELIMINARY FOUNDATION DISCUSSIONS As discussed previously, the preliminary exploratory test borings were performed in advance of the design of the planned future WVNET Administration and Data building. PSI understands the new structure is planned for the northern portion of the site, and that the temporary structures for the construction phase are planned to be placed within the southern portion of the site. In order to provide final geotechnical foundation recommendations, specific structural loading, tolerable settlements and proposed grading including finished floor elevations will be required. PSI briefly lists and discusses various foundation support options below: Based on our preliminary investigation, footings bearing on the existing Residuum soils may be sized and designed on the basis of a net allowable bearing pressure of 2,000 ± 500 pounds per square foot (psf). Footings bearing on the Weathered Rock can be designed for a net allowable bearing pressure of 4,000 ± 500 psf. A better determination of the allowable bearing pressure can be made after further investigation of the existing soils within the planned structural footprints. Shallow Foundations should bear at a minimum depth of 42 inches (3½ feet) beneath final exterior grade for frost depth protection. Given the high plasticity, fine grained soils and the previous construction performed at this site, we do not recommend conventional shallow foundation support of the proposed improvements without removal of any existing loose and/or highly plastic fill materials and replacement with structural fill. Depending upon the design and layout of the planned permanent structure, Deep Foundation systems may want to be considered should heavy loading conditions (i.e. greater than 300 kip column loads) be anticipated, for the mitigation of the potential for excessive differential settlements if shallow footings are to bear on different soil types, or if isolated areas of deep unsuitable soils are identified within the planned footprint. Deep foundation systems which could be utilized at this site include Helical Piers, Auger-Cast-in-Place (ACIP) Piles, and Aggregate Piers. 13

17 Utilization of multiple foundation system types to support a single structure can lead to differential settlement and damage to the structure as different portions of the structure settle at different rates and is therefore discouraged here. Based on the test borings, it appears that the existing low plasticity Residuum soils encountered can generally remain in place and be used to support the proposed temporary structures and lightly loaded features of the planned structure. However, some of the Residuum soils encountered in our exploration are considered unsuitable for foundation support of the planned permanent structure. Due to the presence of high plasticity Residuum materials at shallow depths (from the ground surface to approximately 5 feet below existing grade) noted in Boring B-2, we recognize the possibility of more high plasticity materials to exist at the ground surface across the site; these materials, if encountered during construction, could affect the planned structures. The quantity and thickness of these soils cannot be determined from the limited scope of our preliminary investigation. 3.5 SLAB-ON-GRADE CONSIDERATIONS The following preliminary considerations are intended for the preliminary design of any potential slab-on-grade: Floor slab subgrade should be proofrolled and prepared as described under Site Preparation and Earthwork. It is likely that the uncodumented fill will be encountered in the vicinity of the existing structure. Loose and uncompacted Fill will likley require a partial undercut followed by compaction of the excavation base and replacement of the excavated fill material in controlled compacted lifts. A free-draining granular blanket of crushed stone or gravel should be placed under the floor slab for lateral drainage and as a moisture capillary barrier. If desired a vapor barrier can be placed directly under the concrete floor slab and over the granular material at the direction of the Structural Engineer. Typical vapor barriers aid with reducing moisture transmission through concrete floor slabs but are not inteded as barriers to soil gas or vapor-borne contaminants. If there is concern about controlling migration of other soil gasses, a barrier specifically designed for that purpose should be used. Such a barrier could also serve as the vapor barrier. Welded wire fabric should be used in the slab to reduce the size of shrinkage cracking. The floor slab should be jointed in accordance with ACI recommendations. The column points and periphery walls should be isolated from the floor slab to reduce the possibility of the floor slab cracking due to relative displacement. 14

18 Exterior slabs should be isolated from the building. These slabs should be reinforced to function as independent units. Movement of these slabs should not be transmitted to the building foundation or superstructure. 3.6 CONSTRUCTION DEWATERING Since groundwater was not encountered at shallow depths below the existing grades, we do not anticipate water will infiltrate into shallow foundation or utility excavations. Additional water will be introduced into excavations due to local precipitation during construction if the area is exposed. Our past experience indicates that the foundation and subgrade bearing soils encountered on-site will soften considerably when exposed to free water. The contractor should keep excavations dry to prevent the softening of these materials. For the purposes of managing water that may enter an excavation, we recommend that collection pits with pumps be used to remove the groundwater from the excavation. The sump pits should be backfilled with open graded stone (AASHTO #57 recommended) and should be surrounded by a properly graded filter medium. The purpose of the filter medium is to prevent clogging of the drainage system by the infiltration of fine-grained soils. If lowering of the groundwater by more than about 2 feet is required, vacuum well points in the underlying silt will likely be needed to dewater excavations. 3.7 RECOMMENDATIONS FOR FINAL GEOTECHNICAL REPORT To be able to appropriately document the subsurface conditions at this site supplementary borings will need to be performed. Each planned improvement will require a different number of borings to be performed to specific depths based on the foundation system desired. The following is a list of typical considerations for different foundation systems: A single boring should be advanced for every 5000 ft 2 of the planned building footprint, with a minimum of two borings per planned structure. For any structures with a footprint over 40,000 ft 2, the boring scheme should be altered to have one boring for every 10,000 ft 2, with an additional boring for every 400 feet if building perimeter. Additional borings should be placed wherever an irregular loading condition or special design feature will be present, such as a pipe organ, statue, baptismal, chimney, large stationary mechanical device, or elevator. Borings for shallow foundations should extend an appropriate depth (typically 2 to 3 times the width of the foundation) below the frost depth and not be terminated in any fill, organics or loose (SPT N-value of 5 or less) materials. 15

