EARTH ENGINEERING INCORPORATED Geo technical Engineers & Geologists REPORT OF GEOTECHNICAL INVESTIGATION SCOTT HALL BUILDING ADDITION GLOUCESTER COUNTY COLLEGE 1400 TANYARD ROAD SE WELL GLOUCESTER COUNTY, NEW JESERY Prepared For: Gloucester County College 1400 Tanyard Road Sewell, New Jersey 08080 EEl Project No. 25130.JO January 20, 2012 (Revision #1) Corporate Headquarters Southern Newv Jersey Central Pennsylvania Lehigh Valley 15 W Germantown Pike, Suite 200 403 Commerce Lane 5010 Ritter Road, Suite 116 149 Main Street East Norriton, PA 19401 West Berlin, NJ 08091 Mechanicsburg, PA 17055 Emmaus, PA 18049 (610)277-0880 FAX 277-0878 (856)768-1001 FAX 768-1144 (717)697-5701 FAX 697-5702 (610)967-4540 FAX 967-4488 www.earthengineering.com [email protected]
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EARTHENGINEERINGINCORPORATED
Geo technical Engineers & Geologists
REPORT OFGEOTECHNICAL INVESTIGATION
SCOTT HALL BUILDING ADDITIONGLOUCESTER COUNTY COLLEGE
1400 TANYARD ROADSE WELL
GLOUCESTER COUNTY, NEW JESERY
Prepared For: Gloucester County College1400 Tanyard RoadSewell, New Jersey 08080
EEl Project No. 25130.JO
January 20, 2012 (Revision #1)
Corporate Headquarters Southern Newv Jersey Central Pennsylvania Lehigh Valley15 W Germantown Pike, Suite 200 403 Commerce Lane 5010 Ritter Road, Suite 116 149 Main Street
East Norriton, PA 19401 West Berlin, NJ 08091 Mechanicsburg, PA 17055 Emmaus, PA 18049(610)277-0880 FAX 277-0878 (856)768-1001 FAX 768-1144 (717)697-5701 FAX 697-5702 (610)967-4540 FAX 967-4488
A Unified Soil Classification System (USOS) Group Symbol and ASTM Group Name
have been assigned to the soil based on the laboratory testing. The results of the laboratory
testing conducted on the representative soil sample are presented below in Table 1. A
gradation curve, graphically depicting the results of the particle size analysis, is presented
within the Appendix.
- TABLE I -Standard Classification Test Results
Boring Location TB-i & B-2
Sample Depths 2.5' - 8.0'
Stratum jStratum 11
Particle Size Distribution
Percent Passing Sieve 1.5' 100
3/4' 100
3/6 "100
NQ 4 100
NQ 10 99.8
NQ 40 99.4
NO 100 96.8
NII200 70.7
Atterberg Limits _____________
Liquid Limit Non-Plastic
Plastic Limit Non-Plastic
Plasticity Index Non-Plastic
Natural Moisture Content (percent) 21.3
Unified Soil Classification System (USCS) Group Symbol ML
ASTM Group Name Silt with Sand
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V. SUBSURFACE CONDITIONS
Geology
According to the Bedrock Geological Map of the Central and Southern New Jersey
prepared by the United States Geological Service in 1998, the area of investigation lies within a
geologic structural region known as the Coastal Plain. The Coastal Plain consists generally of
poorly consolidated sediments of Tertiary and Cretaceous age. The geologic formation of the
Coastal Plain sediments within the area of the project site is known as the Hornerstown
Formation (geologic symbol - Tht). This formation is of the lower Paleocene, Danian age and
consists predominately of sand, glauconite, fine to medium-grained, locally clayey, massive,
dark-gray to dusky-green; weathers dusky yellow or red brown, extensively bioturbated, locally
has a small amount of quartz at base. Glauconite grains are typically dark green and have
botryoidal shapes. The Hornerstown weathers readily to iron oxide because of its high
glauconite content. Based on the soil samples retrieved during the investigation, the residual
soils encountered within the test borings are characteristic of the Hornerstown Formation
described above.
Soils
Each of the soil samples recovered from the test boring investigation were examined
and visually classified by EEl, both in the field and in the laboratory. The surface of the site in
the area of the proposed construction was covered by topsoil ranging from approximately 7.0 to
12.0 inches in thickness. It should be noted that the determination of "topsoil" was a cursory
field evaluation not supported by laboratory testing. The topsoil's ability to support plants
and/or vegetation was not determined or implied by EEl. In addition, the depth or thickness of
topsoil is expected to vary across the project site area and may be more or less than those
stated above. It should also be noted that a 4.0 inch layer of asphalt was identified beneath the
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surf icial topsoil in test boring B-1. This asphalt layer appears to represent a previously paved
walkway which once provided access between campus facilities.
