HCEA Geotechnical Report

Transcription

Geotechnical Engineering Study
Penn Commons Residential Development
East Buffalo Township, Union County, PA
HCEA Project No.: T15107
Prepared For:
Mr. Bruce Quigley
Union County Housing Associates, Inc.
1610 Industrial Blvd.
Suite 700
Lewisburg, PA 17837
Prepared By:
Hillis-Carnes Engineering Associates, Inc.
2929 Stewart Drive, Suite 302
State College, PA 16801
October 12, 2015
HILLIS-CARNES ENGINEERING ASSOCIATES, INC.
State College, PA 16801
814-231-0552
www.hcea.com
Mr. Bruce Quigley
1610 Industrial Blvd.
Suite 700
Lewisburg, PA 17837
RE:
East Buffalo Township, Union County, PA
Dear Mr. Quigley:
Hillis-Carnes Engineering Associates, Inc. (HCEA) has completed the geotechnical
engineering study for the above-referenced project that is to be located in East Buffalo
Township, Union County, Pennsylvania.
This portion of the exploration consisted of excavating eight (8) test pits, laboratory
testing, performing engineering analyses, and preparing this written report of findings
and conclusions.
Should you have any questions or require additional information, please contact us.
Sincerely,
Robert Etters, P.E.
Branch Manager
James. P. Thornton, P.E.
Senior Geotechnical Engineer
Corporate Headquarters - Annapolis Junction, MD
Maryland  Washington, DC  Delaware  Pennsylvania  Virginia
ENGINEERING ASSOCIATES, INC.
2929 Stewart Drive, Suite 302
October 12, 2015
TABLE OF CONTENTS
LETTER OF TRANSMITTAL ........................................................................................................................ i
1.0 PURPOSE AND SCOPE ...................................................................................................................... 1
2.0 PROJECT CHARACTERISTICS .......................................................................................................... 1
3.0 GEOLOGIC INFORMATION................................................................................................................. 2
4.0 FIELD EXPLORATION.......................................................................................................................... 3
5.0 LABORATORY TESTING ..................................................................................................................... 3
6.0 SUBSURFACE CONDITIONS .............................................................................................................. 4
6.1
Surficial Materials................................................................................................................ 4
6.2
Fill Materials ........................................................................................................................ 5
6.3
Natural Materials ................................................................................................................. 6
6.4
Groundwater Conditions ..................................................................................................... 6
6.5
Site Seismicity..................................................................................................................... 7
7.0 EVALUATIONS AND RECOMMENDATIONS ..................................................................................... 7
7.1
General Site Preparation .................................................................................................... 7
7.2
Fill Selection, Placement and Compaction......................................................................... 8
7.3
Cold/Wet Weather Earthmoving Considerations ............................................................... 9
7.4
Foundations ....................................................................................................................... 9
7.5
Ground-Supported Slabs .................................................................................................. 10
7.6
Groundwater and Drainage .............................................................................................. 11
7.7
Benching/Sloping Considerations .................................................................................... 11
7.8
Pavement Design Considerations .................................................................................... 12
7.9
Rock Removal Considerations ......................................................................................... 12
7.10
Lateral Earth Pressure Considerations ............................................................................ 12
8.0 RECOMMENDED ADDITIONAL SERVICES..................................................................................... 14
9.0 REMARKS ........................................................................................................................................... 14
APPENDIX:
A.
B.
C.
D.
E.
F.
G.
General Geotechnical Notes
Project Location Plan
USGS Geology Map
Test Pit Location Plan
Test Pit Logs
Representative Photographs
Laboratory Testing Data
East Buffalo Township, Union County, Pennsylvania
1.0
PURPOSE AND SCOPE
The purpose of this study was to determine the general subsurface conditions at the
test pit locations and to evaluate those conditions with respect to the concept and
design of a foundation system, ground-supported slabs and site work for the
proposed construction.
The evaluations and recommendations presented in this report were developed
from an analysis of the project characteristics and an interpretation of the general
subsurface conditions at the site based on test pit information. The soil descriptions
shown on the test pit logs represent the approximate boundaries between
underlying materials, however; these transitions may be gradual. Such variations
can best be evaluated during construction and, if necessary, any minor design
changes can be made at that time.
An evaluation of the site with respect to potential construction problems and
recommendations dealing with the earthwork and inspection during construction are
also included. The inspection is considered necessary to verify the subsurface
conditions and to verify that the soils-related construction phases are performed
properly.
The Appendix contains a summary of the field and laboratory work on which this
report is based.
Our services for this project were performed in accordance with HCEA Proposal No.
P150186STC, dated August 5, 2015. Authorization to perform this exploration and
