Soils_and_Foundation_Report.pdf

SOILS AND FOUNDATIONS REPORT

NO. 05-13

PROJECT VT ERFO APPA 2011-1(3)

SARGENT BROOK BRIDGE

APPALACHIAN NATIONAL SCENIC TRAIL

RUTLAND COUNTY, VERMONT

U.S. Department of Transportation Federal Highway Administration

Eastern Federal Lands Highway Division 21400 Ridgetop Circle

Sterling, VA 20166 August, 2013

TABLE OF CONTENTS

REPORT .................................................................................................................. PAGE

INTRODUCTION

General Project Description Regional Geology

PROCEDURES AND RESULTS

Sampling Data Summary Findings

DESIGN ANALYSIS AND RECOMMENDATIONS

Bridge Foundations

CONSTRUCTION CONSIDERATIONS

DISCLAIMER/LIMITATIONS CLAUSE

APPENDICES

APPENDIX A – Figures APPENDIX B – Boring Location Map APPENDIX C – Subsurface Profile APPENDIX D – Boring Logs APPENDIX E – Design Analysis APPENDIX F – Bridge Plans and Elevations APPENDIX G – Representative Photographs

DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

SOILS AND FOUNDATIONS REPORT

NO. 05-13

APPALACHIAN NATIONAL SCENIC TRAIL

INTRODUCTION

General

This report presents the results of our subsurface exploration, geotechnical analyses and recommendations for Project VT ERFO APPA 2011-1(3). The project site is located in the Appalachian National Scenic Trail in Rutland County, Vermont. Site location and vicinity map is presented in Figure 1 in Appendix A.

Project Description

This project consists of the reconstruction of Sargent Brook Bridge that carries Town Highway 13 over Sargent Brook Creek and provides access to the Appalachian Trail.

Highway 13 is a 12 ft wide, 2-way, gravel road. The Bridge was washed-out during Hurricane Irene in 2011 . The west abutment has been completely washed-out leaving significantly eroded bank. The east abutment concrete footing, apparently supported on rock, is still in place. Representative photographs from the project site are provided in Appendix G.

The proposed Bridge will be 65 ft long, single span, precast pre-stressed The proposed west bridge abutment (Abutment 1) and east abutment (Abutment 2) will be supported on spread footings. The Bridge layout plan and elevation is provided in Appendix F.

Regional Geology

The Geologic Map of Vermont, (2011)indicates that the project area is located within the Biotite-quartz-plagioclase gneiss formation of the Mount Holly complex group.

This formation is described as well layered, dark-gray to medium gray weathered biotite-quartz-plagioclase gneiss, hornblende amphibolite, minor lenses of schistose gneiss, quartzite and epidote-biotite quartz gneiss, and dark-green chloritic highly altered diopside gneiss and quartzite having green layers rich in white mica, possibly fuchsite.

Refer to Figure 2 of Appendix A for a Geologic Map of the project area.

APPALACHIAN SCENIC TRAIL

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

PROCEDURES AND RESULTS

Eastern Federal Lands Highway Division’s (EFLHD) subsurface exploration team performed drilling operations between September 21st and 22nd, 2012. The subsurface exploration program consisted of drilling one soil boring at the west bank of Sargent Brook creek. The boring was advanced to its termination depth using CME 750 ATV-mounted rotary drill rig. The boring location was selected by EFLHD geotechnical engineer based on the accessibility of the drilling rig and the location of existing structures.

It should be mentioned that no drilling operations were performed at abutment 2 since the site was not accessible to the drilling rig.

Sampling

The Boring was advanced through boulders and alluvial material using rotary drilling techniques and samples were retrieved using a double-walled NQ wireline core barrel.

Rock core samples were preserved in wooden boxes and transported to EFLHD’s Materials Testing Laboratory in Sevierville, TN for testing and storage.

Boring location was determined in the field by measuring distances from survey marks present on-site and by a hand held GPS. Boring elevation was determined from plan topography. The approximate location of boring is shown on the Boring Location Map in Appendix B.

Data Summary

The results of field tests and measurements were recorded on the driller’s logs and appropriate data sheets in the field. These data sheets and logs contain information concerning the boring methods, samples attempted and recovered, and lithology. They also contain interpretations by the exploration foreman of the subsurface conditions based on the performance of the equipment and cuttings brought to the surface by the drilling tools. Therefore, the field data represents both factual and interpretative information. The boring logs, provided in Appendix D, represent an interpretation of field data and description of the soil and rock samples by a geotechnical engineer.

These records occasionally do not include all data recorded on driller’s logs and field data sheets, but do include all information considered relevant to the design and preparation of this report.

