HomeMy WebLinkAboutBID - 7585 POUDRE TRAIL AT MULBERRY & LEMAYADDENDUM NO. 1
SPECIFICATIONS AND CONTRACT DOCUMENTS
Description of BID 7585: Poudre Trail at Mulberry & Lemay
OPENING DATE: 3:00 PM (Our Clock) January 6, 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:
Exhibit 1 – Revised Bid Schedule
Exhibit 2 – Questions & Answers
Exhibit 3 – Descriptions of Revisions
Exhibit 4 – Revised Specifications
Exhibit 5 – Revised Drawings
Exhibit 6 – Geotechnical Report
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
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 1 of 55
EXHIBIT 1 – REVISED BID SCHEDULE
(Please note that the Bid Schedule has also been uploaded as a separate Microsoft Excel file.)
BID
NO.
CONTRACT
ITEM NO.
CONTRACT DESCRIPTION UNIT
TRAIL
PLAN
STRUCTURAL
PLAN
TOTAL
UNITS
UNIT PRICE TOTAL
1 201 Clearing and Grubbing LS 1 0 1
$ ‐
2 202 Removal of Tree EA 9 0 9
$ ‐
3 202 Removal of Manhole EA 1 0 1
$ ‐
4 202 Removal of Pipe LF 37 0 37
$ ‐
5 202 Removal of End Section EA 1 0 1
$ ‐
6 202 Removal of Concrete SY 311 0 311
$ ‐
7 202 Removal of Asphalt Mat SY 510 0 510
$ ‐
8 202 Removal of Riprap CY 67 0 67
$ ‐
9 202 Remove and Replace Concrete Bridge Deck SY 0 183 183
$ ‐
10 203 Unclassified Excavation CY 160 0 160
$ ‐
11 203 Borrow (Complete in Place) CY 489 0 489
$ ‐
12 206 Structure Excavation CY 0 449 449
$ ‐
13 206 Structure Backfill (Class I) CY 0 280 280
$ ‐
14 207 Topsoil (Remove, Stockpile, Redistribute) CY 401 0 401
$ ‐
15 208 Erosion Log (12 Inch) LF 1121 0 1121
$ ‐
16 208 Concrete Washout Structure EA 1 0 1
$ ‐
17 208 Vehicle Tracking Pad EA 2 0 2
$ ‐
18 208 Erosion Control Supervisor HR 40 0 40
$ ‐
19 210 Reset Structure (Existing 165' Bridge ‐ at Lemay) EA 0 1 1
$ ‐
20 210 Unload Structure (Existing 165' Bridge ‐ at alt. site) EA 0 1 1
$ ‐
21 210 Unload Structure (Existing Steel Railing ‐ at alt. site) EA 0 1 1
$ ‐
22 211 Dewatering LS 1 0 1
$ ‐
23 212 Seeding (Native) AC 0.6 0 0.6
$ ‐
31 514 Pedestrian Railing (Steel) LF 0 200 200
$ ‐
32 601 Concrete Class D CY 0 198 198
$ ‐
33 602 Reinforcing Steel LB 0 11562 11562
$ ‐
34 602 Reinforcing Steel (Epoxy Coated) LB 0 9853 9853
$ ‐
35 603 24 Inch Reinforce Concrete Pipe LF55055
$ ‐
36 603 24 Inch Reinforce Concrete End Section EA 1 0 1
$ ‐
37 603 12 Inch Plastic Pipe LF26026
$ ‐
38 604 Manhole Slab Base (5 Foot) EA 1 0 1
$ ‐
39 608 Concrete Sidewalk (6 Inch) SY99099
$ ‐
40 608 Concrete Bikeway (5 Inch) SY 1182 0 1182
$ ‐
41 608 Concrete Bikeway (Special) SY 167 0 167
$ ‐
42 625 Construction Surveying LS 1 0 1
$ ‐
43 621 Structure Temporary Access Road LS 1 0 1
$ ‐
44 626 Mobilization LS 1 0 1
$ ‐
45 628 Bridge Girder and Deck Unit ‐ 100' EA 0 1 1
$ ‐
46 630 Traffic Control LS 1 0 1
$ ‐
47 630 Flagging HR 80 0 80
$ ‐
48 630 Traffic Control Inspections DAY 30030
$ ‐
49 630 Traffic Control Management ‐ Working Days DAY 90 0 90
$ ‐
50 700 F/A Minor Contract Revisions FA 1 0 1
$80,000.00 $ 80,000.00
51 700 F/A Erosion Control FA 1 0 1
$10,000.00 $ 10,000.00
52 700 F/A OJT FA 1 0 1 $ ‐
TOTAL
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 3 of 55
EXHIBIT 2 – QUESTIONS & ANSWERS
(1) Page B03 of B15 (span 2) illustrates a low chord distance of 12” below top of
concrete deck?
The low chord distance (dimension) for span 2 should be 12”
(2) Detail A on B11 of B15 shows this distance from top of deck to low chord at 18”?
This is an error. The low chord distance (dimension) for span 2 should be 12”.
This will be corrected on the drawings for construction.
(3) Detail A/B09 on page B10 of B15 shows the back wall height of 3’-0” and 18” from
top of deck to low steel. Could you please identify the depth required from top of
deck to low steel?
Per page B10 of 15, Abutment Notes “1. VERIFY BACKWALL HEIGHT WITH
BRIDGE MANUFACTURER AND COORDINATE WITH MANUFACTURER'S
SHOP DRAWINGS PRIOR TO ABUTMENT CONSTRUCTION.”
(4) Are we to use the 10” x 10” top and bottom chord member sizes per the drawing for
aesthetics? If smaller sizes can be used to save funding, should they be used,
given they meet all design criteria?
Yes, 10”x10” is specified for aesthetic purposes to match span 1 (existing bridge)
(5) The plans illustrate a 6” concrete deck. Is this the desired depth or could a 5” deck
possibly work, again to save funding?
A 5” concrete deck would be acceptable.
(6) Page B03 of B15 also illustrates an overall truss depth of 8’-10”. Is this mandatory?
– if using smaller chord members, this height can be reduced. We can maintain the
overall truss height and possibly use smaller chord members.
Yes, this is mandatory. The members must match the specified 8’10” so span 2
matches span 1 from bridge deck to top of rail.
