HomeMy WebLinkAboutBID - 8035 ARTHUR DITCH BRIDGE REPLACEMENT - CANYON STREET (2)ADDENDUM NO. 2
SPECIFICATIONS AND CONTRACT DOCUMENTS
Description of BID 8035: Arthur Ditch Bridge Replacement Canyon Avenue
OPENING DATE: 3:00 PM (Our Clock) December 10, 2014
To all prospective bidders under the specifications and contract documents described
above, the following changes/additions are hereby made and detailed in the following
sections of this addendum:
THE BID OPENING HAS BEEN MOVED TO DECEMBER 10, 2014 AT 3:OOPM,
OUR CLOCK.
No further questions will be answered.
Exhibit 1 – Questions and Answers.
Exhibit 2 – Revised Bid Schedule - The bid sheet has been revised / attached
that includes a $3500.00 F/A line item for landscape related repairs and
improvements.
Exhibit 3 - Included is a copy of the geotechnical report for this project which
includes future repair locations that were sampled at the same time.
Please contact John Stephen, CPPO, LEED AP, Senior Buyer at (970) 221-6777 with
any questions regarding this addendum.
RECEIPT OF THIS ADDENDUM MUST BE ACKNOWLEDGED BY A WRITTEN
STATEMENT ENCLOSED WITH THE BID/QUOTE STATING THAT THIS
ADDENDUM HAS BEEN RECEIVED.
Financial Services
Purchasing Division
215 N. Mason St. 2nd Floor
PO Box 580
Fort Collins, CO 80522
970.221.6775
970.221.6707
fcgov.com/purchasing
Exhibit 1 - Questions and Answers
1. Is the existing box culvert precast or cast in place?
a. The existing box at the downstream tie in point on Mulberry is precast,
installed about 2004. The box being removed and replaced is cast in
place.
2. Are the dimensions of the existing box culvert as shown on the upstream tie in
consistent for the entire box to be removed (12’ X 3.5’)?
a. Yes, however, these are the approximate inside dimensions. The wall
thicknesses have varied along the alignment as discovered over time.
Historically the existing box wall thickness has been 9”-12”. Without
absolute confirmation of what this location entails, we could not specify
exact dimensions of the existing, only provide historical reference of what
has been found in other locations.
3. Does the precast box require epoxy coated reinforcing steel?
a. No, final precast box design will be reviewed via shop drawing; however,
the reinforcing steel for the precast section will NOT require epoxy
coating.
4. What is the intent of the milling?
a. The roadway profile changes are considerable at this location. Staff has
analyzed station by station cross sections of existing vs. proposed. Some
areas, as shown on page 6 require the full-depth section of existing HMA
to be removed, while others areas will receive a milling of depths from 0-7”
inches. The roadway will then need a series of leveling courses and full
section build up to achieve a consistent base for the final 2” lift of HMA.
1 Clearing and Grubbing LS 1 $ - $ -
2 Removal of Portions of Structures (RCB) LF 312 $ - $ -
3 Removal of Inlet EACH 2 $ - $ -
4 Removal of Pipe LF 21 $ - $ -
5 Removal of Curb and Gutter LF 637 $ - $ -
6 Removal of Concrete (4"-8") SY 237 $ - $ -
7 Removal of Asphalt Mat (6"-9") SY 1068 $ - $ -
8 Removal of Asphalt Mat (Planing) (less than 3") SY 506 $ - $ -
9 Removal of Asphalt Mat (Planing) (3"-7.5") SY 600 $ - $ -
10 Removal of Wall LF 92 $ - $ -
11 Removal of Bollard EACH 2 $ - $ -
12 Removal of Posts (Including Attached Chain) EACH 12 $ - $ -
13 Potholing HOUR 16 $ - $ -
14 Embankment CY 14 $ - $ -
15 Muck Excavation CY 10 $ - $ -
16 Structure Excavation CY 841 $ - $ -
17 Structural Backfill (Class 1) CY 336 $ - $ -
18 Filter Material (Class A) CY 148 $ - $ -
19 Topsoil CY 20 $ - $ -
20 Silt Fence LF 193 $ - $ -
21 Erosion Control Supervisor HR 40 $ - $ -
22 Aggregate Bags LF 86 $ - $ -
23 Stabilized Construction Entrance EACH 1 $ - $ -
24 Concrete Washout Structure EACH 1 $ - $ -
25 Storm Drain Inlet Protection (Type II) EACH 7 $ - $ -
26 Remove & Stockpile Modular Wall LF 34 $ - $ -
27 Adjust Manhole EACH 2 $ - $ -
28 Dewatering LS 1 $ - $ -
29 Sod SF 1560 $ - $ -
30 Landscape Boarder (Timber Treated) (8' long) EACH 8 $ - $ -
31 Aggregate Base Course (Class 6) TON 103 $ - $ -
32 Aggregate Base Course (Special) (3"-4" Cobble) CY 8 $ - $ -
33 Hot Mix Asphalt (Grading S) (75) (PG 64-22) TON 216 $ - $ -
34 Hot Mix Asphalt (Grading SX) (75) (PG 64-22) TON 253 $ - $ -
35 Hot Mix Asphalt (Temporary) TON 29 $ - $ -
36 Waterproofing Membrane SY 195 $ - $ -
37 Concrete Class D (RCB) CY 44 $ - $ -
38 Concrete Wall (Mulberry St) LF 48 $ - $ -
39 Reinforcing Steel (Epoxy) LB 12837 $ - $ -
40 15 Inch Reinforced Concrete Pipe (CIP) (CLASS III) LF 119 $ - $ -
41 9'x2.5' Concrete Box Culvert (4-sided) (Precast) LF 582 $ - $ -
42 Single Curb Inlet EACH 2 $ - $ -
43 Manhole Ring & Cover (30-Inch) EACH 2 $ - $ -
44 Manhole Ring & Cover (36-Inch) EACH 1 $ - $ -
45 Fence (Plastic) LF 475 $ - $ -
46 Fence (Temporary) LF 668 $ - $ -
47 Concrete Driveways (6-Inch) SY 38 $ - $ -
48 Concrete Sidewalk (4-Inch) SY 162 $ - $ -
49 Curb and Gutter (Infall) LF 460 $ - $ -
50 Curb and Gutter (Outfall) LF 151 $ - $ -
51 Temporary Curb (8" Vertical Barrier) (DT-701) LF 87 $ - $ -
52 Sanitary Facility EACH 1 $ - $ -
53 Mobilization LS 1 $ - $ -
54 Concrete Barrier (Temporary)(includes resets) LF 132 $ - $ -
55 Barricade (Type 3 M-A)(Temporary) EACH 8 $ - $ -
56 Construction Traffic Sign (Panel Size A) EACH 9 $ - $ -
57 Construction Traffic Sign (Panel Size B) EACH 4 $ - $ -
58 Traffic Control Management DAY 20 $ - $ -
59 Traffic Control Inspection DAY 45 $ - $ -
60 Flagging HR 80 $ - $ -
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525)
Three Intersections
Fort Collins, Colorado
December 3, 2013
Terracon Project No. 20135038
Prepared for:
J-U-B Engineers, Inc.
