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Article 25 - MA03104 Old Shepard St Dam Canton Design Report - Signed
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Source page 41
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Source page 42
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Source page 43
Groundwater: Project: Old Shepard Street Dam Repairs, MA03104 Boring No. SA-1-OW
Depth: In obs. 7.4 ft 7.5 ft. 7.5 ft. 7.75 ft. Location: Canton, Massachusetts Sheet 1 of 2
Time: well: 1 hr 2 hr 4.5 hr. 2/29 Contractor: Northern Drill Sampler Type: Split spoon ID 1.375" OD 2"
Foreman: Tim Tucker Hammer Wt.: 140 lb Fall: 30"
Casing Blows
Start Date: 2/17/2016 Drill Technique: Casing ID 4" OD 4.5"
Sample No.
Field Tests
Depth (ft.) Finish Date: 2/17/2016 Rig Type: Mobile Drill B-48 Track Mount
Blows/6"
Pen. (in.)
Rec. (in.)
Remarks
SACE Staff: N. Olson Project Number: 052-15-022
Surface El.: + 116 ft Datum: NGVD 1929 Equipment
Description & Classification Stratum Installed
0
0.2 SS-1 24 14 16 ~2 in. asphalt. ASPHALT 1
19 Dense, brown, fine to coarse SAND, little non-plastic
14 Silt, little fine to coarse Gravel, moist.
Concrete
13
Protective Casing
2 SS-2 24 13 8 Medium dense, brown, fine to coarse SAND, some non-
7 plastic Silt, little fine Gravel, moist.
10 ft of 2" ID PVC Well riser
5
5 Driller adv. casing and roller bit to ~4 ft. after SS-2.
Bentonite
4 SS-3 24 7 6 Medium dense, brown, fine to coarse SAND, some fine
6 Gravel, little Silt, wet.
5
6
9
FILL
6 SS-4 24 2 10 Medium dense, brown, fine to medium SAND, litle silt,
9 little fine gravel, trace coarse sand. 2 in. piece of
7 coarse gravel in sampler tip.
4 Driller adv. casing ~4 to ~8 ft. after SS-4. Gravel jammed
between drill rods and casing, casing dropped to ~8.5 ft.
8.5 SS-5 24 4 3 SS-5A: ~2 in. similar to SS-4.
1 SS-5B: ~2 in. dark brown, fine SAND, little fines, little
fine Gravel, trace coarse sand, trace organics, wet.
10 1/12"
Driller adv. casing and roller bit to ~10.5 ft. after SS-5.
10.5 SS-6 18 0 4 No recovery
Drive Casing (blows not recorded)
5
4
Sand backfill
12 SS-7 24 10 11 Dense, gray, fine to coarse SAND and fine to coarse
10 ft. 2" ID Slotted PVC Well
21 GRAVEL, little non-plastic Silt, wet.
21
4.5" diameter borehole
27 Driller adv. casing and roller bit to ~14 ft. after SS-7.
14 SS-8 24 16 20 Similar to SS-7.
20
15
20
21
SILTY SAND AND GRAVEL
19 SS-9 5 0 100/5" No recovery.
20
Driller advanced roller bit ahead of casing ~19 to 21 ft.,
and noted boulder ~19.5 to 20.5 ft.
when casing removed to 20 ft.
Hole collapsed at 21.5 ft. bgs
24 SS-10 24 17 23 Very dense, grayish brown, fine to coarse GRAVEL and
35 fine to coarse SAND, trace silt, wet.
25
26
33
1. Driller drove spoon and casing with 140-lb automatic hammer. 2. SA measured pond water
Remarks
El. ~113.5 ft. during drilling
Soil/rock strata and groundwater surface, where indicated, are approximate. Transitions may be gradual.
Variations between exploration locations and over time should be expected.
Boring No.: SA-1-OW Location: See Exploration Location Plan 668 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 44
Groundwater: Project: Old Shepard Street Dam Repairs, MA03104 Boring No. SA-1-OW
Depth: See Sheet 1 Location: Canton, Massachusetts Sheet 2 of 2
Time: Contractor: Northern Drill Sampler Type: Split spoon ID 1.375" OD 2"
Foreman: Tim Tucker Hammer Wt.: 140 lb Fall: 30"
not recorded) Casing Blows
Start Date: 2/17/2016 Drill Technique: Casing ID 4" OD 4.5"
Sample No.
Field Tests
Depth (ft.) Finish Date: 2/17/2016 Rig Type: Mobile Drill B-48 Track Mount
Blows/6"
Pen. (in.)
Rec. (in.)
Remarks
SACE Staff: N. Olson Project Number: 052-15-022
Surface El.: + 116 ft Datum: NGVD 1929 Equipment
Description & Classification Stratum Installed
Drive cas. (blows
SILTY SAND AND GRAVEL
29 SS-11 24 15 26 Similar to SS-10.
40
30
51
71 Driller advanced roller bit to ~31.5 ft., noted boulder, then
advanced casing to ~31.5 ft.
Open Hole
Driller noted boulder ~31.5 to 33 ft. based on drilling
difficulty.
34 SS-12 24 14 36 Similar to SS-10.
23
35
26
25
Boring terminated at ~36 ft. Drillers installed observation
well in boring.
40
45
50
55
Remarks
Soil/rock strata and groundwater surface, where indicated, are approximate. Transitions may be gradual.
Variations between exploration locations and over time should be expected.
Boring No.: SA-1-OW Location: See Exploration Location Plan 668 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 45
Groundwater: Project: Old Shepard Street Dam Repairs, MA03104 Boring No. SA-2-OW
Depth: 3.9 ft. in casing In obs. 5.4 ft. 6.8 ft. Location: Canton, Massachusetts Sheet 1 of 1
Time: End of drilling well: 2 hr 2/29 Contractor: Northern Drill Sampler Type: Split spoon ID 1.375" OD 2"
Foreman: Tim Tucker Hammer Wt.: 140 lb Fall: 30"
Casing Blows
Start Date: 2/17/2016 Drill Technique: Casing ID 4" OD 4.5"
Sample No.
Field Tests
Depth (ft.) Finish Date: 2/17/2016 Rig Type: Mobile Drill B-48 Track Mount
Blows/6"
Pen. (in.)
Rec. (in.)
Remarks
SACE Staff: N. Olson Project Number: 052-15-022
Surface El.: + 116 ft Datum: NGVD 1929 Equipment
Description & Classification Stratum Installed
0
0.2 SS-1 24 15 12 ~2 in. asphalt. ASPHALT
4 ft of 2" ID PVC Well
18 ~5 in. black sand and gravel, moist.