(7) How involved is the Colorado DOT with the bridge? The DOT is on the drawing title
block of the drawings.
The project received a Federal Grant for partial funding of the construction and is
thus a CDOT Local Agency project. The Owner of the improvements will be the
City of Fort Collins, but the contract documents and construction administration
of the project will be per all applicable Federal requirements for repay funding
compliance. All improvements are constructed outside of CDOT R.O.W.
(8) What is the required top of deck to low steel dimension? On the elevation view it
says 30” but on the section view for Span 2 it shows what appears to be 1’-0”. I am
assuming the portions of the section views are switched around.
The low chord distance (dimension) for span 2 should be 12”. Span 1 is an
existing bridge.
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 4 of 55
(9) Who is to provide the bearing pads for both bridges? Can the existing pads for
span 1 be re-used?
The CONTRACTOR is to provide all materials for both bridges. The existing
bearing pads for span 1 cannot be re-used. New pads must be provided by
CONTRACTOR of this project.
(10) Is a 404 permit required for this project?
The Owner has acquired a Nationwide Permit No. 14 for the project (File No.
NOW-2012-1268-DEN). The CONTRACTOR is responsible for 100%
compliance of all work accomplished in accordance with the terms and conditions
of the nationwide permit.
(11) Where is the pay item for the concrete bridge deck on the new bridge (span 2)
located?
In the summary of structural quantities on sheet 26, item 601 (Class D Concrete)
It is divided into 4 sections, superstructure, abutment 1, pier 2, and abutment 3.
(12) What if the river does not go down before runoff?
The CONTRACTOR is responsible for any and all methods of construction for
completing the Work according to the terms of the Agreement. This includes
dewatering within the construction area. Coffer dams to divert flows may be an
option if allowed by the 404 permit.
(13) Where is the Riprap quantity coming from? It looks like a lot of riprap is missing
from under the Lemay Bridge area. Maybe from the recent flood?
An item and quantity for Type M Riprap has been added to the bid schedule. Per
City of Fort Collins requirements, no riprap with a “pink” color will be acceptable.
The color needs to be approved by the ENGINEER.
(14) Where is the Borrow (CIP) quantity coming from?
The quantity for this item has been increased. The item will come from an offsite
source and comply with CDOT specifications.
(15) Where is the access to the north bank?
An access easement exists through the carwash property on the north side. An
exhibit is attached that describes this easement. Any damage to asphalt,
concrete pavement, curb & gutter must be replaced and restored to satisfaction
of the City inspector.
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 5 of 55
EXHIBIT 3 – DESCRIPTIONS OF REVISIONS
I. Revisions to the Plans/Bid Tab:
A. BID TAB - The bid schedule has been amended as follows:
Item # 9 – 202 Remove and Replace Concrete Bridge Deck (ADDED) –
183 SY
Item #49 – F/A Minor Contract Revisions – Total $80,000
Item #50 – F/A Erosion Control – Total $20,000
B. A new line item has been added to the project under section 202:
Remove and Replace Concrete Bridge Deck – SY. Spec. is attached (1
page)
This line item has been ADDED. It is intended for use on the existing 165’
pedestrian bridge. The bridge 165’ is to be delivered to the Owner by
CDOT with the existing concrete deck in place with only a small portion of
the deck removed over the mechanically spliced area. This item will be
approved for use as determined by the ENGINEER. Project special
specifications are provided.
C. SHEET 6 – Summary of Approximate Quantities has been revised and attached.
(1 page)
D. SHEET 10 – has been revised. “POUDRE RIVER TRAIL, STA 4+00.00 –
5+25.00” detail has been removed. The revised sheet is attached. (1 page)
II. Revisions to the Project Contract Documents:
A. The following has been added to Section 00800 Supplementary Conditions
SC-4.2 – Subsurface and Physical Conditions
o 4.2.1.1.1 The following report(s) of exploration and tests of subsurface
conditions at the site of Work: (29 pages)
GEOTECHNICAL INVESTIGATION,POUDRE TRAIL BRIDGE
CROSSING, LEMAY AVENUE AND MULBERRY STREET, FORT
COLLINS, COLORADO, Project No. FC05838-125, April19, 2012
B. A new project special item has been added to the project under section 202:
Remove and Replace Concrete Bridge Deck – SY
This line item has been ADDED. It is intended for use on the existing 165’
pedestrian bridge. The bridge 165’ is to be delivered to the Owner by
CDOT with the existing concrete deck in place with only a small portion of
the deck removed over the mechanically spliced area. This item will be
approved for use as determined by the ENGINEER. Project special
specifications are provided.
C. The following map exhibits have been added as additional information:
Map for construction staging. (1 page)
Map for Access to City property along north bank of the Poudre River. (1
page)
Shop drawings for the existing 10’x330’ steel pedestrian bridge (15 pages)
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 6 of 55
FEDERAL AID PROJECT NO. STE M455-105
CONSTRUCTION PROJECT CODE NO. 18399
SP-23
REVISION OF SECTION 202
REMOVE AND REPLACE CONCRETE BRIDGE DECK
Section 202 of the Standard Specifications is hereby revised for this project as follows:
Subsection 202.01 shall include the following:
This work includes the removal and replacement of the existing concrete bridge deck on the 165’ bridge. The
limits of removal shall be determined in the field following delivery from the CDOT project and inspection of the
City Representative.
Subsection 202.11 shall include the following:
The removal and replacement of the existing concrete bridge deck will be measured by the square yard of material
replaced.
Payment will be made under:
Pay Item Pay Unit
Remove and Replace Concrete Bridge Deck Square Yard
Work shall include concrete, forms, reinforcement, tooling, finishing equipment, and labor necessary to complete
the work. Work shall also include disposal of existing concrete deck material.