Underlying this surficial material, the subsurface soil conditions encountered during the
investigation were generally uniform. Based upon the classifications of the soils, a generalized
subsurface soil profile was developed which consists of one (1) fill layer and three (3) naturally
occurring soil strata. Cross-sections of each test boring displaying the various strata and other
information obtained from the field investigation are included within the Appendix on the Boring
Profiles. The test boring information is also shown on the Boring Logs included within the
Appendix. A general description of the soils encountered is as follows:
FILL
The soil designated as FILL was only encountered in test boring B-3 immediately
beneath the surf icial topsoil and extended downward to a depth of approximately 1 .5 feet below
the existing ground surface. This soil was found to consist primarily of dark brown to orange to
brown fine to medium sand with varying secondary constituent amounts silt and gravel. The
FILL appears to represent soil placed during previous site construction activities.
An SPT (N) value of 10 blows on the sampling barrel per foot of penetration was
recorded during the sampling of this soil. Based on the SPT (N) value, the FILL material exists
in a loose density state. Visual classification of the FILL shows this soil to be marginally
granular and non-plastic.
STRATUM I
The soil designated as Stratum I was encountered in test borings B-i and B-3
immediately below the topsoil/asphalt layer or FILL soils and extended downward to depths
measuring approximately 2.5 (B-i) and 4.0 (B-3) feet below the existing ground surface. This
soil was found to consist primarily of brown to orange fine to coarse sand with varying
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secondary constituent amounts of gravel and silt.
An SPT (N) value of 14 blows on the sampling barrel per foot of penetration was
recorded during the sampling of this soil. Based on the SIPT (N) value, the soils of Stratum I
exist in a medium dense state. Visual classification of Stratum I shows this soil to be generally
granular and non-plastic.
STRATUM 11
The soil designated as Stratum 11 was encountered in each test boring immediately
below the surficial topsoil and/or Stratum I and extended downward to depths ranging from
approximately 14.0 to 20.0 feet below the existing ground surface. This soil was found to
consist primarily of reddish orange to brown to tan fine sand with varying secondary constituent
amounts of silt.
SPT (N) values ranging from 6 to 13 blows on the sampling barrel per foot of
penetration were recorded during the sampling of this soil. Based on these SPT (N) values, the
soils of Stratum 11 exist in a loose to medium dense state. In general, the soils of Stratum 11
were found to be marginally granular. However, the upper zones of Stratum 11 were found to
contain abundant interlayers of gray to greenish gray sandy silt. Laboratory tests conducted on
a representative sample of the upper zones of Stratum 11 show this soil to be primarily fine-
grained (silt), non-plastic, and possess a natural moisture content of 21.3%. The upper zones
of Stratum 11 have been classified under the USOS classification system as Silt with Sand,
USOS group symbol of ML.
STRATUM III
The soil designated as Stratum Ill was encountered in each of the test borings
performed immediately below Stratum 11 and extended downward to the termination depths of
the test borings at approximately 25.0 feet below existing ground surface. This soil was found
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to consist primarily of dark green to orange to brown silt with varying secondary constituent
amounts of fine to medium sand and clay.
SIPT (N) values ranging from 10 to 20 blows on the sampling barrel per foot of
penetration were recorded during the sampling of this soil. Based on these SPT (N) values, the
soils of Stratum Ill were found to range from stiff to very stiff in consistency. Visual
classification of Stratum Ill shows this soil to be generally fine-grained (silt and clay) and range
from slightly-plastic to non-plastic.
Groundwater
The static groundwater level was not encountered in any of the test borings performed
during the field investigation. Mottling of the soils, which maybe an indication of seasonal high
groundwater, was also not encountered during the investigation. It should be noted that these
observations were made at the time of the drilling operation and groundwater table elevations
may vary with daily, seasonal, and climatic variations.
VI. CONCLUSIONS AND RECOMMENDATIONS
The geotechnical investigation has revealed that the proposed construction area is
underlain by the non-plastic, marginally granular soils referenced as FILL which are underlain
by the non-plastic, primarily granular soils of Stratum 1; which are underlain by the non-plastic,
marginally granular soils of Stratum 11; which are ultimately underlain by the slightly plastic to
non-plastic, fine-grained (silt and clay) soils of Stratum Ill.
As previously discussed, a building finished basement floor elevation of approximately
+82.12 feet is currently under consideration and is used for analysis within this report.
