Upload
others
View
3
Download
1
Embed Size (px)
Citation preview
MTEC Innovations, Inc. ▪ 216 East Government Street, Pensacola, Florida 32502 (850) 462-9360 ▪ www.mtecinnovations.com
mtec
REPORT OF GEOTECHNICAL EXPLORATION
FTFA 14-3001 - Construct Bin Wall at HERD
Eglin AFB, Florida
MTEC Project Number 2014-101
November 10, 2014
Revised: January 5, 2015
Prepared For:
Peterson Engineering, Inc.
75 South F Street
Pensacola, Florida 32502
216 E. Government Street
Pensacola, Florida 32502
850-462-9360
www.mtecinnovations.com
November 10, 2014
Revised: January 5, 2015
Peterson Engineering, Inc.
75 South F Street
Pensacola, Florida 32502
Attention: Mr. Greg Peterson, P.E.
Subject: Report of Geotechnical Exploration
FTFA 14-3001 – Construct Bin Wall at HERD
Eglin AFB, Florida
MTEC Project No. 2014-101
Mr. Peterson,
MTEC Innovations, Inc. (MTEC) is pleased to provide you with this report detailing the results of
our subsurface exploration for the proposed FTFA 14-3001, Construct Bin Wall at HERD on Eglin
AFB, FL. These services were provided in general accordance with our Proposal Number 2014-
104-G, dated September 5, 2014. This report presents the findings of our subsurface exploration
and provides geotechnical recommendations with respect to our understanding to our
understanding of the proposed development.
We appreciate the opportunity to have worked with you on this project. We hope this report
meets your needs and addresses the geotechnical issues concerning the proposed
construction. If you have any questions, or if we can be of further assistance, please feel free to
call us.
Sincerely,
MTEC Innovations, Inc.
Jeff McCarthy, P.E., LEED AP Josh Lindstrom, P.E.
Principal Engineer Senior Geotechnical Engineer
TABLE OF CONTENTS
1.0 INTRODUCTION ........................................................................................................................ 1
2.0 PROJECT INFORMATION ......................................................................................................... 1
2.1 Project Description ............................................................................................................ 1
2.2 Field Exploration ................................................................................................................. 2
2.3 Laboratory Testing ............................................................................................................. 2
3.0 FINDINGS .................................................................................................................................... 2
3.1 Surface Conditions ............................................................................................................ 2
3.2 Subsurface Conditions ..................................................................................................... 2
4.0 RECOMMENDATIONS .............................................................................................................. 3
4.1 General ................................................................................................................................ 3
4.2 Groundwater Control ....................................................................................................... 3
4.3 Foundation Design ............................................................................................................ 3
4.4 Site Preparation ................................................................................................................. 4
4.5 Construction Related Services ....................................................................................... 5
Appendix
Site Location Map
Boring Location Plan
Boring Logs
Field Procedures
January 5, 2015
FTFA 14-3001 Construct Bin Wall Revetment
MTEC Project Number 2014-101
-1-
1.0 INTRODUCTION
This report provides the results of our geotechnical exploration for the installation of new bin walls
at the existing HERD facility on Eglin Air Force Base, Florida. Our exploration was substantially
performed as outlined in our proposal dated September 5, 2014. As outlined in the proposal, this
report includes:
� Our understanding of the scope of work for the project as it relates to the Geotechnical
exploration.
� A description of the site as well as field and laboratory work performed.
� A description of the soil conditions and the depth to groundwater encountered during
our field exploration.
� A discussion of any potential design and/or construction related issues indicated by the
exploration that could impact the proposed development, such as weak organic laden
soils, a shallow groundwater table, etc.
� An estimate of total and differential settlements of foundation based on available
structural loading data.
� Recommendations for subgrade preparation requirements including control of
groundwater during construction.
� Recommendations for foundation design and construction including foundation type,
allowable bearing capacity, bearing depth, and quality control during construction.
� An assessment of the suitability of on-site soils for re-use as structural fill and backfill.
Additionally, the criteria for suitable fill materials will be provided.
