Geotechnical Engineering Report Turner Turnpike Widening – Bridge B Bridge Crossing: South 257 th West Avenue Creek County, Oklahoma June 1, 2016 Terracon Project No. 04155197 Prepared for: Garver, LLC Tulsa, Oklahoma Prepared by: Terracon Consultants, Inc. Tulsa, Oklahoma
46
Embed
Geotechnical Engineering Report - PIKEPASS: B - 04155197.Bridge-B.Report... · Geotechnical Engineering Report Turner Turnpike Widening – Bridge B (South 257th West Avenue) Creek
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Geotechnical Engineering Report Turner Turnpike Widening – Bridge B
GENERAL COMMENTS ................................................................................................. 6
APPENDIX A – FIELD EXPLORATION
Exhibit A-1 Site Location Map
Exhibit A-2 Boring Location Plan
Exhibit A-3 Field Exploration Description
Exhibits A-4 to A-9 Boring Logs
Exhibit A-10 Fence Diagram: Subsurface Profile
Exhibit A-11 Rock Core Photographs
APPENDIX B – SUPPORTING INFORMATION
Exhibit B-1 Laboratory Testing
Exhibits B-2 to B-3 Grain Size Distribution
Exhibit B-4 to B-8 Table B.1 - B.5: LPILE Parameters for Lateral Capacity Analysis
APPENDIX C – SUPPORTING DOCUMENTS
Exhibit C-1 General Notes
Exhibit C-2 Unified Soil Classification System
Exhibit C-3 AASHTO Soil Classification System
Exhibit C-4 General Notes – Description of Rock Properties
Responsive ■ Resourceful ■ Reliable 1
GEOTECHNICAL ENGINEERING REPORTTURNER TURNPIKE WIDENING – BRIDGE C
BRIDGE CROSSING: SOUTH 257TH WEST AVENUECREEK COUNTY, OKLAHOMA
Terracon Project No. 04155197June 1, 2016
INTRODUCTION1.0
This geotechnical engineering report has been completed for the proposed bridge along South257th West Avenue over the Turner Turnpike Widening in Creek County, Oklahoma (Appendix A,Exhibit A-1). Six borings, designated B-1, B-2, B-2A, B-3, B-4, and B-5 were drilled for theproject to depths of approximately 35 to 55.5 feet below the existing ground surface. The boringlogs and a boring location plan showing the approximate boring locations are provided inAppendix A of this report.
The purpose of these services is to provide information and geotechnical engineeringrecommendations relative to:
n subsurface soil and rock conditions n bridge foundationsn groundwater conditions n LPILE parameters for lateral analysis
PROJECT INFORMATION2.0
2.1 Project Description
Item Description
Boring Layout See Appendix A, Figure A-2 Boring Location Diagram.
Proposed Construction
Bridge B will be a 4-span bridge to be constructed along South 257th
West Avenue over the proposed Turner Turnpike Widening in CreekCounty, Oklahoma. We understand that the interior bridge bentlocations as well as Abutment No. 1 will be supported on drilledshafts and the Abutment No. 2 will be supported on driven piles.
Geotechnical Engineering ReportTurner Turnpike Widening – Bridge B (South 257th West Avenue)Creek County, Oklahoma ■ June 1, 2016 ■ Terracon Project No. 04155197
Responsive ■ Resourceful ■ Reliable 2
2.2 Site Location and Description
Item Description
Location South 257th West Avenue crossing over I-44 (Turner Turnpike) inCreek County, Oklahoma.
SUBSURFACE CONDITIONS3.0
3.1 Geology
Based on information published in the Oklahoma Department of Transportation manual,“Engineering Classification of Geologic Materials: Division Eight”, the geology of the bridgelocation consists of the Nellie Bly Unit. This unit consists predominantly of yellowish-brownshale and sandy shale with sandstone and siltstone. The shale ranges from clay shale in lowerportion to silty and sandy shale upward. The total thickness of this unit ranges from about 80 to280 feet.
