GEOTECHNICAL EVALUATION WISSAHICKON CHARTER SCHOOL EAST WASHINGTON LANE PHILADELPHIA, PENNSYLVANIA. October Prepared for:

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1 GEOTECHNICAL EVALUATION WISSAHICKON CHARTER SCHOOL EAST WASHINGTON LANE PHILADELPHIA, PENNSYLVANIA October 2011 Prepared for: Mt. Airy Transit Village, Inc Germantown Avenue, Suite 200 Philadelphia, Pennsylvania Prepared by: Duffield Associates, Inc. 211 North 13 th Street, Suite 704 Philadelphia, Pennsylvania Brian J. Devine, P.E. Geotechnical Engineer James F. Cloonan, P.E., LEED AP Senior Geotechnical Engineer Project No GB

2 TABLE OF CONTENTS SECTION DESCRIPTION PAGE EXECUTIVE SUMMARY... i I. INTRODUCTION...1 II. FIELD AND LABORATORY TESTING PROGRAMS...3 A. PREVIOUS FIELD PROGRAMS PERFORMED BY OTHERS...3 B. STANDARD PENETRATION TEST BORINGS...3 C. BACKHOE EXCAVATED TEST PITS...4 D. LABORATORY TESTING...4 III. SUBSURFACE CONDITIONS...4 A. GENERALIZED SITE GEOLOGY...4 B. STRATIGRAPHIC CONDITIONS...5 IV. DISCUSSION OF ANALYSIS...7 A. PREVIOUS SITE USE AND PROPOSED SITE PREPARATION...7 B. PROPOSED FOUNDATIONS AND SLAB-ON-GRADE...9 C. SITE PAVEMENTS...10 V. CONCLUSIONS AND RECOMMENDATIONS...10 A. DESIGN...11 B. CONSTRUCTION...14 APPENDICES Appendix A Site Location Sketch Test Boring and Test Pit Location Sketch Appendix B Test Boring Logs (14) Appendix C Test Pit Logs (6) Appendix D General Notes

3 EXECUTIVE SUMMARY This report summarizes Duffield Associates, Inc. s (Duffield Associates) geotechnical evaluation for the proposed school building to be constructed on the parcels located at 815 and 825 East Washington Lane in Philadelphia, Pennsylvania. The proposed development consists of the redevelopment of two abandoned properties for the construction of a school campus. The school campus is proposed to consist of a one to two-story school structure covering a footprint on the order of 50,000 square feet. The currently proposed layout consists of the school building extending from Washington Lane towards the center of the site, with parking areas and a field to west. The site is currently configured into a northern parcel and a southern parcel. The northern parcel consists of a partially demolished industrial site, which formerly contained a fuel distribution and automotive service company. The southern parcel consists of a paved lot, which was formerly used as a staging area for construction. Varied industrial development has occurred at the site dating from the 1920s. Recently, buildings have been demolished and a number of aboveground and underground storage tanks removed. A total of 14 Standard Penetration Test borings and six test pit excavations were performed at the site between September 6 and 9, The majority of the southern parcel is currently paved, and the northern parcel is covered by a combination of exposed concrete slabs, cobblestone pavers and gravel areas. Beneath the surface stratum, the subsurface conditions observed generally consisted of a layer of fill materials consisting primarily miscellaneous debris with varying amounts of silt or sand soils underlain by dense micaceous sand soils to the extent of the test borings. In several of the test borings, a layer of apparent natural fine-grained silt soils was encountered overlying the sand soils. The micaceous sand soils were consistent with residual soils derived from the in-place weathering of the underlying bedrock material. The soil density generally increased with depth. Refusal to the advancement of the drilling augers was encountered above the proposed termination depth in the majority of the test borings. Groundwater was encountered within the fill materials throughout the site. Based on the fine-grained and dense soils underlying fill materials, the groundwater generally appears to be perched in the miscellaneous fill stratum. The site of the proposed development was previously utilized as an industrial site and a construction storage yard. Historical mapping indicates that there were many combinations of structures on the site, mainly situated along the northern half of the site. At the time of this evaluation, the majority of the structures have been removed to grade; however, there are indications that the majority of the below-grade portions of these structures remain across large portions of the site. The remaining portions include abandoned foundation elements. Due to the previous and proposed site usage, it is recommended that the abandoned foundation elements and miscellaneous fills be removed in their entirety from the proposed buildings areas. While it may be possible to leave a portion of the fill soils beneath the proposed pavement and landscaped areas, it is recommended that the pavement, concrete slabs, abandoned foundation elements and miscellaneous fill materials be removed in their entirety from the site. i

4 Based on the observed subsurface conditions and the building loads assumed, it is Duffield Associates opinion that the proposed structures could be supported on a shallow foundation system and slab-on-grade supported on the natural site soils of medium consistency or greater, encountered below the concrete and miscellaneous fill soils or on structural fill placed and compacted as recommended herein. It is recommended that the proposed foundations be designed for a maximum allowable bearing pressure of 3,000 pounds per square foot (psf). This analysis has assumed a shallow foundation system with a minimum burial depth of 36 inches for exterior footings. Total settlement for foundation bearing on the soils recommended herein is estimated to be on the order of 1 inch, and post-construction differential settlement is estimated to be less than ½ inch over a distance of 20 feet. The previously placed fill soils at the site are not considered suitable for supporting a shallow foundation system and should be removed where encountered from beneath the proposed building foundations. These fill soils were observed to extend to depths of greater than 10 feet below existing grade in portions of the site. Depending on the final site grading, a significant undercutting of the fill materials from within the building area may be required during construction. Additionally, while not encountered uniformly across the site, refusal on apparent bedrock was encountered at several locations at shallow depths A more complete summary of the field and laboratory testing programs and the subsurface conditions observed are included in the following report. Additionally, more detailed recommendations for the design and construction of the proposed building foundations, floor slab and site pavements are also provided. ii

5 I. INTRODUCTION This report summarizes Duffield Associates, Inc. s (Duffield Associates) geotechnical evaluation for the proposed school building to be constructed at 815 and 825 East Washington Lane, to the northwest of the intersection of East Washington Lane and Chew Avenue in Philadelphia, Pennsylvania. Included in this report is a summary of the data obtained during the field and laboratory testing programs and a discussion of the subsequent geotechnical analysis. Recommendations for the design and construction of the proposed building foundations and building slab-on-grade, as well as the site pavements are also provided. These services were provided in general accordance with an agreement between Duffield Associates and Mt. Airy Transit Village, Inc., dated August 16, 2011, executed on August 18, An evaluation of the suitability of the site soils for infiltration practices is summarized in a separate report dated October To assist with the preparation of this report, Duffield Associates was provided the following: A series of AutoCAD files of the existing site features and topography of the proposed layout for the new school building and associated paving by the project architect, (Metcalfe Architecture and Design); A Phase I Environmental Site Assessment Report titled Former Edwin Bennis & Sons Property, Philadelphia, Pennsylvania, prepared by Envirosearch Consultants, Inc., dated June 12, 2006; A report titled Phase II Environmental Site Assessment at 825 East Washington Lane, Philadelphia, PA prepared by Urban Engineers, dated July 11, 2007; A Phase I Environmental Site Assessment titled Mt. Airy Transit Village Phase 1, 815 East Washington Lane, Philadelphia, Pennsylvania, prepared by ephase, Inc., dated April 21, 2008; A Phase II Environmental Site Assessment Report titled City of Philadelphia, Mt. Airy Transit Village, 815 East Washington Lane, Philadelphia, prepared by EarthQuest, dated June 16, 2008; and A series of documents related to the removal of storage tanks from the 825 East Washington Lane portion of the site. Based on Duffield Associates site observations and the information provided, it is understood that it is proposed to redevelop two abandoned properties. The redevelopment is currently proposed to consist of a one to two-story school structure covering a footprint on the order of 50,000 square feet. The currently proposed layout consists of the school structure extending from Washington Lane to the central portion of the site, with parking areas and a field to west. The school building layout is proposed to incorporate an existing one-story building at Washington Lane, and may be constructed with a similar finished floor elevation, or may be stepped into the site. 1