EXHIBIT 4 - REVISED SPECIFICATIONS
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 7 of 55
EXHIBIT 5 - REVISED DRAWINGS
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 8 of 55
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 9 of 55
TCTLITHOMPSON
INCORPORATED
GEOTECHNICAL INVESTIGATION
POUDRE TRAIL BRIDGE CROSSING
LEMAY AVENUE AND MULBERRY STREET
FORT COLLINS, COLORADO
CITY OF FORT COLLINS
Park Planning and Development
215 North Mason Street
Fort Collins, Colorado 80522
Attention: Mr. Jason Stutzman
Project No. FC05838-125
April19, 2012
351 Linden Street 1 Suite 140 1 Fort Collins, Colorado 80524 I Phone: 970-206-9455 I Fax: 970-206-9441
EXHIBIT 6 - GEOTECHNICAL REPORT
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 10 of 55
~ CTLITHOMPSON
I N C 0 a P 0 a A T E D
GEOTECHNICAL INVESTIGATION
POUDRE TRAIL BRIDGE CROSSING
LEMAY AVENUE AND MULBERRY STREET
FORT COLLINS, COLORADO
CITY OF FORT COLLINS
Park Planning and Development
215 North Mason Street
Fort Collins, Colorado 80522
Attention: Mr. Jason Stutzman
Project No. FC05838-125
351 Linden Street I Suite 140 I Fort Collins, Colorado 80524
Telephone: 970-206-9455 Fax: 970-206-9441
April 19, 2012
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 11 of 55
TABLE OF CONTENTS
SCOPE
SUMMARY OF CONCLUSIONS
SITE CONDITIONS
PROPOSED CONSTRUCTION
INVESTIGATION
SUBSURFACE CONDITIONS
Ground Water
Seismicity
SITE DEVELOPMENT
Fill Placement
Excavation
Dewatering
BRIDGE FOUNDATIONS
Drilled Piers Bottomed in Bedrock
Laterally Loaded Piers and Piles
Closely Spaced Pier Reduction Factors
RETAINING WALL FOUNDATIONS
Footings
SCOUR
LATERAL EARTH PRESSURES
WATER-SOLUBLE SULFATES
LIMITATIONS
FIGURE 1 -LOCATIONS OF EXPLORATORY BORINGS
FIGURE 2- SUMMARY LOGS OF EXPLORATORY BORINGS
FIGURE 3- EXAMPLE LATERAL EARTH PRESSURE DISTRIBUTIONS
APPENDIX A- RESULTS OF LABORATORY TESTING
APPENDIX B- SAMPLE SITE GRADING SPECIFICATIONS
1
1
2
2
2
3
3
3
3
3
4
5
6
6
8
8
9
9
10
11
12
13
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 12 of 55
SCOPE
This report presents the results of our Geotechnical Investigation for the proposed
Poudre Trail pedestrian bridge at Lemay Avenue and Mulberry Street in Fort Collins,
Colorado. The purpose of the investigation was to evaluate the subsurface conditions
and provide foundation recommendations and geotechnical design criteria for the
project.
The report was prepared from data developed during field exploration, laboratory
testing, engineering analysis and experience with similar conditions. The report includes
a description of subsurface conditions found in our exploratory borings and discussions
of site development as influenced by geotechnical considerations. Our opinions and
recommendations regarding design criteria and construction details for site
development, foundations, lateral earth loads, and drainage are provided. If the
proposed construction changes, we should be requested to review our
recommendations contained in this report to determine if they apply to the new proposed
construction. Our opinions are summarized in the following paragraphs. Further
descriptions of the subsurface conditions, results of our field and laboratory
investigations and our opinions, conclusions and recommendations are included in the
subsequent sections of this report.
SUMMARY OF CONCLUSIONS
1 . Subsurface conditions encountered in our borings were generally
consistent across the site. Soils encountered consisted of approximately
3 to 7 feet of slightly silty sand over 2 to 9 feet of sandy gravel. Claystone
was encountered in all of our borings at depths ranging from
approximately 6Y2 to 12 feet (EI. 4921.5 to 4923.5) below the existing
ground surface. Groundwater levels were measured at depths of
approximately 6 to 9% feet (EI. 4922 to 4925) below the existing ground
surface. Existing groundwater levels are not expected to significantly
affect the proposed construction, but will likely affect drilled pier
installation.
2. We understand the proposed bridge abutments and center pier will be
constructed with drill pier foundations. We understand the preferred
foundation type for the retaining structures are spread footing
foundations. Foundation discussion and criteria for drilled pier and
footing foundations are provided in this report.
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125 1
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 13 of 55
SITE CONDITIONS
The proposed pedestrian bridge crossing is located southeast of the intersection
of Lemay Avenue and Mulberry Street in Fort Collins, Colorado. The site is located in
the green belt of the Cache Ia Poudre River. Ground cover consists of natural grasses,
weeds and trees. The site slopes gradually toward the river. Water levels observed in
the river were relatively shallow with depths averaging only a couple feet across the
width of the river. The Poudre Trail is currently located on the south side of the river
east of Lemay Avenue.
PROPOSED CONSTRUCTION
Based on plans provided and conversations with our client, we understand the
proposed bridge will span a total length of approximately 250 feet. Two prefabricated
steel pedestrian bridges of approximately 160 and 90 feet will be used to span the
Poudre River at this location. The crossing will have the two abutments to the north and
south and a central pier between to connect the separate bridges. We understand
associated wing walls will be located at each abutment as well as a retaining wall south
of the southern abutment.
INVESTIGATION
Subsurface conditions at the site were investigated by drilling four exploratory
borings. The approximate locations of the borings are shown on Figure 1 . Our field
representative observed drilling, logged the soils and bedrock found in the borings and
obtained samples. Summary logs of the borings, including results of field penetration
resistance tests, are presented on Figure 2.
Samples obtained during drilling were returned to our laboratory and visually
examined by the geotechnical engineer for this project. Laboratory testing included
moisture content, dry density, swell-consolidation, gradation, and water-soluble sulfate
tests. Results of laboratory tests are presented in Appendix A and summarized in Table
A-1.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838·125 2
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 14 of 55
SUBSURFACE CONDITIONS
Subsurface conditions encountered in our borings were generally consistent
across the site. Soils encountered consisted of approximately 3 to 7 feet of slightly silty
sand over 2 to 9 feet of sandy gravel. Claystone was encountered in all of our borings at
depths ranging from approximately 6~ to 12 feet (EI. 4921.5 to 4923.5) below the
existing ground surface. Further description of the subsurface conditions is presented
on our boring logs and in our laboratory testing.
Ground Water
Groundwater levels were measured at depths of approximately 6 to 9~ feet (EI.