3.2 Soil and Rock Conditions
The subsurface conditions encountered in the borings are shown on the boring logs and arebriefly described below. The stratification lines shown on the boring logs represent theapproximate boundary between soil and rock types; in-situ, the transition between materials maybe gradual and indistinct. Classification of bedrock materials was made from disturbed samplesand rock cores. Petrographic analysis may reveal other rock types.
Description Approximate Depth toBottom of Stratum Material Encountered Consistency/Density
Stratum 4 3Encountered to boringtermination depths ofabout 35 to 55.5 feet
Shale, sandstoneShale: Soft to hardSandstone: Poorly
cemented to cemented
Geotechnical Engineering ReportTurner Turnpike Widening – Bridge B (South 257th West Avenue)Creek County, Oklahoma ■ June 1, 2016 ■ Terracon Project No. 04155197
Responsive ■ Resourceful ■ Reliable 3
Description Approximate Depth toBottom of Stratum Material Encountered Consistency/Density
Continued from page 31. Encountered in borings B-1, B-2, B-2A B-4 and B-5.2. Encountered in boring B-3.3. Fat clay was encountered in boring B-1 from about 18.5 feet to 24 feet.4. Encountered in boring B-5
Laboratory tests were conducted on selected soil and rock core samples. The test results arepresented on the boring logs in Appendix A and on test report form in Appendix B.
The following table indicates the ground surface elevations and the approximate top of competentbedrock depth and elevation at the respective boring locations. The depth to the top of competentbedrock encountered in the borings corresponds to the depths at which the penetration from aStandard Penetration test (SPT), conducted in accordance to ASTM D 1586, was less than orequal to 6 inches with 50 blows. Based on current “State of Oklahoma Department ofTransportation Specifications for the Geotechnical Investigations of Bridges and RelatedStructures”, we understand that the required rock penetration does not begin until competentbedrock is encountered. The rock penetration consists of seven continuous passing Texas ConePenetrometer (TCP) tests spaced at 5-foot intervals for a total of 30 feet of bedrock penetration inaccordance with the ODOT Specifications for Geotechnical Investigations. Thus, depths to top ofcompetent rock and the corresponding elevations shown in table do not necessarily coincide withthe depths to top of weathered rock and the corresponding elevations shown on the boring logs.
Approximate Competent Bedrock Depth and Elevation
BoringNo.
GroundElevation
(feet)Competent Bedrock Material
Depth to Top ofCompetent Rock
(feet)
Elevation of Top ofCompetent Rock
(feet)B-1 802.9 Shale 24 779
B-2 764.3 Sandstone 5 759.5
B-2A 764.5 Sandstone 5 759.5
B-3 767.7 Sandstone 9 758.5
B-4 773.8 Shale 9 765
B-5 808.5 Shale 8.5 768.5
Geotechnical Engineering ReportTurner Turnpike Widening – Bridge B (South 257th West Avenue)Creek County, Oklahoma ■ June 1, 2016 ■ Terracon Project No. 04155197
Responsive ■ Resourceful ■ Reliable 4
3.3 Groundwater
The boreholes were observed while drilling and 24 hours after boring completion for the presenceand level of groundwater. Below depths of about 1.5 to 9 feet, we advanced the borings usingwet rotary drilling techniques. We observed groundwater at the following depths and times:
Boring
Groundwater Levels (feet)
While Drilling After Drilling 24 hours After DrillingDepth Elevation Depth Elevation Depth Elevation
B-1Not
encounteredto 1.5 feet
Notencounteredto 801.5 feet
18.5 784.5 5.5 797.5
B-2Not
encounteredto 5 feet
Notencounteredto 759.5 feet
34 730.5 4.5 760
B-2ANot
encounteredto 5 feet
Notencounteredto 801.8 feet
34 730.5Not
determinedN/A
B-3Not
encounteredto 9 feet
Notencounteredto 758.5 feet
6 761.5Not
determinedN/A
B-4Not
encounteredto 5 feet
Notencounteredto 769 feet
35 739 14 760
B-5Not
encounteredto 5 feet
Notencounteredto 772 feet
29 748 29 748
Long-term monitoring with observation wells, sealed from the influence of surface water, would berequired to accurately define the potential range of groundwater conditions. Fluctuations in thegroundwater level should be expected due to seasonal variations in the amount of rainfall, runoff,water level in the creek and other factors not apparent at the time the borings were drilled. Thepossibility of groundwater level fluctuations and the presence of perched water should beconsidered when designing and developing the construction plans for the project.