6 The existing site consists of two parcels. The southern parcel (designated as 815 East Washington Lane) is a paved open area bounded by a low concrete/masonry wall. The referenced environmental assessments indicate that this parcel has been previously utilized as a construction storage yard with several buildings and warehouses, which were demolished by the City of Philadelphia to construct the current paved area in the 1960s. As part of the demolition of the site, several underground tanks were reportedly removed. The site slopes from the west to the east, with the site grades ranging in elevation from approximately 243 feet to 251 feet, project datum. The northern parcel (designated as 825 East Washington Lane) was previously an industrial site and the former home of Edwin F. Bennis & Sons, which was constructed in the 1920s and remained in operation until the 1990s. The site was reportedly used primarily as a fuel distribution center and garage. When the business closed in the 1990s, storage tanks at the site continued to be used until recently. The referenced environmental reports include closure reports prepared for the aboveground and underground storage tanks removed from the site in the mid-2000s. Currently, with the exception of a single building along Washington Lane, the former buildings and storage tanks at the site have been demolished to the ground surface; however, slabs-on-grade and belowgrade portions of the structure (excluding the underground storage tanks) remain. There is also a communication tower in the western corner of the site, which is to remain and is beyond the portion of the site proposed to be redeveloped. This portion of the site generally slopes downward from the west to the east, with the site grades ranging in elevation from approximately 245 feet to 255 feet, project datum. The area around the communications tower is separated from the school site by a retaining wall. The tower is founded at an elevation of approximately 260 feet. Structural loading information for the proposed school building was not available at the time of this evaluation. It is assumed that the two-story school structure will generally be constructed at grade, and be supported with shallow foundations consisting of continuous wall footings and isolated columns. For the purposes of this evaluation, column loads on the order of 100 kips have been assumed. The proposed site grading and finished floor elevations for the buildings were not available at the time of this evaluation. No existing underground utilities were delineated within the vicinity of the proposed building by representatives of PA One Call. However, due to the previous usage at the site, abandoned utilities may be encountered at the site. The available site survey indicated the presence of several stormwater inlets and stormwater utilities. 2

7 II. FIELD AND LABORATORY TESTING PROGRAMS A. PREVIOUS FIELD PROGRAMS PERFORMED BY OTHERS The referenced Phase II Environmental Site Assessments included a field evaluation phase. The field program for each site consisted of the performance of a limited geophysical survey, as well as the performance of geoprobe borings. The information presented in these assessments was utilized to supplement the information obtained as part of the current evaluation. B. STANDARD PENETRATION TEST BORINGS Fourteen Standard Penetration Test (SPT, performed in general accordance with ASTM D 1586) borings were performed between September 7 and 9, The test borings, designated TB-4, TB-7 through TB-15, and TB-18 through TB-20, were extended to depths ranging from 2 feet to 20 feet below the existing ground surface. In one case, where refusal to further penetration of the test boring augers was encountered at shallow depths (i.e., less than 3 feet), the borings was offset approximately 60 feet from the original locations for another attempt at penetration. Additional proposed test borings located across portions of the site were inaccessible to the drilling equipment and have not been included at this time. The test borings were generally located within areas accessible to the drilling rig and clear of marked utilities. The test boring locations were determined by Duffield Associates representative referencing existing site features. The approximate test boring locations are indicated on the Test Boring and Test Pit Location Sketch enclosed with this report in Appendix A. The test borings were performed by Soil Borings Inc. of Haddonfield, New Jersey, as a subcontractor to Duffield Associates, utilizing a truck-mounted Mobile B-80 drill rig with hollow-stem augers. Duffield Associates representative was present to review the performance of the test borings. Test boring logs, which describe the conditions observed during the field program, are enclosed in Appendix B of this report. At completion of the drilling, the boreholes were backfilled with the soil cuttings. Further restoration of the borehole locations was beyond the scope of work performed for this geotechnical evaluation. However, additional settlement of the materials backfilled in the boreholes may occur, resulting in a depression or hole in the ground surface. Consequently, future maintenance and restoration of the site may be required. 3

8 C. BACKHOE EXCAVATED TEST PITS Between September 6 and 9, 2011, six backhoe excavated test pits (TP-1 through TP-4, TP-6, and TP-7) were excavated at the site. The test pits were extended to depths ranging from 3 feet to 10.5 feet below the existing ground surface and were located within areas accessible to the backhoe and clear of marked utilities. The test pit locations were determined by Duffield Associates representative referencing existing site features. The approximate test pit locations are indicated on the Test Boring and Test Pit Location Sketch. The test pits were excavated utilizing a rubber-tired backhoe owned and operated by CGC Geoservcies, LLC of Hockessin, Delaware, as a subcontractor to Duffield Associates. Test pit logs, which describe the conditions observed during the field exploration program, are enclosed in Appendix C of this report. At completion of the test pits, the pits were backfilled with the excavated material and leveled off with the surrounding grades. No additional compactive effort or site restoration was performed other than that outlined above. Further restoration of the test pit locations was beyond the scope of work performed for this evaluation. D. LABORATORY TESTING Following completion of the field program, soil samples were returned to Duffield Associates laboratory for testing of selected samples. The laboratory testing program for this evaluation included the determination of natural water content (ASTM D 2216) and the determination of the silt/clay content in accordance with the United Soil Classification System (USCS) (percent finer than a No. 200 sieve, ASTM D 1140) for a total of 14 soil samples obtained during the field evaluation. The results of these laboratory tests are included on the test boring logs in Appendix B. No environmental characterization of the soils encountered was performed as part of this evaluation. III. SUBSURFACE CONDITIONS A. GENERALIZED SITE GEOLOGY Based on mapping available from the Pennsylvania Geological Survey, the project site is located within the Wissahickon Formation of the Lower Paleozoic Period. The Wissahickon Formation is composed primarily of Albite-chlorite schist, Marburg schist, and Oligoclase-mica schists. The alluvium soils at the site generally consist of the soil of the Chester Formation; however, the site is classified as Urban Land, which can be indicative of significant previous site disturbance. 4

9 B. STRATIGRAPHIC CONDITIONS The majority of the southern parcel (815 East Washington Lane) is currently paved, and the northern parcel (825 East Washington Lane) is covered by a combination of exposed concrete slabs, cobblestone pavers, and gravel areas. Beneath the surface stratum, the subsurface conditions observed during the performance of the test borings and test pits generally consisted of a layer of fill materials consisting primarily miscellaneous debris with varying amounts of silt or sand soils underlain by dense micaceous sand soils to the extent of the test borings. In several of the test borings, a layer of apparent natural fine-grained silt soils were observed to overlie the sand soils. The micaceous sand soils were consistent with residuals soils derived from the in-place weathering of the underlying bedrock material. The soil density generally increased with depth. Typically, where the borings were proposed to extend to a depth of 20 feet, refusal to the advancement of the drilling augers was encountered above the proposed termination depth. Auger refusal was encountered in each of the test borings at depths ranging from 2 feet to 16 feet below the existing ground surface, with the exception of test borings TB-10, TB-11, TB-13 and TB-14, corresponding to an approximate elevation range of 227 to 245 feet (project datum). The fill materials encountered consisting primarily of miscellaneous debris was generally observed to extend to greater depths in the western portion of the site where the elevations are higher. The fill varied in consistency, however, generally contained significant amounts of construction demolition type debris when observed in the test pit excavations. For discussion purposes, subsurface conditions encountered can be further described as follows: 5