4922 to 4925) below the existing ground surface. Groundwater levels will vary
seasonally and with water level in the Cache Ia Poudre River. Existing groundwater
levels are not expected to significantly affect the proposed construction, but will likely
affect drilled pier installation.
Seismicity
This area, like most of central Colorado, is subject to a low degree of seismic risk.
As in most areas of recognized low seismicity, the record of the past earthquake activity
in Colorado is somewhat incomplete.
According to the 2009 International Building Code and the subsurface conditions
encountered in our borings, this site classifies as a Site Class C. Only minor damage to
relatively new, properly designed and built structures would be expected. Wind loads,
not seismic considerations, typically govern dynamic structural design in this area.
SITE DEVELOPMENT
Fill Placement
The existing on-site soils are suitable for re-use as fill material provided debris or
deleterious organic materials are removed.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838·125
If import material is required, we
3
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 15 of 55
recommend importing granular soils. Import fill should contain no particle larger than 3
inches, 10 to 40 percent silt and clay-sized particles (percent passing No. 200 sieve) and
exhibit a liquid limit less than 30 and a plasticity index less than 15.
Areas to receive fill should be scarified, moisture-conditioned and compacted to
at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T
99). The properties of the fill will affect the performance of foundations, slabs-on-grade,
and pavements. Sand soils used as fill should be moistened to within 2 percent of
optimum moisture content. The fill should be moisture-conditioned, placed in thin, loose
lifts (8 inches or less) and compacted as described above. We should be retained to
observe placement and compaction of fill during construction. Fill placement and
compaction activities should not be conducted when the fill material or subgrade is
frozen.
Site grading in areas of landscaping where no future improvements are planned
can be placed at a dry density of at least 90 percent of standard Proctor maximum dry
density (ASTM D 698, AASHTO T 99). Example site grading specifications are
presented in Appendix B.
Excavation
The materials found in our borings can be excavated using conventional heavy-
duty excavation equipment. Excavations should be sloped or shored to meet local,
State and Federal safety regulations. Based on our investigation and OSHA standards,
we believe the sand soils classify as Type C soils. Type C soils require a maximum
slope inclination of 1.5:1 in dry conditions. Excavation slopes specified by OSHA are
dependent upon types of soil and groundwater conditions encountered. The contractor's
"competent person" should identify the soils and/or rock encountered in the excavation
and refer to OSHA standards to determine appropriate slopes. Stockpiles of soils, rock,
equipment, or other items should not be placed within a horizontal distance equal to one-
half the excavation depth, from the edge of excavation. Excavations deeper than 20 feet
should be braced or a professional engineer should design the slopes.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125 4
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 16 of 55
The width of the top of an excavation may be limited in some areas. Bracing or
"trench box" construction may be necessary. Bracing systems include sheet piling,
braced sheeting and others. Lateral loads on bracing depend on the depth of
excavation, slope of excavation above the bracing, surface loads, hydrostatic pressures,
and allowable movement. For trench boxes and bracing allowed to move enough to
mobilize the strength of the soils, with associated cracking of the ground surface, the
"active" earth pressure conditions are appropriate for design. If movement is not
tolerable, the "at rest" earth pressures are appropriate. We suggest an equivalent fluid
pressure of 40 pcf for the "active" earth pressure condition and 55 pcf for the "at rest"
earth pressure condition, assuming level backfill. These pressures do not include
allowances for surcharge loading or for hydrostatic conditions. We are available to
assist further with bracing design if desired.
Dewatering
Ground water was encountered in our borings at depths between 6 feet and 9%
feet. Groundwater levels and water levels in the Cache Ia Poudre River may rise or fall
with seasons. Depending on the time of construction and water levels in the river,
groundwater levels could be higher than measured in our borings.
Excavations within approximately two feet of ground water should consider
temporary dewatering prior to and/or during construction. Dewatering can be
accomplished using a series of trenches, sumps, and granular materials from which
water can be pumped, or by a system of well points. The sumps should be several feet
below the bottom of the excavations to pump water down through the soil rather than up
through the bottom of the excavation. Pumping water up through the base of the
excavation will likely result in destabilization of the base of the excavation. The ground
surface surrounding the excavation should be sloped to direct runoff away from the
excavation.
For excavations planned several feet below groundwater levels, a series of well
points may be needed to dewater the excavation effectively. The contractor should
anticipate extensive dewatering and possibly caving soils in excavations below the water
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL I T PROJECT NO. FC05838·125 5
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 17 of 55
table. The design of a well point system will likely require further exploratory drilling to
deeper depths and permeability tests both of which were not in the scope of this study.
We are available to help with this design if requested.
BRIDGE FOUNDATIONS
We understand that drilled pier foundations are planned for the proposed bridge
abutments and center pier. We believe this is an appropriate foundation system for the
subsurface conditions encountered and proposed construction. Design and construction
criteria for drilled piers are provided below. These criteria were developed from analysis
of field and laboratory data and our experience. We estimate potential foundation
movements of up to one inch could occur for foundations designed and constructed to
the criteria below. The recommended foundation can be used provided all design and
construction criteria presented in this report are followed.
Drilled Piers Bottomed in Bedrock
1. Piers should bottom in competent bedrock and have a minimum length of
at least 25 feet.
2. Piers should be designed for an ultimate end bearing capacity, qp. of
105,000 psf and an ultimate skin friction capacity, q5 , of 10,500 psf
required for the LRFD method. These values correspond to a maximum
allowable end pressure of 35,000 psf and an allowable skin friction of
3,500 psf for the portion of the pier in bedrock using the ASD method.
Skin friction should be neglected for the portion of the pier in overburden
soils or within 3 feet of grade beams. The ultimate capacities using LRFD
method assume a weighted load factor of 1.5 and a resistance factor of
0.5 for end bearing and side shear values.
3. Piers should be designed with a length/diameter ratio less than 30.
4. Pier drilling should produce shafts with relatively undisturbed bedrock
exposed. Excessive remolding and caking of bedrock cuttings on pier
walls should be removed.