BRIDGE FOUNDATION CONSIDERATIONS4.0
Driven pile foundations can be used to support Abutment No. 2 and drilled shafts can be used tosupport the interior bents and Abutment No. 1. Shale and sandstone was encountered in thebridge borings. The shale and sandstone will adequately support the bridge structure. Specificrecommendations regarding the design and construction of driven pile and drilled shaft
Geotechnical Engineering ReportTurner Turnpike Widening – Bridge B (South 257th West Avenue)Creek County, Oklahoma ■ June 1, 2016 ■ Terracon Project No. 04155197
Responsive ■ Resourceful ■ Reliable 5
foundations are presented in the following sections. The tables attached in Appendix B presentdesign parameters to be used in LPILE analyses.
The bedrock bearing materials were encountered at the following depths/elevations:
BoringTop of Bedrock Bearing Material (feet)
Depth ElevationB-1 24 779
B-2 5 759.5
B-2A 5 759.5
B-3 9 758.5
B-4 9 765
B-5 8.5 768.5
4.1 Driven Piles
Driven steel HP piles driven to practical refusal in the bedrock can be used to support theabutments. According to AASHTO’s LRFD Bridge Design Specifications, the nominalresistance of piles driven to bear on hard rock where pile penetration into the rock formation isminimal is controlled by the structural limit state of the pile. Pile capacity will depend on thecross-section and the steel grade. The piles should be designed using a maximum workingstress in the pile of 25 percent of the steel’s yield strength.
Pile driving through the native overburden soils is not expected to be difficult based on theresults of the borings. However, variations can occur in the density and strength of the soil andthe depth and quality of the bedrock. Because of the high driving resistance anticipated in thebedrock materials, we recommend that the piles be equipped with driving tips that can endurehigh driving stresses.
Piles should be installed in accordance with Section 514 of ODOT’s Standard Specifications forHighway Construction. All piles should be driven until satisfactory driving resistance isdeveloped for the design load bearing capacity using an appropriate pile driving formulaapproved by ODOT. Pre-drilling will be required in order to achieve minimum pile lengths.
Driven pile foundations designed and constructed as recommended above are expected toexperience total settlements of less than 1 inch.
Geotechnical Engineering ReportTurner Turnpike Widening – Bridge B (South 257th West Avenue)Creek County, Oklahoma ■ June 1, 2016 ■ Terracon Project No. 04155197
Responsive ■ Resourceful ■ Reliable 6
4.2 Drilled Shafts
We understand a bridge engineer will design drilled shafts based on the Texas Conepenetrometer values provided on the attached boring logs. We recommend that the proposeddrilled shafts bear in the shale or sandstone bedrock.
A heavy-duty drill rig equipped with a rock auger or core barrel will be required to penetrate thebedrock. Based on the Texas Cone Penetrometer values measured in our borings, the drillingcontractor should anticipate difficult drilling in the shale bedrock.
Based on the results of the borings, casing may be required to maintain open pier excavationsand control water inflow. To facilitate pier construction, concrete should be on-site and ready forplacement as pier excavations are completed. A sufficient head of concrete should bemaintained in the casing as it is being pulled to prevent an influx of soft soil or water into theexcavations. Also, concrete having a slump of at least 5 inches should be used to prevent theconcrete from arching in the casing.
4.3 Seismic Considerations
Reference Site Classification
2012 AASHTO LRFD Bridge Design Specifications 1 C
1. In general accordance with the 2012 AASHTO LRFD Bridge Design Specifications, Table 3.10.3.1-1 –Site Class Definitions.