15 ~15 in. dense, brown, fine to coarse SAND, little non-
Concrete
12 plastic Silt, little fine to coarse Gravel, moist. (Sample)
Protective Casing
2 SS-2 24 7 8 Similar to SS-1 except medium dense, wet.
13
13
FILL
9 Driller adv. casing and roller bit 0 to 4 ft. after SS-2.
Drive Casing (blows not recorded)
Bentonite
4 SS-3 24 7 11 Medium dense, brown, fine to coarse SAND, little non-
6 plastic Silt, trace fine gravel, wet.
5
7
3
6 SS-4 24 9 4 Similar to SS-3 except loose.
3
10 ft. 2" ID Slotted PVC Well
1
1 Driller adv. casing and roller bit ~4 to 8 ft. after SS-4.
8 SS-5 24 0 3 SS-5: No recovery.
2 Driller attempted to push 3 in. sampler from 8 to 10 ft.,
1 no recovery.
1 Driller adv. casing and roller bit ~8 to 10 ft. after SS-5.
4.5" diameter borehole
10
10 SS-6 24 6 2 Similar to SS-3 except loose.
3
Sand backfill
1
6
12 SS-7 24 18 29 Dense, grayish brown, fine to coarse SAND and fine to
SILTY SAND AND GRAVEL
23 coarse GRAVEL, little Silt, wet.
20
18
14 SS-8 24 9 14 Similar to SS-7 except medium dense.
15
15
14
13
Boring terminated at ~16 ft. Drillers installed observation
well in boring.
20
25
1. Driller drove spoon and casing with 140-lb automatic hammer. 2. SA measured pond water
Remarks
El. ~113.5 ft. during drilling
Soil/rock strata and groundwater surface, where indicated, are approximate. Transitions may be gradual.
Variations between exploration locations and over time should be expected.
Boring No.: SA-2-OW Location: See Exploration Location Plan 668 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 46
Project: Number: 052-15-022 Sheet 1 of 1
Name: Old Shepard Street Dam Repairs, MA03104
Original Work: Canton, Massachusetts
By: NAO Date: March 15, 2016 Subject: Laboratory Testing
Checked By: JET Date: April 1, 2016 Particle Size Analysis - ASTM D 422-63(2002)
Boring Number: SA-1 Sieve Particle Specification
Percent Finer
Sample Number: SS-3 Designation Size (mm) Percent Finer
Sample Depth: 4 - 6 ft 3/4" 19 100.0
1/2" 12.5 98.9
Sample Description: 3/8" 9.5 90.3
Brown, hard, subangular, fine to coarse SAND, #4 4.75 79.1
some fine Gravel, little fines. #8 2.36 69.1
#10 2 66.6
#16 1.18 57.9
#30 0.6 47.4
Coefficients, Proportions and USCS Classification #50 0.3 36.8
D10 = 0.03 mm % Gravel = 21 #100 0.15 28.0
D30 = 0.18 mm % Sand = 62 #140 0.106 22.1
D60 = 1.30 mm % Coarse Sand = 13 #200 0.075 17.3
Cu = 51.4 % Medium Sand = 24 Hydrometer 0.035 11.7
Cc = 0.88 % Fine Sand = 25 0.023 9.3
% Fines = 17 0.013 7.0
USCS Classification % Silt Size = 13 0.010 6.0
SM % Clay Size = 4 0.007 4.8
0.003 3.1
Comments: 0.001 1.8
Sample dispersed using Apparatus A (60
seconds)
Particle Size Distribution Plot
#100
#140
#200
3/4"
1/2"
3/8"
#10
#16
#30
#50
#4
#8
100
90
80
70
Percent Finer
60
50
40
30
20
10
0
100 10 1 0.1 0.01 0.001
Particle Size (mm)
Copyright © 2016 Stephens Associates Consulting Engineers LLC
Revisions:
By: Date:
By: Date:
www.stephensengineers.com 68 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 47
Project: Number: 052-15-022 Sheet 1 of 1
Name: Old Shepard Street Dam Repairs, MA03104
Original Work: Canton, Massachusetts
By: NAO Date: November 30, 2016 Subject: Laboratory Testing
Checked By: JET Date: November 30, 2016 Particle Size Analysis - ASTM D 422-63(2002)
Boring Number: SA-1 Sieve Particle Specification
Percent Finer
Sample Number: SS-5A Designation Size (mm) Percent Finer
Sample Depth: 8.5 - 8.7 ft. 3/4" 19 100.0
1/2" 12.5 96.0
Sample Description: 3/8" 9.5 91.3
Dark brown, hard, subangular, fine to medium #4 4.75 85.9
SAND, little fines, little fine Gravel, trace coarse #8 2.36 79.4
sand. #10 2 78.4
#16 1.18 74.0
#30 0.6 67.1
Coefficients, Proportions and USCS Classification #50 0.3 56.9
D10 = 0.03 mm % Gravel = 14 #100 0.15 40.1
D30 = 0.11 mm % Sand = 67 #140 0.106 27.2
D60 = 0.37 mm % Coarse Sand = 8 #200 0.075 19.1
Cu = 11.8 % Medium Sand = 16 Hydrometer 0.037 10.7
Cc = 1.12 % Fine Sand = 43 0.023 8.7
% Fines = 19 0.014 7.1
USCS Classification % Silt Size = 15 0.010 5.7
SM % Clay Size = 4 0.007 4.8
0.003 3.0
Comments: 0.001 1.9
Sample dispersed using Apparatus A (60
seconds)
Particle Size Distribution Plot
#100
#140
#200
3/4"
1/2"
3/8"
#10
#16
#30
#50
#4
#8
100
90
80
70
Percent Finer
60
50
40
30
20
10
0
100 10 1 0.1 0.01 0.001
Particle Size (mm)
Copyright © 2016 Stephens Associates Consulting Engineers LLC
Revisions:
By: Date:
By: Date:
www.stephensengineers.com 68 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 48
Project: Number: 052-15-022 Sheet 1 of 1
Name: Old Shepard Street Dam Repairs, MA03104
Original Work: Canton, Massachusetts
By: NAO Date: November 30, 2016 Subject: Laboratory Testing
Checked By: JET Date: November 30, 2016 Particle Size Analysis - ASTM D 422-63(2002)
Boring Number: SA-1 Sieve Particle Specification
Percent Finer
Sample Number: SS-7 Designation Size (mm) Percent Finer
Sample Depth: 12 - 14 ft. 1-1/2" 37.5 100.0
1" 25 78.2
Sample Description: 3/4" 19 73.0
Gray, hard, subangular, fine to coarse SAND and 1/2" 12.5 72.2
fine to coarse GRAVEL, little fines. 3/8" 9.5 68.0