10 SUBSURFACE APPROXIMATE STRATUM THICKNESS (FT.) GENERALIZED DESCRIPTION [1] A B [2] [2] Bituminous Concrete, Concrete Slab, Cobblestone Pavers, Grass, or Gravel Cover Miscellaneous FILL: Gray, brown debris (building stones, metal, pipe, wood, concrete chucks, terracotta pipe, plastic, glass), some to trace fine to medium sand, trace to little silt; Gray brown silt, little to some fine to coarse sand, trace debris (brick and bituminous concrete fragments, class, masonry stones) (very soft to very stiff consistency); or Gray red-brown fine to medium sand, little to and silt, trace debris (very loose to medium density). C [3] Gray, brown SILT, little to trace fine sand, (medium to stiff consistency); USCS: ML D [4] --- Weathered ROCK: Gray-brown fine to medium micaceous sand, trace to some silt, trace coarse sand/ gravel, (medium to very dense density); USCS: SM or; Gray-brown clay and fine micaceous sand (stiff consistency) USCSL CL NOTES: 1. The soil descriptions utilized herein and on the test boring logs are defined in the General Notes in Appendix D. 2. Stratum B was not encountered in test borings TB-18 and TB-20/20A, and not fully penetrated in test borings TB-14, TB-10/10A, and test pit TP Stratum C was only encountered in test borings TB-8, TB-10, TB-12, TB-19, and test pit TP Stratum D was not fully penetrated in any of the test borings or test pits. Groundwater observations made during the performance of the test borings are indicated on the logs included in Appendix B and the test pit logs in Appendix C. Groundwater was encountered in a majority of the test borings at depths ranging from 1 to 13 feet below the existing ground surface. Where observed at shallow depths (such as in test boring TB-9, TB-10, TB-13, TB-15, and TB-18), the groundwater was observed in the fill materials just above the natural site soils indicating a possible localized perched groundwater condition, which could be encountered at even higher elevations throughout the site. Additionally, the current site grading results in large areas, which pond water on the surface following precipitation events. 6

11 IV. DISCUSSION OF ANALYSIS A. PREVIOUS SITE USE AND PROPOSED SITE PREPARATION The site of the proposed development was previously an area of industrial use. Historical mapping (e.g., Sanborn Insurance maps) indicates that the site was the home of a former fuel distribution center dating to the 1920s and a construction storage yard dating to the 1950s. The City of Philadelphia demolished the site structures and constructing a parking lot on the southern parcel. The industrial buildings of the northern parcel have recently been demolished. The data provided indicates that the site had various uses and structures. While the majority of the structures have been removed, the remaining aboveground and buried portions of the abandoned structures and the miscellaneous fills, which were left in their place, will likely have an impact on the proposed construction. Due to the subsurface conditions, the following should be considered when planning site work and earthwork construction. Bulk Grading Design. While the project is in the preliminary design phases and there are several concepts which have been developed, a final design has not yet been formalized. The current concept for the school structure incorporates the single remaining structure along Washington Lane, and the new school building matching the existing finished floor elevation. If the design moves forward with this concept, a significant cut would be required to achieve the finished floor elevation of the school building. This would require significant excavation of the existing miscellaneous fill and debris. It would also likely result the excavation of dense weathered rock. In the area of test boring TB-20, adjacent to the existing building, the dense weathered rock prevented the drill augers from extending more than 3 feet below the ground surface. Additionally, a lower finished floor elevation will result in a significant volume of excavated soils to manage at the site. It is noted that if the design team considers a concept with a higher finished floor elevation, significant bulk excavation may still be required to remove unsuitable soils encountered within the building area. A second grading concept considered by the design team is the balance of cuts and fills at the sites. While a balance of cuts and fills can minimize the costs associated with trucking excess soil materials from the site or importing fill, the presence of the significant amounts of miscellaneous fill containing debris may limit this approach. Much of the debris would need to be removed from the miscellaneous material before reusing these materials for site fills. Project quantity calculations and budgets should account for the removal and disposal of debris from the site. 7

12 Further Demolition of Existing Site Structures. Due to the previous and proposed site usage, the abandoned foundation elements and miscellaneous fills (encountered to depths of up to 5 feet on the eastern portion of the site and 10 to 13 feet in the western portion of the site) should be removed in their entirety from the proposed building areas. This will likely include the removal of a substantial amount of concrete and previous foundation elements. While the abandoned structures on the northern parcel are generally visible, the southern parcel has been paved and any abandoned foundation structures which may be present are not easily identifiable from the surface. These materials should be removed until apparent natural soils are encountered. The resulting excavations should be backfilled with structural fill placed and compacted as recommended herein. Reuse and landscaping will require that the existing paved surface treatments (i.e., pavement, concrete slab, cobblestones) be removed from the entire site, including the proposed roadway and landscaped areas. Following pavement removal, the condition of the underlying soils can be better observed. Exposing the subgrade soils, removing abandoned foundation structures, and proofrolling the entire site should assist in determining the extent to which the subgrade soils are suitable for subsequent construction. Reuse of On-Site Soils. The miscellaneous fill material was observed to be highly variable in consistency and composition. The reuse of the available site soils as backfill will require the removal of large debris to develop a more homogenous material capable of being placed and compacted to specified criteria. Typically, modification involves removing material, such as plastic wood and metal, followed by screening and/or crushing of the material in order to develop a more homogeneous material. If reuse of the on-site material (miscellaneous fill) is proposed, the design team should consider following modifications: Screen the material through a 6-inch sieve. The purpose of this preliminary screening is to segregate the larger debris fragments from the bulk material. All reinforced concrete, organics (such as timber, wood, roots, etc.), metal (e.g., steel, iron pipe, metal flashing, etc.), terra cotta, and other deleterious material should be removed and disposed of off site; Crush material to 3 inches or less. Following removal of the unsuitable material described above, it is recommended that the resulting material be crushed so that the largest particle size is less than 3 inches; and Mix resulting material. In order to create a more homogeneous mix, it is recommended that the crushed material be thoroughly mixed. 8

13 The resulting on-site material could be utilized in bulk fill applications within the parking area and landscaped areas. Material should be placed and compacted as directed in the Conclusions and Recommendations section of this report. It is anticipated that this modified on-site material may contain a significant percentage of fine-grained soil (silts and clays). Fine-grained soils are moisture sensitive and sensitive to construction traffic (i.e., the more moisture and/or construction traffic the soils are exposed to, the more they will tend to degrade and become unsuitable). Therefore, some drying of these material may be required to achieve the recommended compaction criteria B. PROPOSED FOUNDATIONS AND SLAB-ON-GRADE Based on the information obtained by the field and laboratory testing of the subsurface soils, it is Duffield Associates opinion that the natural site soils encountered beneath the miscellaneous fill materials (Strata A and B) are generally suitable for supporting the proposed buildings on a conventional, shallow foundation system and slab-on-grade. Miscellaneous fill materials and abandoned foundation elements were encountered throughout the site to depths of up to 4 feet in the eastern portion of the site and to depths of 8 to 13 feet in the western portion of the site. Structural fill, placed over natural soils and compacted as recommended in this report, is also considered suitable for supporting a shallow foundation system. Analysis indicates that the proposed two-story school building foundations bearing on the natural soils, or on compacted structural fill placed and compacted as recommended here in, could be sized for a maximum allowable bearing pressure of 3,000 pounds per square foot (psf). This analysis has assumed a shallow foundation system with a minimum width of 3 feet for isolated footings and 2 feet for continuous footings, and a minimum burial depth of 18 inches for interior footings and a minimum of 36 inches for exterior footings. It is noted that if significant cuts are performed across a large portion of the site (as is currently being considered) the foundation may bear primarily on dense weathered rock soils or bedrock. It may be practical to utilize a higher allowable bearing capacity of 5,000 psf for foundations bearing directly on the dense weathered rock. Estimates of foundation settlement were performed to aid in evaluating the effects of the building loads on the subsurface conditions. Based on this analysis, it is estimated that maximum total foundation settlement for the proposed buildings should be on the order of 1 inch or less. Due to the generally unsaturated soils encountered and the relatively shallow bedrock soils, most of the estimated settlement should occur relatively quickly following the application of loads. Post-construction total and differential settlement is estimated to be on the order of ½ inch or less over a distance of 20 feet. These magnitudes of total and differential settlement are generally considered to be within tolerable limits. 9