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

Groundwater level readings were not taken during drilling since water was used for coring.

Findings

Descriptions of the subsurface conditions encountered during the drilling operations conducted at the project site are presented below. The stratification lines designating the interfaces on the boring logs represent approximate boundaries. The transition between materials may be gradual. It should be noted that due to difficulties encountered when auguring through the alluvial deposits, which primarily consisted of cobbles and boulders, auger drilling was switched to rotary drilling, which resulted in washing out all fine materials.

Fill – Fill material consisting of brown silty sand, gravel, and cobbles was visually observed, approximately, in the upper 5 ft of the eroded west bank in the vicinity of the washed out west abutment location. No soil sample was collected since auger refusal was encountered at the ground surface. Photograph No. 4 in Appendix G illustrates the existing fill material.

Alluvial Deposits – Alluvial deposits consisting of cobbles, boulders, pebbles, gravel, sand, silt, and traces of clay was encountered below the fill material and extended to a depth of 28.9 ft below existing site grades (Elev. 1709.2 ft). The recovery for this layer ranged from 0.8 to 4.1 ft. It’s possible that the layer between the depths of 23.9 to 28.9, below existing ground surface, is highly weathered rock, meaning shallower bedrock than identified below.

Rock – Very hard, grayish-blue, relatively sound to sound, Quartzite Sandstone rock, was encountered underneath the alluvial deposits and extended to the termination depth of 38.1 ft below existing site grades (Elev. 1700.0 ft). Core recovery ranged from 99% to 100%. The RQD values ranged from 84% to 98%.

DESIGN ANALYSIS AND RECOMMENDATIONS

Our recommendations are based on visual observations, soil and groundwater conditions reported on the boring log and geometry and loading information from the Bridge and Highway Design branches.

Scour Evaluation Scour analysis was performed by the Hydraulic team and yielded no contraction scour for the bridge but considered a long-term degradation of 1 ft.

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

Bridge Foundations It is our opinion that the proposed bridge can be supported on spread footing s.

Strength and Service Limit States

Bearing resistance was computed according to AASHTO LRFD Bridge Design Specifications, Sixth Edition, 2012 and Interim Revisions. Design assumptions included supporting Abutment 1 on medium dense silty sand and gravel soil or better material and Abutment 2 on highly weathered rock or better material. The rock at the location of Abutment 2 was only visually evaluated.

For Abutment 1, bearing resistance chart was developed, consisting of nominal bearing resistance versus effective footing width for estimated settlement of 1 and 1.5 inches (i.e., settlement curves). The chart also provides maximum factored bearing resistance for strength limit state. The bearing resistance chart is provided in Appendix E.

Nominal bearing resistance was determined using conventional equation and bearing capacity factors presented in the AASHTO design manual. Settlement was computed based on Hough method. The effective footing width should account for load eccentricity.

A nominal bearing resistance of 10 ksf is recommended for Abutment 2 for foundation supported on highly weathered rock or better material.

Resistance factor of 0.45 was applied to the nominal bearing resistances to obtain factored bearing resistances following AASHTO (2012) Specifications, Table 10.5.5.2.2-1. Factored bearing resistance shall not exceed the factored compressive resistance of the footing concrete (AASHTO (2012) Specifications, Section 10.6.3.2.2).

Resistance factor for service limit state is 1.0.

Lateral loads can be resisted by sliding friction along the bottom of the footing-rock interface. A maximum friction factor of 0.5 and 0.7 is recommended for sliding resistance along the base of the footing for Abutment 1 and Abutment 2 respectively.

Geotechnical resistance factors for sliding for cast-in-place concrete and precast concrete placed on sand are 0.8 and 0.9, respectively, based on AASHTO (2012) Specifications, Table 10.5.5.2.2-1.

Settlement Settlement of less than 1 inch is anticipated using Service Limit State (Service-I) for both abutments. Anticipated settlement would predominantly be elastic settlement that will occur over a short period of time.

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

CONSTRUCTION CONSIDERATIONS

Excavation – All excavation activities are to be performed in accordance with applicable OSHA standards and with Section 204 of the FP-03 Specifications. Any signs of instability or movement shall be reported immediately to the CO.

Soil Supported Foundations – For spread footing supported on soils, clear any soft or loose material before placing the foundation. If such soil is encountered during construction, over excavate and backfill with either compacted fill or “lean concrete”.