#4 4.75 62.0
#8 2.36 55.2
#10 2 53.4
Coefficients, Proportions and USCS Classification #16 1.18 46.1
D10 = 0.04 mm % Gravel = 38 #30 0.6 35.0
D30 = 0.45 mm % Sand = 50 #50 0.300 22.7
D60 = 3.90 mm % Coarse Sand = 9 #100 0.150 15.8
Cu = 92.6 % Medium Sand = 25 #200 0.075 11.8
Cc = 1.27 % Fine Sand = 17 Hydrometer 0.035 9.5
% Fines = 12 0.023 7.9
USCS Classification % Silt Size = 9 0.013 6.1
SW-SM % Clay Size = 3 0.010 5.2
0.007 4.1
Comments: 0.003 2.4
Sample dispersed using Apparatus A (60 0.001 1.6
seconds)
Particle Size Distribution Plot
1-1/2"
#100
#200
3/4"
1/2"
3/8"
#10
#16
#30
#50
#4
#8
1"
100
90
80
70
Percent Finer
60
50
40
30
20
10
0
100 10 1 0.1 0.01 0.001
Particle Size (mm)
Copyright © 2016 Stephens Associates Consulting Engineers LLC
Revisions:
By: Date:
By: Date:
www.stephensengineers.com 68 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 49
Project: Number: 052-15-022 Sheet 1 of 1
Name: Old Shepard Street Dam Repairs, MA03104
Original Work: Canton, Massachusetts
By: NAO Date: November 30, 2016 Subject: Laboratory Testing
Checked By: JET Date: November 30, 2016 Particle Size Analysis - ASTM D 422-63(2002)
Boring Number: SA-2 Sieve Particle Specification
Percent Finer
Sample Number: SS-4 Designation Size (mm) Percent Finer
Sample Depth: 6 - 8 ft. 3/4" 19 100.0
1/2" 12.5 100.0
Sample Description: 3/8" 9.5 96.1
Brown, hard, fine to coarse subangular SAND, #4 4.75 89.7
little fines, trace fine subangular gravel. #8 2.36 81.9
#10 2 79.7
#16 1.18 72.8
#30 0.6 64.7
Coefficients, Proportions and USCS Classification #50 0.3 51.2
D10 = 0.02 mm % Gravel = 10 #100 0.15 34.1
D30 = 0.13 mm % Sand = 70 #140 0.106 25.5
D60 = 0.47 mm % Coarse Sand = 10 #200 0.075 19.7
Cu = 22.2 % Medium Sand = 22 Hydrometer 0.035 12.6
Cc = 1.61 % Fine Sand = 38 0.023 10.3
% Fines = 20 0.013 8.0
USCS Classification % Silt Size = 15 0.010 6.7
SM % Clay Size = 5 0.007 5.6
0.003 3.7
Comments: 0.001 1.9
Sample dispersed using Apparatus A (60
seconds)
Particle Size Distribution Plot
#100
#140
#200
3/4"
1/2"
3/8"
#10
#16
#30
#50
#4
#8
100
90
80
70
Percent Finer
60
50
40
30
20
10
0
100 10 1 0.1 0.01 0.001
Particle Size (mm)
Copyright © 2016 Stephens Associates Consulting Engineers LLC
Revisions:
By: Date:
By: Date:
www.stephensengineers.com 68 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 50
Transmittal
Date: 16 February 2016 Number of Pages (incl. cover):
To: Nathaniel A. Olson, PhD, PE Tel. 978-988-2115
Stephens Associates Consulting Engineers, Number:
LLC Fax 978-988-2117
668 Main St., Ste. 250 Number:
Wilmington, MA 01887
E-Mail: naolson@stephensengineers.com
Copies James Turner Tel.
to: Stephens Associates Consulting Engineers, Number:
LLC Fax
668 Main St., Ste. 250 Number:
Wilmington, MA 01887
E-Mail:
Laboratory Testing Services for Deteriorating Concrete Removed from the Old Shepard Street
Project:
Dam, Massapoag Brook, Canton, MA
Project
From: Daniela M. Mauro 160046
Number:
Delivered Via: U.S. Mail Fax Hand Carried E-Mail
Overnight Messenger Pick up with Attachments
Copies Delivered U.S. Mail Fax Hand Carried E-Mail
Via: Overnight Messenger Pick up with Attachments
Comments:
Nathan,
Attached please find the petrography report for Core SA-C3 and the compression testing report
for Core SA-C4.
Please review the reports and let me know if you have any questions or would like to discuss any
of the results.
Thanks again for reaching out to us for your testing needs, we look forward to hopefully working
with you again in the future.
Sincerely,
Daniela M. Mauro
Per Your Request Approved No Correction
For Your Information/Records Approved as Noted Not Approved
For Your Approval/Comments Revise and Resubmit Resubmit for Record Copy
For Your Review/Comments Returning to You Please Return
I:\BOS\Projects\2016\160046.00-TEST\WP\001DMMauro-T-160046.ras.docxSource page 51
PETROGRAPHIC EXAMINATION RESULTS
Date: 16 February 2016
Material: Concrete Test: ASTM C856 Conducted by: Daniela M. Mauro
Project: 160046 – Laboratory Testing Services for Deteriorating Concrete Removed
from the Old Shepard Street Dam, Massapoag Brook, Canton, MA
Subject: Petrographic Examination of Hardened Concrete
SAMPLE DESCRIPTION
The test sample is composed of a single partial-depth concrete core identified as SA-C3, as
shown in Photos 1 through 3.
Prior to cutting the sample, we impregnated the core with blue-dyed epoxy so that the core would
remain intact during sample preparation. After we impregnated the sample, we cut a longitudinal,
nominal 1 in. thick section from the center of the core. We polished the cut section to produce a
flat, smooth surface for use in conducting our petrographic examination (Photo 4). We also
prepared an ultrathin (20 to 25 µm) section from face opposing the polished cross section. For
the ultrathin section, we also added a blue dye to the epoxy resin that we use to strengthen the
paste during the preparation and of the ultrathin section. We examined both the polished section
and the prepared ultrathin section during our petrographic examination.