Fort Collins, Colorado
Prepared by:
Terracon Consultants, Inc.
Fort Collins, Colorado
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ............................................................................................................ i
1.0 INTRODUCTION .............................................................................................................1
2.0 PROJECT INFORMATION .............................................................................................1
2.1 Project Description ...............................................................................................1
2.2 Site Location and Description...............................................................................2
3.0 SUBSURFACE CONDITIONS ........................................................................................2
3.1 Typical Subsurface Profile ...................................................................................2
3.2 Laboratory Testing ...............................................................................................3
3.3 Groundwater ........................................................................................................3
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ......................................4
4.1 Geotechnical Considerations ...............................................................................4
4.1.1 Existing, Undocumented Fill .....................................................................4
4.1.2 Shallow Groundwater ...............................................................................4
4.1.3 Expansive/Collapsible Soils ......................................................................5
4.2 Earthwork.............................................................................................................5
4.2.1 Site Preparation ........................................................................................5
4.2.2 Demolition ................................................................................................6
4.2.3 Excavation ................................................................................................6
4.2.4 Subgrade Preparation ...............................................................................7
4.2.5 Fill Materials and Placement ......................................................................7
4.2.6 Compaction Requirements ........................................................................8
4.2.7 Grading and Drainage ...............................................................................9
4.2.8 Corrosion Protection .................................................................................9
4.3 Foundations .........................................................................................................9
4.3.1 Box Culvert - Design Recommendations ................................................10
4.3.2 Box Culverts - Bedding Recommendations .............................................11
4.4 Seismic Considerations......................................................................................11
4.5 Lateral Earth Pressures .....................................................................................12
5.0 GENERAL COMMENTS ...............................................................................................13
TABLE OF CONTENTS (continued)
Appendix A – FIELD EXPLORATION
Exhibit A-1 Site Location Map
Exhibits A-2 to A-4 Boring Location Plan
Exhibit A-5 Field Exploration Description
Exhibits A-6 to A-14 Boring Logs
Appendix B – LABORATORY TESTING
Exhibit B-1 Laboratory Testing Description
Exhibit B-2 Atterberg Limits Test Results
Exhibits B-3 to B-4 Grain-size Distribution Test Results
Exhibits B-5 to B-7 Swell-consolidation Test Results
Appendix C – SUPPORTING DOCUMENTS
Exhibit C-1 General Notes
Exhibit C-2 Unified Soil Classification System
Exhibit C-3 Laboratory Test Significance and Purpose
Exhibits C-4 and C-5 Report Terminology
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable i
EXECUTIVE SUMMARY
A geotechnical investigation has been performed for the proposed Arthur Ditch Bridge
Replacements to be constructed near the intersections of West Mulberry Street and Canyon
Avenue, West Oak Street and South Whitcomb Street, and West Olive Street and South Loomis
Avenue in Fort Collins, Colorado. Nine (9) borings, presented as Exhibits A-6 through A-14 and
designated as Boring No. 1-1 through Boring No. 3-3, were performed to depths of approximately
15½ to 20½ feet below existing site grades. This report specifically addresses the
recommendations for the three (3) proposed concrete box culvert replacements. Borings
performed in these areas are for informational purposes and will be utilized by others.
Based on the information obtained from our subsurface exploration, the site can be developed for
the proposed project. However, the following geotechnical considerations were identified and will
need to be considered:
Existing, undocumented fill was encountered in the borings performed on this site to depths
ranging from about 1½ to 5 feet below existing site grades. However, we believe deeper
fills are present at each site corresponding with the construction of the existing box culverts.
At the time this report was prepared, we did not possess any compaction test records for
the existing fill. Recommendations for the existing fill are presented in this report.
Comparatively soft and/or very moist to nearly saturated soils are anticipated at bearing
depths of the proposed box culverts. These materials should be stabilized prior to
construction of the proposed box culverts and placement of fills to achieve desired
grades.
The proposed replacement box culverts can be constructed on a reinforced concrete
slab within a properly bedded excavation underlain by stable, prepared subgrade
consisting of either properly compacted subgrade or engineered fill. If a pre-cast box
culvert is selected, the base of the structure will constitute a reinforced concrete slab; no
foundation will be necessary.
The 2012 International Building Code, Table 1613.5.2 IBC seismic site classification for all
three sites is D.
Close monitoring of the construction operations discussed herein will be critical in
achieving the design subgrade support. We therefore recommend that Terracon be
retained to monitor this portion of the work.
This summary should be used in conjunction with the entire report for design purposes. It
should be recognized that details were not included or fully developed in this section, and the
report must be read in its entirety for a comprehensive understanding of the items contained
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable ii
herein. The section titled GENERAL COMMENTS should be read for an understanding of the
report limitations.
Responsive Ŷ Resourceful Ŷ Reliable 1
GEOTECHNICAL ENGINEERING REPORT
Arthur Ditch Bridge Replacement (RFP 7525)
Three Intersections
Fort Collins, Colorado
Terracon Project No. 20135038
December 3, 2013
1.0 INTRODUCTION
This report presents the results of our geotechnical engineering services performed for the
proposed Arthur Ditch Bridge Replacements to be constructed near the intersections of West
Mulberry Street and Canyon Avenue, West Oak Street and South Whitcomb Street, and West
Olive Street and South Loomis Avenue in Fort Collins, Colorado. The purpose of these services
is to provide information and geotechnical engineering recommendations relative to:
subsurface soil conditions foundation design and construction
groundwater conditions seismic considerations
grading and drainage earthwork
lateral earth pressures
Our geotechnical engineering scope of work for this project included the initial site visit, the
advancement of nine (9) test borings to depths ranging from approximately 15 to 25 feet below
existing site grades, laboratory testing for soil engineering properties and engineering analyses
to provide geotechnical design and construction recommendations.
Logs of the borings along with Boring Location Plans (Exhibits A-2 through A-4) are included in
Appendix A. The results of the laboratory testing performed on soil samples obtained from the
site during the field exploration are included in Appendix B.
2.0 PROJECT INFORMATION
2.1 Project Description
Item Description
Site layout Refer to the Boring Location Plans (Exhibits A-2 through A-4 in
Appendix A)
Proposed construction We understand the three existing box culverts will be replaced with
new concrete box culverts.
Grading We anticipate cuts and fills on the order of 10 feet will be required
to complete the proposed box culvert replacements.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
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2.2 Site Location and Description
Item Description
Location
The three proposed box culvert replacement sites are located near
the intersections of West Mulberry Street and Canyon Avenue,
West Oak Street and South Whitcomb Street, and West Olive
Street and South Loomis Avenue in Fort Collins, Colorado.
Existing improvements
The existing concrete box culverts are located in residential
neighborhoods (West Oak Street and South Whitcomb Street;
West Olive Street and South Loomis Avenue) and the parking lot of
a city pool (Canyon Avenue between West Mulberry Street and
West Magnolia Street).
Current ground cover
The proposed construction areas are covered with asphalt
pavements, concrete curb and gutter, concrete flatwork, and
landscaping.
Existing topography The sites are relatively flat.