14 However, the actual settlement tolerance of the building should be verified with the project s structural engineer. If the design structural loading is different than that assumed herein, the estimated settlement magnitude may also be different. The design team should review the loads assumed herein and the estimated settlement magnitudes, and compare them with the design conditions and the tolerances established for the structure. If the loading conditions assumed herein are not accurate, additional analysis may be required to evaluate the settlement magnitude under the design conditions. C. SITE PAVEMENTS The presence of the miscellaneous fill materials should be considered in the design of the site pavements. Several alternatives for construction of the site pavements can be considered. Typically, a least risk alternative would be to remove the miscellaneous fill materials in their entirety and replace them with structural fill. However, based on the depth of the fill encountered on the site, this alternative may not be economically practical. The near surface miscellaneous fill observed in several borings was in a medium dense condition; therefore, with some subgrade preparation and field review to identify and remediate localized soft or debris-laden areas, it may be practical to construct the pavement section over the miscellaneous fill. However, there could be additional risk of uneven pavement settlement and increased future maintenance. To reduce the potential for large differential settlement over a short distance, existing fill soils should be capped with a geotextile fabric and approximately 8 to 12 inches of compacted structural fill beneath the pavement section to bridge over the variable underlying conditions. A second geotextile beneath the pavement section is also recommended to help bridge over the variable fills. Underdrains should also be considered in topographically low areas of the pavement to facilitate drainage of the pavement base course. Specific paving section recommendations, as well as a description of a typical underdrain, are provided in the Conclusions and Recommendations section of this report. V. CONCLUSIONS AND RECOMMENDATIONS Due to the site s past varied industrial use, large portions of the site have been previously occupied by various structures. Field observations indicate that while the abovegrade portions of these structures have been removed, significant at-grade and belowgrade portions remain. The presence of these abandoned foundation elements will likely influence the site redevelopment. Effective removal of these abandoned features during the initial phases of the site preparation can improve the constructability and long-term 10

15 performance of the proposed redevelopment. While there is the potential that portions of the miscellaneous soil fill observed could remain in place across portions of the site, it is recommended that the foundation elements and buried structures be removed in their entirety. Effective construction review by a qualified geotechnical engineer during the demolition and site grading is recommended to review the extent to which the miscellaneous fills and abandoned buried structures are removed. Based on the data obtained in the field and laboratory testing programs and the subsequent geotechnical analysis, the following conclusions and recommendations are presented. A. DESIGN 1. Allowable Foundation Bearing Capacity. It is Duffield Associates opinion that the natural site soils (Strata C and D) encountered beneath a layer of miscellaneous fill materials are generally suitable for supporting the proposed buildings on a conventional, shallow foundation system and slab-on-grade. Structural fill, placed and compacted as recommended in this report, is also considered suitable for supporting the proposed structure on a shallow foundation system and slab-on-grade. The proposed buildings could be supported on a shallow foundation system designed with a maximum net allowable bearing pressure of 3,000 psf. Total foundation settlements for the buildings are estimated to be on the order of 1 inch or less. Post-construction differential settlement for the buildings foundations are estimated to be on the order of ½ inch or less over a distance of 20 feet. These magnitudes of total and differential settlement are generally considered to be within tolerable limits. However, the actual settlement tolerance of the building should be verified with the project s structural engineer. Higher allowable bearing capacities may be practical if the building is proposed to be supported only on the weathered rock materials (i.e., the clayey soils of Stratum C are removed). If the actual structural loadings are different than the assumed building types discussed herein, the estimated settlement magnitude may also be different. If the loading conditions assumed and utilized herein are not accurate, additional analysis may be required to evaluate the settlement magnitude under the actual design conditions. 2. Foundation Burial Depth and Size. The base of all exterior spread footings in areas exposed to frost should be placed at least 36 inches below final exterior grade. Interior foundations, which will not be exposed to frost, should be placed at least 18 inches below the proposed finished floor elevation. Building foundations should be proportioned with a minimum dimension of 3 feet for isolated footings and 2 feet for continuous footings, regardless of bearing pressure. 11

16 3. Slab-on-Grade. Ground-supported floor slabs should be designed as free floating and should not be connected to the structural elements (e.g., walls, framing, etc.) of the building. Isolation joints should be utilized at the interface of proposed ground-supported floor slab and structural elements to accommodate potential differential settlement. A minimum 10 mil polyethylene vapor barrier and free draining subbase, consisting of at least 4 inches of poorly-graded crushed stone aggregate, such as AASHTO SP-57 stone, should be provided beneath all floor slabs. Subgrade conditions should be modeled for design utilizing a subgrade modulus, K S, of 150 pci. Due to the previous environmental considerations at the site, a vented subgrade should be considered for building areas constructed over environmentally sensitive areas. A typical vented subgrade consists of a series of perforated pipes installed in a stone bedding and vented to the exterior of the building. In addition, a plastic vapor barrier below the slab-ongrade and a vapor resistant joint seal should be considered at all joints in the slab. 4. Control Joints. Masonry walls should be provided with frequent control joints placed at architecturally convenient locations, such as windows and doorways, to provide a preferred location for the differential settlement to occur without cracking the walls. 5. Retaining Wall Design. Backfill pressures on unyielding retaining walls restrained from rotation at the top, including below-grade portions of the building foundation walls, should be analyzed using the at rest earth pressure coefficient, K O. The active and passive earth pressure coefficients, K A and K P, respectively, should be utilized for the design of yielding retaining walls, such as cantilevered walls. All retaining walls (including below-grade portions of the building) should be provided with free-draining, granular backfill materials and a drainage system and/or weep holes to relieve hydrostatic pressures on the walls. Recommended lateral earth pressure parameters for design are presented below. Soils K A K P K O Coeff. of Sliding Friction Moist Unit Weight (pcf) Undisturbed On-Site Soils (Stratum C) Undisturbed On-Site Soils (Stratum D) Imported Granular Fill (with less than 10% passing a No. 200 sieve) Seismic Design Parameters. Based on subsurface conditions encountered during the field exploration at the site and review of regional geologic maps, a 12