Nominal Length: 10 in. to 10-3/4 in. Diameter: 5-1/2 in.
Dimensions:
Condition:
The as-received sample exhibited cracking and was broken into multiple pieces. The exterior
surface of the core exhibits exposed sand grains (Photo 1). We observed dark rims and white
material around coarse aggregat particles on broken surfaces (Photo 3). We observe
microsfractures, as well as macrofractures, throughout the full depth of the core.
The interior surface of the core exhibits a fractured surface from sample removal.
Cracking:
The submitted core sample contains both macroscopic and microscopic fractures. The core is
broken into multiple pieces along large fractures (Photo 4). These large fractures break
aggregates and paste, and travel through well-developed air voids.
On a microscopic scale, we observe evidence of alkali silica reaction (ASR). We observe siliceous
aggregate particles that contain fractures emanating from with the aggregate into the paste (PhotoSource page 52
Petrographic Report – Project 160046 -2- 16 February 2016 5). Within the fractures, we observe ASR gel (Photo 6). We also observe fractures from ASR- affected aggregates traveling throughout the cement paste and into adjacent aggregates, as well as through air voids. Throughout the concrete, we observe interconnecting fractures due to the ASR. Coloration: The concrete paste exhibits a medium grey color, with light areas of paste around some coarse aggregate particles. The exterior 2 in. of the core contains a higher paste volume as compared to the body of the core. The higher paste volume contains air voids that are filled with white deposits, which make this area of the core appear lighter as compared to the rest of the core. Carbonation Depth: We observe leaching and carbonation along the exterior surface of the core sample. The leached paste, which appears devoid of cementitious hydration products, is superficial and extends to 1/32 in. from the exterior surface. Carbonation along the exterior of the core extends approximately 3/16 in. into the body of the core (Photo 7), and travels up to 1/2 in. along fractures perpendicular to the exterior face. Deterioration: We observe a thin (1/32 in.) layer of leached paste along the exterior of the concrete that is devoid of cementitious hydration products. Within the concrete, we observe evidence of ASR, with cracks emanating from aggregates into the paste, with occasional interconnecting cracks within the paste. The cracks contain ASR gel. REINFORCING STEEL None observed. AGGREGATE DESCRIPTION Coarse Aggregate: The coarse aggregate consists of nominal 1 in. rounded aggregate. The concrete exhibits a moderate to well-developed paste-to-aggregate (P/A) bond strength on a fresh fracture surface. We observe an abundance of air voids along occasional coarse aggregate particles, which results in a weaker P/A bond strength as compared to aggregate particles that do not contains high volumes of air voids surrounding them. We observe darker colored reaction rims around occasional coarse aggregate particles. Type: The coarse aggregate is composed of a variety of rock particles including granite, felsite, and rhyolite.
Source page 53
Petrographic Report – Project 160046 -3- 16 February 2016 Shape/Gradation: The coarse-aggregate particles are rounded in shape. The aggregate appears to be gap graded, with only occasional 3/4 in. nominal aggregate present. Distribution: We observe coarse aggregate segregation. The exterior 2-1/2 in. of concrete contains significantly less coarse aggregate particles than the rest of the core sample. Fine Aggregate: The fine aggregate consists of natural sand. Type: The fine aggregate is composed of siliceous sand, mainly composed of quartz, with lesser amounts of feldspar, igneous rock, and sand-sized, angular particles of the coarse aggregate. Shape/Gradation: The sand particles are sub angular to sub round in shape, and uniformly graded. Distribution: The fine-aggregate particles are uniformly distributed. PASTE STRUCTURE Texture: Overall, the paste structure exhibits a microcrystalline to sugary texture, with sub translucent to opaque color, and a sub vitreous to dull luster. Composition: The concrete contains portland cement (Photo 8). The paste structure exhibits a normal to advanced degree of cement hydration, as determined by the frequency of residual (partially hydrated) and relict (fully hydrated) particles of portland cement. Supplementary Cementitious Materials: We do not observe supplementary cementitious materials such as fly ash or ground-granulated blast furnace slag. Bleeding: We do not observe evidence of excessive bleeding.
Source page 54
Petrographic Report – Project 160046 -4- 16 February 2016
Water/Cementitious Material (w/cm) Ratio:
Based on the color, texture, and overall composition of the paste structure that we observe, the
concrete in Core SA-C3 contains a w/cm that we estimate to be in the range of 0.35 to 0.45, with
the majority of the paste exhibiting features closer to the higher end of the range.
AIR-VOID SYSTEM
The concrete is intentionally air-entrained. Based on a comparison with known laboratory
standards, we estimate that the core contains 7% to 8% total air. The air void system appears
over-developed, and contains an abundance of very fine air voids (Photo 9). We observe strings
of air voids surrounding occasional coarse aggregate particles.
DETERIORATION MECHANISMS
Sulfate Attack:
None observed.
Ettringite (form and distribution):
Normal. We observe ettringite partially to full-lining air voids and growing within cracks in the
concrete. The distribution and form of ettringite is normal.
Alkali Aggregate Reactivity (ASR):
We observe evidence of ASR that includes coarse aggregate particles with reaction rims, cracking
emanating from reactive aggregate particles into the surrounding cement paste and adjacent
aggregate particles, and deposits of ASR gel within cracks and aggregates.
Using our rating method, outlined in the attached document SGH Z010-15, we rate the extent of
the ASR as moderate, with a rating of “3” on a scale of 0 to 6, defined as follows:
Rating 3 - Moderate cracking (moderate evidence of deleterious ASR).
Cracks are beginning begin to form interconnecting networks and often may
exceed 50 μm in width. The ASR crack network will begin to link sites of expansive
reactive aggregate particles. Internal and peripheral cracking of aggregates may
be obvious and incorporated into the overall network. The contents of these cracks
may include substantial deposits of ASR gel, secondary sulfate minerals,
portlandite, or carbonate minerals.
Corrosion:
None observed. The submitted sample does include portions of reinforcing steel.