3.0 SUBSURFACE CONDITIONS
3.1 Typical Subsurface Profile
Specific conditions encountered at each boring location are indicated on the individual boring
logs included in Appendix A. Stratification boundaries on the boring logs represent the
approximate location of changes in soil types; in-situ, the transition between materials may be
gradual. Based on the results of the borings, subsurface conditions on the project site can be
generalized as follows:
Material Description Approximate Depth to Bottom of
Stratum (feet) Consistency/Density/Hardness
Existing asphalt pavement
About 2 to 91/2 inches except in
Boring No. 3-1.
--
Existing aggregate base
course
About 3 to 4 inches in Boring Nos. 1-
2 and 1-3 only.
--
Existing concrete slab
About 3 inches in Boring No. 2-2
only.
--
Fill materials consisting of lean
clay, sand, silt, and gravel
About 1½ to 5 feet below existing site
grades in Boring Nos. 1-1, 1-2, 2-1,
2-2, 2-3, 3-2, and 3-3 only.
--
Sandy lean clay
About 9 to 20½ feet below existing
site grades.
Medium stiff to very stiff
Well-graded sand with silt and
gravel
To the maximum depth of exploration
of about 20½ feet in all borings
except Boring No. 2-1, 2-2, and 2-3.
Very loose to dense
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 3
3.2 Laboratory Testing
Representative soil samples were selected for swell-consolidation testing and exhibited 0.6 to
1.1 percent compression when wetted. Samples of site soils selected for plasticity testing
exhibited low to medium plasticity with liquid limits ranging from 25 to 43 and plasticity indices
ranging from 5 to 21. Corrosivity testing was not completed at the time we prepared this report.
Once this testing has been completed, we will provide test results under separate cover.
Laboratory test results are presented in Appendix B.
3.3 Groundwater
The boreholes were observed while drilling and after completion for the presence and level of
groundwater. The water levels observed in the boreholes are noted on the attached boring logs,
and are summarized below:
Boring Number Depth to groundwater while
drilling, ft.
Elevation of groundwater while
drilling, ft.
1-1 17 4984.6
1-2 18 4984.6
1-3 17 4984.4
2-1 17 4985.1
2-2 16 4986.4
2-3 16 4986.0
3-1 13 4989.0
3-2 13 4989.4
3-3 13.5 4988.7
These observations represent groundwater conditions at the time of the field exploration, and
may not be indicative of other times or at other locations. Groundwater levels can be expected
to fluctuate with varying seasonal and weather conditions, and other factors.
Groundwater level fluctuations occur due to seasonal variations, amount of rainfall, runoff and
other factors not evident at the time the borings were performed. Therefore, groundwater levels
during construction or at other times in the life of the culverts may be higher or lower than the
levels indicated on the boring logs. The possibility of groundwater level fluctuations should be
considered when developing the design and construction plans for the project.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
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4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION
4.1 Geotechnical Considerations
Based on subsurface conditions encountered in the borings, the site appears suitable for the
proposed construction from a geotechnical point of view provided certain precautions and
design and construction recommendations described in this report are followed. We have
identified geotechnical conditions that could impact design and construction of the proposed
concrete box culverts and other site improvements.
4.1.1 Existing, Undocumented Fill
As previously noted, existing undocumented fills were encountered to depths up to about 5 feet
in the borings drilled at the site. However, we believe deeper fills are present at all three
locations and the fills were placed as part of the construction of the existing channels. We do
not possess any information regarding whether the fill was placed under the observation of a
geotechnical engineer.
Support of concrete box culverts on or above existing fill soils is discussed in this report.
However, even with the recommended construction testing services, there is an inherent risk for
the owner that compressible fill or unsuitable material within or buried by the fill will not be
discovered. This risk of unforeseen conditions cannot be eliminated without completely
removing the existing fill, but can be reduced by performing additional testing and evaluation.
Demolition and removal of the existing box culverts, as well as excavations for the proposed box
culverts, will likely result in complete removal of existing fill below the new structures. However,
we recommend complete removal of existing fill during demolition and recompacting below
repair elements such as pavements, concrete flatwork, curb, and gutter.
While we did not encounter existing fill below a depth of about 5 feet within our test borings, it is
possible that fill may be encountered at greater depths during site excavations. We recommend
that foundation excavations be observed on a full-time basis during construction and the project
team considers budget contingencies for unanticipated fill removal and replacement.
4.1.2 Shallow Groundwater
As previously stated, groundwater was measured at depths ranging from about 13 to 18 feet
below existing site grades. Terracon recommends maintaining a separation of at least 3 feet
between the bottom of proposed concrete box culvert foundations and measured groundwater
levels. It is also possible and likely that groundwater levels below this site may rise. Our
experience in the area suggests a rise in groundwater levels of 3 to 5 feet should be expected
during spring runoff.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 5
4.1.3 Expansive/Collapsible Soils
Laboratory testing indicates the on-site sandy lean clay soils, near the anticipated foundation
depths, exhibited 0.6 to 1.1 percent compression upon wetting at the samples in-situ moisture
content. However, it is our opinion these materials will exhibit a higher expansive potential if the
clays undergo a significant loss of moisture.
This report provides recommendations to help mitigate the effects of soil shrinkage and
expansion. However, even if these procedures are followed, some movement and cracking in
the box culverts and surrounding pavements/concrete flatwork should be anticipated. The
severity of cracking and other damage such as uneven culvert foundations and cracked
pavements/concrete flatwork will probably increase if any modification of the site results in
excessive wetting or drying of the on-site clays. Eliminating the risk of movement and distress
is generally not be feasible, but it may be possible to further reduce the risk of movement if
significantly more expensive measures are used during construction. It is imperative the
recommendations described in section 4.2.7 Grading and Drainage of this report be followed
to reduce movement.
4.2 Earthwork
The following presents recommendations for site preparation, demolition, excavation, subgrade
preparation and placement of engineered fills on the project. All earthwork on the project should
be observed and evaluated by Terracon on a full-time basis. The evaluation of earthwork should
include observation of over-excavation operations, testing of engineered fills, subgrade
preparation, subgrade stabilization, and other geotechnical conditions exposed during the
construction of the project.
4.2.1 Site Preparation
Prior to placing any fill, strip and remove existing vegetation, existing pavements, the
undocumented existing fill, and any other deleterious materials from the proposed construction
areas.
Stripped organic materials should be wasted from the site or used to re-vegetate landscaped
areas after completion of grading operations. Prior to the placement of fills, the site should be
graded to create a relatively level surface to receive fill, and to provide for a relatively uniform
thickness of fill beneath proposed structures.
If fill is placed in areas of the site where existing slopes are steeper than 5:1 (horizontal:vertical),
the area should be benched to reduce the potential for slippage between existing slopes and fills.
Benches should be wide enough to accommodate compaction and earth moving equipment, and
to allow placement of horizontal lifts of fill.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
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4.2.2 Demolition
Demolition of the existing concrete box culverts should include complete removal of all foundation
systems, below-grade structural elements, pavements, and exterior flat work within the proposed
construction areas. This should include removal of any utilities to be abandoned along with any
loose utility trench backfill or loose backfill found adjacent to existing foundations. All materials
derived from the demolition of existing structures and pavements should be removed from the
site.
