PRELIMINARY GEOTECHNICAL REPORT. State College Redevelopment State College Borough, Centre County, Pennsylvania. CMT Laboratories File No.

Transcription

1 PRELIMINARY GEOTECHNICAL REPORT State College Redevelopment State College Borough, Centre County, Pennsylvania CMT Laboratories File No Prepared for: National Development Council One Battery Park Plaza 24 Whitehall Street Suite 710 New York, NY Prepared by: CMT Laboratories, Inc Carolean Industrial Drive State College, PA December 9, 2016 Shad E. Hoover, P.E. Principal Whitney E. Greenawalt, P.E. Project Engineer

2 PRELIMINARY GEOTECHNICAL REPORT State College Redevelopment State College Borough, Centre County, Pennsylvania CMT Laboratories File No Prepared for: National Development Council One Battery Park Plaza 24 Whitehall Street Suite 710 New York, NY Prepared by: CMT Laboratories, Inc Carolean Industrial Drive State College, PA December 9, 2016 CMT Laboratories, Inc Carolean Industrial Drive, State College, PA Phone: Fax:

3 INDEX Page LIST OF TABLES...iii 1.0 INTRODUCTION PROJECT AND SITE INFORMATION GENERAL GEOLOGIC INFORMATION FIELD INVESTIGATION Groundwater Conditions LABORATORY TESTING PROGRAM SUBSURFACE CONDITIONS PRELIMINARY RECOMMENDATIONS Sinkholes Rock Removal Foundations Seismic EXCAVATIONS COMMENTS...8 APPENDIX: A. USGS Project Location Map B. Geology Map C. Test Boring Location Plan D. General Geotechnical Notes E. Test Boring Logs F. Laboratory Testing Data G. Bibliography ii

4 LIST OF TABLES Page Table 6.1 Moisture-Plasticity Characteristics and Particle-Size Test Results...5 Table 6.2 Unconfined Compressive Strength of Rock Cores Test Results...5 iii

5 1.0 INTRODUCTION This preliminary report presents the results of a subsurface exploration for the State College Redevelopment project located in State College Borough, Centre County, Pennsylvania. Our services for this project were performed in accordance with CMT Proposal No , dated October 21, Authorization to perform this exploration was given in the form of a Proposal Acceptance and Work Authorization Agreement, signed by Mr. Robert Davenport, on November 21, The purpose of the preliminary subsurface exploration program was to determine the pertinent subsurface conditions and to obtain information on which to base recommendations regarding preliminary foundation design and general site preparation. The scope of services for this report does not include an environmental assessment for the presence or absence of wetlands, hazardous, radioactive or toxic materials in the soil, surface water, groundwater, or air on, below or around the site. Any statements in this report or on the Test Boring Logs regarding odors, colors or unusual or suspicious items are strictly for the information of the client. 2.0 PROJECT AND SITE INFORMATION The project is located in State College Borough, Centre County, Pennsylvania. Specifically, the proposed redevelopment is located between Allen Street and Fraser Street, spanning from Highland Alley to W. Foster Avenue. The redevelopment consists of seven (7) lots, identified as Lots A through G, and this report presents the results of a subsurface investigation performed at Lot D, the existing Allen Street Parking Lot. The location of the project is shown on the Project Location Map presented in Appendix A. The surface of the site at the proposed construction consists of an existing asphalt pavement parking lot and few mature trees. Surface drainage appears to be moderate to good with runoff down slope towards the existing storm sewer system. Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 1 CMT File No