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

DISCLAIMER/LIMITATIONS CLAUSE

The subsurface explorations and tests described in the aforementioned Procedures and Results section have been conducted in accordance with standard practices and procedures (except as specifically noted). The results of these exploration and tests represent conditions at the specific locations indicated. Subsurface conditions between these locations may vary. The Design Analysis and Recommendations section of this report include interpretations and recommendations developed by the Government in the process of preparing the design. These interpretations are not intended as a substitute for the personal investigation, independent interpretation, and judgment of the Contractor.

Prepared by:

Mohammed Elias, Ph.D., P.E.

Geotechnical Engineer

Reviewed by:

Mounir Abouzakhm, P.E.

Division Geotechnical Engineer

APPENDIX A

Figures

Project VT ERFO APPA 2011-1(3)

Mohammed.Elias Oval

Mohammed.Elias Line

Line

ATTACHMENT 2

Boring Locations Plan, Boring General Notes, and Boring Logs

N A

IL

30" TREE

NAIL

S9

NAI

L

BORE

Mohammed.Elias Text Box Boring B-1

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Callout Exiting East Abutment

Mohammed.Elias Typewritten Text Sargent Brook Creek

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Mohammed.Elias Typewritten Text

Typewritten Text

ROCK CORING GENERAL NOTES

Depth and Elevation: Use large marks as 1’ (300mm) increments. Record proper elevations.

Core: Draw sketch of core breaks as it is oriented in the core box (align all core breaks so they fit together properly before drawing sketch). Starting at the top of core measure each piece of core down its centerline to 1/100 of a foot. Record this measurement along the left side of the core sketch at the break.

VISUAL METHODS FOR ROCK IDENTIFICATION

Description: 1. Draw a heavy line through description at depth to which core run penetrated.

2. Describe the rock type.

3. Note the condition of the core break on the right side of the core sketch

Mud seam (MS); Sand seam (SS); Weathered surface (WS); Fresh break (FB)

4. Record coring time in minutes.

5. Record to nearest 1/100 foot the core recovered (after alignment in core box). Discard any debris at top of core, which obviously fill into the core hole.

6. Calculate per cent core recovery and record: CR = Ufeet of core recoveredU feet cored

Color: Wet the rock with water and describe the color including the color of any unusual or reoccurring markings on the core (i.e. light green with dark green bands, foliation lines).

Foliation: Foliation planes are parallel planes of different minerals forming a banded appearance on the rock.

The foliation planes are usually of a different color than the surrounding rock. Also the rock shears along the foliation planes if struck with a hammer. Record the following:

Close spaced (CS) – 1/8” (3mm) or closer; Medium spaced (MS) – 1/8” to 1/4” (3mm to 6mm);

Open spaced (OS) – 1/4” (6mm) or larger

The angle to the horizontal should be measured (with a protractor) and recorded for the rock core.

(Several different angles can be found in each 5’ to 10’ core.)

Hardness: Very Soft (VS) – Can be deformed or crumbled by hand; Soft (S) – Can be scratched with a fingernail Moderately Hard (MH) – Can be scratched easily with a knife; Hard (H) – Can be scratched with difficulty with a knife; Very hard (VH) – Cannot be scratched with a knife

Weathering: Use the proper number 1 through 5.

1. UUnweathered:U No evidence of any mechanical or chemical alteration along discoloration evidenced.

2. USlightly weatheredU: Discoloration is evident, on surface, slight alteration no discontinuities, less than 10% of the volume is altered, strength is substantially unaffected.

3. UModerately weathered:U Discoloring is evident, surface is pitted and altered with alteration penetrating will below rock surfaces, weathering "halos” evident, 10% to 50% of the rock is altered, strength is noticeably less than fresh rock.

4. UHighly weathered: UEntire mass is discolored; alteration pervades nearly all of the rock with some pockets of slightly weathered rock noticeable, some minerals leached away, retains only a fraction of original strength (with wet strength usually lower than dry strength).

5. UDecomposed:U Rock is reduced to a soil with relict rock structure (saprolite), can be generally molded and crumbled by hand.

Rock Quality Designation (RQD) = UΣ[Lengths of all pieces of the core ≥ 4” (100mm)]U x 100 Total length of core run