analysis was given in the form of a signed contract agreement signed by Mr. Bruce
Quigley, Union County Housing Associates on August 7, 2015.
2.0
PROJECT CHARACTERISTICS
The proposed project site is located north of Wilson Alley and Rural Avenue
between North 10th and North 11th Street, East Buffalo Township, Union County,
PA. The site is further bounded by rails to trails along the north. The general
location of the site is shown on a Project Location Plan presented in Appendix B.
Penn Commons
Page 2 of 15
The precise location of the project is shown on a Site Plan prepared by Stahl –
Sheaffer Engineering, LLC. (SSE) and dated July 1, 2015. This drawing was
received via email from SSE’s Project Engineer Mr. Michael Maxwell, P.E. as
part of the RFP. This drawing was incorporated into the Test Pit Location Plan in
Appendix D.
It is our understanding that the proposed construction includes the construction
of seven (7), one (1) and two (2)-story wood-framed structures with concrete
slabs on-grade. Finished floor elevations are expected to approximately match
existing grade with maximum cuts and fills not expected to exceed one (1) foot.
The investigation was performed with the initial intent of utilizing frost protected
shallow foundation (FPSF) system for the perimeter foundations. Based on the
results of this investigation, alternative foundation recommendations are
presented in this report.
At the time of the investigation the surface of the site is variable and includes
grass, concrete, residential structures and asphalt pavement. Additionally,
structures previously occupied portions of the site and have been razed. It is
expected that the remaining structures will also be removed during the
preliminary phase of upcoming construction.
Maximum wall loads of 3,000 pounds per lineal foot and maximum floor loads of
50 pounds per square foot (psf) are expected. Also, we have assumed
maximum tolerable total and differential settlement values of one (1) inch and
one-half (1/2) of an inch, respectively.
3.0
GEOLOGIC INFORMATION
According to the Department of Environmental Resources, Office of Resources
Management, Bureau of Topographic and Geologic Survey (1982), rock formations
at the proposed area are undivided between the Keyser and Tonoloway formations.
Both formations are comprised primarily of limestone. The Keyser formation is
comprised of dark gray, highly fossiliferous, crystalline to nodular limestone: shaly
limestone near the top and the Tonoloway formation is comprised of medium-gray
laminated limestone containing interbedded zones of medium and light gray shale
and siltstone. The rock formations are moderately resistant to weathering and the
surface drainage is typically good. Excavation in both formations is difficult when
rock is encountered.
Penn Commons
4.0
Page 3 of 15
FIELD EXPLORATION
Prior to commencement of field operations, the project was registered with the
Pennsylvania One-Call System, Inc. and this phase of the project was assigned
Serial Number 20152192220.
Utilities were identified within the proposed
construction footprint, we recommend that the contractors verify the locations of any
utilities prior to commencement of construction activities. It should be noted that
unmarked utilities were identified in the northeastern area of the site in the vicinity of
test pit location TP-8. This included storm lines and possibly fiber optics and natural
gas.
The field investigation consisted of eight (8) test pits excavated utilizing a rubbertracked excavator owned and operated by J-Mar Construction, Inc. These test pits
were extended to depths greater than the bearing elevation at most locations. At
test pit location TP-7 excavation was hindered due to the presence of a concrete
slab. Test pit TP-8 was abandoned due to unmarked utilities and the possible
presence of a fiber optic and natural gas utilities. These locations are shown on the
Test Pit Location Plan in Appendix D of this report.
Details of the subsurface conditions encountered in our field exploration program
are shown on the individual Test Pit Logs included in Appendix E. Additionally,
representative photographs taken prior to and upon completion of the investigation
are included in Appendix F.
All test pits were checked for apparent groundwater levels at the time of excavation
and prior to backfilling the pits with the excavated soil.
The stratifications shown on the Test Pit Logs represent the conditions only at the
actual test pit locations at the time the exploration took place. Variations should be
expected between the test pit locations. In addition, the Test Pit Logs show the
approximate boundaries between subsurface materials. Actual transitions between
subsurface materials may be gradual.
Representative soil samples were collected and transported to HCEA's laboratory
for additional testing.
5.0
LABORATORY TESTING
In addition to the visual classification of the soil samples, moisture content
determination tests were performed on representative samples. The moisture
content is the ratio of the weight of the water in the sample to the dry weight of
the sample. These tests were performed in general compliance with ASTM
D2216.
Penn Commons
Page 4 of 15
Moisture-plasticity characteristics of two (2) composite soil samples 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 procedure was performed in
compliance with ASTM D4318.
A particle-size analysis was performed on the same soil samples in compliance
with ASTM D422. The procedure includes a sieve analysis for particle sizes
greater than the #200 sieve and a hydrometer analysis for particle sizes smaller
than the #200 sieve. Using this information, the samples were classified using
the Unified Soil Classification System (USCS), ASTM D2487.
The following is a summary of the soil classification results with individual results
enclosed in Appendix G:
6.0
HCEA
Sample
Number
Location
Liquid
Limit (LL)
Plasticity
Index
(PI)
USCS
L15150
Composite Sample: TP-4,
32-99+" and TP-6, 24-43"
40
19
CL
L15151
Composite Sample: TP-1, 29106+" and TP-5, 19-109+"
24
8
CL
SUBSURFACE CONDITIONS
Details of the subsurface conditions encountered are shown on the individual test pit
logs enclosed in Appendix E of this report. A brief description of the subsurface
conditions and pertinent engineering characteristics of the soils are outlined below.
6.1
Surficial Materials