17 site Class C of the 2006 International Building Code is recommended for the analysis of seismic conditions, as defined by Table Site Grading. Site grading should be designed to provide positive drainage away from the proposed buildings. Positive site drainage should be maintained throughout the construction activities. 8. Pavement Design. Based on anticipated traffic loading consisting primarily of passenger vehicles in the proposed parking areas (with limited access to busses, trash collection vehicles, and other truck traffic) and the assumed and encountered subgrade conditions, the following minimum pavement section is recommended. 2 inches Bituminous Concrete Wearing Course, Type ID-2 W.C. 3 inches Bituminous Concrete Binder Course, Type ID-2 B.C. 8 inches Graded Aggregate Base Course, Type 2A Geotextile Fabric, Propex 315 or equivalent 13 inches Total Depth The site is underlain with variable thickness and consistency miscellaneous fill materials. In addition, abandoned structures, such as apparent foundation walls, were observed at shallow depths at the site. These abandoned foundations and buried structures should be removed. Constructing pavements over these miscellaneous soil materials increase the risk of differential settlement, localized deterioration, and increased maintenance costs. This risk can be reduced (but not eliminated) by constructing the site pavements over an improved subgrade designed to bridge over these materials. To reduce the potential for large differential settlement over a short distance, these fill soils should be capped with approximately 8 to 12 inches of compacted structural fill placed over a second geotextile fabric beneath the pavement section to help bridge over the variable underlying conditions. All pavement construction and materials should conform to the Pennsylvania Department of Transportation Construction Specifications, dated April 2007 and as subsequently revised. Underdrains are recommended to facilitate drainage within the pavement base course particularly at topographic low areas. A typical underdrain system consists of 4-inch perforated polyethylene pipe (e.g., ADS or equivalent) in an AASHTO SP-57 stone bedding. The underdrain should be a minimum of 12 inches by 12 inches and should be wrapped in a geotextile fabric (e.g., Propex 401 or equivalent). 13

18 9. Assumptions. The loading conditions assumed in this evaluation should be verified by the project team prior to the completion of their design. If the proposed loading conditions vary from those considered and assumed, Duffield Associates should be notified to possibly modify the recommendations provided herein, as required. B. CONSTRUCTION 1. Site Preparation. The majority of the southern parcel is currently an exposed bituminous concrete paved lot and the northern parcel is a combination of paved areas, concrete slabs-on-grade and debris stockpiles. Additionally, there are visual indications of the previous structures on the surface. Due to the previous and proposed site usage, it is recommended that the abandoned foundation elements and miscellaneous fills be removed in their entirety from the proposed buildings areas. This will likely include the removal of a substantial amount of concrete and previous foundation elements. While not observed at the time, there is also the potential that additional underground tanks, storage or vault areas could be encountered due to the previous site usage. These elements should be removed until apparent natural soils are encountered and, if necessary, the resulting excavations should be backfilled with structural fill placed and compacted as recommended herein. It is recommended that the existing bituminous concrete and cobblestone pavement, concrete slabs, and buried structures be removed from the entire site, including proposed roadway and landscaped areas. Exposing the subgrade soils and proofrolling the entire site should assist in determining the extent to which these soils are suitable for subsequent construction. Depending on the Owner s level of risk acceptance of future maintenance costs, the miscellaneous fill can be left in the site areas a minimum of 10 feet beyond the perimeter of the proposed building foundations and slabs. 2. Proofrolling and Subgrade Preparation. At the start of construction, the bituminous concrete, pavers, and concrete covering the site should be removed. Following bulk excavation, removal of the previous foundation elements and buried structures, and prior to footing excavation, placement of fill, or construction of the floor slabs, it is recommended that the exposed subgrade be proofrolled. The proofroll should also be performed across the proposed pavement and landscaped areas. The proofroll should be performed using a minimum 10-ton vibratory roller or a fully loaded tandem dump truck in the presence of a qualified soils technician working under the supervision of a geotechnical engineer. The purpose of the proofrolling is to densify the exposed subgrade and to identify yielding subgrade conditions. Yielding subgrade conditions encountered within the proposed building and pavement areas should be undercut to firm subgrade conditions and be backfilled in accordance with the recommendations of this report. Provisions for the undercutting and subsequent replacement of these materials should be 14

19 anticipated by the construction contract documents and project budget estimates. The subgrade review should also confirm the consistency and texture of the exposed soils with the conditions encountered by this evaluation as described herein. 3. Foundation Subgrade Review. All foundations should be placed on firm, dry, non-frozen subgrade consisting of natural site soils (described as Strata C and D) or structural fill placed and compacted as recommended herein. Foundation excavations should be reviewed by a qualified technician working under the supervision of a geotechnical engineer who is familiar with the recommendations of this report. Subgrade review should be performed prior to the placement of reinforcing steel or concrete and should verify the presence of natural soils. If these conditions are not encountered at the proposed foundation depth, additional excavation should be performed until they are uniformly encountered across the base of the foundation s excavation or, if recommended by the project geotechnical engineer, the natural soils can be densified in place. Foundation undercut areas should be backfilled with structural fill, as recommended herein. 4. Existing Utilities. While no existing utilities were delineated within the vicinity of the proposed building area, the presence of existing or abandoned utilities should be anticipated due to the sites previous usage. Where utilities are delineated within the proposed building footprints, it is recommended that these utilities be removed and relocated outside of the building areas. The resulting excavations for removed utilities should be backfilled with structural fill, placed, and compacted in accordance with the recommendations of this report. Alternatively, existing pipes could be abandoned, left in place, and grouted full. If the utilities cannot be relocated outside of the proposed building, or if new utilities are proposed, foundations should be designed to bear at, or below, the invert elevations of the pipe. 5. Reuse of On-Site Soils as Structural Fill. On-site soils free of organic material, topsoil, miscellaneous fill, debris, and rock fragments in excess of 3 inches in their largest dimension may be suitable as structural fill. A majority of the on-site materials excavated from the proposed building area appeared to consist of predominately fine-grained soils with varying amounts of debris; however, the reuse of fine-grained soils can often cause difficulty during construction. Miscellaneous fill materials containing wood or building debris (other than concrete or brick fragments smaller than 3 inches in diameter) are not considered suitable structural fill. It is understood that due to outside considerations, it is proposed to balance the site with a minimal net cut/fill. Based on the conditions encountered, this will result in the reworking of significant amounts of miscellaneous fill materials, some of which hss likely to contain debris and large pieces of stone and building rubble. In order to use this material as structural fill, the large debris should be removed from the stockpile. The design and grading plan 15

20 should consider zones where these materials can be placed as fill, which may be less sensitive to settlement and away from the buildings. If these soils are to be reworked for use on site and the small debris cannot be practically removed with the larger debris, the design team could consider utilizing this material beneath landscaped areas. 6. Imported Structural Fill. Imported structural fill should consist of predominately granular soils conforming to the following requirements: Sieve % Passing 1½ 100 No No No AASHTO SP-57 stone or graded aggregate (PennDOT Type 2A modified ) can also be utilized as structural fill and should be considered where localized, relatively deep fills are required. AASHTO SP-57 stone should also be utilized as fill where drainage is required. 7. Compaction Requirements. Structural fill utilized within the proposed building areas should be placed in loose lifts with a maximum thickness of 8 inches. Each lift of fill placed within the proposed structure area (defined as the area extending at least 10 feet beyond the building perimeters) should be compacted to at least 95% of the maximum dry density, as determined by the Modified Proctor test (ASTM D 1557). Structural fill for utility trenches and pavement areas, located outside of the building areas should be compacted to at least 90% of the maximum dry density. The placement and compaction of structural fill should be monitored on a full-time basis by a qualified technician under the supervision of a geotechnical engineer. 8. Groundwater Control. Groundwater was encountered in several of the test borings at depths as shallow as 1 foot below the existing ground surface wthin the miscellaneous fill materials. Based on the subsurface conditions encountered, regional groundwater conditions will likely be below the depth of typical shallow foundations. However, due to the presence of shallow dense soils and miscellaneous fill, it is likely that that localized perched groundwater or stormwater runoff will be encountered across the site within the excavations of the miscellaneous fills. Therefore, localized sumping may be required. Wherever significant quantities of stormwater or groundwater are encountered during excavation, it may become necessary for the resulting excavation to be overexcavated by several inches and backfilled with AASHTO SP 57 stone to facilitate sumping and protect the exposed subgrade during construction. 9. Protection of Subgrade Soils. Exposure of subgrade soils to precipitation and construction traffic will likely weaken the soils and result in yielding 16