Soundness: Use the proper number 1 through 5

1. Weathered RQD = 0% to 25%

2. Highly jointed to Jointed RQD = 25% to 50%

3. Jointed to Relatively sound RQD = 50% to 75%

4. Relatively sound to Sound RQD = 75% to 100%

Rock Quality: Use the proper number 1 through 5

1. Very Poor RQD = 0% to 25%

2. Poor RQD = 25% to 50%

3. Fair RQD = 50% to 75%

4. Good RQD = 75% to 90%

5. Excellent RQD = 90% to 100%

Order of Description

1. Hardness

2. Color

3. Soundness (a.k.a. Weathering and Rock Quality)

4. Main Rock Formation – Composes more than 50% of the core run

5. Texture – Very Fine (VF), Fine (F), Medium (M), and Coarse (C)

6. Modifying Term – “and” : 40% to 50% of the core run “some” : 30% to 40% “little” : 10% to 30%

“trace” : 10% or less

7. Minor Rock Type(s)

8. Other (Foliation angle, etc.)

UExamples:U

1. Moderately hard, blue-gray to gray, weathered BIOTITE GNEISS BOULDER, medium texture

Recovery = 24%

RQD = 17%

2. Very hard, gray and white, relatively sound to sound BIOTITE GNEISS, medium to fine texture, some quartz veins, foliation angle = 20 degrees

Recovery = 100%

RQD = 100%

-Fresh break @ approximately 47’

Brown,SILTY SAND and GRAVEL , some cobbles.

- FILL -

Moderatley hard gray and brown,COBBLES and BOULDERS , some gravel with observed alluvial deposits wash-out.

possible highly weathered rock from 23.9 to 28.9 ft

R-1

R-2

R-3

R-4

R-5

R-6

R-7

5.0

28.9

1.9

2.9

0.8

2.1

2.9

4.1

(Blows / ft)

D ep th S ca le ft)

No auger boring was used.

Boring was backfilled with auger cuttings upon completion.

SPT

Clear

Boring Began: 9/21/12 W.L.

2 in.

9/22/12 K. Thornton R. KingsleyOperator:

West Abutment

U. S. DEPARTMENT OF TRANSPORTATION

Weather:

SAMPLE

hrs

Remarks:

Auger Cuttings UD

10 60

T yp e

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

Plastic Limit Liquid Limit

40 80

MATERIAL DESCRIPTION

G ra ph ic

L og

Boring No.:

Hammer Wt. & Type:

Surface Elevation:

Water Content %

Inspector:Caved at:

Hammer Drop:

Project Name:

N o.

Rutland County, VT La ye r

D ep th ft)

VT ERFO APPA 2011-1(3), Appalachian National Scenic Trail - NPS

P P

/R Q

D (t sf

E le va tio n (f ee t)

Standard Penetration Test Data

Encountered at:

After

Groundwater Depth:

Project Location:

At Completion:

Completed:

Hole Diameter:

Boring Method:

Rock Core Diam:

Vane Shear

Boring Location:

30 in.

140 lbs/Automatic 2 in.

B lo w s pe r in

B-1

1738.1 ft

Penetrometer

Sample Types:

Rock Core

R ec ft/

BORING LOG

B

O R

IN

G

L O

G

4/

/1

:3

M

P R

O

JE

C T

S \A

P P

A \V

T

-1

(3

T E

C H

S E

R V

\G E

O T

E C

H \S

U B

S U

R F

A C

E I

N V

E S

T

IG

A T

IO

N

\B O

R

IN

G L

O G

S \V

T E

R F

O A

P P

A

1-

1( 3)

.G P

J 1733.1

1709.2

Very hard, grayesh-blue, QUARTZITE SANDSTONE, fine texture

Recovery = 99%, RQD = 84% (Continued) same as above Recovery = 100%, RQD = 98%

Note: total run was 4.2 ft

Boring terminated @ 38.1 ft

R-7

R-8

33.9

38.1

5.0

4.2

(Blows / ft)

D ep th S ca le ft)

No auger boring was used.

Boring was backfilled with auger cuttings upon completion.

SPT

Clear

Boring Began: 9/21/12 W.L.

2 in.

9/22/12 K. Thornton R. KingsleyOperator:

West Abutment

U. S. DEPARTMENT OF TRANSPORTATION

Weather:

SAMPLE

hrs

Remarks:

Auger Cuttings UD

10 60

T yp e

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

Plastic Limit Liquid Limit

40 80

MATERIAL DESCRIPTION

G ra ph ic

L og

Boring No.:

Hammer Wt. & Type:

Surface Elevation:

Water Content %

Inspector:Caved at:

Hammer Drop:

Project Name:

N o.

Rutland County, VT La ye r

D ep th ft)

VT ERFO APPA 2011-1(3), Appalachian National Scenic Trail - NPS

P P

/R Q

D (t sf

E le va tio n (f ee t)

Standard Penetration Test Data

Encountered at:

After

Groundwater Depth:

Project Location:

At Completion:

Completed:

Hole Diameter:

Boring Method:

Rock Core Diam:

Vane Shear

Boring Location:

30 in.

140 lbs/Automatic 2 in.