5. Piers should be reinforced their full length with sufficient reinforcing steel
to resist a tensile load in the event of swelling. For design purposes, the
tensile load (in kips) can be estimated as 5.5 times the pier diameter (in
inches). A minimum steel-to-pier cross-sectional area ratio of 0.005 using
Grade 60 steel is recommended. Reinforcement should extend into
abutments or grade beams.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125 6
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 18 of 55
6. Abutments should be well reinforced. The structural engineer should
design the reinforcement.
7. Piers should have a center-to-center spacing of at least three pier
diameters when designing for vertical loading conditions, or they should
be designed as a group. Piers aligned in the direction of lateral forces
should have a center-to-center spacing of at least six pier diameters.
Reductions for closely spaced piers are discussed in the following
section.
8. A 6-inch continuous void should be constructed beneath abutments or
grade beams between piers to concentrate structural deadload on the
piers. The presence of this void should be taken into consideration when
designing scour protection.
9. Concrete should have a slump of 6 inches (+/- 1 inch). Concrete should
be ready and placed in the pier holes immediately after the holes are
drilled, cleaned, observed and the reinforcing steel is set.
10. Ground water was encountered in our borings. Where ground water is
encountered during drilling, pump or tremie pipe placement of concrete
may be required for proper cleaning, dewatering, and placement of
concrete during pier installation. Concrete should not be placed by free
fall in pier holes containing more than 3 inches of water.
11. We anticipate casing may be required for piers. Concrete should be
ready and placed in the pier holes immediately after the holes are drilled,
cleaned and observed and reinforcing steel set. At least 5 feet of
concrete should be maintained above the groundwater level prior to (and
during) casing removal.
12. Some pier-drilling contractors use casing with an 0.0. equal to the
specified pier diameter. This results in a pier diameter less than
specified, typically on the order of 2 inches smaller in diameter. The
design and specification of piers should consider the alternatives. If full
size casing is desired (1.0. of casing equal to specified pier diameter) it
should be clearly specified. If design considers the potential reduction in
diameter, then the specification should include a tolerance for a smaller
diameter for cased piers.
13. Some movement of the drilled pier foundation is anticipated to mobilize
the skin friction. We estimate this movement to be on the order of 1/4 to
1/2 inch. Differential movement may be equal to the total movement.
14. The installation of the drilled pier foundations should be observed by a
representative of our firm to confirm the piers are bottomed in the proper
bearing strata and to observe the contractor's installation procedures.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125 7
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 19 of 55
Laterally Loaded Piers and Piles
Several methods are available to analyze laterally loaded piers. With a pier or
pile length to diameter ratio of 7 or greater, we believe the method of analysis developed
by Matlock and Reese is most appropriate. The method is an iterative procedure using
applied loading and soil profile to develop deflection and moment versus depth curves.
The computer programs LPILE and COM624 were developed to perform this procedure.
Suggested criteria for LPILE analysis are presented in the following table.
TABLE A
SOIL INPUT DATA FOR LPILE or COM624
I I Granular Soils I Bedrock I
Material Type
Sand Below Water
Table Clay
Effective Unit Weight (pci) 0.04 0.07
Cohesive Strength, c (psi) - 40
Friction Angle (0
) 35 -
Soil Strain, E50 (in/in) - 0.003
p-y Modulus k5 (pci) 60 2,000
The E50 represents the strain corresponding to 50 percent of the maximum
principle stress difference.
Closely Spaced Pier Reduction Factors
For axial loading, a minimum spacing of three diameters is recommended. At
one diameter (piers touching) the skin friction reduction factor for both piers would be
0.5. End bearing values would not be reduced provided the bases of the piers are at
similar elevations. Linear interpolation can be used between one and three diameters.
Piers in-line with the direction of the lateral load should have a minimum spacing
of six diameters (center-to-center) based upon the larger pier. If a closer spacing is
required, the modulus of subgrade reaction for initial and trailing piers should be
reduced. At a spacing of three diameters, the effective modulus of subgrade reaction of
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL I T PROJECT NO. FC05B3B·125 8
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 20 of 55
the first pier can be estimated by multiplying the given modulus by 0.6. For trailing piers
in a line at three-diameter spacing, the factor is 0.4. Linear interpolation can be used for
spacing between three and six diameters.
Reductions to the modulus of subgrade reaction can be accomplished in LPILE
by inputting the appropriate modification factors for the p-y curves. Reducing the
modulus of subgrade reaction in trailing piers will result in greater computed deflections
on these piers. In practice, the grade beam can force deflections of piers to be equal.
Load-deflection graphs can be generated for each pier in the group using the
appropriate p-multiplier values. The sum of the piers' lateral load resistance at selected
deflections can be used to develop a total lateral load versus deflection relationship for
the system of piers.
For lateral loads perpendicular to the line of piers a minimum spacing of three
diameters can be used with no capacity reduction. At one diameter (piers touching) the
piers can be analyzed as a single unit. Linear interpolation can be used for intermediate
conditions.
RETAINING WALL FOUNDATIONS
Retaining walls, including wing walls, are planned at this site. If integral with the
abutments, walls should be founded with the same foundation type as the abutments. If
not integral, spread footing foundations may be used. We recommend constructing
footing foundations with a separation to bedrock of no less than 3 feet. Design and
construction criteria for footing are provided below. These criteria were developed from
analysis of field and laboratory data and our experience. We estimate potential
foundation movements of up to one inch could occur for foundations designed and
constructed to the criteria below. The recommended foundation can be used provided
all design and construction criteria presented in this report are followed.
Footings
1. Footings should be constructed on undisturbed natural soils or properly
compacted fill (see Fill Placement). Where soil is loosened during
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125 9
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 21 of 55
excavation, it should be removed and replaced with on-site soils
compacted following the criteria in the Fill Placement section of this
report.
2. Footings constructed on the natural soils and/or engineered fill can be
designed for a net allowable soil pressure of 3,000 psf. The soil pressure
can be increased 33 percent for transient loads such as wind or seismic
loads.
3. Footings should have a mm1mum width of at least 16 inches.
Foundations for isolated columns should have minimum dimensions of 24
inches by 24 inches. Larger sizes may be required depending on loads
and the structural system used.
4. The soils beneath footing pads can be assigned an ultimate coefficient of
friction of 0.4 to resist lateral loads. The ability of grade beams, or footing
backfill to resist lateral loads can be calculated using a passive equivalent
fluid pressure of 300 pcf. This assumes the backfill is densely compacted
and will not be removed. Backfill should be placed and compacted to the
criteria in the Fill Placement section of the report.