21 subgrade conditions. Positive site grading should be maintained to direct drainage away from excavations. Subgrade soils disturbed by precipitation and construction traffic should be either scarified and recompacted or undercut and replaced with structural fill. Subgrade disturbance could be reduced by maintaining positive surface drainage throughout the construction period and limiting construction traffic on the exposed subgrade soils. Where construction traffic is required over the subgrade soils, construction could be staged to allow portions of the existing pavement and unexcavated cut soils to remain in place during the initial phases of construction. Alternatively, a temporary haul road, consisting of at least 8 inches of crushed stone over a geotextile fabric (e.g., Propex 315 or equivalent) should be considered. 10. Excavation Safety. All utility and foundation excavation should be performed in accordance with OSHA guidelines. The predominately granular soils, as well as the miscellaneous fill soils observed at the site can be characterized as Type C soils. Should it be required, all temporary sheeting and shoring should be designed by a qualified engineer registered in the Commonwealth of Pennsylvania. 11. Subsurface Data. All contractors interested in bidding on phases of this work, which involve subsurface conditions, should be given full access to this report so that they can develop their own interpretations of the available data. These recommendations have been prepared according to generally accepted soil and foundation engineering standards, and are based on the conditions encountered by the sampling performed at the site. It is noted that, although soil quality has been inferred from the interpolation of the sampling data, subsurface conditions beyond the sampling points are, in fact, unknown. As a result, these recommendations may require modifications based on the conditions encountered and exposed during construction excavation. Should any conditions encountered during construction differ from those described in this report, this office should be notified immediately in order to review and possibly modify these recommendations. The cost for this construction review is not part of the existing agreement. This report applies solely to the size, type, and location of the structures described herein. In the event that changes are proposed, this report will not be considered valid unless the changes have been reviewed and the recommendations of this report modified and reapproved in writing by Duffield Associates, Inc. WORD\9111GB.1011-WISSAHICKONCHARTER.RPT 17

22 APPENDIX A SITE LOCATION SKETCH TEST BORING AND TEST PIT LOCATION SKETCH

23 SITE NOTE: THIS LOCATION SKETCH IS ADAPTED FROM THE U.S.G.S. TOPOGRAPHIC MAP, 7.5 MINUTE SERIES, FOR GERMANTOWN, PENNSYLVANIA DATE: 1 SEPTEMBER 2011 SITE LOCATION SKETCH DESIGNED BY: BJD DUFFIELD SCALE: 1"=2000' PROJECT NO CA WISSAHICKON CHARTER SCHOOL DRAWN BY: CHECKED BY: MCM BJD SHEET: FIGURE 1 PHILADELPHIA ~ PENNSYLVANIA FILE: A-9111CA-01

24 SEPTA RAILROAD CLEARVIEW STREET TB-14 TB-13 TP-4 TP-3 TB-15 TB-10 TB-19 TP-6 TB-18 TB-20A TB-20 WASHINGTON STREET BJD DESIGNED BY: DRAWN BY: MCM DUFFIELD CHECKED BY: BJD B-9111CA-01 FILE: TP-7 TB-9 TB-8 TP-2 BRINTON STREET TB-12 TB-11 TP-1 CHEW AVENUE TB-7 TB-4 TEST BORING AND TEST PIT LOCATION SKETCH WISSAHICKON CHARTER SCHOOL PHILADELPHIA ~ PENNSYLVANIA KEY: NOTE: DATE: 1 SEPTEMBER 2011 TB-1 TP-1 - APPROXIMATE TEST BORING LOCATION - APPROXIMATE INFILTRATION TEST LOCATION THIS SKETCH IS ADAPTED FROM AN ELECTRONIC FILE TITLED "CHEW-WASHINGTON TOPO ARCH CONV.DWG," PROVIDED TO DUFFIELD ASSOCIATES BY METCALFE ARCHITECTURE. SCALE: 1"=80' PROJECT NO CA SHEET: FIGURE 2

25 APPENDIX B TEST BORING LOGS (14)

26 TEST BORING TB- 4 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 9, 2011 : September 9, 2011 : PJH : Cloudy : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 TOPSOIL (4") Miscellaneous FILL: brown, black silt, little to some debris (gravel and and brick fragments), little to some medium to fine sand (brick fragment in shoe) S Miscellaneous FILL: brown, black silt, little to some debris (gravel and and brick fragments), little to some medium to fine sand S Miscellaneous FILL: brown, black silt, little to some debris (gravel and and brick fragments), little to some medium to fine sand S Miscellaneous FILL: brown, black silt, little to some debris (brick fragments), little to some medium to fine sand, trace to little gravel S SM Apparent WEATHER ROCK: multicolored fine to medium micacious sand, little silt, trace coarse sand/ gravel sized rock fragments S / NOTES: 1. Boring terminated at approximately 15 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. No groundwater encontered to a depth of 15 feet b.e.g.s 4. Auger refusal at approximately 15 feet b.e.g.s.

27 TEST BORING TB- 7 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 7, 2011 : September 7, 2011 : PJH : Overcast : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Bituminous Concrete (6 inches) Miscellaneous FILL: green-brown silt, little to some medium to fine sand, trace debris (wood) S Apparent WEATHERED ROCK: orange, brown fine micacious sand, and silt, trace coarse sand S Apparent WEATHERED ROCK: light brown, yellow-brown, dark brown fine to medium micaceous sand, little to some silt S / SM Apparent WEATHERED ROCK: brown, orange, dark brown, gray micaceous fine to medium sand, little silt, trace gravel sized rock fragments S / Apparent WEATHERED ROCK: dark brown, black fine to medium micaceous sand, little gravel sized rock fragments, trace silt S-5 50/ NOTES: 1. Boring terminated at approximately 16 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 13 feet b.e.g.s. 4. Water level through augers at approximately 10.3 feet with augers at approximately 15 feet b.e.g.s. 5. Auger refusal at approximately 16 feet b.e.g.s.

28 TEST BORING TB- 8 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 7, 2011 : September 7, 2011 : PJH : Overcast : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Bituminous Concrete (6 inches) ML Apparent FILL: dark brown, black silt. little fine sand Brown SILT, little to some fine to medium sand S-1A S-1B Apparent WEATHERED ROCK: dark brown, black, gray fine to medium micaceous sand, little gravel sized rock fragments, little silt S SM Apparent WEATHERED ROCK: dark brown, black, gray fine to medium micaceous sand, little gravel sized rock fragments, little silt S Apparent WEATHERED ROCK: dark brown, black, gray fine to medium micaceous sand, little gravel sized rock fragments, little silt S / NOTES: 1. Boring terminated at approximately 10.5 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 8 feet b.e.g.s. 4. Water level through augers at approximately 5 feet with augers at approximately 10 feet b.e.g.s. 5. Auger refusal at approximately 10.5 feet b.e.g.s.

29 TEST BORING TB- 9 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 7, 2011 : September 7, 2011 : PJH : Overcast : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Bituminous Concrete (5 inches) 245 Miscellaneous FILL: dark brown, black silt, little gravel, trace fine to coarse sand S Miscellaneous FILL: dark brown, black silt, some fine to coarse sand, trace gravel S Miscellaneous FILL: dark brown, black silt, trace to little debris (brick fragments), little to some fine to medium sand, trace gray clay clods S / CL Apparent WEATHERED ROCK: red-brown, orange silty clay, and fine micaceous fine sand S SM Apparent WEATHERED ROCK: Brown, gray, tan WEATHERED ROCK, little to some fine to medium sand, micaceous S / NOTES: 1. Boring terminated at approximately 15 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 6 feet b.e.g.s. 4. Water level through augers at approximately 6 feet with augers at approximately 6.5 feet b.e.g.s. 5. Auger refusal at approximately 15 feet b.e.g.s.

