3-Reconstruction of Bridge 2904 Proposal Report Attachment Structure Foundation Recommendations.pdf

E-Mailed June 15, 2023 (marena@hrg-inc.com)

Revised January 11, 2024

Herbert, Rowland & Grubic, Inc. (HRG)

220 West Kensinger Drive, Suite 100

Cranberry Township, PA 16066

Attention: Matthew J. Arena, P.E.

Project Engineer

Re: Bridge No. 2904

T-546 (Bend Rd.) Over Branch of

Little Neshannock Creek

Wilmington Township, Mercer County, Pennsylvania

GMI Project No. 22025

Structure Foundation Recommendations

Gentlemen:

GeoMechanics, Inc. is pleased to present Structure Foundation Recommendations for the above-referenced bridge replacement project in Sugar Grove, Wilmington Township, Mercer

County, Pennsylvania.

Our original report has been revised to reflect the additional boring 2904-2A that was drilled at Abutment 2 to provide additional subsurface data, and the revised ABLRFD analysis for

Abutment 2 that was provided by HRG.

We wish to once again extend our appreciation for this opportunity to be of service to you on this interesting and challenging project. Should you have any questions regarding the attached recommendations or require additional information, please contact us.

Very truly yours, GEO-MECHANICS, INC.

Betty J. Murphy Walter M. Lorence, P.E.

Vice President Executive Vice President

\BJM

z:\2022\22025\Reports\Bridge 2904\Bridge 2904 Report Rev 2024-01-11 (22025).docx

FOUNDATION RECOMMENDATIONS

1. Summary of Foundation Recommendations

2. Foundation Recommendations

Based on our analyses of the test boring and laboratory testing information obtained specifically for this project, the following recommendations are presented as guidelines for the design and construction of the proposed bridge carrying Bend Road (T-546) over the Branch of Little

Neshannock Creek in Wilmington Township, Mercer County, Pennsylvania.

2.1 Type and Depth of Foundations

• Use conventional spread footings bearing on dense to very dense Glacial Till for foundation support.

• Place the bottom of the footing a minimum of 6 feet below streambed.

• Refer to Section 1 - Summary of Foundation Recommendations above for the design bearing elevations, ultimate bearing resistance and resistance factor for design.

STR-1

Max. Fin.

(ksf)

SER-1

Max. Fin.

(ksf)

Abutment 1 18.83 7.57 6.30 4.40 16.54 0.45 7.44 <1

Wing A 16.99 10.88 4.27 2.92 17.05 0.45 7.67 <1

Wing B 17.25 9.88 4.23 2.89 15.82 0.45 7.12 <1

Abutment 2 16.50 7.50 6.13 4.3 14.20 0.45 6.39 <1

Wing C 14.92 10.58 3.54 2.43 15.22 0.45 6.89 <1

Wing D 14.92 10.08 3.52 2.42 15.39 0.45 6.93 <1

Factored

Bearing

Resistance

(ksf)

Estimated

Settlement

(in.)

2904-1 988.12

Glacial

Till

2904-2 and

2904-2A

989.92

Substructure Applicable

Boring(s)

Bottom of

Footing

Elevation

(ft.)

Footing

Width

(ft.)

Depth of

Embedment

Df

(ft.)

Bearing

Material

Foundation Pressure Ultimate

Bearing

Resistance

(ksf)

Bearing

Resistance

Factor

2.2 Lateral Earth Pressure Criteria

• Depending on their flexibility, the abutments and wingwalls should be designed as either rigid or flexible retaining walls and utilize current

Department design criteria for fully saturated soils to estimate the “at-rest” or “active” lateral earth pressures, respectively, acting against the walls. For cast-in-place abutments and wingwalls, assuming flexible wall design and horizontal backfill, use an equivalent hydrostatic pressure of 35 PCF in designing the walls plus traffic surcharge loads and full hydrostatic pressure for any water retained in the structure backfill.

• Backfill behind the abutments and wingwalls in accordance with PennDOT

Standard Drawing RC-12M.

• Provide adequate drainage behind the abutments and wingwalls to reduce the buildup of any hydrostatic pressure in accordance with PennDOT Standard drawing BC-751M.

2.3 Foundation Preparation

• Completely remove the existing structure prior to construction of the proposed abutments and wings.