Consideration could be given to re-using the asphalt and concrete provided the materials are
processed and uniformly blended with the on-site soils. Asphalt and/or concrete materials should
be processed to a maximum size of 2-inches and blended at a ratio of 30 percent
asphalt/concrete to 70 percent of on-site soils.
4.2.3 Excavation
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment. Excavations into the on-site soils may encounter weak
and/or nearly saturated soil conditions with possible caving conditions.
The soils to be excavated can vary significantly across the site as their classifications are based
solely on the materials encountered in widely-spaced exploratory test borings. The contractor
should verify that similar conditions exist throughout the proposed area of excavation. If different
subsurface conditions are encountered at the time of construction, the actual conditions should be
evaluated to determine any excavation modifications necessary to maintain safe conditions.
Although evidence of underground facilities such as septic tanks, vaults, and basements was not
observed during the site reconnaissance, such features could be encountered during construction.
If unexpected fills or underground facilities are encountered, such features should be removed
and the excavation thoroughly cleaned prior to backfill placement and/or construction.
Any over-excavation that extends below the bottom of foundation elevation should extend laterally
beyond all edges of the foundations at least 8 inches per foot of over-excavation depth below the
culvert base elevation. The over-excavation should be backfilled to the culvert base elevation in
accordance with the recommendations presented in this report.
Depending upon depth of excavation and seasonal conditions, surface water infiltration and/or
groundwater may be encountered in excavations on the site. It is anticipated that pumping from
sumps may be utilized to control water within excavations. Well points may be required for
significant groundwater flow, or where excavations penetrate groundwater to a significant depth.
The subgrade soil conditions should be evaluated during the excavation process and the stability
of the soils determined at that time by the contractors’ Competent Person. Slope inclinations
flatter than the OSHA maximum values may have to be used. The individual contractor(s) should
be made responsible for designing and constructing stable, temporary excavations as required to
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 7
maintain stability of both the excavation sides and bottom. All excavations should be sloped or
shored in the interest of safety following local, and federal regulations, including current OSHA
excavation and trench safety standards.
As a safety measure, it is recommended that all vehicles and soil piles be kept a minimum lateral
distance from the crest of the slope equal to the slope height. The exposed slope face should be
protected against the elements
4.2.4 Subgrade Preparation
After the existing fill, existing concrete box culverts, and deleterious materials have been
removed from the construction areas, the top 8 inches of the exposed ground surface should be
scarified, moisture conditioned, and recompacted to at least 95 percent of the maximum dry unit
weight as determined by ASTM D698 before any new fill/bedding or foundation is placed.
If pockets of soft, loose, or otherwise unsuitable materials are encountered at the bottom of the
excavations, the proposed culvert elevations may be reestablished by over-excavating the
unsuitable soils and backfilling with compacted engineered fill.
After the bottom of the excavation has been compacted, engineered fill can be placed to bring
the culvert subgrade to the desired grade. Engineered fill should be placed in accordance with
the recommendations presented in subsequent sections of this report.
The stability of the subgrade may be affected by precipitation, repetitive construction traffic or
other factors. If unstable conditions develop, workability may be improved by scarifying and
drying. Alternatively, over-excavation of wet zones and replacement with granular materials
may be used, or crushed gravel and/or rock can be tracked or “crowded” into the unstable
surface soil until a stable working surface is attained. Use of fly ash or geotextiles could also be
considered as a stabilization technique. Laboratory evaluation is recommended to determine
the effect of chemical stabilization on subgrade soils prior to construction. Lightweight
excavation equipment may also be used to reduce subgrade pumping.
4.2.5 Fill Materials and Placement
The on-site soils or approved granular and low plasticity cohesive imported materials may be used
as fill material. The soil removed from this site that is free of organic or objectionable materials,
as defined by a field technician who is qualified in soil material identification and compaction
procedures, can be re-used as fill for the replacement concrete box culverts. It should be noted
that on-site soils may require reworking to adjust the moisture content to meet the compaction
criteria.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
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Imported soils (if required) should meet the following material property requirements:
Gradation Percent finer by weight (ASTM C136)
4” 100
3” 70-100
No. 4 Sieve 50-100
No. 200 Sieve 10-50
Soil Properties Value
Liquid Limit 30 (max.)
Plastic Limit 15 (max.)
Maximum Expansive Potential (%) Non-expansive1
1. Measured on a sample compacted to approximately 95 percent of the maximum dry unit weight as
determined by ASTM D698 at optimum moisture content. The sample is confined under a 100 psf
surcharge and submerged.
4.2.6 Compaction Requirements
Engineered fill should be placed and compacted in horizontal lifts, using equipment and
procedures that will produce recommended moisture contents and densities throughout the lift.
Item Description
Fill lift thickness
9 inches or less in loose thickness when heavy, self-
propelled compaction equipment is used
4 to 6 inches in loose thickness when hand-guided
equipment (i.e. jumping jack or plate compactor) is used
Minimum compaction requirements
95 percent of the maximum dry unit weight as determined
by ASTM D698
Moisture content cohesive soil (clay) -1 to +3 % of the optimum moisture content
Moisture content cohesionless soil
(sand)
-3 to +2 % of the optimum moisture content
1. We recommend engineered fill be tested for moisture content and compaction during placement.
Should the results of the in-place density tests indicate the specified moisture or compaction limits
have not been met, the area represented by the test should be reworked and retested as required
until the specified moisture and compaction requirements are achieved.
2. Specifically, moisture levels should be maintained low enough to allow for satisfactory compaction
to be achieved without the fill material pumping when proofrolled.
3. Moisture conditioned clay materials should not be allowed to dry out. A loss of moisture within
these materials could result in an increase in the material’s expansive potential. Subsequent
wetting of these materials could result in undesirable movement.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 9
4.2.7 Grading and Drainage
All grades must be adjusted to provide effective drainage away from the proposed replacement
concrete box culverts and existing site improvements during construction and maintained
throughout the life of the proposed project. Infiltration of water into foundation excavations must
be prevented during construction. Water permitted to pond near or adjacent to the perimeter of
the proposed box culverts and replacement pavement/concrete flatwork repairs (either during or
post-construction) can result in significantly higher soil movements than those discussed in this
report. As a result, any estimations of potential movement described in this report cannot be
relied upon if positive drainage is not obtained and maintained, and water is allowed to infiltrate
the fill and/or subgrade.
Backfill against foundations and box culvert walls should be properly compacted and free of all
construction debris to reduce the possibility of moisture infiltration.
4.2.8 Corrosion Protection
Testing for corrosivity potential was not completed at the time this report was prepared. Once
we have completed the testing we will submit a supplemental report with the test results and
recommendations for corrosive potential.
4.3 Foundations
The proposed replacement box culverts can be constructed on a reinforced concrete slab within
a properly bedded excavation underlain by stable, prepared subgrade consisting of either
properly compacted subgrade or engineered fill. Conventional-type spread footing foundations
may also be used to support other related structures. If pre-cast box culverts are selected, the
base of the structure will constitute a reinforced concrete slab; no foundation will be necessary.