30 TEST BORING TB-10 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 7, 2011 : September 7, 2011 : PJH : Overcast : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL Bituminous Concrete (5 inches) Miscellaneous FILL: dark brown, black silt, little to trace gravel, little to trace debris (brick fragments) S Miscellaneous FILL: dark brown, black silt, little to trace debris (brick fragments), trace fine sand S Miscellaneous FILL: dark brown, red fine to medium sand, and silt, trace debris (brick fragments) S Miscellaneous FILL: dark brown, red fine to medium sand, and silt, trace debris (brick fragments) Gray clayey SILT, little fine sand S-4A S-4B ML Apparent WEATHERED ROCK: dark gray, yellow, light brown fine to medium micacious sand, little silt S SM Apparent WEATHERED ROCK: yellow-brown, light brown fine to medium micacious sand, little silt S NOTES: 1. Boring terminated at approximately 20 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 9 feet b.e.g.s. 4. Water level through augers at approximately 13 feet with augers at approximately 15 feet b.e.g.s.

31 TEST BORING TB-11 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 8, 2011 : September 8, 2011 : PJH : Rain : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL Bituminous Concrete (6 inches) Miscellaneous FILL: brown, light brown, black debris (bricks), and rock fragments, some fine to coarse sand S Miscellaneous FILL: dark brown, black gravel/rock fragements, little coarse to fine sand S Miscellaneous FILL: dark brown, black gravel/rock fragements, little coarse to fine sand S Miscellaneous FILL: dark brown, black debris (bricks), and gravel/rock fragements, little coarse to fine sand S Apparent WEATHERED ROCK: gray, blue silty clay, little fine sand, trace medium sand S CL SM Apparent WEATHERED ROCK: gray, blue silty clay, little fine sand Apparent WEATHERED ROCK: brown, yellow, light brown fine sand, some silt S-6A S-6B NOTES: 1. Boring terminated at approximately 20 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. No groundwater encontered to a depth of 20 feet b.e.g.s 4. Strong chemical odor obseved at 13 feet b.e.g.s.

32 TEST BORING TB-12 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 7, 2011 : September 7, 2011 : PJH : Overcast : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL Bituminous Concrete (7 inches) Miscellaneous FILL: brown, dark brown silt, trace to little rock fragments, little to some medium to fine sand S Miscellaneous FILL: brown, light brown silt, trace to little debris (brick fragments), little to some medium to fine sand S Miscellaneous FILL: brown, light brown silt, trace to little debris (brick fragments), little to some medium to fine sand S Miscellaneous FILL: brown, light brown silt, trace to little debris (brick fragments), little to some medium to fine sand S ML Brown, orange, gray SILT, trace fine sand Apparent WEATHERED ROCK: brown, black, dark gray fine to medium micaceous sand, little silt S-5A S-5B NOTES: 1. Boring terminated at approximately 16 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. No groundwater encontered to a depth of 16 feet b.e.g.s 4. A petroleum like odor observed during drilling within the fill materials. 5. Auger refusal at approximately 16 feet b.e.g.s.

33 TEST BORING TB-13 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 7, 2011 : September 7, 2011 : PJH : Overcast : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : 250 feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev. 250 ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL Bituminous Concrete (7 inches) Miscellaneous FILL: black, brown fine sand, some silt, trace to little gravel, trace to little debris (brick fragments) S Miscellaneous FILL: black, brown fine sand, some silt, trace to little gravel, trace to little debris (brick fragments) S Miscellaneous FILL: black, brown fine sand, some silt, trace to little gravel, trace to little debris (brick fragments) S Miscellaneous FILL: black, brown fine sand, some silt, trace to little gravel, trace to little debris (brick fragments) S Apparent WEATHERED ROCK: gray fine to medium micaceous sand, little silt, trace gravel S SM Apparent WEATHERED ROCK: gray fine to medium micaceous sand, little silt, trace gravel S / NOTES: 1. Boring terminated at approximately 20 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 13 feet b.e.g.s. 4. Water level through augers at approximately 12 feet with augers at approximately 14 feet b.e.g.s. 5. A petroleum like odor observed during drilling..

34 TEST BORING TB-14 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 9, 2011 : September 9, 2011 : PJH : Cloudy : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Cobble Stone Pavers (3 inches) 250 Miscellaneous FILL: black, brown silt, trace to little rock fragments, little to some medium to fine sand S Miscellaneous FILL: black, brown silt, trace to little rock fragments, little to some medium to fine sand S NOTES: 1. Boring terminated at approximately 5 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. No groundwater encontered to a depth of 5 feet b.e.g.s 4. A petroleum like odor observed during drilling within the fill materials.

35 TEST BORING TB-15 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 9, 2011 : September 9, 2011 : PJH : Cloudy : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Cobble Stone Pavers (6 inches) 245 Miscellaneous FILL: black, brown silt, little to some fine to medium sand, trace to little debris (brick fragments) S Possible FILL: gray, brown fine to medim sand and silt, trace to little gravel S Apparent WEATHERED ROCK: black, dark gray fine to medium micaceous sand, little silt, trace gravel S SM Apparent WEATHERED ROCK: black, dark gray fine to medium micaceous sand, little silt, trace gravel S / NOTES: 1. Boring terminated at approximately 13 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 3 feet b.e.g.s. 4. A petroleum like odor observed during drilling.. 5. Water level through augers at approximately 4 feet with augers at approximately 13 feet b.e.g.s. 6. Auger refusal at approximately 13 feet b.e.g.s.

36 TEST BORING TB-18 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 9, 2011 : September 9, 2011 : PJH : Cloudy : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL Cobble Stone Pavers (5 inches) Apparent WEATHERED ROCK: brown, gray fine to medum sand, litlte silt, trace rock fragments, S Apparent WEATHERED ROCK: brown, gray fine to medium micaceous sand, little to trace silt, trace gravel S NOTES: 1. Boring terminated at approximately 5.5 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 1 feet b.e.g.s. 4. A petroleum like odor observed during drilling.. 5. Auger refusal at approximately 5.5 feet b.e.g.s.

37 TEST BORING TB-19 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 9, 2011 : September 9, 2011 : PJH : Cloudy : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels During Drilling Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION At completion SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Concrete (2 inches) 245 Apparent FILL: gray, brown silt, little to some fine to medium sand, trace to little rock fragments, micaceous S Apparent FILL: gray, brown silt, little to some fine to medium sand, trace to little rock fragments, micaceous S ML Brown, gray silt, little fine micaceous sand S Apparent WEATHERED ROCK: brown fine to medium micaceous sand, little to some silt, trace gravel S SM 235 SM Apparent WEATHERED ROCK: multicolored fine to medium micaceous sand, little silt trace gravel S / NOTES: 1. Boring terminated at approximately 16 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. Wet on spoon encountered at approximately 1 feet b.e.g.s. 4. Water level through augers at approximately 2 feet with augers at approximately 3 feet b.e.g.s. 5. Auger refusal at approximately 16 feet b.e.g.s.

38 TEST BORING TB-20 (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 8, 2011 : September 8, 2011 : PJH : Rain : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL 0 Brick Pavers (6 inches) 245 SM Apparent WEATHERED ROCK: gray, brown, light brown fine to medium micacous sand, little silt S-1 50/ NOTES: 1. Boring terminated at approximately 3 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. No groundwater encontered to a depth of 3 feet b.e.g.s 4. Auger refusal at approximately 3 feet b.e.g.s.