GENERAL REMARKS
The concrete in Core SA-C3 exhibits evidence of moderate ASR and minor chemical leaching of
the near surface of the concrete.Source page 55
Petrographic Report – Project 160046 -5- 16 February 2016 The concrete contains portland cement, with no other cementitious materials or pozzolans such as slag or fly ash. Overall, the w/cm ratio is generally uniform, and in the range of 0.35 to 0.45. We do not observe evidence of retempering of the concrete, which would result in a variable w/cm ratio throughout the core. Along the exterior of the core, we observe a thin, 1/32 in. zone of leached cement paste. The paste is leached of cementitious hydration products and is more porous than the underlying cement paste. The thin zone of leached paste is most likely due to the repeated exposure to water during service. Below the leached paste, we observe carbonated paste to a nominal depth of 3/16 in., with some carbonation reaching 1/2 in. along fractures. The concrete exhibits coarse aggregate segregation, where the exterior 2 in. of concrete contains a lower volume of coarse aggregate particles as compared to deeper in the concrete. The coarse aggregate is nominal 1 in. with few 3/4 in particles present. The coarse aggregate is composed of rounded particles of granite, felsite, and rhyolite. The fine aggregate is a natural, siliceous sand. The concrete is chemically air entrained, and we estimate that overall the core contains 7% to 8% air. The air void system is very fine, with many small air voids distributed throughout the paste. We observe strings and clusters of air voids around aggregate particles. Overall, the air system appears overly developed, with a multitude of small air voids, and few medium to large size voids. We also observe fracturing throughout the sample that breaks the core into multiple pieces. The large fractures appear to be from sample removal operations, because we do not observe carbonation along their perimeters. We also observe that the fractures travel through the cement paste, aggregate particles, and fully-developed air voids, indicating they occurred after final set of the concrete. While the fractures appear to be from sample removal, they may also follow planes of weakness and microcracks that are due to ASR. In the core, the smaller fractures that we observe are due to ASR. We observe reaction rims on coarse aggregate particles, fractures beginning within reactive aggregate particles and extending into the surrounding paste and through adjacent aggregate particles, as well as ASR gel within and around these fractures. These observations are consistent with evidence of ASR. According to our ASR rating scale which is outlined in document SGH Z010-15 and attached to this report, the severity of the ASR is moderate, with a rating of “3.” We do not observe evidence of other deterioration mechanisms such as sulfate attack or cyclic freezing and thawing damage within the concrete. I:\BOS\Projects\2016\160046.00-TEST\WP\001DMMauro-LR-160046.ras.docx
Source page 56
Photo 1
As received photograph of the exterior surface of Core SA-C3. The exterior
surface of the core exhibits exposed sand grains.
Photo 2
As received photograph of a portion of Core SA-C3. Note the fracturing in the
concrete.
SGH Project 160046 / February 2016Source page 57
Photo 3
As received photograph of a fractured surface parallel to the exterior surface of
Core SA-C3. Note the white material around coarse aggregate particles (red
arrows).
SGH Project 160046 / February 2016Source page 58
Photo 4
Polished cross section of Core SA-C3. Note cracks throughout the sample.
SGH Project 160046 / February 2016Source page 59
Photo 5
Coarse aggregate particle with internal fracturing that extends into the surrounding
cement paste (red arrows).
Photo 6
ASR gel in fractures throughout the core (red arrows point to ASR gel deposits
within a crack). Image is shown in cross polarized light with a full wave plate
inserted.
SGH Project 160046 / February 2016Source page 60
Photo 7
Along the exterior of the core, we observe a more porous, leached cement paste
(above red dotted line). Below the leached paste, we observe carbonated paste
(above the yellow dotted line.)
Photo 8
General view of the cement paste, showing cement grains (red arrows) and
entrained air voids (yellow arrows). Photo taken in cross polarized light with a full
wave plate inserted.
SGH Project 160046 / February 2016Source page 61
Photo 9
The core contains approximately 7% to 8% entrained air. The air voids are fine,
and often cluster around coarse aggregate particles (red arrows).
SGH Project 160046 / February 2016Source page 62
Laboratory Procedure/Method: C39 - Compressive Strength of Cylindrical Concrete Specimens
Exceptions to Procedure/Method:
Project: Laboratory Testing Services for Deteriorating Concrete Removed from the Old Shepard Street Dam, Massapoag Brook, Canton, MA
Sample Identification:
Submitted by: DMMauro
Date Submitted: 13 January 16
Curing Conditions/History: N/A
Date and time cast (if known): N/A
Date and time cored (if known): N/A
Location where sample was made: N/A
Specifics Relating to Uniqueness of Sample: None
Moisture Diameter (in.) Uncapped Length (in.) Capped Length (in.) Ends Perp. To
Specimen Ends Plane ± 0.002
Condition Mass (g) Axis ± 0.5°
ID 1 2 1 2 3 4 5 (center) 1 2 3 4 5 (center) in. (Yes/No)
(Dry/Moist) (Yes/No)
SA-C4 Dry 3.681 3.684 4.906 4.911 4.931 4.928 4.929 5.036 5.043 5.041 5.038 5.046 1961.91 Yes Yes
Average Cross- Capped Defects in
Specimen Uncapped Maximum Compressive Type of Density
Diameter sectional Length L/D L/D Factor Age Specimen
ID 2 Length (in.) Load (lbf.) Strength1 (psi) Fracture (pcf)
(in.) Area (in ) (in.) or Cap
SA-C4 3.683 10.651 4.921 5.041 1.37 0.94 53000 4680 III N/A No 142.7
Note 1: Compressive strength is rounded to the nearest 10 psi. When averaging two or more companion cylinders, calculate the average strength using
unrounded individual compressive strength values. ASTM C39 Sec. 9.1.6
file: I:\BOS\Projects\2016\160046.00-TEST\WP\001DMMauro-Worksheet-160046.ras.docx.xlsx
sheet: Data Entry Page 1 of 1 1:30 PM 2/16/2016Source page 63
Laboratory Method
Method Name: ASR Index Rating Scale
SGH Method SGH Z010-15
Designation:
Effective Date: 14 May 2015 Author: DMMauro
Expiration Date: 14 May 2016 Approver: AGDavies
QA Review: DPValentine
Last Revision Date: 14 May 2015 Reason for Annual review
Revision:
Supersedes (Title): N.A.
1. SCOPE
This test method describes how to assign an index rating scale value to polished concrete
sections that are affected by alkali silica reactivity (ASR).
2. QUALIFICATIONS
All ASR index rating scale evaluations shall be performed by or under the technical direction of
a full time supervising petrographer with at least 5 years of experience in conducting
petrographic examinations on concrete and concrete-making materials.
3. EQUIPMENT
Stereo reflected-light microscope.