19 In the case that a deep foundation option is to be included in the final report, the depths any borings should be advanced for the purposes of providing recommendations for a deep foundation system will be determinate upon the thickness of the materials which are to be bypassed near the surface and the expected maximum load to be supported. The findings of this preliminary report will be incorporated with the findings of any supplemental investigation(s) to produce a final geotechnical report. Before a final report can be completed, additional information will be necessary, which was not available at the time this report was completed. Particularly, final floor elevations, a determination of the maximum loading conditions, tolerable settlements for the structure and a planned footprint location will be necessary for each planned structure. The final report will require an appropriate laboratory testing program to appropriately characterize the soil strata encountered and document the various soil parameters of each. Depending on the foundation system desired at each location, the drilling program will likely want to include undisturbed sampling of the fine grained materials encountered at this site. 16

20 4 REPORT LIMITATIONS The recommendations submitted are based on the available subsurface information obtained by PSI and design details furnished by WVNET and their consultants for the proposed project. If there are any revisions to the plans for this project or if deviations from the subsurface conditions noted in this report are encountered during construction, PSI should be notified immediately to determine if changes in the foundation recommendations are required. If PSI is not retained to perform these functions, we will not be responsible for the impact of those conditions on the geotechnical recommendations for the project. PSI did not provide, nor was it requested to provide, any service to investigate or detect the presence of moisture, mold or other biological contaminants in or around any structure, or any service that was designed or intended to prevent or lower the risk of the occurrence of the amplification of the same. Client acknowledges that mold is ubiquitous to the environment with mold amplification occurring when building materials are impacted by moisture. Client further acknowledges that site conditions are outside of PSI s control, and that mold amplification will likely occur, or continue to occur, in the presence of moisture. As such, PSI cannot and shall not be held responsible for the occurrence or recurrence of mold amplification. The client must also acknowledge that some project sites may have impacted soil or groundwater associated with a known or unknown hazardous material release. Also, at sites that have been previously graded, it is possible that buried debris, organics, or other deleterious materials may be present on the site. Impacted soil and groundwater as well as buried degradable materials may produce vapor intrusions into new and existing buildings, which could compromise the indoor air quality of the structure(s). The geotechnical scope of services did not include an assessment of these potential conditions at this site. Vapor intrusion is a non-scope consideration that PSI would be pleased to help you assess at your request. PSI warrants that the findings, recommendations, specifications, or professional advice contained herein have been made in accordance with generally accepted professional geotechnical engineering practices in the local area at the date of this report. No other warranties are implied or expressed. After the plans and specifications are more complete, PSI should be retained and provided the opportunity to review the final design plans and specifications to check that our engineering recommendations have been properly incorporated into the design documents. At that time, it may be necessary to submit supplementary recommendations. This report has been prepared for the exclusive use of WVNET and its consultants for the specific application to the PROPOSED WVNET ADMINISTRATION & DATA CENTER PROJECT IN MORGANTOWN, WEST VIRGINIA. 17

21 APPENDIX A SITE VICINITY PLAN AND BORING LOCATION PLAN

22 Figure 1 - Site Location Plan PSI Project No WVNET Admin/Data Building June 11, 2014 SITE The Department cannot verify the accuracy or completeness of this information or alignment of images. Created on: 06/04/ feet