6 Detailed topographical information was not provided at the time of this report; however, the site appears to be relatively level, with an approximate difference in elevation of 4 feet across the proposed site. Proposed building and site information was unavailable at the time of this report. The above information was utilized in our preliminary geotechnical analysis. Therefore, if any of this information has changed, is incorrect or additional information becomes available, please inform CMT so that we may amend the recommendations presented in this report, if appropriate. 3.0 GENERAL The following preliminary recommendations are based on general subsurface information shown on the Test Boring Logs provided in Appendix E. The descriptions shown on these logs represent the conditions only at the individual testing locations and variations may occur and should be expected between the testing locations. Upon receipt of more detailed project information, we anticipate that additional test borings will be required in order to make final geotechnical recommendations. 4.0 GEOLOGIC INFORMATION According to the Department of Environmental Resources, Office of Resources Management, Bureau of Topographic and Geologic Survey (1982), bedrock formation at the proposed area is classified as the Axemann Formation, as shown on the Geology Map in Appendix B. The bedrock of the Axemann Formation consists of light-gray, fossiliferous and coarsely crystalline limestone with silty, fine-grained dolomitic limestone. Some oolitic and conglomeratic limestone is present within this formation. The joints have a blocky pattern which are well developed, moderately abundant and regularly spaced. The bedrock is moderately resistant to weathering and is slightly weathered to a shallow depth. The limestone is difficult to excavate and the bedrock pinnacles are a particularly Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 2 CMT File No

7 problem. The cut-slope stability of the formation is good, although, steeply dipped beds inclined toward cut may require moderate to gentle slopes. 5.0 FIELD INVESTIGATION Prior to commencement of field operations, the project was registered with the Pennsylvania One-Call System, Inc., and the project was assigned Serial No We recommend that the contractors verify the locations of any utilities prior to commencement of construction activities. A total of six (6) test borings were drilled and extended to approximate depths ranging between 13 and 20 feet below the existing surface grades. The test borings were located and surveyed in the field by others. The approximate locations of the test borings are shown on the Test Boring Location Plan provided in Appendix C. The soil sampling was performed in accordance with ASTM D1586. All sampling intervals and Standard Penetration Test values were recorded and are shown on the Test Boring Log. The results of the Standard Penetration Tests indicate the relative density and comparative consistency of the soils and thereby provide a basis for estimating the relative strength and compressibility of the soil profile components. Where auger refusal was encountered in all test boring locations except TB-6, prior to reaching the termination depth, the underlying materials were cored with NQ-II wireline equipment. Auger refusal is the designation applied when the power auger can no longer penetrate the underlying materials and is indicative of the upper surface of bedrock, boulders or hard fill materials. The recovery and RQD (Rock Quality Designation) percentages are shown on the Test Boring Logs. Analysis and interpretation of the recovery and RQD percentages provide a general description of the overall rock quality. The stratifications shown on the Test Boring Log represent the conditions only at the actual boring locations. Variations should be expected between the boring locations. In addition, the Test Boring Logs show the approximate boundaries between subsurface materials. Actual transitions between subsurface materials may be gradual or abrupt. Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 3 CMT File No

8 5.1 Groundwater Conditions Groundwater was not encountered within any of the test pits at the time of our field operations. Note that groundwater levels fluctuate seasonally as a function of rainfall and the permeability of the soil/bedrock. A perched groundwater table may have an effect on the excavation procedures during construction. We recommend evaluation of any perched conditions by the geotechnical engineer at the time of construction. 6.0 LABORATORY TESTING PROGRAM The samples obtained during the drilling operation were sealed in labeled containers and transported to our laboratory for inspection, testing and classification. Remaining samples will be retained for a minimum of one (1) year for future reference. In addition to the visual classification of the soil samples, moisture content determination tests were performed on representative split-spoon samples. The moisture content is the ratio of the weight of the water in the sample to the dry weight of the sample. This test was performed in general compliance with ASTM D2216. Several test procedures were performed on composite soil samples taken from the site. A general description of each test is provided in the following paragraphs. Moisture-plasticity characteristics of one (1) composite soil sample were determined by means of the Atterberg Limit test. The test determines the moisture content at which the soil begins to act as a viscous liquid (Liquid Limit LL) and the moisture content at which the soil changes from a plastic state to a semi-solid state (Plastic Limit PL). The difference between the Liquid Limit and the Plastic Limit is the Plasticity Index (PI). The test procedures were performed in compliance with ASTM D4318. Particle-size analyses were performed on the same composite soil sample in compliance with ASTM D422. The analysis includes a sieve analysis for particle sizes greater than the #200 sieve and a hydrometer analysis for particle sizes finer than the #200 sieve. Using this information, the sample was classified using the Unified Soil Classification System (USCS), ASTM D2487. Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 4 CMT File No