A surficial vegetation/topsoil layer was encountered at test pit locations TP-1,
TP-2, TP-3 and TP-4 and ranged in thickness between 2 and 25 inches.
Topsoil thicknesses noted on the Test Pit Logs should not be used solely to
Penn Commons
Page 5 of 15
estimate topsoil quantities at the site. In general, topsoil contains organic
matter due to the decay of vegetation and natural weathering processes and
should be considered highly compressible.
A concrete slab was present at the surface at test pit locations TP-6 and TP7 and measured 5 inches in thickness. Limestone gravel was present at the
surface at the remaining test pit locations, TP-5 and TP-8, 3 inches and 8
inches, respectively.
6.2
Fill Materials
Fill materials were encountered beneath the previously described surficial
layers at all test pit locations and was highly variable in composition and
consistency. At test pit locations TP-1 and TP-3 the fill consisted of a mixture
of clay and shale, was moderately compacted and extended to depths of 19
and 8 inches, respectively. Of special note, the shale was predominantly
black and appears to representative of the Marcellus Formation which is
locally present. This formation contains abundant pyrite (iron disulfide) and
siderite (ferrous carbonate) concretions and nodules and is classified as
potentially expansive.
The fill material at test pit location TP-2 consists of a mixture of sand and
gravel as well as debris comprised of bottles, metal and other glass. This
stratum also appeared to contain other burnt remnants. Appendix F, Plates
2 and 3, show the in-place and excavated material encountered at this
location. This fill layer extended to a depth of 78 inches with the debris
extending to a more shallow depth.
A mixture of black ash and cinders was encountered at test pit locations TP4 and TP-5. The material was found to be damp, loosely compacted and
extended to depths ranging between 13 and 32 inches.
Beneath the concrete pavement at test pit locations TP-6 and TP-7 the fill
consisted primarily of sand, cinders and gravel. The material was wet and
poorly compacted. This material extended to depths of 24 and 36 inches,
respectively. It should be noted that an additional concrete slab was
encountered at TP-7 at the 36 inch depth as well as a concrete wall along
the east side of the excavation. Standing water was also present at this
location (See Plate 8 in Appendix F). This water is likely a perched condition
confined by the below grade concrete slab.
The fill materials at test pit location TP-8 are comprised of limestone gravel.
This material extended to a depth of 18 inches at which an unmarked
Penn Commons
Page 6 of 15
abandoned utility was encountered. Since no utilities were identified at this
location, the test pit was terminated.
6.3
Natural Materials
The natural soils were encountered beneath the fill materials at all
locations which could be advanced to a depth exceeding the expected
bearing elevation. HCEA Sample Numbers L15150 and L15151 are
representative of these materials and were classified as CL, lean clay and
sandy lean clay. These materials exhibited stiff to hard consistency with
moisture contents ranging between 15 and 30 percent. This material
extended to test pit termination depth at all locations with particle size
increasing with depth.
Although the material was generally difficult to excavate at test pit
termination depth, refusal was not encountered. Refusal is the term used
to describe the condition at which the material could not be further
penetrated utilizing the excavation equipment used to perform the
investigation.
In general, as depth increased, the amount of weathered sandstone also
increased. This material was found to have a stiff to hard consistency,
based upon hand penetrometer values and probing. Varying amounts of
mottling were observed throughout this stratum.
Mottling is the term used to describe the process by which
microorganisms in an anaerobic (without oxygen) environment obtain
energy from nutrients in the soil. When these nutrients are depleted, the
remaining soil appears gray in color. Generally, mottling is recognized as
an indicator of a water table or saturated soil conditions. For this situation,
the relatively impermeable clay soil layer restricts water flow. As a result,
the infiltrated water is unable to percolate through to the normal
freestanding groundwater table. The presence and extent of this condition
are usually attributed to drainage and precipitation.
6.4
Groundwater Conditions
Groundwater was not encountered within the test pit excavations. As
previously described, the water encountered at test pit location TP-7
appears to be a perched condition. However, it should be noted that
groundwater levels fluctuate seasonally as a function of precipitation, the
permeability of the subsurface materials and proximity to nearby water
bodies.
Penn Commons
6.5
Page 7 of 15
Site Seismicity
According to the 2012 International Building Code, Section 1613.3.2
(Chapter 20 of ASCE 7), seismic Site Class D should be specified for this
project.
7.0
EVALUATIONS AND RECOMMENDATIONS
The subject site is considered suitable for the proposed construction, provided
the geotechnical recommendations and suggested construction guidelines
presented in this report are utilized in both the design and construction phases of
this project.
If there are any changes to the project characteristics or if different subsurface
conditions are encountered during construction, HCEA should be consulted so that
the recommendations of this report can be reviewed and revised, if necessary.
7.1
General Site Preparation
Site preparation should include the removal of topsoil, any unapproved manplaced materials; frozen, wet, soft or very loose soils; and any other
deleterious materials. Particular attention should be given to the removal of
black carbonaceous if encountered beneath ground supported structures.
These operations should be performed in a manner consistent with good
erosion and sediment control practices. This would include the removal of
the existing structures as well as the concrete slabs present in the eastern
portion of the site. Additionally, the below grade slab should be rubblized to
provide for an outlet of infiltrated water.
After the initial stripping process is completed, areas of the site to receive fill,
should be proofrolled. Based on the moisture content of the soil at the time of