Construction at or near the anticipated bottom of foundation elevation (approximately +81.12
feet) will situate the base of the foundation elements on or above the Stratum I and/or Stratum
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11 soils. Based on the geotechnical engineering data collected from the site, it is EEl's opinion
that the soils of Stratum 1, Stratum 11, and/or structural fill placed under engineering control are
capable of supporting foundation loads imposed by the installation of the proposed building
addition using a shallow foundation system.
Additionally, slab elements can be supported on the soils of Stratum 1, Stratum 11, and/or
structural fill placed under engineering control assuming the building pad is thoroughly proof-
rolled and compacted. Proof-rolling and subsequent fill placement to achieve the proposed
building pad subgrade elevation should be field inspected by a qualified representative of the
Geotechnical Engineer of Record.
Support of the soils beneath the existing Scott Hall Building foundations must be
maintained during construction to prevent settlement. Therefore, at no time shall the soils
below the existing footings be left unsupported. In order to avoid imparting additional load on
the existing adjacent building foundations, the base of new foundations should match the base
elevation of adjacent existing footings. Alternately, foundations bearing at different elevations
should be positioned (or stepped) so that the base of the closest points of the adjacent
foundations is located one horizontal to one vertical from the other. If these conditions cannot
be achieved, then shoring or underpinning of the existing foundations will be required.
The actual need and design of a shoring or underpinning system will be based on the
existing foundation bottom elevation and the material type below the existing foundation
elements. It is noted that the design of the shoring or underpinning system necessary to
provide support of the existing foundation elements is beyond the scope of this report.
Foundation construction between the existing Scott Hall Building and the proposed
basement slab level of the addition is expected to situate portions of the new foundation
elements on suspected fill soils placed during initial construction of the Scott Hall Building. Due
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to site access issues, EEl was unable to investigate the subsurface material underlying this
portion of the proposed building addition. However, based on the fact that these fill soils were
utilized for support of the existing Scott Hall Facility, EEl expects that these soils will be suitable
for support of the proposed building addition provided they are absent of organic/deleterious
materials and that site preparation procedures are performed in accordance with this report.
Ultimately, the suitability of the fill soils for support of the building addition foundations should
be evaluated at the time of construction by a qualified representative of the Geotechnical
Engineer of Record.
The recommendation to support the proposed building addition on shallow foundations
is provided under the premise that site preparations as described in this report are followed.
Site preparation procedures are required to prepare the proposed foundation areas for
satisfactory support of the structure and will include removal of any unsuitable or deleterious
material encountered below the surface and proof rolling of the site. Details regarding site
development requirements are presented below.
Site Preparation
Initial site preparation measures should include the complete removal of all asphalt,
concrete walkway, and any deleterious materials including organics, topsoil, trees, and root
mass from within structural areas. Structural areas should be defined as those within the
confines of the proposed structure and areas extending a minimum of 5 feet beyond the
proposed building footprint. Structural areas should also include all paved areas and those
covered by concrete.
Following removal of these materials and immediately prior to the placement of any
structural fill, the proposed construction area should be proof-rolled and compacted. it is
recommended that a steel drum vibratory roller having a minimum static weight of 10 tons be
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utilized for this purpose. Proof-rolling and compaction procedures are necessary to compact
and verify the integrity of the upper zones of the soils. Visual observation revealed portions of
the FILL exhibit elevated moisture contents. The elevated moisture state of these soils may
result in soft/loose zones that appear during the proof-rolling effort. Soft/loose zones of soil
attributed to excessive soil moisture can be aerated and dried in-place. Following adequate
drying time, the soils can be densified in-place. Alternately, any soft/loose zones of soil can be
removed and replaced with structural fill, as outlined in the Backfill and Compaction section of
this report. The proof-rolling effort should be observed and evaluated by a qualified
representative of the Geotechnical Engineer of Record.
Backfill and Compaction
Following the site preparation as discussed above, structural fill required to elevate the
site to the planned subgrade elevations may be placed. Any imported structural or load bearing
soil which is required should meet the following criteria:
- Free of organic matter, ash, cinders, and demolition debris
- Particle size distribution that is well graded
- Plasticity index less than 10
- less than 15 percent by weight rock fragments larger than 3", less than30 percent by weight larger than 3/4" and less than 30 percent by weightsmaller than the No. 200 sieve.
As previously discussed, visual evaluation performed on the FILL material along with
visual evaluation and laboratory testing performed on representative samples of Stratum I and
Stratum 11 show these soils are suitable for use as structural fill during site development. It
should be noted that the FILL and Stratum 11 soils contain large amounts of fine grained
material (silt and fine sand) which will prove difficult to place under engineering control during
adverse weather conditions. Currently, the Stratum 11 soils appear to exist in an excessively
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moist state. These soils will require significant aeration and drying time if they are to be utilized
as structural fill. Aeration and drying of excessively moist soils are best accomplished in warm
dry summer months. No other sources of on-site soils are expected to be available during
development of the site. The recommendation for use of on-site soils as structural fill is based
on analysis of soil samples retrieved from the test borings. Confirmation of soil suitability
should be made during construction by a qualified geotechnical engineer.