9 A summary of the moisture-plasticity characteristics and particles-size test results are shown on the following table. Table 6.1 Moisture-Plasticity Characteristics and Particle-Size Test Results CMT Sample Number Test Boring Depth (ft) Liquid Limit (LL) Plasticity Index (PI) USCS TB-5 & TB CL Unconfined compression tests were performed on four (4) intact limestone rock core specimens. These tests were performed in general compliance with ASTM D , Method C, and a summary of these tests is provided in Table 6.2. Table 6.2 Unconfined Compressive Strength of Rock Cores Test Results Test Total Load Compressive Type of Boring Depth (ft) (lb) Strength (psi) Fracture TB ,290 12,760 Columnar TB ,520 13,485 Columnar TB ,120 14,654 Columnar TB ,300 10,165 Columnar A more detailed analysis of all laboratory testing is presented in Appendix F of this report. 7.0 SUBSURFACE CONDITIONS Details of the subsurface conditions encountered in our field exploration are shown on the Test Boring Logs, included in Appendix E. A brief description of the materials encountered is presented in this section. The surface of the site, at all test boring locations, consists of a layer of asphalt pavement, measuring approximately 6 inches in thickness, with a subbase comprised of Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 5 CMT File No

10 granular material similar in composition to PennDOT 2RC stone, which measures approximately 5 to 12 inches in thickness. Underlying the asphalt pavement, at test boring location TB-3, is a layer of fill material which extends to the auger refusal depth of 4.7 feet below the existing surface grades. The fill material consists primarily of clay and sand-sized particles, with varying amounts of gravel and brick fragments. The engineering characteristics of the fill materials, such as strength and compressibility, are likely to be variable. Underlying the asphalt pavement, at all test boring locations except TB-3, is a layer of natural residual soils which extends to the approximate auger refusal depths ranging between 2 and 13 feet below the existing surface grades. The natural residual soils consist primarily of clay and silt-sized particles, with varying amounts of gravel and weathered limestone. CMT Sample Number is representative of this material and was classified as lean clay with sand (USCS Classification CL). The natural residual soils have moisture contents ranging between 4 and 30 percent and generally exhibited a very soft to hard consistency based on the Standard Penetration Tests and hand penetrometer values. The fill material and natural residual soils, at all test boring locations except TB- 6, are underlain by limestone bedrock, which was cored upon encountering auger refusal at approximate depths ranging between 2 and 7 feet below the existing surface grades. In general, the limestone bedrock is in a very broken to massive, weathered to fresh, and hard to very hard condition. The rock core recovery values within the bedrock range between 43 and 100 percent, and Rock Quality Designation (RQD) values range between 0 and 88 percent. Refer to the Test Boring Logs for further data regarding the rock core recovery and RQD percentages. 8.0 PRELIMINARY RECOMMENDATIONS The conclusions and preliminary recommendations presented in this report are based on the data obtained from the field exploration and laboratory testing programs, information regarding the proposed construction and our knowledge of geomechanics. The subject site is considered suitable for the proposed construction. Additional test Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 6 CMT File No

11 borings and geotechnical analysis will be required after more detailed project data is provided. Preliminary recommendations for the proposed construction are provided in the following sections. 8.1 Sinkholes Sinkholes are a relatively common occurrence in the geologic formations at the site. The potential for sinkhole formation is high and will be especially high during construction activities. Therefore, every effort should be taken during construction to prevent the accumulation and infiltration of stormwater runoff in the vicinity of proposed structures (buildings, pavements, etc.). In the event sinkholes develop during or after construction, a CMT geotechnical engineer should be consulted prior to any excavation and/or disturbance within the immediate vicinity of the sinkhole. A collaborative effort by CMT and the structural and civil engineers should be undertaken to determine the appropriate measures to repair the sinkholes. 8.2 Rock Removal Based on the subsurface conditions encountered during drilling activities, bedrock removal will likely be required during construction. Conventional heavy construction equipment, i.e. dozer with ripper, is considered adequate for rock removal; however, rock removal methodology is the responsibility of the contractor provided that it is acceptable to the owner and is conducted in accordance with all applicable ordinances. 8.3 Foundations Based on the subsurface conditions encountered during our field exploration program, conventional shallow foundations may be considered appropriate Lot D. Typical maximum net allowable bearing capacities of 2,000 pounds per square foot (psf) Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 7 CMT File No