5. Exterior footings should be protected from frost action. We believe 30
inches of frost cover is appropriate for this site.
6. Foundation walls and grade beams should be well reinforced both top
and bottom. We recommend the amount of steel equivalent to that
required for a simply supported span of 15 feet.
7. We should be retained to observe completed footing excavations to
confirm that the subsurface conditions are similar to those found in our
borings.
SCOUR
Scour potential should be evaluated for the proposed bridge and retaining wall
foundations. The depth of scour can affect foundations by undermining footings and
also reducing the lateral support of the soils and bedrock on pier foundations. The
overburden sand and gravel are susceptible to scour. The claystone encountered in our
borings is typically considered to be subject to minimal scouring. Pier foundations
should be considered for retaining wall where scour depths extend below possible
footing foundations. Pier foundations should be protected from significant scouring to
reduce the potential loss of lateral support.
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838·125 10
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 22 of 55
LATERAL EARTH PRESSURES
The lateral loads acting on abutments and retaining walls are dependent on the
height and type of wall, backfill configuration and backfill type. For the purposes of
design, we have assumed less than 10 feet of fill will be retained by abutments and
retaining walls and the backfill will be on-site or similar soils.
Abutment and retaining walls should be designed to resist lateral earth pressures
that act upon the wall. Table C below provides the necessary equivalent fluid pressure
values for the backfill soils anticipated at this site. The pressures given do not include
allowances for surcharge loads such as sloping backfill, vehicle traffic, or excessive
hydrostatic pressure.
TABLE C
EQUIVALENT FLUID PRESSURE VALUES
Loading Condition Equivalent Hydrostatic
Fluid P~essure
Active ("'A) pet 40
At-Rest ("/a) pcf 55
Passive ("/p) pcf 300
Horizontal Friction Coefficient 0.4
The appropriate load distribution to apply for design depends not only on the soil
and bedrock type, but also on the wall type and restraint. Graphical examples of typical
loading conditions are presented on Figure 3. For abutments and retaining walls that
are restrained from rotation, the walls should be designed to resist the "at rest" earth
pressure. For walls which are free to rotate to develop the shear strength of the soils,
such as wing walls not tied to the abutments, the walls should be designed to resist the
"active" earth pressure. Resistance to lateral loads can be provided by friction between
concrete and soil and/or by "passive" earth pressure. Passive earth pressure should be
ignored for the top one foot of soils against the structure since it can be easily removed
with time. The proper application of these loading conditions is the responsibility of the
wall designer.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL I T PROJECT NO. FC05B3B·125 11
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 23 of 55
The hydrostatic pressure can be reduced by providing a drain and weep holes
behind the abutments and retaining walls. The drain should be reasonably well-graded
sands and gravels with a maximum of 5 percent passing the No. 200 sieve and a
maximum particle size of 3 inches that is at least 12 inches wide and placed against the
back of an abutment or wing wall. The top 2 feet of backfill above the drain should be
compacted clays. Weep holes should be 4 inches in diameter, spaced 10 feet center-to-
center at the bottom of an abutment or wall. At least two weep holes should be provided
per wall at the bottom of the wall. The back of the weep holes should connect to the
drain, be protected from clogging and be screened to prevent drain materials from falling
out of the weep holes. A manufactured drain such as Miradrain could be substituted for
the drain sand and gravel. Manufactured drains should be installed following the
manufacturers recommendations.
Wall backfill should be placed in 8-inch maximum loose lifts, moistened to within
2 percent of optimum moisture content and compacted to at least 95 percent of standard
Proctor maximum dry density (ASTM D 698). The placement and compaction of fill
should be observed and tested by a representative of our firm during construction.
WATER-SOLUBLE SULFATES
Concrete that comes into contact with soils can be subject to sulfate attack. We
measured water-soluble sulfate concentrations in four samples from this site.
Concentrations measured were 0.16 percent or less, with two samples having sulfate
concentrations between 0.1 and 0.2 percent. Water-soluble sulfate concentrations
between 0.1 and 0.2 percent indicate Class 1 exposure to sulfate attack, according to
the American Concrete Institute (ACI). ACI indicates adequate sulfate resistance can be
achieved by using Type II cement with a water-to-cementitious material ratio of 0.50 or
less. ACI also indicates concrete in Class 1 exposure environments should have a
minimum compressive strength of 4000 psi. In our experience, superficial damage may
occur to the exposed surfaces of highly permeable concrete, even though sulfate levels
are relatively low. To control this risk and to resist freeze-thaw deterioration, the water-
to-cementitious material ratio should not exceed 0.50 for concrete in contact with soils
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125 12
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 24 of 55
that are likely to stay moist due to surface drainage or high water tables. Concrete
should be air entrained.
LIMITATIONS
Although our borings were spaced to obtain a reasonably accurate picture of
subsurface conditions, variations not indicated in our borings are always possible. We
should be retained to observe pier hole drilling and footing excavations to confirm soils
are similar to those found in our borings. Placement and compaction of fill, backfill,
subgrade and other fills should be observed and tested by a representative of our firm
during construction.
We believe this investigation was conducted in a manner consistent with that
level of skill and care ordinarily used by members of the profession currently practicing
under similar conditions in the locality of this project. No warranty, express or implied, is
made.
If we can be of further service in discussing the contents of this report or in the
analysis of the proposed construction from the geotechnical point of view, please
contact the undersigned.