Design recommendations for box culvert foundations are presented in the following paragraphs.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 10
4.3.1 Box Culvert - Design Recommendations
Description Value
Maximum allowable bearing pressure 1
On-site sandy lean clay: 2,000 psf
Imported fill: 3,000 psf
Lateral earth pressure coefficients 2
On-site sandy lean clay:
Active, Ka = 0.41
Passive, Kp = 2.46
At-rest, Ko = 0.57
Imported fill:
Active, Ka = 0.27
Passive, Kp = 3.69
At-rest, Ko = 0.42
Sliding coefficient 2
On-site sandy lean clay:
µ = 0.37
Imported fill:
µ =0.56
Moist soil unit weight
On-site sandy lean clay:
ܵ = 120 pcf
Imported fill:
ܵ =130 pcf
Minimum embedment depth below finished
grade 3
30 inches
1. The recommended maximum allowable bearing pressure assumes any unsuitable fill or soft soils,
if encountered, will be over-excavated and replaced with properly compacted engineered fill.
2. The lateral earth pressure coefficients and sliding coefficients are ultimate values and do not
include a factor of safety. The box culvert designer should include the appropriate factors of
safety.
3. For frost protection and to reduce the effects of seasonal moisture variations in the subgrade
soils. The minimum embedment depth is relative to lowest adjacent grade.
For structural design of concrete slabs-on-grade, a modulus of subgrade reaction of 100 pounds
per cubic inch (pci) may be used for foundations supported on the existing cohesive type soils,
and 200 psi if placed on at least 1-foot of granular imported structural fill material.
Terracon should be retained to observe the foundation excavation and subgrade stabilization (if
necessary) prior to construction. If the soil conditions encountered differ significantly from those
presented in this report, supplemental recommendations will be required.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 11
4.3.2 Box Culverts - Bedding Recommendations
To provide for proper support of box culverts, the site must first be prepared. Box culvert
installations should be done by an experienced contractor who understands the importance of
bedding the structure properly. The bedding under the box culverts must be able to support the
full load of the installed box culvert, its contents, and the loading above the box culvert.
The surface and subsurface water should be controlled so dry conditions are available during
excavation and site preparation. Furthermore, during and after installation, dewatering methods
must be used to prevent the migration of bedding materials and to prevent fines from getting
into the groove. Any unsuitable or unstable materials below the plan foundation should be
removed. Rocks within 6 inches of the box bottom should be removed. After the appropriate
excavations are performed and the subgrade is judged stable, the box culverts should be placed
or constructed on compacted granular backfill to the specified line and grades.
Terracon recommends a bedding thickness of at least 6 inches. The bedding should consist of
well-graded crushed stone or crushed gravel meeting the requirements of ASTM C33, gradation
67 (3/4-inch to No. 4) and should be installed and compacted to provide uniform support for the
full length and width of each box culvert section. A 2-inch minimum thickness leveling course of
fine granular base material can be used as required to achieve a level bedding surface. The
final grading for the bedding should be done with a laser or level and grade stakes. For the final
grading, the granular material should be screeded using a screed board as long as the width of
the outside span of the box. If properly done, the final grading will allow an easier installation
while setting the box culvert sections. Improper bedding could prevent the tongue of the box
from being properly started into the groove. It is very important that time be spent to ensure the
box culvert bedding preparation is done correctly.
4.4 Seismic Considerations
Code Used Site Classification
2012 International Building Code (IBC) 1 D 2
1. In general accordance with the 2012 International Building Code, Table 1613.5.2.
2. The 2012 International Building Code (IBC) requires a site soil profile determination extending a
depth of 100 feet for seismic site classification. The current scope requested does not include the
required 100 foot soil profile determination. The borings completed for this project extended to a
maximum depth of about 20½ feet and this seismic site class definition considers that similar soil
conditions exist below the maximum depth of the subsurface exploration. Additional exploration to
deeper depths could be performed to confirm the conditions below the current depth of exploration.
Alternatively, a geophysical exploration could be utilized in order to attempt to justify a more favorable
seismic site class. However, we believe a higher seismic site class for this site is unlikely.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 12
4.5 Lateral Earth Pressures
Reinforced concrete walls with unbalanced backfill levels on opposite sides should be designed
for earth pressures at least equal to those indicated in the following table. Earth pressures will
be influenced by structural design of the walls, conditions of wall restraint, methods of
construction and/or compaction and the strength of the materials being restrained. Two wall
restraint conditions are shown. Active earth pressure is commonly used for design of
free-standing cantilever retaining walls and assumes wall movement. The "at-rest" condition
assumes no wall movement. The recommended design lateral earth pressures do not include a
factor of safety and do not provide for possible hydrostatic pressure on the walls.
EARTH PRESSURE COEFFICIENTS
Earth Pressure
Conditions
Coefficient for Backfill
Type
Equivalent Fluid
Density (pcf)
Surcharge
Pressure,
p1 (psf)
Earth
Pressure,
p2 (psf)
Active (Ka)
Imported fill - 0.27
On-site sandy clay - 0.41
35
49
(0.27)S
(0.41)S
(35)H
(49)H
At-Rest (Ko)
Imported fill - 0.42
On-site sandy clay - 0.57
55
68
(0.42)S
(0.57)S
(55)H
(68)H
Passive (Kp)
Imported fill – 3.69
On-site sandy clay – 2.46
480
295
---
---
---
---
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 13
Applicable conditions to the above include:
For active earth pressure, wall must rotate about base, with top lateral movements of about
0.002 H to 0.004 H, where H is wall height;
For passive earth pressure to develop, wall must move horizontally to mobilize resistance;
Uniform surcharge, where S is surcharge pressure;
In-situ soil backfill weight a maximum of 120 pcf and imported soil backfill weight a
maximum of 130 pcf;
Horizontal backfill, compacted between 95 and 98 percent of maximum dry unit weight as
determined by ASTM D698;
Loading from heavy compaction equipment not included;
No hydrostatic pressures acting on wall;
No dynamic loading;
No safety factor included in soil parameters; and
Ignore passive pressure in frost zone.
To control hydrostatic pressure behind the wall we recommend that a drain be installed at the
foundation wall with a collection pipe leading to a reliable discharge. If this is not possible, then
combined hydrostatic and lateral earth pressures should be calculated for sandy lean clay
backfill using an equivalent fluid weighing 90 and 100 pcf for active and at-rest conditions,
respectively. For granular backfill, an equivalent fluid weighing 85 and 90 pcf should be used
for active and at-rest, respectively. These pressures do not include the influence of surcharge,
equipment or floor loading, which should be added.
5.0 GENERAL COMMENTS
Terracon should be retained to review the final design plans and specifications so comments
can be made regarding interpretation and implementation of our geotechnical recommendations
in the design and specifications. Terracon also should be retained to provide observation and
testing services during grading, excavation, foundation construction and other earth-related
construction phases of the project.
The analysis and recommendations presented in this report are based upon the data obtained
from the borings performed at the indicated locations and from other information discussed in
this report. This report does not reflect variations that may occur between borings, across the
site, or due to the modifying effects of construction or weather. The nature and extent of such
variations may not become evident until during or after construction. If variations appear, we
should be immediately notified so that further evaluation and supplemental recommendations
can be provided.