23 feet meters

24 APPENDIX B BORING LOGS

25 DATE STARTED: 6/19/14 DRILL COMPANY: PSI, Inc. DRILLER: J Dudley Jr. LOGGED BY: J Dudley Jr. COMPLETION DEPTH 19.7 ft DRILL RIG: CME 55x300 DATE COMPLETED: 6/19/14 BORING B-1 BENCHMARK: 0 ELEVATION: N/A LATITUDE: LONGITUDE: STATION: N/A OFFSET: N/A REMARKS: Elevation (feet) Depth, (feet) 0 Graphic Log Sample Type Sample No. S-1 Recovery (inches) 18 MATERIAL DESCRIPTION Apprpoximately 4.0 inches of TOPSOIL RESIDUUM - Stiff, moist, yellow brown and dark brown, sandy SILT, with rock fragments USCS Classification ML N=8 Moisture, % 10 0 STRENGTH, tsf Qu While Drilling Upon Completion Delay DRILLING METHOD: Hollow Stem Auger SAMPLING METHOD: SS, 3' Centers HAMMER TYPE: Automatic BORING LOCATION: EFFICIENCY N/A Refer to boring location plan REVIEWED BY: J. Smith SPT Blows per 6-inch (SS) Water STANDARD PENETRATION TEST DATA N in blows/ft PL Moisture LL Qp 4.0 Additional Remarks N/E N/E N/A S-2 18 WEATHERED ROCK - Hard, moist, light brown and dark brown, CLAYSHALE, sampled as a SILT, with rock fragments SILT (USCS ML) N=30 11 Non-Plastic Fines=90.7% 5 11 S-3 18 Grades to very hard N=56 >> ML 10 S-4 18 Grades to very stiff, dark brown, orange brown, and light brown N=28 S-5 7 Grades to very hard and light brown 35-50/1" >> WEATHERED ROCK - Dense, moist, dark brown, orange brown and light brown, SHALE, sampled as a Silty GRAVEL 15 S-6 18 GM N=41 WEATHERED ROCK - Very hard, moist, light brown and light gray, CLAYSHALE, sampled as a SILT, with rock fragments ML S /2" Boring terminated at approximately 19.5 feet Professional Service Industries, Inc. 850 Poplar Street Pittsburgh, PA Telephone: (412) PROJECT NO.: PROJECT: WVNET Admin/Data Center LOCATION: 837 Chestnut Ridge Rd. City of Morgantown Monongalia Co., PA The stratification lines represent approximate boundaries. The transition may be gradual. Sheet 1 of 1

26 DATE STARTED: 6/19/14 DRILL COMPANY: PSI, Inc. DRILLER: J Dudley Jr. LOGGED BY: J Dudley Jr. COMPLETION DEPTH 10.7 ft DRILL RIG: CME 55x300 DATE COMPLETED: 6/19/14 BORING B-2 BENCHMARK: 0 ELEVATION: N/A LATITUDE: LONGITUDE: STATION: N/A OFFSET: N/A REMARKS: Elevation (feet) Depth, (feet) 0 Graphic Log Sample Type Sample No. S-1 Recovery (inches) 18 MATERIAL DESCRIPTION Approximately 3.5 inches of TOPSOIL RESIDUUM - Firm, moist, light brown, orange brown and black, sandy Lean CLAY, with organics USCS Classification N=7 Moisture, % 16 STANDARD PENETRATION TEST DATA N in blows/ft PL Moisture LL STRENGTH, tsf Qu While Drilling Upon Completion Delay DRILLING METHOD: Hollow Stem Auger SAMPLING METHOD: SS, 3' Centers HAMMER TYPE: Automatic BORING LOCATION: EFFICIENCY N/A Refer to boring location plan REVIEWED BY: J. Smith SPT Blows per 6-inch (SS) Water 2.0 Qp 4.0 Additional Remarks N/E N/E N/A S-2 18 Fat CLAY (USCS CH) Grades to stiff, orange brown and light gray CL N=13 23 >> LL = 52 PL = 27 Fines=77.5% 5 S-3 18 RESIDUUM - Very stiff, moist, light gray and light brown, sandy Lean CLAY Lean CLAY (USCS CL) CL N=19 14 LL = 26 PL = S-4 2 WEATHERED ROCK - Very dense, moist, gray, dark gray and yellow brown, SHALE, sampled as a Silty SAND, with rock fragments SM 50/2" >> Auger refusal encountered at approximately 10.5 feet Professional Service Industries, Inc. 850 Poplar Street Pittsburgh, PA Telephone: (412) PROJECT NO.: PROJECT: WVNET Admin/Data Center LOCATION: 837 Chestnut Ridge Rd. City of Morgantown Monongalia Co., PA The stratification lines represent approximate boundaries. The transition may be gradual. Sheet 1 of 1