• Continuously dewater all foundation excavations extending below groundwater.

• Prior to placement of Class C cement concrete and foundation concrete, the foundation bearing surfaces are to be inspected by the Representative.

• Thoroughly proof-roll the bottom of the foundation excavation prior to placing fille. If soft, wet zones are disclosed during proof-rolling, overexcavate them to a maximum depth of two (2) feet; and backfill with coarse aggregate or lean concrete under controlled conditions. For depths of unsuitable materials greater than two (2) feet below the foundation elevation, immediately notify the Representative.

• Upon approval of the bearing surface, place Class C cement concrete and / or a mud mat over the entire bearing surface prior to the end of work shift to minimize exposure of the bearing surface to groundwater or to surface water.

2.4 Temporary Excavations

• Design all temporary excavations in accordance with current OSHA requirements (29 CFR Part 1926.650-.652, Subpart P) assuming Type C

Soils.

2.5 Notes on Drawings

• Include the following general notes pertaining to geotechnical considerations on the structure drawings:

1. Completely remove the existing structure.

2. Bottom of excavations may be ordered at any elevation by the

Representative in order to provide a proper foundation.

3. Thoroughly proof-roll the bottom of the foundation excavation prior to placing fill. If soft, wet zones are disclosed during proof-rolling, overexcavate them to a maximum depth of two (2) feet; and backfill with coarse aggregate or lean concrete under controlled conditions. For depths of unsuitable materials greater than two (2) feet below the foundation elevation, immediately notify the Representative.

4. Upon approval of the bearing surface, place Class C cement concrete and / or a mud mat over the entire bearing surface prior to the end of work shift to minimize exposure of the bearing surface to groundwater or to surface water.

5. Notify the Representative at least 48 hours before the requested date and time of the inspection of an excavation. The Contractor is responsible for providing sufficient dewatering so that the excavations are dry enough to be inspected by the Representative.

6. Continuously dewater all foundation excavations extending below groundwater.

7. The Contractor is responsible for the stability of all temporary excavations.

Direct surface runoff away from the excavations. Perform all excavations in accordance with OSHA requirements.

2.6 Limitations

• During construction, if subsurface conditions are encountered that differ significantly from those reported herein, GeoMechanics, Inc. (GMI) should be notified immediately so that the analyses and recommendations presented herein can be reviewed and/or revised accordingly.

• In preparing this report, our professional services have been performed, our data has been obtained and our conclusions and recommendations have been prepared in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties either expressed or implied. GMI assumes no responsibility for interpretations made by others based upon work or evaluations made by GMI.

TEST BORING RECORDS

Test Boring Records Included:

Borings 2409-1, 2409-2 and 2904-2A

50/.2

1.5

4.5

7.5

10.5

13.5

16.5

19.5

21.7

0.0

6.0

9.0

18.0

Brown SILTY CLAY and SAND, Some Gravel, Stiff, Damp

.Gravel Content Increases With Depth

(Fill)

Light Brown-Gray SAND and GRAVEL, Some Silt, Very Dense, Dry .Sub-Angular Sandstone Gravel

(Alluvial)

DArk Brown to Gray SILTY GRAVEL and SAND, Some Clay, Medium Dense to Dense, Wet to Damp

.Dense From 12.0-13.5'

(Glacial Till)

Gray SILTY SAND and GRAVEL, Some Clay, Very Dense, Damp

.Very Calcareous

(Glacial Till)

Wet @ 12.0'

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-1 Elevation 1010± Sheet No. 1 of sheets

Drill Rig CME-55 For Mercer County Bridge No. 2904 Water Level: O-Hr. 15.4 24 Hrs. T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 10/4/22 Completed 10/4/22 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log JAD

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)

D E S C R I P T I O N REMARKS

975.6

50/.4

25.5

28.5

31.5

34.4

25.0

30.0

34.4

Continued From Previous Page

Gray Sandy Silt, Little Gravel, Trace Clay, Hard, Damp .Sand and Gravel Content Decreases With Depth

(Glacial Till)

Bottom of Boring @ 34.4'

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-1 Elevation 1010± Sheet No. 2 of sheets

Drill Rig CME-55 For Mercer County Bridge No. 2904 Water Level: O-Hr. 15.4 24 Hrs. T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 10/4/22 Completed 10/4/22 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log JAD