12 and 15,000 psf for stable soils and intact bedrock, respectively, may be considered after careful review of project information and potentially additional subsurface data. Additional test borings, geotechnical analysis and more detailed project and loading information will be required. Although shallow bedrock was encountered within the test borings located in Lot D, it is important to note that variations in the subsurface material should be expected throughout the entire proposed redevelopment site. Upon completion of additional test boring programs throughout the site and review of specific structural and loading information, subsurface improvements or deep foundations may be required. Subsurface improvements may include overexcavation and replacement of bearing materials and/or limited mobility displacement grouting. 8.4 Seismic According to the 2012 International Building Code, Section (Chapter 20 of ASCE 7), seismic Site Class C may be specified for Lot D. 9.0 EXCAVATIONS The contractor is responsible for designing and constructing stable, temporary excavations and should shore, slope or bench the sides of the excavations as required to maintain stability of both the excavation sides and bottom. The contractor is responsible for following the guidelines presented in the current version of the United States Department of Labor, Occupational Safety and Health Administration (OSHA), Part 1926, Subpart P, titled Excavations. This information is presented solely for the information of the client, and in no way is CMT Laboratories, Inc. responsible for the construction site safety or the Contractor s activities COMMENTS This preliminary report has been prepared to assist in determining the geotechnical feasibility for the proposed State College Redevelopment project located in Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 8 CMT File No

13 State College Borough, Centre County, Pennsylvania. CMT should be given the opportunity to review the grading plan as well as the proposed building type and loading data to assist in the development of a final geotechnical investigation. This preliminary report has been prepared for the exclusive use of National Development Council. Preliminary Geotechnical Report December 9, 2016 State College Redevelopment 9 CMT File No

14 APPENDIX A USGS PROJECT LOCATION MAP

15

16 APPENDIX B GEOLOGY MAP

17 Obf Bellefonte Fm. 00 Axemonn Fm. On Nittany Fm. 051 This Map is from Map 61 - Atlas of Preliminary Geologic Quadrangle Maps of Pennsylvania PA Geological Survey

18 APPENDIX C TEST BORING LOCATION PLAN

19

20 APPENDIX D GENERAL GEOTECHNICAL NOTES

21 General Geotechnical Notes SOIL DESCRIPTION The Unified Soil Classification System is used to identify the soil unless otherwise noted. SAMPLE TYPES SS Split Spoon - 1 3/8" I.D., 2" O.D., unless otherwise noted. ST Shelby Tube - 3" O.D., unless otherwise noted. GS Grab Sample (Bulk sample from auger cuttings). NQ Rock Core Sampled with Q Wireline Diamond Bit - 2" I.D. SOIL PROPERTY SYMBOLS N Standard Penetration Resistance - Blows per foot of a 140 pound hammer falling 30 inches on a 2" O.D. split-spoon sampler. q p Pocket Penetrometer measurement of unconfined compressive strength - tsf M c Soil Moisture Content - %. GR Graphical Representation of the soil strata (see below). LL Liquid Limit - %. PI Plasticity Index - %. Rec Percent Core Recovery - Ratio of the length of rock core obtained, to the core interval. RQD Rock Quality Designation - Ratio of the sum of core segments greater than 4", to the core interval. Apparent groundwater level. CONSISTENCY AND RELATIVE DENSITY CLASSIFICATION RELATIVE PROPORTIONS Cohesive Soils q p - (tsf) Granular Soils SPT "N" Value Descriptive Term Percent Very Soft Loose 0 4 Trace 1 10 Soft Loose 5 10 Little Firm (Medium) Slightly Compact Some Stiff Medium Dense And Very Stiff Dense Hard Very Dense 50+ SOIL/ROCK STRATA LEGEND ROCK QUALITY DESCRIPTION RQD Rock Quality Clays Dolomite/Limestone 0-25% Very Poor Silts Shale 25-50% Poor Sands & Gravels Sandstone 50-75% Fair Organic Materials Siltstone 75-90% Good Fill Materials Cobbles/Boulders % Excellent PARTICLE SIZE Boulders 12 in + Coarse Sand 5 mm mm Silt mm mm Cobbles 12 in - 3 in Medium Sand 0.6 mm mm Clay mm - Gravel 3 in - 5 mm Fine Sand 0.2 mm mm CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