topsoil removal, drying may be required prior to proofrolling or sealing of the
soil surface.
The proofrolling operations should be performed using a 20 ton, fully loaded
dump truck or another pneumatic tire vehicle of similar size and weight. The
purpose of the proofrolling will be to provide surficial densification and to
locate any near surface pockets of soft or loose soils requiring undercutting
or other form of modification. Proofrolling will help to reveal the presence of
unstable materials and is particularly important in evaluating fill material.
A Geotechnical Engineer or experienced Soils Inspector should witness the
proofrolling operations and determine whether any areas require
undercutting and/or stabilization.
Penn Commons
Page 8 of 15
In areas where proofrolling is not practical, such as in below-grade
excavations, we recommend that the project’s Geotechnical Engineer or
designated representative visually inspect and manually probe the subgrade
materials.
Traffic from the various construction equipment may create pumping and a
general deterioration of the soils. It is our recommendation that the
contractor be fully advised of these potential problems. Additionally, the
contractor should not permit water to pond on the site and exposed
subgrades should be sloped and sealed at all times to facilitate rainfall runoff.
7.2
Fill Selection, Placement and Compaction
All material to be used as fill or backfill should be inspected, tested and
approved by the Geotechnical Engineer. In general, the on-site soils with a
Unified Soil Classification of CL are considered suitable for reuse as
structural fill beneath floor slabs, utilities, sidewalks, pavements and areas to
be landscaped. Soils having moisture contents above the typical optimum
percentage required for proper compaction will require drying and/or aeration
prior to placement. The difficulty associated with drying is significantly
affected by seasonal conditions. It should be noted that lateral confinement
of poorly graded materials will be required in order to limit horizontal
movement and subsequent settlement or instability of the structural fill.
If imported fill material is required, those materials should have Unified Soil
Classifications of CL or better, contain no rock greater than 3 inches in
diameter, and should not contain more than 1 percent (by weight) of organic
matter or other deleterious material. Uniformly graded materials, such as
PennDOT 2B or AASHTO #57 stone, can only be utilized as structural fill
with the permission of the Geotechnical Engineer. Potentially expansive
materials such as mine tailings, pyritic shale and slag should not be used as
structural fill. Other materials should be considered on a case-by-case basis
and approved by the project’s Geotechnical Engineer.
All fill should be placed in relatively horizontal 8-inch (maximum) loose lifts
and should be compacted to a minimum of 100 percent of the Standard
Proctor (ASTM D-698) maximum dry density. Fill materials in landscape and
other non-structural areas should be compacted to at least 90 percent of the
Standard Proctor maximum dry density if significant subsidence of the fill
under its own weight is to be avoided. Field moisture contents should be
maintained within 2 percentage points of the optimum moisture content in
order to provide adequate compaction.
Penn Commons
Page 9 of 15
A sufficient number of in-place density tests should be performed by an
experienced Engineering Technician on a full-time basis to verify that the
proper degree of compaction is being obtained.
7.3
Cold/Wet Weather Earthmoving Considerations
In order to facilitate construction during late fall, winter and early spring,
special considerations should be recognized. Specifically, “cold weather”
and “wet weather” can significantly reduce the potential to practically lower
soil moisture content to optimum compaction levels. “Cold weather” is when
temperatures drop below freezing at any time or when temperatures are
consistently sustained below 40º F. “Wet weather” is any period of time with
increased precipitation and can occur during any time of the year. The
following considerations are offered if fill operations are anticipated during the
aforementioned difficult conditions:
1. The natural moisture contents of imported soils above optimum
percentages will require modification. The moisture content may
need to be lowered by spreading out the wet materials in thin layers
and discing in order to facilitate evaporation. This methodology
becomes less practical during “wet weather” and “cold weather”
conditions.
2. Any compacted structural fill materials should be positively graded
and sealed with a smooth-drummed roller as soon as practical after
achieving finished grade or immediately prior to any anticipated
precipitation event. These measures will help to reduce the potential
for rutting and pumping of the subgrade and ponding of undrained
water.
3. Imported granular and well-graded structural fill, along with a
stabilizing geosynthetic grid, may aid in facilitating construction during
difficult weather conditions. The use of properly graded crushed rock
as a working surface will aid in creating a stable working pad.
The geotechnical engineer should review all design and construction
operations that specifically address earthwork in “cold weather” and
“wet weather” conditions.
7.4
Foundations
Based on the subsurface conditions encountered during our field exploration
program and our understanding of the proposed project, conventional
shallow foundations and installation of a slab-on-grade system will require
removal of a significant amount of fill material. An alternative to this system
Penn Commons
Page 10 of 15
would be a drilled shaft foundation and a structural slab. These shafts would
extend through the unsuitable fill material to the underlying stiff, residual clay
soil stratum.
The diameter of the shaft should be based on the design considerations
mentioned previously. Reinforcing steel and concrete strength requirements
should be determined by the Structural Engineer.
When the drilling operations are finished, concrete should be placed inside
the casing as soon as possible. If casing is required, it should be removed
as the concrete is being placed. It is recommended that concrete be placed
the same day that the shaft is drilled.