GENERAL COMMENTS5.0
Terracon should be retained to review the final design plans and specifications so commentscan be made regarding interpretation and implementation of our geotechnical recommendationsin the design and specifications. Terracon also should be retained to provide observation andtesting services during grading, excavation, foundation construction and other earth-relatedconstruction phases of the project.
The analysis and recommendations presented in this report are based upon the data obtainedfrom the borings performed at the indicated locations and from other information discussed inthis report. This report does not reflect variations that may occur between borings, across thesite, or due to the modifying effects of construction or weather. The nature and extent of suchvariations may not become evident until during or after construction. If variations appear, weshould be immediately notified so that further evaluation and supplemental recommendationscan be provided.
Geotechnical Engineering Report
Turner Turnpike Widening – Bridge B (South 257th West Avenue)
Creek County, Oklahoma ■ June 1, 2016 ■ Terracon Project No. 04155197
Responsive ■ Resourceful ■ Reliable 7
The scope of services for this project does not include either specifically or by implication any
environmental assessment of the site or identification or prevention of pollutants, hazardous
materials or conditions. If the owner is concerned about the potential for such contamination or
pollution, other studies should be undertaken.
This report has been prepared for the exclusive use of our client for specific application to the
project discussed and has been prepared in accordance with generally accepted geotechnical
engineering practices. No warranties, either express or implied, are intended or made. Site safety,
excavation support, and dewatering requirements are the responsibility of others. In the event
that changes in the nature, design, or location of the project as outlined in this report are planned,
the conclusions and recommendations contained in this report shall not be considered valid
unless Terracon reviews the changes and either verifies or modifies the conclusions of this report
B-1LATERAL CAPACITY ANALYSESDESIGN SOIL PARAMETERS FOR
UNDRAINED CONDITIONSTurner Turnpike Widening - Bridge B
Terracon Project No. 04155197Creek County, Oklahoma
LPILE LPILESoil Effective Undrained Internal Soil
Depth to SoilLayer Modulus Unit Shear Friction Strain
Soil LPILE Top Bottom k2 Weight Strength3 Angle RQD4 Factor
Layer Soil Type (feet) (feet) (pci) (pcf) (psf) (degrees) (%) e50/krm 1 Weak Rock (8) 0 5.5 10,000 130 100 0 63 0.00052 Weak Rock (8) 5.5 18.5 10,000 68 100 0 63 0.00053 Stiff Clay without Free Water (8) 18.5 24 1,008 58 4,000 0 0.00484 Weak Rock (8) 24 55.5 30,000 68 300 0 79 0.0005
NOTES:
1. Design depth to subsurface water is about 5.5 feet.2. Value given for Weak Rock is Eri in psi.3. Uniaxial compressive strength for rock, in psi.4. Value given for RQD estimated from field data and sample examination.
Exhibit B-4
TABLE B.2
B-2LATERAL CAPACITY ANALYSESDESIGN SOIL PARAMETERS FOR
UNDRAINED CONDITIONSTurner Turnpike Widening - Bridge B
Terracon Project No. 04155197Creek County, Oklahoma
LPILE LPILESoil Effective Undrained Internal Soil
Depth to SoilLayer Modulus Unit Shear Friction Strain
Soil LPILE Top Bottom k2 Weight Strength3 Angle RQD4 Factor
1. Design depth to subsurface water is about 4.5 feet.2. Value given for Weak Rock is Eri in psi.3. Uniaxial compressive strength for rock, in psi.4. Value given for RQD estimated from field data and sample examination.