The scope of services for this project does not include either specifically or by implication any
environmental or biological (e.g., mold, fungi, bacteria) 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.
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable 14
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 described 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 in writing.
APPENDIX A
FIELD EXPLORATION
SITE LOCATION MAP
A-1
20135038
11/5/2013
EDB
BCJ
EDB
EDB
Not to scale
Project Manager:
Drawn by:
Checked by:
Approved by:
Project No.
Scale:
File Name:
Date:
Exhibit
Project Site
Arthur Ditch Bridge Replacement (RFP 7525)
1901Colorado Sharp Point Drive, Suite C Fort Collins, Colorado 80525 Fort Collins,
PH. (970) 484-0359 FAX. (970) 484-0454
BORING LOCATION PLAN
1901 Sharp Point Drive, Suite C Fort Collins, Colorado 80525 A-2
PH. (970) 484-0359 FAX. (970) 484-0454
20125038
11/19/2013
EDB
BCJ
EDB
EDB
1” = 80’
Project Manager:
Drawn by:
Checked by:
Approved by:
Project No.
Scale:
File Name:
Date:
DIAGRAM IS FOR GENERAL LOCATION Exhibit
ONLY, AND IS NOT INTENDED FOR
CONSTRUCTION PURPOSES
0’ 40’ 80’
APPROXIMATE SCALE
Approximate Boring Location
1-1
Arthur Ditch Bridge Replacement (RFP 7525)
Northeast of the Intersection of Canyon Ave. and West Mulberry St.
Fort Collins, Colorado
LEGEND
1-1
1-2
1-3
West Mulberry Street
BORING LOCATION PLAN
1901 Sharp Point Drive, Suite C Fort Collins, Colorado 80525 A-3
PH. (970) 484-0359 FAX. (970) 484-0454
20125038
11/19/2013
EDB
BCJ
EDB
EDB
1” = 80’
Project Manager:
Drawn by:
Checked by:
Approved by:
Project No.
Scale:
File Name:
Date:
DIAGRAM IS FOR GENERAL LOCATION Exhibit
ONLY, AND IS NOT INTENDED FOR
CONSTRUCTION PURPOSES
0’ 40’ 80’
APPROXIMATE SCALE
Approximate Boring Location
2-1
Arthur Ditch Bridge Replacement (RFP 7525)
Intersection of South Whitcomb St. and West Oak St.
Fort Collins, Colorado
LEGEND
2-1
2-2
2-3
South Whitcomb Street
West Oak Street
BORING LOCATION PLAN
1901 Sharp Point Drive, Suite C Fort Collins, Colorado 80525 A-4
PH. (970) 484-0359 FAX. (970) 484-0454
20125038
11/19/2013
EDB
BCJ
EDB
EDB
1” = 80’
Project Manager:
Drawn by:
Checked by:
Approved by:
Project No.
Scale:
File Name:
Date:
DIAGRAM IS FOR GENERAL LOCATION Exhibit
ONLY, AND IS NOT INTENDED FOR
CONSTRUCTION PURPOSES
0’ 40’ 80’
APPROXIMATE SCALE
Approximate Boring Location
3-1
Arthur Ditch Bridge Replacement (RFP 7525)
Intersection of South Loomis Ave. and West Olive St.
Fort Collins, Colorado
LEGEND
3-1
3-2
3-3
South Loomis Avenue
West Olive Street
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable Exhibit A-5
Field Exploration Description
The locations of borings were selected by the project team during an on-site meeting. The
borings were located in the field by measuring from existing site features. The ground surface
elevation was surveyed at each boring by the City of Fort Collins.
The borings were drilled with a CME-45 truck-mounted rotary drill rig with solid-stem augers.
During the drilling operations, lithologic logs of the borings were recorded by the field engineer.
Disturbed samples were obtained at selected intervals utilizing a 2-inch outside diameter split-
spoon sampler and a 3-inch outside diameter ring-barrel sampler. Penetration resistance
values were recorded in a manner similar to the standard penetration test (SPT). This test
consists of driving the sampler into the ground with a 140-pound hammer free-falling through a
distance of 30 inches. The number of blows required to advance the ring-barrel sampler 12
inches (18 inches for standard split-spoon samplers, final 12 inches are recorded) or the interval
indicated, is recorded as a standard penetration resistance value (N-value). The blow count
values are indicated on the boring logs at the respective sample depths. Ring-barrel sample
blow counts are not considered N-values.
A CME automatic SPT hammer was used to advance the samplers in the borings performed on
this site. A greater efficiency is typically achieved with the automatic hammer compared to the
conventional safety hammer operated with a cathead and rope. Published correlations between
the SPT values and soil properties are based on the lower efficiency cathead and rope method.
This higher efficiency affects the standard penetration resistance blow count value by increasing
the penetration per hammer blow over what would be obtained using the cathead and rope
method. The effect of the automatic hammer's efficiency has been considered in the interpretation
and analysis of the subsurface information for this report.
The standard penetration test provides a reasonable indication of the in-place density of sandy
type materials, but only provides an indication of the relative stiffness of cohesive materials
since the blow count in these soils may be affected by the moisture content of the soil. In
addition, considerable care should be exercised in interpreting the N-values in gravelly soils,
particularly where the size of the gravel particle exceeds the inside diameter of the sampler.
Groundwater measurements were obtained in the borings at the time of site exploration. After
completion of drilling, the borings were backfilled with auger cuttings, sand (if needed), and
asphalt patch (if needed). Some settlement of the backfill and/or patch may occur and should
be repaired as soon as possible.
A-3
A-3
A-3
A-4
A-4
A-4
APPENDIX B
LABORATORY TESTING
Geotechnical Engineering Report
Arthur Ditch Bridge Replacement (RFP 7525) Ŷ Fort Collins, Colorado
December 3, 2013 Ŷ Terracon Project No. 20135038
Responsive Ŷ Resourceful Ŷ Reliable Exhibit B-1
Laboratory Testing Description
The soil samples retrieved during the field exploration were returned to the laboratory for
observation by the project geotechnical engineer. At that time, the field descriptions were
reviewed and an applicable laboratory testing program was formulated to determine engineering
properties of the subsurface materials.
Laboratory tests were conducted on selected soil samples. The results of these tests are
presented on the boring logs and in this appendix. The test results were used for the
geotechnical engineering analyses, and the development of foundation and earthwork
recommendations. The laboratory tests were performed in general accordance with applicable
locally accepted standards. Soil samples were classified in general accordance with the Unified
Soil Classification System described in Appendix C.