Based on the maximum anticipated structural loads, the maximum tolerable
settlement, and the general soil conditions which were encountered, it is our
judgment that the in-place soils are capable of providing a net allowable
bearing capacity of 2,500 pounds per square foot.
Assuming the net loading on the footings does not exceed 2,500 pounds per
square foot and the recommendations in this report are followed, postconstruction total and differential settlement should be less than the assumed
tolerable values.
If soft or loose pockets are encountered in the footing excavations, the
unsuitable materials should be removed and the footings should be located
at a lower elevation.
If unsuitable material is encountered, an overexcavation or other
modification procedure would be necessary.
If during foundation
excavation, soils are encountered that are not indicative of those
described in this report, a geotechnical engineer should be consulted for
guidance on how to proceed with the excavation.
Exterior footings and footings in unheated areas should be located at depths
of at least 42 inches below final exterior grades so as to provide adequate
protection from frost heave.
7.5
Ground-Supported Slabs
As previously described, concrete slabs-on-grade will require special
attention to evaluate fill at the intended location. An overexcavation and
replacement should be expected if this type of construction is utilized.
Penn Commons
Page 11 of 15
Floor slabs should be supported on approved, firm natural soils or new
compacted fill. The slab subgrade should be prepared in accordance with the
procedures outlined in Sections 7.1 through 7.2 of this report. In particular,
the slab subgrade should be heavily proofrolled to delineate any soft or loose
areas requiring undercutting and/or stabilization. The natural soils are
expected to provide a subgrade modulus of reaction (k) of 100 pounds per
square inch per inch (psi/inch).
To reduce stress concentrations on any grade slabs and to provide a uniform
bearing surface that may be associated with dissimilar fill materials, we
recommend a minimum of 6 inches of compacted PennDOT 2A stone be
placed between all grade slabs and the underlying subgrade. The stone will
also act as a drainage course for any moisture below the slabs. It is also
recommended that construction joints on the slab surface and isolation joints
between the slab and structural walls be provided (such that the slab would
be ground-supported).
7.6
Groundwater and Drainage
Due to the absence of groundwater during our field exploration, it is unlikely
that a groundwater table will be encountered during excavation operations;
however, wet soil conditions may be encountered near the soil/bedrock
interface. If perched groundwater is encountered, every effort should be
made to keep the excavations dry. An open pump, gravity drainage system
or other conventional dewatering procedure should be sufficient for these
temporary purposes.
Any water infiltration resulting from precipitation, surface run-off, or perched
water should be able to be controlled by means of sump pits and pumps, or
by gravity ditching procedures. If encountered, groundwater should be
maintained a minimum of 2 feet below the bottom of all excavations during
construction. If conditions are encountered that cannot be handled in such a
manner, the Geotechnical Engineer should be consulted.
Adequate drainage should be provided at the site to minimize any increases
in the moisture contents of the foundation soils. Grades should be sloped
away from the structure to prevent the ponding of water. The site drainage
should also be such that run-off onto adjacent properties is controlled
properly.
7.7
Benching/Sloping Considerations
For slopes less than 10 feet in height, maximum slopes of 1.5:1V and 2.5:1V
should be utilized for temporary (less than 24 hours) and permanent fill
Penn Commons
Page 12 of 15
operations, respectively, in soil or weathered rock. All slopes should be
visually inspected for stability.
Erosion control will be required at the face of all permanent slopes in soil. If
any slopes are proposed to be greater than the above values, or for slopes
greater than 10 feet in height, an in-depth slope stability analysis will be
required to ensure the integrity of the created slope.
If benching or sloping of the excavations is not practical, temporary
bracing/shoring will be required. Subsurface drainage must be considered in
the design of temporary bracing/shoring systems.
7.8
Pavement Design Considerations
A California Bearing Ratio (CBR) of 5 is typical for the natural, residual soil.
Based on the presence and non-uniformity of the fill material; a more
conservative value may be warranted. All pavements should contain
adequate surface and subsurface drainage. The subgrade should be
prepared according to Sections 7.1 and 7.2.
7.9
Rock Removal Consideration
Based on the materials encountered during the subsurface exploration and
our understanding of the project, it is unlikely that the removal of bedrock will
be required.
However, if deep excavations are planned, special excavation techniques,
such as air-rotary drilling or pneumatic jack hammering may be required in
order to facilitate rock removal. The method required for rock removal will
depend on the weathered and intact nature of the bedrock. It is the
responsibility of the Contractor to determine the rock removal method,
provided that method is acceptable to the owner and in compliance with any
applicable ordinances and regulations.
7.10
Lateral Earth Pressure Considerations
It is expected that the planned retaining walls will be required to resist lateral
earth pressures imposed by the backfill materials. The following table
presents geotechnical parameters that can be utilized to design the lateral
pressure distribution behind any permanent retaining structures.
The parameters listed below, which may be used to compute lateral
pressures on the walls, are considered to be representative of the existing
soils and typical for PennDOT 2A subbase. However, actual unit weights
and friction angles will vary from one material to another. It is, therefore,
Penn Commons
Page 13 of 15
recommended that appropriate soil testing be conducted on proposed fill
materials to ensure that the actual soil properties do not result in higher than
anticipated lateral pressures.
Material
γ
(pcf)