2.0 PROJECT INFORMATION
2.1 Project Description
Based on this information we understand that a new, pre-engineered steel bin wall is planned at
the existing HERD facility. The bins will reportedly be used to replace the existing earthen berms
as a blast barrier. We understand that the proposed steel bins are 10’ wide and will be erected
to a maximum height of 32 feet above current grades. An approximately 800’ long section of
bin wall will is proposed along the north side of the existing asphalt road north of Buildings 1221,
1227, and 1233. A U-shaped section of Bin Walls will be placed to east, south, and west of the
three above mentioned Buildings. Additionally, an approximately 72 foot section will be placed
across the existing pavement to the east Building 1221. We understand that material from the
existing earthen berms will be used to backfill the steel bins.
We understand that the bin wall manufacturer will likely be Conntech and have had several
phone conversations with their local sales representative regarding the bin wall installation. We
understand that the bin wall will likely be embedded 3 feet below final grades. Additionally, we
understand that the bin wall infill material Specification will consist of a clean coarse material
with 10% fines, or less and that bin wall backfill requirements will likely consist of compacting 8-
inch loose lifts to 90% of the materials Standard Proctor density (ASTM 698).
January 5, 2015
FTFA 14-3001 Construct Bin Wall Revetment
MTEC Project Number 2014-101
-2-
Our recommendations are based upon the above information. If any of this information is
incorrect, any changes are anticipated, please inform MTEC Innovations, Inc. so that we may
evaluate our recommendations.
2.2 Field Exploration
Our field exploration was performed on October 20, 2014 and consisted of three (3) standard
penetration test (SPT) borings drilled to a depth of 30 feet below grade. Additionally, a
composite sample was collected from the existing berms for classification and index testing. The
location of the boring is provided on the Boring Location Plan and the Boring Logs are provided
in the Appendix of this report.
2.3 Laboratory Testing
Representative soil samples obtained during our field exploration were examined by a
geotechnical engineer. The samples were visually classified in general accordance with ASTM D
2488 (Unified Soil Classification System). Additionally, one (1) fines content test was performed
on a bulk sample collected from the existing berm material to determine. The fines content was
performed in general accordance with ASTM D1140 (Amount of Material finer than No. 200
Sieve). The results of the fines content test are included below:
Laboratory Test Results
Sample Location Sample Depth % Finer than No. 200 Sieve USCS Soil
Classification
Top of berm at
southeast corner of
Building 1227
3-5 ft. below
grade 4.5 SP
3.0 FINDINGS
3.1 Surface Conditions
The portion of the site that will contain the two sections of bin wall placed north of Buildings 1221,
1227, and 1233 appears to be relatively free of surface impediments. Those two areas are
vegetated primarily with sparse grasses and shrubs. Existing earthen berms and pipe racks are
present along the perimeter of the three Buildings. Small pine trees and shrubs are present along
the south side of Building 1233.
3.2 Subsurface Conditions
Beneath a thin layer of topsoil, the borings generally encountered loose to medium dense sand
(SP) soils to the bottom depth of 30 feet below existing grade. The material encountered in the
berms appeared to be native sandy soils from previous construction activities.
January 5, 2015
FTFA 14-3001 Construct Bin Wall Revetment
MTEC Project Number 2014-101
-3-
4.0 RECOMMENDATIONS
4.1 General
This section of the report provides our recommendations for groundwater control, foundation
design, site preparation, and construction related services. The following recommendations are
made based upon a review of the attached soil test data, our understanding of the proposed
construction, and experience with similar projects and subsurface conditions. If the proposed
grades, dimensions, construction methodology and/or materials change significantly from those
previously discussed, we request the opportunity to review and possibly amend our
recommendations with respect to any changes. The discovery of any subsurface conditions
during construction which deviate from those encountered in the boring should be reported to
us immediately for observation, evaluation and recommendations.
4.2 Groundwater Control
Groundwater was not encountered at the time of our field exploration. We do not anticipate
that groundwater control measures will be necessary for the proposed construction. It should be
noted that the groundwater table will fluctuate seasonally depending upon local rainfall. The
rainy season in Northwest Florida is normally between June and September.