Water content Plasticity index
Grain-size distribution
Consolidation/swell
Dry density
0
10
20
30
40
50
60
0 20 40 60 80 100
CL or OL CH or OH
ML or OL
MH or OH
PL PI
9.0
9.0
9.0
4.0
9.0
9.0
Boring ID Depth Description
SANDY LEAN CLAY (CL)
SILTY SAND
SANDY LEAN CLAY
SILTY, CLAYEY SAND
SANDY LEAN CLAY
SANDY LEAN CLAY
CL
SM
CL
SC-SM
CL
CL
Fines
P
L
A
S
T
I
C
I
T
Y
I
N
D
E
X
LIQUID LIMIT
"U" Line
"A" Line
35
43
41
25
38
34
17
34
20
20
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
6 16
20 30
40 50
1.5 6 200
810
72.9
44.8
60.9
14.5
55.0
0.9
1.6
2.3
0.0
7.3
14
LL PL PI
%Silt %Clay
1 4
3/4 1/2
60
fine
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
17
34
20
20
18
18
9
21
5
20
D100
Cc Cu
SILT OR CLAY
4
D30 D10 %Gravel %Sand
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
6 16
20 30
40 50
1.5 6 200
810
0.9 62.0
14
LL PL PI
%Silt %Clay
1 4
3/4 1/2
60
fine
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
16 18
D100
Cc Cu
SILT OR CLAY
4
D30 D10 %Gravel %Sand
3-2 SANDY LEAN CLAY(CL) 34
3-2 9.5
9.0
GRAIN SIZE IN MILLIMETERS
PERCENT FINER BY WEIGHT
coarse fine
3/8 3 100
3 2 140
COBBLES
GRAVEL SAND
USCS Classification
37.1
D60
coarse medium
9.0
Boring ID Depth
Boring ID Depth
GRAIN SIZE DISTRIBUTION
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
100 1,000 10,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D4546
NOTES: Sample exhibited 0.6 percent compression upon wetting under an applied pressure of 1,000 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135038
PROJECT: Aurthur Ditch Bridge
Replacement
SITE: Three intersections
Fort Collins, Colorado
CLIENT: J-U-B Engineers, Inc.
Fort Collins, Colorado
EXHIBIT: B-5
Specimen Identification
9.0 ft
Classification , pcf
1-3 81 26
WC, %
SANDY LEAN CLAY (CL)
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS 20135038.GPJ TERRACON2012.GDT 12/3/13
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
100 1,000 10,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D4546
NOTES: Sample exhibited 0.7 percent compression upon wetting under an applied pressure of 1,000 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135038
PROJECT: Aurthur Ditch Bridge
Replacement
SITE: Three intersections
Fort Collins, Colorado
CLIENT: J-U-B Engineers, Inc.
Fort Collins, Colorado
EXHIBIT: B-6
Specimen Identification
9.0 ft
Classification , pcf
2-1 94 24
WC, %
SANDY LEAN CLAY(CL)
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS 20135038.GPJ TERRACON2012.GDT 12/3/13
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
100 1,000 10,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D4546
NOTES: Sample exhibited 1.1 percent compression upon wetting under an applied pressure of 1,000 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135038
PROJECT: Aurthur Ditch Bridge
Replacement
SITE: Three intersections
Fort Collins, Colorado
CLIENT: J-U-B Engineers, Inc.
Fort Collins, Colorado
EXHIBIT: B-7
Specimen Identification
9.0 ft
Classification , pcf
3-2 99 19
WC, %
SANDY LEAN CLAY(CL)
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS 20135038.GPJ TERRACON2012.GDT 12/3/13
APPENDIX C
SUPPORTING DOCUMENTS
Exhibit: C-1
Unconfined Compressive
Strength Qu, (tsf)
0.25 to 0.50
0.50 to 1.00
1.00 to 2.00
2.00 to 4.00
> 4.00
less than 0.25
Non-plastic
Low
Medium
High
DESCRIPTION OF SYMBOLS AND ABBREVIATIONS
Hand Penetrometer
Torvane
Dynamic Cone Penetrometer
Photo-Ionization Detector
Organic Vapor Analyzer
SAMPLING
WATER LEVEL
FIELD TESTS
(HP)
(T)
(DCP)
(PID)
(OVA)
GENERAL NOTES
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 0.075mm
Passing #200 sieve (0.075mm)
Particle Size
< 5
5 - 12
> 12
Percent of
Dry Weight
Descriptive Term(s)
of other constituents
RELATIVE PROPORTIONS OF FINES
0
1 - 10
11 - 30
> 30
Plasticity Index
Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry
weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have
less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and
silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be
added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined
on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.
LOCATION AND ELEVATION NOTES
Percent of
Dry Weight
Major Component
of Sample
Trace
With
UNIFIED SOIL CLASSIFICATION SYSTEM
Exhibit C-2
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.
Exhibit C-3
LABORATORY TEST
SIGNIFICANCE AND PURPOSE
Test Significance Purpose
California Bearing
Ratio
Used to evaluate the potential strength of subgrade soil,
subbase, and base course material, including recycled
materials for use in road and airfield pavements.
Pavement Thickness
Design
Consolidation
Used to develop an estimate of both the rate and amount of
both differential and total settlement of a structure. Foundation Design
Direct Shear
Used to determine the consolidated drained shear strength
of soil or rock.
Bearing Capacity,
Foundation Design,
and Slope Stability
Dry Density
Used to determine the in-place density of natural, inorganic,
fine-grained soils.
Index Property Soil
Behavior
Expansion
Used to measure the expansive potential of fine-grained
soil and to provide a basis for swell potential classification.
Foundation and Slab
Design
Gradation
Used for the quantitative determination of the distribution of
particle sizes in soil. Soil Classification
Liquid & Plastic Limit,
Plasticity Index
Used as an integral part of engineering classification
systems to characterize the fine-grained fraction of soils,
and to specify the fine-grained fraction of construction
materials.
Soil Classification
Permeability
Used to determine the capacity of soil or rock to conduct a
liquid or gas.
Groundwater Flow
Analysis
pH
Used to determine the degree of acidity or alkalinity of a
soil. Corrosion Potential
Resistivity
Used to indicate the relative ability of a soil medium to carry
electrical currents. Corrosion Potential
R-Value
Used to evaluate the potential strength of subgrade soil,
subbase, and base course material, including recycled
materials for use in road and airfield pavements.
Pavement Thickness
Design
Soluble Sulfate
Used to determine the quantitative amount of soluble
sulfates within a soil mass. Corrosion Potential
Exhibit C-4
REPORT TERMINOLOGY
(Based on ASTM D653)
Allowable Soil
Bearing Capacity
The recommended maximum contact stress developed at the interface of the foundation
element and the supporting material.
Alluvium
Soil, the constituents of which have been transported in suspension by flowing water and
subsequently deposited by sedimentation.
Aggregate Base
Course
A layer of specified material placed on a subgrade or subbase usually beneath slabs or
pavements.
Backfill A specified material placed and compacted in a confined area.
Bedrock
A natural aggregate of mineral grains connected by strong and permanent cohesive forces.
Usually requires drilling, wedging, blasting or other methods of extraordinary force for
excavation.
Bench A horizontal surface in a sloped deposit.
Caisson (Drilled
Pier or Shaft)
A concrete foundation element cast in a circular excavation which may have an enlarged
base. Sometimes referred to as a cast-in-place pier or drilled shaft.
Coefficient of
Friction
A constant proportionality factor relating normal stress and the corresponding shear stress
at which sliding starts between the two surfaces.
Colluvium
Soil, the constituents of which have been deposited chiefly by gravity such as at the foot of a
slope or cliff.