(degrees)
c
(psf)
Ko
Ka
Kp
On-Site Natural Soil
130
32
0
0.47
0.31
3.25
PennDOT 2A Stone
135
38
0
0.38
0.24
4.20
Legend:
 = Moist Unit Weight
 = Angle of Internal Friction

c = Cohesion
Ko = At-Rest Earth Pressure Coefficient
Ka = Active Earth Pressure Coefficient
Kp = Passive Earth Pressure Coefficient
The geotechnical engineer should review and approve all materials to be
utilized as backfill. Additional laboratory testing and evaluation will be part of
this review process.
Fill material around the walls should be placed as discussed in Section 7.2 of
this report, with the following exceptions:
1)
2)
Compaction of backfill material within ten (10) feet of the wall should
be accomplished using light, hand-operated compaction equipment.
The backfill material should be placed in horizontal lifts not exceeding
six (6) inches in loose thickness where compactive effort application is
hindered.
Where practical, we recommend installation of a drainage system behind
permanent retaining walls. The drainage system could consist of a
perforated drain pipe at the base of the wall, surrounded by a free draining
medium such as PennDOT 2B (AASTHO #57) stone. The stone should
extend to approximately 12 inches above the top of the drain pipe and be
wrapped in a geosynthetic fabric to prevent the migration of fine-grained
particles into the stone and drain pipe. The drainage pipe should be
daylighted down slope, away from the wall and any other existing or
proposed structures.
Penn Commons
8.0
Page 14 of 15
RECOMMENDED ADDITIONAL SERVICES
Additional soil and foundation engineering, testing, and consulting services
recommended for this project are summarized below:
Site Preparation and Proofrolling: A Geotechnical Engineer or experienced Soils
Inspector should inspect the site after it has been stripped and excavated. The
inspector should determine if any undercutting or in-place densification is necessary
to prepare pavement or building subgrades for fill placement.
Fill Placement and Compaction: A Geotechnical Engineer or experienced Soils
Inspector should witness any required filling operations and should take sufficient
in-place density tests to verify that the specified degree of fill compaction is
achieved. He should observe and approve borrow materials used and should
determine if their existing moisture contents are suitable.
Footing Excavation Inspections: A Geotechnical Engineer or experienced Soils
Inspector should inspect the footing excavations for the proposed structure. He
should verify that the design bearing pressure is available and that no loose pockets
exist beneath the bearing surfaces of the footing excavations. Based on the
inspection, the Inspector would either approve the bearing surfaces or recommend
modifications to improve stability.
9.0
REMARKS
This report has been prepared to aid in the evaluation of the site for the proposed
construction. It is considered that adequate recommendations have been provided
to serve as a basis for design. Additional recommendations can be provided as
needed.
These analyses and recommendations are, of necessity, based on the information
made available to us at the time of the actual writing of the report and the on-site
surface and subsurface conditions which existed at the time the test pits were
excavated.
If subsurface conditions are encountered which differ from those reported herein,
this office should be notified immediately so that the analyses and
recommendations can be reviewed and/or revised as necessary. It is also
recommended that:
1. We are given the opportunity to review any plans and specifications in order to
comment on the interaction of the soil conditions as described herein and the
design requirements.
Penn Commons
Page 15 of 15
2. A Geotechnical Engineer or experienced Soils Inspector is present at the site
during the construction phase to verify installation according to the approved
plans and specifications. This is particularly important during excavation,
placement, and compaction of fill materials.
Please note that successful completion of the project is dependent on your
compliance with all of the recommendations provided in this report. While
represented separately, the recommendations represent work that is intertwined.
Our professional services have been performed, our findings obtained, and our
recommendations prepared in accordance with generally accepted engineering
principles and practices. This warranty is in lieu of all other warranties either implied
or expressed. HCEA assumes no responsibility for interpretations made by others
based on work or recommendations by us.
APPENDIX A
GENERAL GEOTECHNICAL NOTES
HILLIS-CARNES
ENGINEERING ASSOCIATES, Inc.
2929 Stewart Drive, Suite 302, State College, PA 16801
Phone: (814)231-0552 • Fax: (814)231-0695
Description of Soils – per ASTM D2487
Major Component
Component Type
Coarse-Grained Soils,
More than 50% is
retained on the No. 200