CTL I THOMPSON, INC. by:
~JJA_
Spencer Schram, El
Project Engineer
(2 Copies)
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTLI T PROJECT NO. FCOSBJB-125
R.B. "Chip" Leadbe
Division Manager
13
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 25 of 55
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CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125
TH-2
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H = HEIGHT OF WALL (FT)
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P = 0.6 * 'YA * H
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p 'YA = ACTIVE HYDROSTATIC UNIT WEIGHT (PCF)
BRACED OR TIE-BACK EXCAVATION
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h9 = HEIGHT OF SLOPE (FT)
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~ = LATERAL PRESSURE. BOTTOM OF WALL (PSF)
'YA = ACTIVE HYDROSTATIC UNIT WEIGHT (PCF)
CANTILEVER WALL-SLOPING BACKFILL (Active with Surcharge)
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05B3B-125
Example Lateral
Earth Pressure
Distributions
FIGURE 3
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 28 of 55
APPENDIX A
RESULTS OF LABORATORY TESTING
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 29 of 55
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APPUEDPRESSURE-KSF
Sample of CLAYSTONE
From TH- 4 AT 14 FEET
1.0
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL I T PROJECT NO. FC05838-125
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
HYDROMETER ANALYSIS SIEVE ANALYSIS
25 HR 7 HR TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS
45 MIN. 15 MIN. 60 MIN. 19 MIN 4 MIN 1 MIN '200 '100 '50 '40 '30 '16 '10 ·a '4 3/a' 3/4' 1~· 3' 5'6' a•
100 r---.-----~,~~-----~r---~, ----r---.---~~--.---.---~------~-----.---.----~~~--~-. 0
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DIAMETER OF PARTICLE IN MILLIMETERS
FINE MEDIUM
CLAY (PLASTIC) TO SILT (NON-PLASTIC)
SANDS
Sample of
From
SAND (SW) GRAVEL 5%
4%
SAND 91%
TH- 3 AT -4-::' F==E=ET=--
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL f T PROJECT NO. FC05838-125
SILT & CLAY
PLASTICITY INDEX
LIQUID LIMIT %
Gradation
Test Results
%
FIGURE A-4
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 33 of 55
TABLE A-1
SUMMARY OF LABORATORY TESTING
- --- ------- ------
SWELL TEST RESULTS PASSING WATER-
MOISTURE DRY APPLIED NO. 200 SOLUBLE
DEPTH CONTENT DENSITY SWELL PRESSURE SIEVE SULFATES
BORING (FEET) (%)
TH-1 14 13.0
TH-2 9 12.1
TH-2 19 17.9
TH-3 4 3.3
TH-3 9 14.0
TH-3 24 13.1
TH-4 4 4.5
TH-4 14 12.7
CITY OF FORT COLLINS· PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTLIT PROJECT NO. FC05838-125
(PCF) (%) (PSF) (%) (%)
122 3.4 1,000
119 3.2 1,000 0.10
104 67.3
4.1 <0.01
87.3 0.16
119 2.5 1,000
0.01
115 2.5 1,000
1P
DESCRIPTION
CLAYSTONE
CLAYSTONE
CLAYSTONE
SAND (SP)
CLAYSTONE
CLAYSTONE
GRAVEL, SANDY (GP)
CLAYSTONE
Page 1 of 1
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 34 of 55
APPENDIX B
SAMPLE SITE GRADING SPECIFICATIONS
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 35 of 55
SAMPLE SITE GRADING SPECIFICATIONS
1. DESCRIPTION
This item shall consist of the excavation, transportation, placement and compaction of
materials from locations indicated on the plans, or staked by the Engineer, as necessary
to achieve building site elevations.
2. GENERAL
The Soils Engineer shall be the Owner's representative. The Soils Engineer shall
approve fill materials, method of placement, moisture contents and percent compaction,
and shall give written approval of the completed fill.
3. CLEARING JOB SITE
The Contractor shall remove all trees, brush and rubbish before excavation or fill
placement is begun. The Contractor shall dispose of the cleared material to provide the
Owner with a clean, neat appearing job site. Cleared material shall not be placed in
areas to receive fill or where the material will support structures of any kind.
4. SCARIFYING AREA TO BE FILLED
All topsoil and vegetable matter shall be removed from the ground surface upon which
fill is to be placed. The surface shall then be plowed or scarified to a depth of 8 inches
until the surface is free from ruts, hummocks or other uneven features, which would
prevent uniform compaction by the equipment to be used.
5. COMPACTING AREA TO BE FILLED
After the foundation for the fill has been cleared and scarified, it shall be disked or
bladed until it is free from large clods, brought to the proper moisture content and
compacted to not less than 95 percent of maximum dry density as determined in
accordance with ASTM D 698 or AASHTO T 99.
6. FILL MATERIALS
On-site materials classifying as CL, SC, SM, SW, SP, GP, GC and GM are acceptable.
Fill soils shall be free from organic matter, debris, or other deleterious substances, and
shall not contain rocks or lumps having a diameter greater than three (3) inches. Fill
materials shall be obtained from the existing fill and other approved sources.
7. MOISTURE CONTENT
Fill materials shall be moisture treated. Clay soils placed below the building envelope
should be moisture-treated to between 1 and 4 percent above optimum moisture content
as determined from Standard Proctor compaction tests. Clay soil placed exterior to the
building should be moisture treated between optimum and 3 percent above optimum
moisture content. Sand soils can be moistened to within 2 percent of optimum moisture
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125
B-1
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 36 of 55
content. Sufficient laboratory compaction tests shall be performed to determine the
optimum moisture content for the various soils encountered in borrow areas.
The Contractor may be required to add moisture to the excavation materials in the
borrow area if, in the opinion of the Soils Engineer, it is not possible to obtain uniform
moisture content by adding water on the fill surface. The Contractor may be required to
rake or disk the fill soils to provide uniform moisture content through the soils.
The application of water to embankment materials shall be made with any type of
watering equipment approved by the Soils Engineer, which will give the desired results.
Water jets from the spreader shall not be directed at the embankment with such force
that fill materials are washed out.
Should too much water be added to any part of the fill, such that the material is too wet
to permit the desired compaction from being obtained, rolling and all work on that section
of the fill shall be delayed until the material has been allowed to dry to the required
moisture content. The Contractor will be permitted to rework wet material in an
approved manner to hasten its drying.
8. COMPACTION OF FILL AREAS
Selected fill material shall be placed and mixed in evenly spread layers. After each fill
layer has been placed, it shall be uniformly compacted to not less than the specified
percentage of maximum dry density. Fill materials shall be placed such that the
thickness of loose material does not exceed 8 inches and the compacted lift thickness
does not exceed 6 inches.
Compaction, as specified above, shall be obtained by the use of sheepsfoot rollers,
multiple-wheel pneumatic-tired rollers, or other equipment approved by the Engineer.
Compaction shall be accomplished while the fill material is at the specified moisture
content. Compaction of each layer shall be continuous over the entire area.