Exhibit B-5
TABLE B.3
B-3LATERAL CAPACITY ANALYSESDESIGN SOIL PARAMETERS FOR
UNDRAINED CONDITIONSTurner Turnpike Widening - Bridge B
Terracon Project No. 04155197Creek County, Oklahoma
LPILE LPILESoil Effective Undrained Internal Soil
Depth to SoilLayer Modulus Unit Shear Friction Strain
Soil LPILE Top Bottom k2 Weight Strength3 Angle RQD4 Factor
Layer Soil Type (feet) (feet) (pci) (pcf) (psf) (degrees) (%) e50/krm 1 Sand (5) 0 3 25 115 0 28 ----2 Stiff Clay without Free Water (3) 3 6 1,008 120 4,000 0 0.00483 Stiff Clay without Free Water (3) 6 9 1,008 58 4,000 0 0.00484 Weak Rock (8) 9 14.5 40,000 68 400 0 63 0.00055 Weak Rock (8) 14.5 40 30,000 68 300 0 79 0.0005
NOTES:
1. Design depth to subsurface water is about 6 feet.2. Value given for Weak Rock is Eri in psi.3. Uniaxial compressive strength for rock, in psi.4. Value given for RQD estimated from field data and sample examination.
Exhibit B-6
TABLE B.4
B-4LATERAL CAPACITY ANALYSESDESIGN SOIL PARAMETERS FOR
UNDRAINED CONDITIONSTurner Turnpike Widening - Bridge B
Terracon Project No. 04155197Creek County, Oklahoma
LPILE LPILESoil Effective Undrained Internal Soil
Depth to SoilLayer Modulus Unit Shear Friction Strain
Soil LPILE Top Bottom k2 Weight Strength3 Angle RQD4 Factor
1. Design depth to subsurface water is about 14 feet.2. Value given for Weak Rock is Eri in psi.3. Uniaxial compressive strength for rock, in psi.4. Value given for RQD estimated from field data and sample examination.
Exhibit B-7
TABLE B.5
B-5LATERAL CAPACITY ANALYSESDESIGN SOIL PARAMETERS FOR
UNDRAINED CONDITIONSTurner Turnpike Widening - Bridge B
Terracon Project No. 04155197Creek County, Oklahoma
LPILE LPILESoil Effective Undrained Internal Soil
Depth to SoilLayer Modulus Unit Shear Friction Strain
Soil LPILE Top Bottom k2 Weight Strength3 Angle RQD4 Factor
1. Design depth to subsurface water is greater than about 29 feet.2. Value given for Weak Rock is Eri in psi.3. Uniaxial compressive strength for rock, in psi.4. Value given for RQD estimated from field data and sample examination.
Exhibit B-8
APPENDIX C
SUPPORTING DOCUMENTS
01 - 1011 - 30
> 30
RELATIVE PROPORTIONS OF FINES
Descriptive Term(s)of other constituents
Percent ofDry Weight
Hand Penetrometer
Torvane
Standard PenetrationTest (blows per foot)
Photo-Ionization Detector
Organic Vapor Analyzer
Texas Cone Penetrometer
TraceWithModifier
Water Level Aftera Specified Period of Time
GRAIN SIZE TERMINOLOGYRELATIVE PROPORTIONS OF SAND AND GRAVEL
TraceWithModifier
Standard Penetration orN-Value
Blows/Ft.
Descriptive Term(Consistency)
Loose
Very Stiff
Standard Penetration orN-Value
Blows/Ft.
Ring SamplerBlows/Ft.
Ring SamplerBlows/Ft.
Medium Dense
Dense
Very Dense
0 - 1 < 3
4 - 9 2 - 4 3 - 4
Medium-Stiff 5 - 9
30 - 50
WA
TE
R L
EV
EL
Auger
Shelby Tube
Grab Sample
FIE
LD
TE
ST
S
DESCRIPTION OF SYMBOLS AND ABBREVIATIONS
Descriptive Term(Density)
Non-plasticLowMediumHigh
BouldersCobblesGravelSandSilt or Clay
10 - 18
> 50 15 - 30 19 - 42
> 30 > 42
_
Water levels indicated on the soil boringlogs are the levels measured in theborehole at the times indicated.Groundwater level variations will occurover time. In low permeability soils,accurate determination of groundwaterlevels is not possible with short termwater level observations.