4.3 Foundation Design
Based on the results of our field exploration, we consider the subsurface conditions at the site
adaptable for support of the proposed bin walls. Provided the site preparation and earthwork
construction recommendations outlined in Section 4.4 of this report are performed, the following
parameters may be used for bin wall design.
4.3.1 Bearing Capacity
Based upon our discussions with the bin wall manufacturer, we have assumed that the proposed
bin wall foundation will be designed for the load applied to the subgrade by the weight of the
bin wall plus 32 feet of compacted infill with a Factor of Safety for bearing capacity of 2.0. We
have based our settlement estimates and Site Preparation recommendations upon this
information.
4.3.2 Bearing Material
We recommend that the bottom of the bin walls be seated on a Graded Aggregate Base
(GAB) bearing pad with minimum dimensions of 3-feet wide by 12-inches deep. The GAB
material should be compacted to at least 98 percent of the Modified Proctor maximum dry
density (ASTM D 1557).
4.3.3 Settlement Estimates
Our settlement estimates for the proposed bin wall are based on the use of site
preparation/earthwork construction techniques as recommended in Section 4.4 of this report.
January 5, 2015
FTFA 14-3001 Construct Bin Wall Revetment
MTEC Project Number 2014-101
-4-
Any deviation from these recommendations could result in an increase in the estimated post-
construction settlement.
Using the existing soil conditions, the assumed maximum structural loads and the field data
which we have correlated to geotechnical strength and compressibility characteristics of the
subsurface soils, we estimate that total settlement could be on the order of one to two inches or
less. It is important to note that this settlement estimate does not include settlement of the infill
material placed inside the bin wall. The infill should be placed and compacted per the bin wall
manufacturer’s recommendations.
Because of the general uniformity of the subsurface conditions and the recommended site
preparation and earthwork construction techniques outlined in Section 4.4 we anticipate that
differential settlement should be on the order of 1 inch or less.
4.4 Site Preparation
Due to the high bearing stresses which will be imparted to the subgrade soils, we recommend
that the Contractor engage MTEC to develop and implement a Quality Control program to
ensure that the bin walls are placed upon a suitable subgrade and the intent of the design is
achieved in the field. We recommend that, at a minimum, the following items be included in the
Site Preparation portion of the construction of the proposed structure:
� Prior to construction, the location of any existing underground utility lines within the
construction area should be established. Provisions should then be made to relocate
interfering utilities to appropriate locations.
� The bin wall manufacturer recommends that the bin wall be embedded a minimum of 3
feet below finished grades; we anticipate that excavation depths on the order of 10 feet
will be required to reach the final bearing depths.
� The excavations required to install the bin walls shall be sloped, shored, braced, etc. as
necessary to provide safe access as described in applicable OSHA standards.
� Upon completion of the excavation, the exposed subgrade soils will need to be densified
via a smooth drum vibratory roller making a minimum of eight (8) overlapping passes.
The vibratory roller should capable of imparting a dynamic drum force of not less than
44,000 pounds.
� The subgrade should be closely observed by the Geotechnical Engineer of Record
during rolling operations to detect signs of pumping, yielding, and shoving. Any deficient
areas detected during the rolling should be corrected. Correction of these areas could
include undercutting unsuitable soils and replacing with compacted granular fill.
However, actual remedial measures can best be determined in the field by the
Geotechnical Engineer at the time of construction
January 5, 2015
FTFA 14-3001 Construct Bin Wall Revetment
MTEC Project Number 2014-101
-5-
� The upper 12 inches of the rolled subgrade should be density tested at a minimum
frequency of one test per 50 lineal feet of bin wall. These materials should be
compacted to at least of 98% of the Modified Proctor (ASTM D1557) maximum dry
density.
� Place and compact a maximum 12-inch thick loose layer of graded aggregate base
material and compact to a minimum of 98% of the Modified Proctor maximum dry
density. Test the exposed GAB at a minimum of one test per 50 lineal feet of bin wall.
� Bin wall infill should be placed in accordance with the selected bin wall manufacturer’s
recommendations. Manufacturer’s recommendations available at the time of this report
consist of placing bin fill in thin horizontal loose lifts not exceeding 8 inches in thickness.