Compaction equipment shall make sufficient trips to insure that the required dry density
is obtained.
9. COMPACTION OF SLOPES
Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable
equipment. Compaction operations shall be continued until slopes are stable, but not
too dense for planting, and there is no appreciable amount of loose soil on the slopes.
Compaction of slopes may be done progressively in increments of three to five feet (3' to
5') in height or after the fill is brought to its total height. Permanent fill slopes shall not
exceed 3:1 (horizontal to vertical).
10. DENSITY TESTS
Field density tests shall be made by the Soils Engineer at locations and depths of his
choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of
several inches. Density tests shall be taken in compacted material below the disturbed
surface. When density tests indicate that the dry density or moisture content of any
layer of fill or portion thereof is below that required, the particular layer or portion shall be
reworked until the required dry density or moisture content has been achieved.
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838-125
B-2
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 37 of 55
11. COMPLETED PRELIMINARY GRADES
All areas, both cut and fill, shall be finished to a level surface and shall meet the
following limits of construction:
A. Overlot cut or fill areas shall be within plus or minus 2/10 of one foot.
B. Street grading shall be within plus or minus 1/10 of one foot.
The civil engineer, or duly authorized representative, shall check all cut and fill areas to
observe that the work is in accordance with the above limits.
12. SUPERVISION AND CONSTRUCTION STAKING
Observation by the Soils Engineer shall be continuous during the placement of fill and
compaction operations so that he can declare that the fill was placed in general
conformance with specifications. All site visits necessary to test the placement of fill and
observe compaction operations will be at the expense of the Owner. All construction
staking will be provided by the Civil Engineer or his duly authorized representative.
Initial and final grading staking shall be at the expense of the owner. The replacement of
grade stakes through construction shall be at the expense of the contractor.
13. SEASONAL LIMITS
No fill material shall be placed, spread or rolled while it is frozen, thawing, or during
unfavorable weather conditions. When work is interrupted by heavy precipitation, fill
operations shall not be resumed until the Soils Engineer indicates that the moisture
content and dry density of previously placed materials are as specified.
14. NOTICE REGARDING START OF GRADING
The contractor shall submit notification to the Soils Engineer and Owner advising them
of the start of grading operations at least three (3) days in advance of the starting date.
Notification shall also be submitted at least 3 days in advance of any resumption dates
when grading operations have been stopped for any reason other than adverse weather
conditions.
15. REPORTING OF FIELD DENSITY TESTS
Density tests made by the Soils Engineer, as specified under "Density Tests" above,
shall be submitted progressively to the Owner. Dry density, moisture content and
percent compaction shall be reported for each test taken.
16. DECLARATION REGARDING COMPLETED FILL
The Soils Engineer shall provide a written declaration stating that the site was filled with
acceptable materials, or was placed in general accordance with the specifications.
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL I T PROJECT NO. FC05838-125
B-3
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 38 of 55
This unofficial copy was downloaded on Feb-27-2012 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay For additional information or an official copy, please contact Engineering Office 281 North College Fort Collins, CO 80521 USA Page
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115
12.7
Swell Consolidation
Test Results
100
PCF
%
FIGURE A-3
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 32 of 55
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APPLIED PRESSURE- KSF
Sample of
From
CLAYSTONE
TH- 3 AT 24 FEET
1.0
CITY OF FORT COLLINS- PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL I T PROJECT NO. FC0583B-125
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
119
13.1
Swell Consolidation
Test Results
100
PCF
%
FIGURE A-2
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 31 of 55
I I
-8~-0.1 ---------------------------------------------------------------~
APPUEDPRESSURE-KSF
Sample of CLAYSTONE
From TH- 1 AT 14 FEET
1.0
CITY OF FORT COLLINS - PARK PLANNING AND DEVELOPMENT
POUDRE TRAIL CROSSING AT LEMAY AVENUE
CTL IT PROJECT NO. FC05838·125
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
122
13.0
Swell Consolidation
Test Results
100
PCF
%
FIGURE A-1
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 30 of 55
El. 4930
27/12
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50/1
4,92
l
4,91
LEGEND: 7
1·:::.:.-J SAND, SLIGHTLY SILTY, SLIGHTLY MOIST, LOOSE, BROWN (SP, SW, SP-SM)
EO] GRAVEL, SANDY, SLIGHTLY MOIST TO WET, MEDIUM DENSE TO DENSE, BROWN (GP)
I ~ CLAYSTONE, MOIST TO WET, HARD TO VERY HARD, GRAY
p
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NOTES:
DRIVE SAMPLE. THE SYMBOL 24/121NDICATES 24 BLOWS OF A 140-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 121NCHES.
DRIVE SAMPLE. THE SYMBOL 30/121NDICATES 30 BLOWS OF A 140-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.0-INCH O.D. SAMPLER 12 INCHES.
WATER LEVEL MEASURED AT TIME OF DRILLING.
WATER LEVEL MEASURED SEVERAL DAYS AFTER DRILLING.
1. THE BORINGS WERE DRILLED ON APRIL 2, 2012, USING 4-INCH DIAMETER
CONTINUOUS-FLIGHT AUGER AND A TRUCK-MOUNTED DRILL RIG.
2. BORING ELEVATIONS ARE APPROXIMATE AND ARE BASED ON TOPOGRAPHY PROVIDED
BY THE CITY OF FORT COLLINS.
3. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN
THIS REPORT.
Summary Logs of
Exploratory Borings
FIGURE 2
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 27 of 55
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Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 26 of 55
24 213 Mulching (Weed Free Hay) AC 0.6 0 0.6
$ ‐
25 304 Aggregate Base Course (Class 5) CY 58 0 58
$ ‐
26 503 Drilled Caisson (24 inch) LF 0 250 250
$ ‐
27 503 Drilled Caisson (54 inch) LF 0 25 25
$ ‐
28 506 Riprap (12‐Inch) CY 184 0 184
$ ‐
29 506 Repurposed Riprap (Pipe Outfall) CY 5 0 5
$ ‐
30 506 Repurposed Riprap (Native Streambed Riprap) LS 0 1 1
$ ‐
Addendum 1 - 7585 Poudre Trail at Mulberry & Lemay Page 2 of 55