CONSISTENCY OF FINE-GRAINED SOILS
(50% or more passing the No. 200 sieve.)Consistency determined by laboratory shear strength testing, field
visual-manual procedures or standard penetration resistance
DESCRIPTIVE SOIL CLASSIFICATION
> 8,000
Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracyof such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey wasconducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographicmaps of the area.
Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dryweight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils haveless than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, andsilts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may beadded according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are definedon the basis of their in-place relative density and fine-grained soils on the basis of their consistency.
Plasticity Index
8 - 15
Split Spoon
Rock Core
PLASTICITY DESCRIPTION
Term
< 1515 - 29> 30
Descriptive Term(s)of other constituents
Water InitiallyEncountered
Water Level After aSpecified Period of Time
Major Componentof Sample
Percent ofDry Weight
(More than 50% retained on No. 200 sieve.)Density determined by Standard Penetration Resistance
Includes gravels, sands and silts.
Hard
Very Loose 0 - 3 0 - 6 Very Soft
7 - 18 Soft
10 - 29 19 - 58
59 - 98 Stiff
less than 500
500 to 1,000
1,000 to 2,000
2,000 to 4,000
4,000 to 8,000> 99
LOCATION AND ELEVATION NOTES
SA
MP
LIN
G
< 55 - 12> 12
No Recovery
RELATIVE DENSITY OF COARSE-GRAINED SOILS
Particle Size
Over 12 in. (300 mm)12 in. to 3 in. (300mm to 75mm)3 in. to #4 sieve (75mm to 4.75 mm)#4 to #200 sieve (4.75mm to 0.075mmPassing #200 sieve (0.075mm)
ST
RE
NG
TH
TE
RM
S Unconfined CompressiveStrength, Qu, psf
4 - 8
GENERAL NOTES
Texas Cone
(HP)
(T)
(b/f)
(PID)
(OVA)
(TCP)
Pressure Meter
Exhibit C-1
UNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification
Group Symbol
Group Name B
Coarse Grained Soils: More than 50% retained on No. 200 sieve
Gravels: More than 50% of coarse fraction retained on No. 4 sieve
Clean Gravels: Less than 5% fines C
Cu 4 and 1 Cc 3 E GW Well-graded gravel F
Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F
Gravels with Fines: More than 12% fines C
Fines classify as ML or MH GM Silty gravel F,G,H
Fines classify as CL or CH GC Clayey gravel F,G,H
Sands: 50% or more of coarse fraction passes No. 4 sieve
Clean Sands: Less than 5% fines D
Cu 6 and 1 Cc 3 E SW Well-graded sand I
Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I
Sands with Fines: More than 12% fines D
Fines classify as ML or MH SM Silty sand G,H,I
Fines classify as CL or CH SC Clayey sand G,H,I
Fine-Grained Soils: 50% or more passes the No. 200 sieve
Silts and Clays: Liquid limit less than 50
Inorganic: PI 7 and plots on or above “A” line J CL Lean clay K,L,M
PI 4 or plots below “A” line J ML Silt K,L,M
Organic: Liquid limit - oven dried
0.75 OL Organic clay K,L,M,N
Liquid limit - not dried Organic silt K,L,M,O
Silts and Clays: Liquid limit 50 or more
Inorganic: PI plots on or above “A” line CH Fat clay K,L,M
PI plots below “A” line MH Elastic Silt K,L,M
Organic: Liquid limit - oven dried
0.75 OH Organic clay K,L,M,P
Liquid limit - not dried Organic silt K,L,M,Q
Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat
A Based on the material passing the 3-inch (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles
or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded
gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.
D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay
E Cu = D60/D10 Cc =
6010
2
30
DxD
)(D
F If soil contains 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.
H If fines are organic, add “with organic fines” to group name. I If soil contains 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,”
whichever is predominant. L If soil contains 30% plus No. 200 predominantly sand, add “sandy” to
group name. M If soil contains 30% plus No. 200, predominantly gravel, add
“gravelly” to group name. N PI 4 and plots on or above “A” line. O PI 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line.