Light source.Source page 64
Laboratory Test Method – Z010-15 -2- Effective Date 14 May 2015
4. SUPPLIES AND REAGENTS
N.A.
5. SAFETY
N.A.
6. STANDARDIZATION/CALIBRATION
N.A.
7. PROCEDURE
Prepare polished samples in accordance with SGH Z008.
Examine the polished concrete sample(s), in accordance with SGH C856, using a
stereo reflected-light microscope. Scan the sample and observe the occurrence of
ASR related features such as, but not limited to, cracks, the presence or absence of
crack networks, cracked aggregates, aggregate reaction rims, the presence of alkali
silica gel in cracks and voids, etc.
Measure sufficient number of crack widths to estimate the mean crack width on the
polished surface.
Compare the findings from the petrographic examination to “Assessment of Severity of
Alkali-Silica Reactivity (ASR) in Hardened Concrete by Petrographic Examination,”
(page 3) to assign an index rating scale value.
8. REPORT
At completing this evaluation, report the following:
A copy of the attached “Assessment of Severity of Alkali-Silica Reactivity (ASR) in
Hardened Concrete by Petrographic Examination,” or this document.
Index Rating Scale Value.
9. PRECISION AND BIAS
There is no established precision and bias for this method. To minimize bias and ensure
precision within a project, the same operator shall perform the ASR rating index assessments
on all samples for the same project.
10. REFERENCES
SGH Z008 Polishing Concrete Samples.
SGH C856 Standard Practice for Petrographic Examination of Hardened Concrete.Source page 65
Laboratory Test Method – Z010-15 -3- Effective Date 14 May 2015
The Diagnosis of Alkali-Silica Reaction, British Cement Association (BCA), 1992.
11. REVISION HISTORY
N.A.
ASSESSMENT OF SEVERITY OF ALKALI-SILICA REACTIVITY (ASR) IN HARDENED
CONCRETE BY PETROGRAPHIC EXAMINATION
The index rating scale (0 – 6) is based on an assessment of the severity of distress caused by
ASR in hardened concrete. Individual rating values are determined by visual and microscopic
examination of nonprepared concrete sections as well as polished and prepared ultrathin
sections. The examinations document the frequency, location, orientation, and origin of
cracking as well as other associated ASR-related features in the hardened concrete. This rating
system is based on a modified “best practice” procedure initially developed at the Building
Research Establishment (BRE) in the U.K., using ASR identification criteria first set out in the
BCA report titled “Diagnosis of Alkali-Silica Reaction” (1992).
Rating Description
0 No cracking detected.
No features or characteristics associated with alkali-silica reaction (ASR) detected.
1 Very slight cracking (No evidence of deleterious ASR).
A condition usually termed described as “microcracking.” Cracks are typically up to 30
µm in width, the majority of which are visible only on interior concrete surfaces,
confined mainly to the cement paste matrix, sometimes at cement/aggregate
interfaces, such as adhesion cracks. Cracks are short, isolated, and usually empty.
No significant internal aggregate cracking, and if present, aggregate fractures are
nonpropagating.
2 Slight cracking (minor or trace evidence of deleterious ASR).
Cracks are typically 30 – 40 µm in width, usually isolated, not forming a network.
Cracks may originate from aggregates but do not generally propagate very far into
surrounding cement matrix. Reaction rims are frequently also evident around the
perimeters of the “reacting” and distressed aggregate particles. Extensive crack
networks are not observed. Some internal and peripheral cracking of aggregates may
be present. Cracks may also be present on the boundaries of aggregate particles as
adhesion cracks. Visible ASR gel deposits in voids and cracks may be observed, but
not necessarily. The cracks are generally open. The cracks and air voids within the
concrete are occasionally partially filled with primary and/or secondary deposits of
sulfate, portlandite, or carbonate minerals.
3 Moderate cracking (moderate evidence of deleterious ASR).
Cracks are beginning begin to form interconnecting networks and often may exceed 50
µm in width. The ASR crack network will begin to link sites of expansive reactive
aggregate particles. Internal and peripheral cracking of aggregates may be obviousSource page 66
Laboratory Test Method – Z010-15 -4- Effective Date 14 May 2015
and incorporated into the overall network. The contents of these cracks may include
substantial deposits of ASR gel, secondary sulfate minerals, portlandite, or carbonate
minerals.
4 Severe cracking (severe evidence for deleterious ASR).
Cracks form an extensive interconnecting system throughout the concrete and often
exceed 100 µm in width. Sites of expansive ASR reaction are linked by heavily-
gel-filled cracks. Frequent internal and peripheral cracking of reacting aggregates may
have occurred. Concretes in this category may also show the effects of severe
leaching (depending on environment), and cracks may contain abundant secondary
ettringite, portlandite, or calcite.
5 Very severe ASR-related cracking.
Very large, open cracks occur frequently throughout the full depth of the examined
section. Cracks sometimes exceed 1.0 mm in width. Frequent aggregate cracking
may be evident (depending on type of rock) as will aggregate cement paste debonding.
Internal severe degradation of the reacting aggregate particles, being consumed by the
reaction, resulting in high porosity and void development, may occur. The effects of
leaching may be very advanced.
6 Heavily fractured ASR-related damage.
Occasional formation of surface spalls or partial disintegration to the point of forming
rubble.
Note
ASR related degradation can be more widespread when it develops concurrently with other
deleterious processes such as delayed ettringite formation (DEF), reinforcement corrosion,
freeze-thaw attack, etc. The presence and extent of such processes should also be assessed
during the petrographic examination.
I:\BOS\Projects\_Overhead\000180.60 BLAB\Testing Procedures\Z010\SGH Z010-15.docxSource page 67
REPAIR DESIGN REPORT
OLD SHEPARD STREET DAM
CANTON, MASSACHUSETTS
APPENDIX B
SEEPAGE AND STABILITY EVALUATION
SA No. 052-15-022 1/12/2018 Page B-1 of 37Source page 68
REPAIR DESIGN REPORT
OLD SHEPARD STREET DAM
CANTON, MASSACHUSETTS
SEEPAGE EVALUATION
SA No. 052-15-022Source page 69
Project: Number: 052-15-022 Sheet 1 of 7
Name: Old Shepard Street Dam
Original Work: Canton, Massachusetts
By: NAO Date: November 14, 2016 Subject: Embankment Seepage Evaluation
Checked By: JET Date: November 14, 2016
Evaluate Seepage at Embankment
Method:
- Model seepage using Plaxis v8.6 finite element software, which produces groundwater head and flow lines (which
together form a flow net), as well as stresses in the spillway and foundation.