22 APPENDIX E TEST BORING LOGS

23 Test Boring Log Boring: TB-1 Project Name: State College Redevelopment Date of Work: 11/29/2016 Site: State College Borough, Centre County, Pennsylvania File No.: Driller/helper: A. Weitoish/G. Eckess Drill Rig: Acker Core Bit: NQ-II Auger Type: 6" SSA Sampling Type: ASTM D-1586 Elevation: N/A Depth Sample Blow "N" q p M c GR Description (ft) Type Counts Value (tsf) (%) Remarks 6" ASPHALT PAVEMENT; 7" SUBBASE; Brown silty CLAY, trace gravel; very SS stiff, damp SS Gray weathered LIMESTONE; very dense SS-3 50/ No Recovery Auger Refusal - 5.4' 5 Gray LIMESTONE; very broken to massive, slightly weathered, very hard NQ-1 Recovery = 100 RQD = NQ-2 Recovery = 62 RQD = 12 Brownish gray LIMESTONE; very broken 15 to massive, slightly weathered, very hard Gray LIMESTONE; slightly broken to NQ-3 Recovery = 98 massive, slightly weathered to fresh, very RQD = 67 hard 20 End of Boring ' No Groundwater Table Encountered CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

24 Test Boring Log Boring: TB-2 Project Name: State College Redevelopment Date of Work: 11/29/2016 Site: State College Borough, Centre County, Pennsylvania File No.: Driller/helper: A. Weitoish/G. Eckess Drill Rig: Acker Core Bit: NQ-II Auger Type: 6" SSA Sampling Type: ASTM D-1586 Elevation: N/A Depth Sample Blow "N" q p M c GR Description (ft) Type Counts Value (tsf) (%) Remarks 6" ASPHALT PAVEMENT; 5" SUBBASE; SS Brown silty CLAY, some weathered SS-2 50/ Auger Refusal - 2.4' limestone; hard, dry to damp Gray LIMESTONE; broken to massive, Recovery = 85 NQ-1 slightly weathered, very hard RQD = 42 5 Light gray LIMESTONE; very broken to massive, weathered to slightly weathered, Recovery = 78 NQ-2 hard to very hard RQD = Gray LIMESTONE; broken to massive, Recovery = 90 NQ-3 slightly weathered to fresh, very hard RQD = End of Boring ' 20 NQ-4 Recovery = 54 RQD = 26 No Groundwater Table Encountered CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

25 Test Boring Log Boring: TB-3 Project Name: State College Redevelopment Date of Work: 11/29/2016 Site: State College Borough, Centre County, Pennsylvania File No.: Driller/helper: A. Weitoish/G. Eckess Drill Rig: Acker Core Bit: NQ-II Auger Type: 6" SSA Sampling Type: ASTM D-1586 Elevation: N/A Depth Sample Blow "N" q p M c GR Description (ft) Type Counts Value (tsf) (%) Remarks 6" ASPHALT PAVEMENT; 7" SUBBASE; FILL - Dark brown sandy clay, some SS gravel, little brick fragments; dry to damp SS Auger Refusal - 4.7' Brownish gray LIMESTONE; very broken, 5 NQ-1 Recovery = 43 weathered to slightly weathered, hard RQD = 0 Gray LIMESTONE; broken to massive, slightly weathered, very hard, few vertical NQ-2 Recovery = 96 fractures 10 RQD = 54 Gray LIMESTONE; very broken to massive, slightly weathered to fresh, very hard End of Boring ' NQ-3 Recovery = 100 RQD = 66 NQ-4 Recovery = 100 RQD = 54 No Groundwater Table Encountered CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