Compaction The densification of a soil by means of mechanical manipulation
Concrete Slab-on-
Grade
A concrete surface layer cast directly upon a base, subbase or subgrade, and typically used
as a floor system.
Differential
Movement Unequal settlement or heave between, or within foundation elements of structure.
Earth Pressure The pressure exerted by soil on any boundary such as a foundation wall.
ESAL
Equivalent Single Axle Load, a criteria used to convert traffic to a uniform standard, (18,000
pound axle loads).
Engineered Fill
Specified material placed and compacted to specified density and/or moisture conditions
under observations of a representative of a geotechnical engineer.
Equivalent Fluid
A hypothetical fluid having a unit weight such that it will produce a pressure against a lateral
support presumed to be equivalent to that produced by the actual soil. This simplified
approach is valid only when deformation conditions are such that the pressure increases
linearly with depth and the wall friction is neglected.
Existing Fill (or
Man-Made Fill) Materials deposited throughout the action of man prior to exploration of the site.
Existing Grade The ground surface at the time of field exploration.
Exhibit C-5
REPORT TERMINOLOGY
(Based on ASTM D653)
Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of moisture.
Finished Grade The final grade created as a part of the project.
Footing A portion of the foundation of a structure that transmits loads directly to the soil.
Foundation The lower part of a structure that transmits the loads to the soil or bedrock.
Frost Depth The depth at which the ground becomes frozen during the winter season.
Grade Beam
A foundation element or wall, typically constructed of reinforced concrete, used to span
between other foundation elements such as drilled piers.
Groundwater Subsurface water found in the zone of saturation of soils or within fractures in bedrock.
Heave Upward movement.
Lithologic
The characteristics which describe the composition and texture of soil and rock by
observation.
Native Grade The naturally occurring ground surface.
Native Soil Naturally occurring on-site soil, sometimes referred to as natural soil.
Optimum Moisture
Content
The water content at which a soil can be compacted to a maximum dry unit weight by a given
compactive effort.
Perched Water
Groundwater, usually of limited area maintained above a normal water elevation by the
presence of an intervening relatively impervious continuous stratum.
Scarify To mechanically loosen soil or break down existing soil structure.
Settlement Downward movement.
Skin Friction (Side
Shear)
The frictional resistance developed between soil and an element of the structure such as a
drilled pier.
Soil (Earth)
Sediments or other unconsolidated accumulations of solid particles produced by the physical
and chemical disintegration of rocks, and which may or may not contain organic matter.
Strain The change in length per unit of length in a given direction.
Stress The force per unit area acting within a soil mass.
Strip To remove from present location.
Subbase A layer of specified material in a pavement system between the subgrade and base course.
Subgrade The soil prepared and compacted to support a structure, slab or pavement system.
Unconfined
Compression
To obtain the approximate compressive strength of soils
that possess sufficient cohesion to permit testing in the
unconfined state.
Bearing Capacity
Analysis for
Foundations
Water Content
Used to determine the quantitative amount of water in a soil
mass.
Index Property Soil
Behavior
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 =
10 60
2
30
D x D
(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.
Modifier
RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY
Trace
With
Modifier
DESCRIPTIVE SOIL CLASSIFICATION
Boulders
Cobbles
Gravel
Sand
Silt or Clay
Descriptive Term(s)
of other constituents
< 15
15 - 29
> 30
Term
PLASTICITY DESCRIPTION
Water levels indicated on the soil boring
logs are the levels measured in the
borehole at the times indicated.
Groundwater level variations will occur
over time. In low permeability soils,
accurate determination of groundwater
levels is not possible with short term
water level observations.
Water Level After
a Specified Period of Time
Water Level After a
Specified Period of Time
Water Initially
Encountered
Modified
Dames &
Moore Ring
Sampler
Standard
Penetration
Test
Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy
of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was
conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic
maps of the area.
STRENGTH TERMS
RELATIVE DENSITY OF COARSE-GRAINED SOILS
(More than 50% retained on No. 200 sieve.)
Density determined by Standard Penetration Resistance
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
< 3
3 - 4
5 - 9
10 - 18
19 - 42
Ring Sampler
Blows/Ft.
> 42
0 - 1
2 - 4
4 - 8
8 - 15
15 - 30
> 30
Standard Penetration or
N-Value
Blows/Ft.
Descriptive Term
(Consistency)
Very Soft
Soft
Medium-Stiff
Stiff
Very Stiff
Hard
Ring Sampler
Blows/Ft.
0 - 6
7 - 18
59 - 98
19 - 58
> _99
Standard Penetration or
N-Value
Blows/Ft.
0 - 3
4 - 9
10 - 29
30 - 50
> 50
Descriptive Term
(Density)
Very Loose
Loose
Medium Dense
Dense
Very Dense
ASTM D422
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135038
PROJECT: Aurthur Ditch Bridge Replacement
SITE: Three intersections
Fort Collins, Colorado
CLIENT: J-U-B Engineers, Inc.
Fort Collins, Colorado
EXHIBIT: B-4
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 20135038.GPJ TERRACON2012.GDT 12/3/13
1-1
1-2
2-1
2-3
3-1
SANDY LEAN CLAY (CL)
SILTY SAND(SM)
SANDY LEAN CLAY(CL)
SILTY, CLAYEY SAND(SC-SM)
SANDY LEAN CLAY(CL)
35
43
41
25
38
0.09
0.197
0.129
0.126
9.5
12.5
9.5
4.75
12.5
1-1
1-2
2-1
2-3
3-1
9.0
9.0
9.0
4.0
9.0
GRAIN SIZE IN MILLIMETERS
PERCENT FINER BY WEIGHT
coarse fine
3/8 3 100
3 2 140
COBBLES
GRAVEL SAND
USCS Classification
26.3
53.7
36.8
85.5
37.7
D60
coarse medium
9.0
9.0
9.0
4.0
9.0
Boring ID Depth
Boring ID Depth
GRAIN SIZE DISTRIBUTION
ASTM D422
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135038
PROJECT: Aurthur Ditch Bridge Replacement
SITE: Three intersections
Fort Collins, Colorado
CLIENT: J-U-B Engineers, Inc.
Fort Collins, Colorado
EXHIBIT: B-3
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 20135038.GPJ TERRACON2012.GDT 12/3/13
18
16
18
9
21
5
20
18
73
45
61
15
55
62
LL USCS
1-1
1-2
2-1
2-3
3-1
3-2
ATTERBERG LIMITS RESULTS
ASTM D4318
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135038
PROJECT: Aurthur Ditch Bridge Replacement
SITE: Three intersections
Fort Collins, Colorado
CLIENT: J-U-B Engineers, Inc.
Fort Collins, Colorado
EXHIBIT: B-2
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. ATTERBERG LIMITS 20135038.GPJ TERRACON2012.GDT 12/3/13
CL-ML
61 F/A Landscaping FA 1 $ 3,500.00 $ 3,500.00
$ 3,500.00
IN WORDS:
TOTAL BASE BID
ARTHUR DITCH BRIDGE REPLACEMENT- CANYON AVENUE
BID SCHEDULE
ITEM NO. ITEM DESCRIPTION UNIT QUANTITY UNIT COST COST