Geometry:
- Use cross-section shown in Model Embankment Section.
Water Levels:
- Normal pool water El. 113.5 ft., 100-year flood water El. 116.5 ft.
- Downstream water El. 105.4 ft. (input), 100-year flood water El. 108.4 ft.
Material Properties:
- All materials - use unit weight sat/unsat = 130 pcf
- Select model permeability based on lab testing and estimates of permeability using Kozeny-Carman method and
engineering judgment, varying model permeability to calibrate model phreatic surface with water levels measured in
observation wells. Refer to table below (horizontal permeability = vertical permeability for each material)
Material Model permeability, cm/s
Upstream pond sediments 1E-05 = 0.00001
Rip-rap 1E-01 = 0.1
Rip-rap dumped into upstream pond sediments 1E-05 = 0.00001
Upstream stone masonry wall (assume mortared, based on model 1E-04 = 0.0001
permeability required for calibration with measured water elevations)
Embankment fill above El. 108 ft. 5E-04 = 0.0005
Embankment fill below El. 108 ft. 1E-03 = 0.001
Silty Sand and Gravel 2E-03 = 0.002
Downstream stone masonry wall 4E-03 = 0.004
Downstream soil 4E-03 = 0.004
Results of Calibration:
Compare model water elevations to observed water elevations at impoundment and in observation wells.
Conclude that model water elevations are generally consistent with range of observed water elevation in wells.
Model Water El. (ft.) Observed Water El., ft.
Impoundment (upstream) 113.5 113.3 - 113.5
SA-2 location (7.5 ft. d/s of embankment crest u/s edge): 109.5 110.6 -109.0
SA-1 location (14.5 ft. d/s of embankment crest u/s edge): 108.6 108.5 - 108.0
Copyright © 2016 Stephens Associates Consulting Engineers LLC
Revisions:
By: Date:
By: Date:
SACE 00-1 (v. 1) 1/00 www.stephensengineers.com 668 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 70
Project: Number: 052-15-022 Sheet 2 of 7
Name: Old Shepard Street Dam
Original Work: Canton, Massachusetts
By: NAO Date: November 14, 2016 Subject: Embankment Seepage Evaluation
Checked By: JET Date: November 14, 2016
Estimate safety factor against internal erosion in foundation at downstream embankment toe
Use method of Fell (2014), section 10.7.3 to estimate the factor of safety against heave (aka "internal erosion,"
"piping," "blowup," "boils," or "liquefaction," etc.) of the foundation soils at the downstream toe of the embankment
which could lead to dam breach. The factor of safety (FS, or FUT) can be calculated for a point in the foundation based
on comparison of total vertical stress with pore pressure. According to Cedergren (1972) "Seepage Control in Earth
Dams" as presented by Fell (2014), values of FUT calculated in this manner should be at least 1.5.
Notes:
- Values of total vertical stress and pore water pressure obtained from Plaxis output.
- SA evaluated FUT for Plaxis "stress points" within 5 ft. below ground surface at downstream embankment toe:
Summary of Results: Load case Normal Pool 100-Year Flood
Factor of Safety based on pore pressure, FUT >3 > 1.6
Fell (2014), section 10.7.3 also presents an alternative method to estimate the factor of safety against heave, which is
based on comparison of seepage exit gradient with critical gradient. According to USACE (1993) "Seepage Analysis
and Control for Dams", values of FUC between 1.5 and 15 have been recommended by various researchers with
values of 2.5 to 5 typically recommended.
where critical gradient = (γsat - γw)/γw (typically taken as 1)
ie, seepage exit gradient (ΔH/ΔL)
Notes:
- Values of ΔH and ΔL obtained from Plaxis output. Critical gradient assumed to be 1.
- SA evaluated FUC between pairs of Plaxis "stress points" immediately below ground surface at
downstream embankment toe. Model stress points spaced ~1 to 2 ft. apart.
Load case Normal Pool 100-Year Flood
Factor of Safety based on seepage gradient, FUC N/A* > 5.8
* FUC at normal pool is not applicable, because model indicates no seepage exits embankment toe at
normal pool
Conclusions
- Model results indicates safety factors against heave of the soils at the embankment toe are generally consistent
with or greater than recommended values.
- Results show that for each method, safety factors are lowest near to downstream toe of embankment wall.
- Refer to following sheets for representative Plaxis model output for Normal Pool and 100-year flood analysis
cases.
Copyright © 2016 Stephens Associates Consulting Engineers LLC
Revisions:
By: Date:
By: Date:
SACE 00-1 (v. 1) 1/00 www.stephensengineers.com 668 Main Street, Wilmington, MA 01887 (978) 988-2115Source page 71
Sheet 3 of 7 Embankment Seepage Evaluation
0.00 30.00 60.00
Upstream Downstream
120.00 Upstream stone masonry wall
Embankment fill > El. 108 ft.
Rip-rap Downstream stone masonry wall
2 3 11 4
Rip-rap dumped into
upstream pond sediments
1 19 16 17
0 5
Upstream pond sediments 20 21 6
Downstream soil
Elevation, ft. (NGVD 1929)
9 18 15 14 12 13 10
Embankment fill > El. 108 ft.
Silty Sand and Gravel
90.00
8 7
Project description
PLAXIS
Finite Element Code for Soil and Rock Analyses
Version 8.6.0.1942
Project name Date
Old Shepard Street Dam
User name
Old Shepard Str... 11/14/2016 Stephens Associates, Consulting Eng.Source page 72
Plaxis 8.6 Sheet 4 of 7 Embankment Seepage Evaluation
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00
NORMAL POOL
120.00 Impoundment water level
Predicted groundwater level
Tailwater
110.00 level
Elevation, ft. (NGVD 1929)
100.00
90.00
80.00
Flow field
Extreme velocity 1.13 ft/day
Project description
PLAXIS
Finite Element Code for Soil and Rock Analyses
Version 8.6.0.1133
Project name
Old Shepard S...
Step
1
Old Shepard Street Dam
Date User name
11/14/16 Stephens Associates, Consulting Eng.Source page 73
Plaxis 8.6 Sheet 5 of 7 Embankment Seepage Evaluation
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00
NORMAL POOL
120.00 Impoundment water level
Predicted groundwater level
Tailwater
110.00 level
Elevation, ft. (NGVD 1929)
100.00
90.00
80.00
Active groundwater head
Extreme groundwater head 116.00 ft
Project description
PLAXIS
Finite Element Code for Soil and Rock Analyses
Version 8.6.0.1133
Project name
Old Shepard S...