sieve
Fine Grained Soils,
More than 50% passes
the No. 200 sieve
Highly Organic Soils
Component Description
Symbol
Gravels – More than 50% of the coarse
fraction is retained on the No. 4 sieve.
Coarse = 1” to 3”
Medium = ½” to 1”
Fine = ¼” to ½”
Sands – More than 50% of the coarse
fraction passes the No. 4 sieve.
Coarse = No.10 to No.4
Medium = No. 10 to No. 40
Fine = No. 40 to No. 200
Silts and Clays
Liquid Limit is less than 50
Low to medium plasticity
Clean Gravels <5%
Passing No. 200 sieve
Gravels with fines, >12%
Passing the No. 200 sieve
GW
GP
GM
GC
Well Graded Gravel
Poorly Graded Gravel
Silty Gravel
Clayey Gravel
Clean Sands <5% Passing
No. 200 sieve
Sands with fines, >12%
Passing the No. 200 sieve
SW
SP
SM
SC
Well Graded Sand
Poorly Graded Sand
Silty Sand
Clayey Sand
Inorganic
ML
CL
OL
Silts and Clays
Liquid Limit of 50 or greater
Medium to high plasticity
Inorganic
Silt
Lean Clay
Organic silt
Organic Clay
Elastic Silt
Fat Clay
Organic Silt
Organic Clay
Peat
Organic
Description
Sand, Gravel, Silt, Clay, etc.
Sandy, silty, clayey, etc.
Some sand, some silt, etc.
Trace sand, trace mica, etc.
With sand, with mica, etc.
Particle Size Identification
Approximate percent
by weight
50% or more
35% to 49%
12% to 34%
1% to 11%
Presence only
Cohesive Soils
Field Description
Easily Molded in Hands
Easily penetrated several inches by thumb
Penetrated by thumb with moderate effort
Penetrated by thumb with great effort
Indented by thumb only with great effort
MH
CH
OH
PT
Primarily Organic matter, dark color, organic odor
Proportions of Soil Components
Component
Form
Noun
Adjective
Some
Trace
With
Organic
Group Name
Particle Size
Boulder
Cobble
Gravel
Sand
Silt/Clay (fines)
Particle dimension
12” diameter or more
3” to 12” diameter
¼” to 3” diameter
0.005” to ¼” diameter
Cannot see particle
Granular Soils
Consistency
Very Soft
Soft
Medium
Stiff
Hard
No. of SPT Blows/ft
0–4
5 – 10
11 – 30
31 – 50
Greater than 50
Relative Density
Very Loose
Loose
Medium Dense
Dense
Very Dense
Other Definitions:
•
•
•
•
•
•
•
Fill: Encountered soils that were placed by man. Fill soils may be controlled (engineered structural fill)
or uncontrolled fills that may contain rubble and/or debris.
Saprolite: Soil material derived from the in-place chemical and physical weathering of the parent rock
material. May contain relic structure. Also called residual soils. Occurs in Piedmont soils, found west of
the fall line.
Disintegrated Rock: Residual soil material with rock-like properties, very dense, N = 60 to 51/0”.
Karst: Descriptive term which denotes the potential for solutioning of the limestone rock and the
development of sinkholes.
Alluvium: Recently deposited soils placed by water action, typically stream or river floodplain soils.
Groundwater Level: Depth within borehole where water is encountered either during drilling, or after a
set period of time to allow groundwater conditions to reach equilibrium.
Caved Depth: Depth at which borehole collapsed after removal of augers/casing. Indicative of loose
soils and/or groundwater conditions.
APPENDIX B
PROJECT LOCATION PLAN
SITE
TB-1
N
TB-2
TB-1
PROJECT LOCATION
SCALE
1:24,000
MAP SOURCE:
0
0.25
0.50
MILES
0.75
1.0
USGS 7.5 Minute Quadrangle Map, State College, PA-2013.
USGS 7.5 Minute Quadrangle Map, Julian, PA-2013.
HCEA Map Created: 10/02/2015. PROJECT LOCATION PLAN
PENN COMMONS RESIDENTIAL DEVELOPMENT
EAST BUFFALO TOWNSHIP
UNION COUNTY, PENNSYLVANIA
HCEA PROJECT NO: T15107
ENGINEERING ASSOCIATES, INC. 2929 Stewart Drive, Suite 302, State College, PA 16801 Local 814‐231‐0552 Fax 814‐231‐0695 www.hcea.com APPENDIX C
USGS GEOLOGY MAP
o
oway F
l
o
n
o
T
an d
Keyser
rma o
S
ided (D
v
i
d
n
u
,
ns
KT)
TB-1
N
Hamilton Group (Dh)
Onandaga and Old Port
TB-2 (Doo)
Forma ons, undivided
TB-1
PROJECT LOCATION
Keyser and Tonoloway Forma ons, undivided (DSKT)
Wills Creek Forma on (Swc)
Bloomsburg and Miﬄintown
Forma ons, undivided (Sbm)
SCALE
0
0.25
0.50
MILES
MAP SOURCE:
0.75
1.0
PA DCNR Map Viewer Internet Website:
www.gis.dcnr.state.pa.us
HCEA Map Created: 10/07/2015.
USGS GEOLOGIC MAP
PENN COMMONS RESIDENTIAL DEVELOPMENT
ENGINEERING ASSOCIATES, INC. 2929 Stewart Drive, Suite 302, State College, PA 16801 Local 814‐231‐0552 Fax 814‐231‐0695 www.hcea.com APPENDIX D
TEST PIT LOCATION PLAN
N
TP-8
TEST PIT LOCATION
TP-5
TP-7
TP-1
TP-2
TP-4
TP-6
TP-3
SCALE
0
60
FEET
90
TEST PIT LOCATION PLAN
ENGINEERING ASSOCIATES, INC. PENN COMMONS RESIDENTIAL DEVELOPMENT
MAP SOURCE:
Sheet No. S2-Site Plan of the Preliminary Land
Development Plan for Penn Commons, East Buffalo Township, Union County, PA by Stahl
Sheaffer Engineering, LLC, State College, PA
dated July 1, 2015.
HCEA Map Created: 10/07/2015.
2929 Stewart Drive Suite 302 State College, PA 16801 Local 814‐231‐0552 Fax 814‐231‐0695 APPENDIX E
TEST PIT LOGS
Test Pit Logs
Project:
East Buffalo Twp., Union Co., PA
Location:
Client:
Date Performed:
28-Aug-15
File Number:
Sheet:
T15107
1 of 3
Test Pit TP-1