Each lift should be compacted to a minimum of 95% of the Standard Proctor (ASTM
D698) maximum dry density.
� We recommend that infill material be placed in horizontal lifts as long as practicable to
avoid differentially loading the underlying materials. Each lift of bin fill be tested at a
frequency of one test per 100 lineal feet, or as required by the bin wall manufacturer.
4.5 Construction Related Services
We recommend that MTEC be retained to perform construction materials testing and
observations on this project. Field tests and observations include verification of foundation
subgrades by performing quality assurance tests on the placement of compacted structural fill
courses and bin wall infill material. We can also provide concrete testing, structural inspections,
and general construction observation services.
The geotechnical engineering design does not end with the development of the construction
documents. The design is an on-going process throughout construction. Because of our
familiarity with the site conditions and the intent of the geotechnical engineering design and
recommendations, we are most qualified to address problems that might arise during
construction in a timely and cost-effective manner.
APPENDIX
mtecINNOVATIONS
3JL
WEH
JL
1
2014-101NOV. 07, 2014
mtecINNOVATIONS
3JL
WEH
JL
2
2014-101NOV. 07, 2014
mtecINNOVATIONS
3JL
WEH
JL
3
2014-101NOV. 07, 2014
FIELD AND LABORATORY PROCEDURES
FIELD PROCEDURES
Soil Test Borings � The soil test borings were performed in general accordance with ASTM D�
1586, "Penetration Test and Split�Barrel Sampling of Soils." A continuous flight auger was used to
drill to the boring termination depth. At regular intervals, the auger was removed and soil samples
were obtained with a standard 1.4�inch I.D., 2.0�inch O.D., split�tube sampler. The sampler was
first seated six inches and then driven an additional foot with blows of a 140�pound hammer
(manual rope�cathead system) falling 30 inches. The number of hammer blows required to drive
the sampler the final foot is designated the "Penetration Resistance." The penetration resistance,
when properly interpreted, is an index to the soil strength and density. The completed boreholes
were backfilled with native soil.
Representative portions of the soil samples, obtained from the sampler, were placed in plastic bags
and transported to our laboratory. The samples were then examined by a geotechnical engineer in
order to confirm the field classifications.
Auger Borings (Hand) � Auger borings were advanced by hand with a soil auger. The soils
encountered were identified, in the field, from cuttings brought to the surface by the augering
process. Representative soil samples were placed in 3mil thick Ziploc bags and transported to our
laboratory where they were examined by an engineer in order to confirm the field classifications.
Field Permeability Test � The borehole permeability test was conducted in order to determine the
in�place permeability rate of the subsurface soils in the area of the planned retention pond. The
results of the test are presented on the attached Field permeability Test Results sheet. To perform
the field permeability test, a 2�inch diameter solid section of PVC pipe was installed in a borehole
augered to the required test depth. Water was added into the pipe and the volume of water required
to maintain a constant head near the top of the pipe was recorded for time intervals until the flow
rate had apparently stabilized. The permeability rate of estimated using the following formula.
q
k = ���������
5.5rh
Where k= coefficient of permeability
q= constant rate of flow into the test hole necessary to maintain a given head
r= inside radius of the casing
h= differential head of water
NOTE: All measurement units (linear dimensions) should be consistent throughout the formula.
LABORATORY TESTING
Water Content � The water content is the ratio, expressed as a percentage, of the weight of water in
a given mass of soil to the weight of the solid particles. This test was conducted in general
accordance with ASTM D�2216.
Fines Content � In this test, the sample is dried and then washed over a No. 200 mesh sieve. The
percentage of soil by weight passing the sieve is the percentage of fines or portion of the sample in
the silt and clay size range. This test was conducted in general accordance with ASTM D�1140.
Grain Size Distribution � The grain size test were performed to determine the particle size and
distribution of the sample tested. The sample was dried, weighed, and washed over a No. 200 mesh
sieve. The dried sample was then passed through a standard set of nested sieves to determine the
grain size distribution of the soil particles coarser than the No. 200 sieve. This test is similar to that
described by ASTM D�422.