B lo w s pe r in

B-1

1738.1 ft

Penetrometer

Sample Types:

Rock Core

R ec ft/

BORING LOG

B

O R

IN

G

L O

G

4/

/1

:3

M

P R

O

JE

C T

S \A

P P

A \V

T

-1

(3

T E

C H

S E

R V

\G E

O T

E C

H \S

U B

S U

R F

A C

E I

N V

E S

T

IG

A T

IO

N

\B O

R

IN

G L

O G

S \V

T E

R F

O A

P P

A

1-

1( 3)

.G P

J

1704.2

1700.0

ATTACHMENT 3

Bridge Layout

LIVE LOAD SPECIAL LOADS

SUPERSTRUCTURE

OVERLOAD

TYPICAL BRIDGE SECTION

SIDEWALKS

RAIL

EPOXY REINFORCEMENT

CONCRETE F’C

-A p r -2

1:

P

M

REMARKS

TRANSITION

DRAINS UTILITIES

D E S I G

N D

A T

A

BRIDGE NAME

ROUTE NAME AND NUMBER

STATE

ACCOUNT NO.

PREPARED BY

SCALE: DATE:

ESTIMATED STRUCTURE COST

FOREST/PARK/OTHER

STREAM NAME

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

PRELIMINARY LAYOUT

COUNTY

PLAN

ELEVATION

G E

O M

E T

R I C

S H

Y D

R A

U L I C

S

S C

O U

R

HYDRAULICS REPORT NO.

MATERIALS REPORT NO.

SCOUR

REMARKS

SLOPE PROTECTION

TOP EL.:

TYPE:

Q

100Q

50Q

2Q

Q Vm WS EL.

REMARKS

CLASS:

BOTTOM EL.:

SLOPE:

DEPTH:

RECEIVED

RECEIVED

PROFILE GRADE DIAGRAM

EL. ARE AT GRADE

AT

M

P r o j e c ts a p p a v t2

-1 (3

B r id g e M ic r o s ta ti o n T

S

L

V

T

E R

F O

-1 (3

T S

L

.d g n

N

5 AASTHO BOX BEAM, TYPE BI-36

PRECAST = 7,000 psi

W-STEEL BEAM, AASTHO M-180

"4 113’-6

T y p

L StructureC

T y p

(Typ.)

3’-0"

15’-3" (Typ.)

"4

(Typ.)

Bridge Length = 65’-0"

L Structure L RoadwayC C

12+00

1.429%

CL

Existing groundline

Cat 8’-0" left of L Existing groundline at 8’-0" right of L

65’-0"

Begin Bridge

Sta. 11+88.71

Elev. 1744.46

End Bridge

Sta. 12+53.71

Elev. 1745.34

1:2 1:

2Propose groundline Existing groundline at

Profile grade

C SARGENT BROOK BRIDGE

TOWN HIGHWAY 13

SARGENT BROOK CREEK

VERMONT

J. ORTIZ

APPALACHIAN NATIONAL SCENIC TRAIL

NOT TO SCALE

RUTLAND

S a rg e n t

B ro o k C re e k

$ 350,000.00

Transverse post-tensioning LC

26°

(Typ.)

abutment Existing

HL-93

160’ VC

V P I

E L

,7

.0

+1.429

-3.773%

Bridge

65’-0"

E L

,7

.4

E L

,7

.3

S ta

.7

S ta

.7

1.429%

NOVEMBER 2012

Timber Guardrail Steel-backed

1’-6"1’-6"

ATTACHMENT 4

Bearing Resistance Chart

2 4 6 8 10 12 14 16

N o m in al B ea ri n g

R es is ta n ce ks f)

Effective Footing Width, Bf (ft)

Project VT ERFO APPA 2011-1(3) Town Highway 13 Over Sargent Brook Creek Bridge

Abutment 1 - Factored Bearing Resistance Chart

Service Limit State for settlement = 1 inch Strength Limit State Service Limit State for settlement = 1.5 inch

ATTACHMENT 5

Representative Photographs

Photograph #1 – Bridge Site - Looking south from Upstream

Photograph #2 – Looking west at the washed-out west Abutment

Photograph #3 - Looking east – Note the existing and prior east Abutments

Photograph #4 – Washed-out West Abutment – Note approximately 5 ft of fill material

Photograph #5 – Alluvial Deposits (Cobbles, boulders, gravel, sand and silt) at the West Abutment

Photograph #6 - East Abutment – Note Rock outcrop

Photograph #7 – Drilling at the proposed West Abutment (Abutment1)

Photograph #8 – Core Boxes from Boring 1, drilled at the West Abutment.