Structural fill should be placed in lifts not exceeding ten (10) inches in loose thickness
and compacted with a smooth-drum vibratory roller having a minimum static weight of 10 tons.
The optimum lift thickness and number of repetitive passes with compaction equipment
necessary to achieve the required percentage compaction values should be determined in the
field with test passes of the chosen compaction equipment. All fill should be placed at the
optimum moisture content ± 3% as determined in accordance with ASTM standard D1557 and
compacted to a minimum percentage of the maximum dry density as indicated in Table 11.
- TABLE 11 -COMPACTION CRITERIA________
Fill Area Percent of Maximum Dry Density as___________________________________per ASTM Standard D 1557
Foundation Support Fill 95 __
Foundation Backfill 95
Slab-On-Grade, Parking Areas 95
Non-Structural ____ _______92
Foundation Design Parameters
After site preparation operations have been satisfactorily completed, native soil and/or
structural fill may be utilized for the support of the proposed building addition using shallow
foundation systems. The soil bearing conditions at the site were evaluated based on the
information derived from this investigation. The following conclusions and engineering
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recommendations are provided regarding the proposed foundation elements:
- Shallow foundations consisting of conventional wall foundations may be used tosupport the structure.
- Wall foundations for the structure should not be less then 1 .5 feet in width.
- Foundations may be designed for an allowable soil bearing pressure of 3000pounds per square foot (3000 PSF). The natural soils of Stratum 1, Stratum 11,and/or structural fill placed under engineering control are capable of supportingfoundation loads imposed by the installation of the proposed building additionusing a shallow foundation system.
- Exterior foundations and those in unheated areas should be placed a minimumof three (3) feet below final exterior grade to minimize the potential for frostheave.
- All foundation bottoms should be completely cleaned of loose material or debrisimmediately prior to the placement of concrete.
- The actual bearing conditions of the soil at the foundation subgrade elevationshould be confirmed in the field during excavation, by inspection under thesupervision of a Professional Engineer qualified in Geotechnical Engineering.
Given the above recommendations and design parameters, it is anticipated that total
settlement of the structure will not exceed 1.0 inches with maximum differential settlement of
foundation elements estimated to be less than 0.5 inches based on an allowable soil bearing
pressure of 3000 PSF.
It is emphasized that caution should be exercised in order not to disturb any foundation
subgrade soils. Should the foundation subgrade be disturbed during excavation, the soils
should be compacted in place or removed and replaced with structural fill. It is also
recommended that footing excavation and placement of concrete be performed during fair
weather conditions. Installation of the foundations should be carried out in accordance with
applicable ACl guidelines, under the direction of a licensed professional engineer.
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Excavation
Excavation during site construction will take place in the soils referenced as FILL,
Stratum 1, and/or Stratum 11. Excavation of weathered or competent bedrock is not anticipated.
In general, these soils should provide minimal excavation difficulties using conventional
equipment and techniques.
Sloping, benching, or shoring of all construction excavation should be conducted in
accordance with 29 CER 1926, Subpart P. A competent person as defined by the
aforementioned regulation is required to confirm the stability of all excavations during
construction. The actual excavation wall slopes, benching, or shoring should be field
determined and should be based on the required depth of excavations and on the soil types
encountered.
Dewatering
As stated previously, groundwater was not encountered during the field investigation.
Therefore, removal of groundwater during foundation construction is not anticipated.
VII. GENERAL SOIL PROPERTIES
The lateral earth pressures that may be used for design purposes of retaining walls or
walls constructed below grade are shown in Table I1l. Retaining walls which are restrained from
deflection such as loading dock, basement, or other structure walls, should be designed for the
at rest (KO) condition. Retaining walls which are free to deflect such as landscaped walls should
be designed for the active (Ka) condition. The data for the FILL, Stratum I, Stratum 1I, and
Stratum Ill soils were determined based upon the laboratory testing and visual classification of
the site soil samples compared to generally accepted published values for the various
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properties. It is recommended that a drainage system be installed for walls constructed below
grade. The presence of a drainage system will serve to minimize hydrostatic pressures caused
by water trapped against the walls.
-TABLE III -
Soil Properties For Computation of Lateral Loads
Soil Property FILL Stratum I Stratum 11 Stratum III
Angle of Internal Friction 30." 2.' 30.0" 28,00
Coefficient of Active Earth Pressure - Ka 0.33 0.31 0.33 0.36