39 TEST BORING TB-20A (Page 1 of 1) Geotechnical Evaluation Wissahickon Charter School Washington Lane and Chew Street Philadelphia, Pennsylvania Project No GB Date Started Date Completed Logged by Weather Driller/Agency : September 9, 2011 : September 9, 2011 : PJH : Cloudy : Rich Easlack/SBI Drilling Equipment Drilling Methods Surface Elevation : Truck Mounted Mobile B-80 : SPT (ASTM D1586, HSA) : feet Project Datum Sample Condition Remolded Water Levels Depth in feet Surf. Elev ft GRAPHIC USCS DESCRIPTION SAMPLES Sample Number Blows per 6 inches Recovery (ft) Moisture Content (%) Percent Passing 200 Sieve WATER LEVEL SM Concrete (2 inches) Apparent WEATHERED ROCK: gray, brown, light brown fine to medium micacous sand, little silt S / NOTES: 1. Boring terminated at approximately 2 feet below existing ground surface (b.e.g.s.). 2. Test boring elevation estimated based on topographic information provided by others. 3. No groundwater encontered to a depth of 2 feet b.e.g.s 4. Auger refusal at approximately 2 feet b.e.g.s.

40 APPENDIX C TEST PIT LOGS (6)

41 TEST PIT DESCRIPTIVE LOG PROJECT: Wissahickon Charter School PROJECT NO.: 9111.GB CLIENT: Mt. Airy Transit Village, Inc. DATE: September 7, 2011 LOGGED BY: JPC Test Pit Depth No. Range (ft.) Generalized Soil Description TP Bituminous Concrete Gravel Base Sample Sample 2.3 Miscellaneous FILL: brown debris (cobble to boulder sized building stone, bricks, metal, pipe, concrete, ect.), little to some fine to medium sand, little silt, trace to little coarse sand (damp to dry) (medium consistency) Miscellaneous FILL: white, gray weathered rock, debris (decomposed concrete) Sample 3.0 Gray, white WEATHERED ROCK (dry) (dense consistency) (schist, gneiss, pegmatite) (broke into cobble to boulder sized fragments) (contorted structure foliations, varying dip) NOTES: (1) Test pit excavated by CGCG utilizing a rubber tire Case backhoe. (2) Test pit terminated approximately 4.5 feet below the existing ground surface due to refusal.

42 TEST PIT DESCRIPTIVE LOG PROJECT: Wissahickon Charter School PROJECT NO.: 9111.GB CLIENT: Mt. Airy Transit Village, Inc. DATE: September 7, 2011 LOGGED BY: JPC Test Pit Depth No. Range (ft.) Generalized Soil Description TP Bituminous Concrete Sample 0.5 Gravel Base Sample Sample Sample 4.0 Miscellaneous FILL: brown debris (cobble to boulder sized building stone, bricks, wood, metal, copper pipe, concrete, ect.), some fine to medium sand, trace to little silt, micaceous (damp to dry) (loose to medium consistency) Miscellaneous FILL: white, gray, yellow fine to medium sand, little to some silt, micaceous (damp, moist) (medium consistency) Gray, white, brown WEATHERED ROCK (dry) (schist, gneiss) (broke into cobble to boulder sized fragments) (contorted, fractured structure) NOTES: (1) Test pit excavated by CGCG utilizing a rubber tire Case backhoe. (2) Test pit terminated approximately 5.5 feet below the existing ground surface due to refusal.

43 TEST PIT DESCRIPTIVE LOG PROJECT: Wissahickon Charter School PROJECT NO.: 9111.GB CLIENT: Mt. Airy Transit Village, Inc. DATE: September 7, 2011 LOGGED BY: JPC Test Pit Depth No. Range (ft.) Generalized Soil Description TP Bituminous Concrete Sample 0.5 Gravel Base Sample Sample Sample 3.0 Miscellaneous FILL: black silt, some to and fine to medium sand, trace organics (roots), micaceous, debris (brick, wood, glass, cobble to boulder sized building stone) (damp) (apparent petroleum-like odor) Miscellaneous FILL: dark gray, brown, dark brown silt, and fine to medium sand, trace coarse sand, trace clay, micaceous, debris (plastic, glass) (damp) (medium consistency) Possible FILL: brown fine to medium sand, and silt, trace organics (roots), micaceous (damp) NOTES: (1) Test pit excavated by CGCG utilizing a rubber tire Case backhoe. (2) Test pit terminated approximately 3.0 feet below the existing ground surface.

44 TEST PIT DESCRIPTIVE LOG PROJECT: Wissahickon Charter School PROJECT NO.: 9111.GB CLIENT: Mt. Airy Transit Village, Inc. DATE: September 7, 2011 LOGGED BY: JPC Test Pit Depth No. Range (ft.) Generalized Soil Description TP Bituminous Concrete Gravel Base Sample 0.5 Sample Sample 10.0 Miscellaneous FILL: brown, gray, dark gray, black fine to medium sand, little to some silt, trace to little coarse sand, debris (bricks, bituminous concrete, glass, terracotta pots, metal, concrete, wood, cobble to boulder sized building stone, ect.) (damp/moist at base) (loose to medium density) (pipe at , infiltrating water into excavation) (apparent petroleum-like odor) Brown, yellow fine to coarse sand, little gravel (cobble sized weathered rock fragments), little to some silt, micaceous (moist/wet) (loose consistency) NOTES: (1) Test pit excavated by CGCG utilizing a rubber tire Case backhoe. (2) Test pit terminated approximately 10.5 feet below the existing ground surface. (3) Slight water seepage observed at 9 feet at completion of excavation.

45 TEST PIT DESCRIPTIVE LOG PROJECT: Wissahickon Charter School PROJECT NO.: 9111.GB CLIENT: Mt. Airy Transit Village, Inc. DATE: September 7, 2011 LOGGED BY: JPC Test Pit Depth No. Range (ft.) Generalized Soil Description TP Bituminous Concrete Gravel Base Sample 5.0 Miscellaneous FILL: brown, gray fine to medium sand, little coarse sand, little silt, debris (cobble to boulder sized building stone, bituminous concrete, concrete, metal, wood, glass bottles, ect.) (dry to damp) (medium consistency) NOTES: (1) Test pit excavated by CGCG utilizing a rubber tire Case backhoe. (2) Test pit terminated approximately 8.0 feet below the existing ground surface.

46 TEST PIT DESCRIPTIVE LOG PROJECT: Wissahickon Charter School PROJECT NO.: 9111.GB CLIENT: Mt. Airy Transit Village, Inc. DATE: September 7, 2011 LOGGED BY: JPC Test Pit Depth No. Range (ft.) Generalized Soil Description TP Bituminous Concrete Sample Sample Sample 6.0 Miscellaneous FILL: red, yellown brown fine to medium sand, some to and silt, little gravel (weathered rock fragments), trace clay, micaceous (damp) (medium consistency) Miscellaneous FILL: brown, gray, dark gray fine to medium sand, little to some silt, trace coarse sand, trace gravel, micaceous, debris (plastic, glass) (moist to wet) (apparent petroleum-like odor) Possible FILL: brown, dark brown, gray silt and fine to medium sand, trace gravel (lignite, charcoal), micaceous (moist to wet) (very loose consistency) (apparent petroleum-like odor) NOTES: (1) Test pit excavated by CGCG utilizing a rubber tire Case backhoe. (2) Test pit terminated approximately 7.0 feet below the existing ground surface. (3) Slight water seepage observed at 5 feet at completion of excavation. (possibly from plastic pipe in fill) (4) Water level at 4.5 feet at 0.3 hours following of excavation to 5 feet (excavation then continued).