Location:
Western Building
Depth
(inches)
Soil Description
Remarks
0-2
Vegetation, Topsoil
Dry.
2 - 19
Medium Brown Clay with Shale [FILL]
Damp and Compact.
19 - 29
Pre-Fill Topsoil Layer
Damp and Dense.
Little or no organics remaining.
Medium Brown Sandy Lean Clay
Damp and Hard.
Moisture Content: 16.7%
29 - 106+
Test Pit TP-2
Location:
West Side, Middle Building
Depth
(inches)
Soil Description
Remarks
0 - 25
Vegetation, Topsoil
Dry.
25 - 78
Sand and Gravel [FILL], with bottles, metals
and burnt remants
Dry and Compact.
Light Brown Lean Clay
Moist.
78 - 109+
Test Pit Logs (con't)
Test Pit TP-3
Location:
South Building
Depth
(inches)
Soil Description
Remarks
0-2
Vegetation, Topsoil
Dry.
2-8
Medium Brown Clay with Shale [FILL]
Damp and Compact.
Stone foundation encountered along
south side of excavation.
Medium Brown Sandy
Lean Clay
Moist.
8 - 96+
Test Pit TP-4
Location:
East Side, Middle Building
Depth
(inches)
Soil Description
Remarks
0-3
Vegetation, Topsoil
Dry.
3 - 32
Black Ash and Cinder [FILL]
Damp and Loosely Compacted.
Light Brown Clay with Mottling
Damp and Hard.
32 - 99+
Test Pit TP-5
Location:
Depth
(inches)
North, Middle Building
Soil Description
Remarks
0-3
Limestone Gravel
Dry.
3 - 13
Black Ash and Cinder [FILL]
Damp and Loosely Compacted.
Light Brown Clay with Mottling
Damp and Hard.
13 - 109+
Page 2 of 3
Test Pit Logs (con't)
Test Pit TP-6
Location:
Southeast Building
Depth
(inches)
Soil Description
Remarks
0-5
Concrete Slab
5-8
Sand [FILL]
Damp and poorly compacted.
8 - 24
Sand, Cinders and Gravel [FILL]
Wet and poorly compacted.
24 - 43
Moist and Stiff.
43 - 96+
Medium Brown Sandy
Lean Clay
Moist and Very Stiff.
Test Pit TP-7
Location:
East Side, Middle Building
Depth
(inches)
Soil Description
0-5
Concrete Slab
5 - 36
Sand, cinders, brick
and concrete remnants [FILL]
36+
Remarks
Wet and poorly compacted.
Standing water
Concrete Slab
Test Pit TP-8
Location:
Depth
(inches)
0 - 18
Northeast Building
Soil Description
Remarks
Limestone Gravel [FILL]
Damp. Test pit was terminated due to
unmarked utilities and possible gas and
fiber optic presence.
Page 3 of 3
APPENDIX F
REPRESENTATIVE PHOTOGRAPHS
Plate 1 (TP-1 Excavation)
Plate 2 (TP-2 Excavation)
Plate 3 (73Burn Debris)
Plate 4 (North Side of Site)
Plate 5 (TP-4 Coal Refuse)
Plate 6 (Mottled Clay)
Plate 7 (Residual Soil)
Plate 8 (TP-7 Standing Water)
Plate 9 (Abandoned Utilities)
Plate 10 (Backfilled Test Pits)
APPENDIX G
LABORATORY TESTING DATA
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
% Gravel
Coarse
Fine
% +3"
0.0
0.0
0.3
Coarse
0.8
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
100.0
99.7
98.9
98.6
97.2
94.3
91.4
88.5
85.8
82.1
71.0
63.6
57.4
44.6
33.9
0.01
GRAIN SIZE - mm.
SIEVE
3/8
#4
#10
#16
#30
#50
#100
#200
0.0229 mm.
0.0149 mm.
0.0093 mm.
0.0069 mm.
0.0051 mm.
0.0027 mm.
0.0012 mm.
0.1
% Sand
Medium
Fine
3.1
Silt
7.3
0.001
% Fines
Clay
31.4
57.1
Soil Description
Atterberg Limits
LL= 40
PL= 21
D90= 0.1100
D50= 0.0036
D10=
USCS=
CL
Coefficients
D85= 0.0195
D30=
C u=
Classification
AASHTO=
PI= 19
D60= 0.0058
D15=
Cc=
A-6(17)
Remarks
* (no specification provided)
Location: Composite of Test Pit 4 (32"-99+") and Test Pit 6 (24"-43")
Sample Number: L15150
Depth: n/a
HILLIS-CARNES ENGINEERING ASSOCIATES
STATE COLLEGE, PA
Tested By: Robert Scandle
Date:
Client: Union County Housing Associate
Project: Penn Commons Housing
Project No:
T15107
Figure
9/3/2015
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
% Gravel
Coarse
Fine
% +3"
0.0
1.9
2.2
Coarse
3.5
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
100.0
99.2
98.1
97.1
95.9
92.4
90.9
87.5
80.3
67.8
58.3
50.9
45.9
38.9
32.7
28.6
22.0
17.1
0.01
GRAIN SIZE - mm.
SIEVE
1.5
1
3/4
3/8
#4
#10
#16
#30
#50
#100
#200
0.0270 mm.
0.0177 mm.
0.0107 mm.
0.0078 mm.
0.0057 mm.
0.0029 mm.
0.0013 mm.
0.1
% Sand
Medium
Fine
7.8
Silt
26.3
0.001
% Fines
Clay
31.0
27.3
Soil Description
Medium Brown Sandy Lean Clay
Atterberg Limits
LL= 24
PL= 16
D90= 0.9429
D50= 0.0249
D10=
USCS=
CL
Coefficients
D85= 0.4435
D30= 0.0065
C u=
Classification
AASHTO=
PI= 8
D60= 0.0883
D15=
Cc=
A-4(2)
Remarks
* (no specification provided)
Location: Composite of Test Pit1 (29"-106+) and Test Pit 5 (19-109+)
Sample Number: L15151
Depth: n/a
HILLIS-CARNES ENGINEERING ASSOCIATES
STATE COLLEGE, PA
Tested By: Robert Scandle
Date:
Client: Union County Housing Associate
Project: Penn Commons Housing
Project No:
T15107
Figure
9/3/2015

HCEA Geotechnical Report

Transcription

Similar documents

Angiosperm Latin Name: Cyperus involucratus Common Name

Angiosperm Latin Name: Clivia miniata Common Name: Kaffir Lily

Geotechnical Report - Presscane (Factory Site)

The Penn Township Campus Landscaping Beautification Project

Garage Access Victory Lane access

experience fuzzy`s pit box lounge

Construction Techniques for VENTILATED

Technical Sheet - Microbes Biosciences

Controlled sinking of a caisson in a weak rock The Peruća dam in

Katy`s Korner Current Project