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)

1.5

4.5

7.5

10.5

13.5

16.5

19.5

22.5

0.0

9.0

15.0

Brown to Gray SILTY GRAVEL, Some Sand, Trace Clay, Very Loose to Loose, Damp to Dry

(Fill)

Brown SILTY Fine SAND, Little Clay, Trace Gravel, Very Loose to Loose, Damp to Dry

(Alluvial)

Gray SILTY GRAVEL, Some Sand, Trace Clay, Medium Dense to Very Dense, Damp to Wet

(Glacial Till) Driller Reported Water @ 18.0'

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-2 Elevation 1009± Sheet No. 1 of sheets

Drill Rig CME-55 For Mercer County Bridge No. 2904 Water Level: O-Hr. 20.8 24 Hrs. T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 10/4/22 Completed 10/4/22 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log TDW

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)

50/.3

25.3

28.5

31.5

35.0

25.0

30.0

35.0

Continued From Previous Page

Gray Sandy Silt, Little Gravel, Trace Clay, Very Stiff Hard, Moist

(Glacial Till)

Bottom of Boring @ 35.0'

ML

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-2 Elevation 1009± Sheet No. 2 of sheets

Drill Rig CME-55 For Mercer County Bridge No. 2904 Water Level: O-Hr. 20.8 24 Hrs. T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 10/4/22 Completed 10/4/22 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log TDW

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)

50/.4

22.5

24.4

0.0

21.0

Unsampled Augering to 21.0'

Gray SILTY GRAVEL, Some Sand, Trace Clay, Medium Dense to Very Dense, Damp

.Traces of Carbonaceous Fines From 21.0-22.5'

(Glacial Till)

Started Sampling @ 21.0'

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-2A Elevation 1009± Sheet No. 1 of sheets

Drill Rig CME-55 Track For Mercer County Bridge No. 2904 Water Level: O-Hr.Backfilled24 Hrs. N/A T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 12/29/23 Completed 12/29/23 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log TDW

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)

50/.2

50/.4

50/.4

28.5

31.5

34.5

37.5

40.5

42.7

45.4

48.9

33.0

Continued From Previous Page

Gray Sandy Silt, Trace to Little Clay, Little to Trace Gravel, Very Hard, Damp to Moist

(Glacial Till)

ML

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-2A Elevation 1009± Sheet No. 2 of sheets

Drill Rig CME-55 Track For Mercer County Bridge No. 2904 Water Level: O-Hr.Backfilled24 Hrs. N/A T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 12/29/23 Completed 12/29/23 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log TDW

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)

942.6

50/.1

50/.4

50/.2

50/.3

50/.1

50/.4

51.6

54.4

57.7

61.3

64.1

66.4

50.0

57.0

60.0

66.4

Continued From Previous Page

Gray CLAYEY SAND, Little Gravel, Little Silt, Very Dense, Moist

(Glacial Till)

Gray SILTY CLAY, Some Sand, Little Gravel, Hard, Damp to Dry

.Gray Component Consists of Claystone/Siltstone Fragments;

Breaks Down Easily With Hand Pressure

(Residual)

Bottom of Boring @ 66.4'

GEO-MECHANICS, INC. TEST BORING RECORD

Surface Driller Matt Hart Boring No. 2904-2A Elevation 1009± Sheet No. 3 of sheets

Drill Rig CME-55 Track For Mercer County Bridge No. 2904 Water Level: O-Hr.Backfilled24 Hrs. N/A T-546 (Bend Road) Over Little Neshannock Creek Casing Hammer: Wt. lbs. Drop in.

Sampler Hammer: Wt. 140 lbs. Drop 30 in. Location Wilmington Township, Mercer County, PA Sampler Size 2 in. O.D. Casing Size 3.25 in. I.D. Started 12/29/23 Completed 12/29/23 Project No. 22025 Core Bit Size N/A Driller's Log Drilling Fluid N/A Orientation Vertical Geologist's Log TDW

E L

E V

A T

IO

N

In-Situ Tests and

Instrumentation

RQD

RUN-REC.

INTERV.

SPOON

BLOWS

BOTTOM

DEPTH

OF

SAMPLE

DEPTH

(Ft.)