27 DATE STARTED: 6/19/14 DRILL COMPANY: PSI, Inc. DRILLER: J Dudley Jr. LOGGED BY: J Dudley Jr. COMPLETION DEPTH 3.7 ft DRILL RIG: CME 55x300 DATE COMPLETED: 6/19/14 BORING B-3 BENCHMARK: 0 ELEVATION: N/A LATITUDE: LONGITUDE: STATION: N/A OFFSET: N/A REMARKS: Elevation (feet) Depth, (feet) 0 Graphic Log Sample Type Sample No. S-1 Recovery (inches) 18 MATERIAL DESCRIPTION Approximately 3.5 inches of TOPSOIL RESIDUUM - Stiff, moist, orange brown, sandy SILT, with trace gravel USCS Classification ML SPT Blows per 6-inch (SS) N=10 Moisture, % Water STANDARD PENETRATION TEST DATA N in blows/ft PL Moisture LL STRENGTH, tsf Qu While Drilling Upon Completion Delay DRILLING METHOD: Hollow Stem Auger SAMPLING METHOD: SS, 3' Centers HAMMER TYPE: Automatic BORING LOCATION: EFFICIENCY N/A Refer to boring location plan REVIEWED BY: J. Smith 2.0 Qp 4.0 Additional Remarks N/E N/E N/A S-2 4 Grades to orange brown, light brown and light gray, with clay Auger refusal encountered at approximately 3.5 feet 50/4" >> Professional Service Industries, Inc. 850 Poplar Street Pittsburgh, PA Telephone: (412) PROJECT NO.: PROJECT: WVNET Admin/Data Center LOCATION: 837 Chestnut Ridge Rd. City of Morgantown Monongalia Co., PA The stratification lines represent approximate boundaries. The transition may be gradual. Sheet 1 of 1

28 GENERAL NOTES SAMPLE IDENTIFICATION The Unified Soil Classification System (USCS), AASHTO 1988 and ASTM designations D2487 and D-2488 are used to identify the encountered materials unless otherwise noted. Coarse-grained soils are defined as having more than 50% of their dry weight retained on a #200 sieve (0.075mm); they are described as: boulders, cobbles, gravel or sand. Fine-grained soils have less than 50% of their dry weight retained on a #200 sieve; they are defined as silts or clay depending on their Atterberg Limit attributes. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. DRILLING AND SAMPLING SYMBOLS SFA: HSA: M.R.: R.C.: H.A.: P.A.: Solid Flight Auger - typically 4" diameter flights, except where noted. Hollow Stem Auger - typically 3¼" or 4¼ I.D. openings, except where noted. Mud Rotary - Uses a rotary head with Bentonite or Polymer Slurry Diamond Bit Core Sampler Hand Auger Power Auger - Handheld motorized auger SOIL PROPERTY SYMBOLS SS: Split-Spoon - 1 3/8" I.D., 2" O.D., except where noted. ST: Shelby Tube - 3" O.D., except where noted. RC: Rock Core TC: Texas Cone BS: Bulk Sample PM: Pressuremeter CPT-U: Cone Penetrometer Testing with Pore-Pressure Readings N: N 60 : Q u : Q p : w%: LL: PL: PI: DD:,, Standard "N" penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. Split-Spoon. A "N" penetration value corrected to an equivalent 60% hammer energy transfer efficiency (ETR) Unconfined compressive strength, TSF Pocket penetrometer value, unconfined compressive strength, TSF Moisture/water content, % Liquid Limit, % Plastic Limit, % Plasticity Index = (LL-PL),% Dry unit weight, pcf Apparent groundwater level at time noted RELATIVE DENSITY OF COARSE-GRAINED SOILS ANGULARITY OF COARSE-GRAINED PARTICLES Relative Density Very Loose Loose Medium Dense Dense Very Dense Extremely Dense N - Blows/foot Description Angular: Subangular: Subrounded: Rounded: Criteria Particles have sharp edges and relatively plane sides with unpolished surfaces Particles are similar to angular description, but have rounded edges Particles have nearly plane sides, but have well-rounded corners and edges Particles have smoothly curved sides and no edges GRAIN-SIZE TERMINOLOGY PARTICLE SHAPE Component Boulders: Cobbles: Coarse-Grained Gravel: Fine-Grained Gravel: Coarse-Grained Sand: Medium-Grained Sand: Fine-Grained Sand: Silt: Clay: Size Range Over 300 mm (>12 in.) 75 mm to 300 mm (3 in. to 12 in.) 19 mm to 75 mm (¾ in. to 3 in.) 4.75 mm to 19 mm (No.4 to ¾ in.) 2 mm to 4.75 mm (No.10 to No.4) 0.42 mm to 2 mm (No.40 to No.10) mm to 0.42 mm (No. 200 to No.40) mm to mm <0.005 mm Description Flat: Elongated: Flat & Elongated: Descriptive Term Trace: With: Modifier: Criteria Particles with width/thickness ratio > 3 Particles with length/width ratio > 3 Particles meet criteria for both flat and elongated RELATIVE PROPORTIONS OF FINES % Dry Weight < 5% 5% to 12% >12% Page 1 of 2