26 Test Boring Log Boring: TB-4 Project Name: State College Redevelopment Date of Work: 11/23/2016 Site: State College Borough, Centre County, Pennsylvania File No.: Driller/helper: A. Weitoish/G. Eckess Drill Rig: Acker Core Bit: NQ-II Auger Type: 6" SSA Sampling Type: ASTM D-1586 Elevation: N/A Depth Sample Blow "N" q p M c GR Description (ft) Type Counts Value (tsf) (%) Remarks 6" ASPHALT PAVEMENT; 9" SUBBASE; Brown silty CLAY, trace gravel; very stiff, SS damp to moist SS Auger Refusal - 4.0' Gray LIMESTONE; very broken to massive, NQ-1 Recovery = 80 5 slightly weathered, very hard RQD = 26 Recovery = 80 NQ-2 CLAY Seam; RQD = 48 Gray LIMESTONE; very broken to slightly 10 broken, slightly weathered, very hard Gray LIMESTONE; broken to massive, slightly weathered to fresh, very hard Recovery = 98 NQ-3 RQD = Light gray LIMESTONE; very broken to massive, slightly weathered, very hard, Recovery = 97 NQ-4 few vertical fractures RQD = End of Boring ' No Groundwater Table Encountered CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

27 Test Boring Log Boring: TB-5 Project Name: State College Redevelopment Date of Work: 11/30/2016 Site: State College Borough, Centre County, Pennsylvania File No.: Driller/helper: A. Weitoish/G. Eckess Drill Rig: Acker Core Bit: NQ-II Auger Type: 6" SSA Sampling Type: ASTM D-1586 Elevation: N/A Depth Sample Blow "N" q p M c GR Description (ft) Type Counts Value (tsf) (%) Remarks 6" ASPHALT PAVEMENT; 9" SUBBASE; Brown silty CLAY, trace gravel; stiff to SS very stiff, damp to moist SS SS Gray weathered LIMESTONE; very dense, SS-4 50/ No Recovery Auger Refusal - 6.6' Gray LIMESTONE; slightly broken to massive, slightly weathered, very hard NQ-1 Recovery = RQD = 62 NQ-2 Recovery = 92 RQD = Gray LIMESTONE; very broken to slightly broken, slightly weathered, very hard Gray LIMESTONE; broken to massive, Recovery = 93 NQ-3 slightly weathered to fresh, very hard RQD = End of Boring ' No Groundwater Table Encountered CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

28 Test Boring Log Boring: TB-6 Project Name: State College Redevelopment Date of Work: 11/30/2016 Site: State College Borough, Centre County, Pennsylvania File No.: Driller/helper: A. Weitoish/G. Eckess Drill Rig: Acker Core Bit: NQ-II Auger Type: 6" SSA Sampling Type: ASTM D-1586 Elevation: N/A Depth Sample Blow "N" q p M c GR Description (ft) Type Counts Value (tsf) (%) Remarks 6" ASPHALT PAVEMENT; 12" SUBBASE; SS Brown silty CLAY, trace gravel; very soft SS to very stiff, dry to moist 5 SS SS-4 WOH Brown silty CLAY, little weathered 10 SS limestone; very soft to very stiff, moist SS Auger Refusal ' End of Boring ' No Groundwater 15 Table Encountered CMT Laboratories, Inc Carolean Industrial Drive State College, PA Phone: (814)

29 APPENDIX F LABORATORY TESTING DATA

30

31

32 APPENDIX G BIBLIOGRAPHY

33 BIBLIOGRAPHY American Society for Testing and Materials (ASTM). Annual Book of Standards Soil and Rock, Volume 04.08, ASTM, West Conshohocken, PA, Bowles, Joseph E. Foundation Analysis and Design, Fifth Edition, The McGraw-Hill Companies, Inc., New York, Das, Braja M. Principles of Geotechnical Engineering, Sixth Edition, PWS Publishing Company, Boston, Geyer, A. R., and Wilshusen, J. P. Environmental Geology Report 1 Engineering Characteristics of the Rocks of Pennsylvania, Second Edition, Pennsylvania Geological Survey, International Code Council, Inc. International Building Code Pennsylvania Department of Transportation. Specifications, PennDOT Pub. 408, Commonwealth of Pennsylvania, Harrisburg, 2007.