Step
1
Old Shepard Street Dam
Date User name
11/14/16 Stephens Associates, Consulting Eng.Source page 74
Plaxis 8.6 Sheet 6 of 7 Embankment Seepage Evaluation
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00
100-YEAR FLOOD
Impoundment water level
120.00 Predicted groundwater level
Tailwater
level
110.00
Elevation, ft. (NGVD 1929)
100.00
90.00
80.00
Flow field
Extreme velocity 1.49 ft/day
Project description
PLAXIS
Finite Element Code for Soil and Rock Analyses
Version 8.6.0.1133
Project name
Old Shepard S...
Step
2
Old Shepard Street Dam
Date User name
11/14/16 Stephens Associates, Consulting Eng.Source page 75
Plaxis 8.6 Sheet 7 of 7 Embankment Seepage Evaluation
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00
100-YEAR FLOOD
Impoundment water level
120.00
Predicted groundwater level
Tailwater
level
110.00
Elevation, ft. (NGVD 1929)
100.00
90.00
80.00
Active groundwater head
Extreme groundwater head 116.50 ft
Project description
PLAXIS
Finite Element Code for Soil and Rock Analyses
Version 8.6.0.1133
Project name
Old Shepard S...
Step
2
Old Shepard Street Dam
Date User name
11/14/16 Stephens Associates, Consulting Eng.Source page 76
REPAIR DESIGN REPORT
OLD SHEPARD STREET DAM
CANTON, MASSACHUSETTS
STABILITY EVALUATION
EXISTING SPILLWAY
SA No. 052-15-022Source page 77
Old Shepard Street Dam, NID No. MA03104 SA Project No. 052-15-022
Canton, MA Stephens Associates Consulting Engineers, LLC
Stability Evaluation - Spillway
Representative Calculation By: N. Olson
Case IIA: Unusual Loading Combination - Ice Date: 11/15/2016
Checked By: J. Turner
Date: 11/15/2016
Problem Geometry Defined:
Purpose: Evaluate sliding and overturning stability of existing Old Shepard Street Dam spillway.
Dist. (ft) 2 4 6 8 10 12 14 16 18 20 22
Assumptions: Approx.
Approx.
- 1956 Drawings show the
Analysis spillway
of new concrete
retaining to beagainst
wall cast integralexisting
with thestone
bridge abutments.
block wall andAssume
on top ofspillway
existing(piers, base
concrete slab and spillway El. (ft)
slab.
El. (ft.) and
abutments), bridge
Dowels (abutments,
will approaches,
be drilled and epoxied into retained
stonesoil,
blockand
wallbridge
to use deck) rotate
weight as a single
of stone rigidto
block wall body.
resist overturning
- Disregard sliding/overturning
and sliding. The resistance
required FS from
for upstream
earthquake sheet piles,
loading is and
>1.03-D effectspool.
at normal from intersection of embankment
Loading for this with bridge approaches.
case is surface
110 driving
- Calculate and resisting
surcharge forces
+ truck load + (soil, water, at
earthquake ice, etc.) over
normal pool.fullTruck
length of bridge
load modeled approaches andloads
as two point spillway (70 ft.).
on back of wall 110
- 1956 drawingsandshow
input"Compacted
as negative Gravel" beneath most of spillway base slab, and also indicate "Maximum Soil Pressure 4,780 psf" at the
anchor loads.
base of bridge abutment and retaining wall footings. Additionally, 1956 borings show "compact fine sand some inorganic silt, and gravel" at
footing bottom elevation, consistent with soils encountered in 2016 SA borings. Assume soil at bridge abutment and retaining wall footing
bottoms is similar to "Gravel Borrow for Bridge Foundations" in current (2015) MassDOT specification, which the 2013 MassDOT LRFD Bridge
Manual assumes has a friction angle of 37 degrees. Assume theExisting wall thickness
soil at bottom = has friction angle of 37 degrees.
of footings
- Assume upstream soil/sediment Assume new wall
has average stem angle of 27
friction 3.5 ft at topand
degrees, (assumed
unit weight of 100 pcf. Assume downstream soil has friction
thickness
angle of 35 degrees, and unit weight = 3.0
of 135 at topat-rest soil based
pcf.ft Use pressures on upstream
upstreamwall)
and downstream. Assume upstream and downstream soil
top El. 107 and 105 ft., disregard resistance of soil at higher elevations downstream Crestthese
(assume El. ≈ 107 ft. Bolivar
resistances Street
are balanced).
(2,107)
- Assume uplift pressure at bridge approaches (including upstream and downstream retaining walls) and beneath spillway base slab based on
(8.5,107)
line of creep method, including sheet piles. Downstream of spillway base slab (i.e. on bottom of bridge abutment footings adjacent to
105 105
downstream water), assume uplift based on tailwater. If bearing pressure at heel of bridge/spillway is negative, assume that tension crack
between structure and soil does not extend farther downstream than sheet piles.
Stability Criteria:
- Use sliding Factors of Safety as recommended by Regulations section 10.14 (k) for significant hazard dams.
- Regulations does not have Proposed
requirements for overturning, but notes that that recommended safety factors also apply to "stress at the rock-
concrete interface and in the foundation."
Concrete
- Judge that soil at base of wall has an allowable bearing pressure of 3 ksf (i.e. ultimate bearing pressure of 9 ksf with FS = 3). For comparison,
the 1956 Bridge Drawings indicate Wall
"Maximum Soil Pressure 4,780 psf."
Load 100
Cases: 100
- Use loading combinations from Regulations
- Case I: Usual Loading Combination - Normal Operating Condition Silty Sand and
Existing Existing
- Case II: Unusual Loading Combination - Flood Discharge, up to and Stone
including flood resulting from 100-year
Gravel Fill storm (water levels from SA
Emergency Action Plan for OldConcrete
Shepard Street Dam, 2012)
- Case IIA: Unusual Loading Combination - Ice (assume 4.7 kips/linear foot, based on 5 ksf contact pressure recommended by FERC 2016 and
Ice thickness estimated using method of USACE 2004 and meteorological data from Blue Hill Observatory in Canton, MA NCDC 2012)
- Case III: Extreme Loading Combination - Normal Operating with Earthquake (assume EQ acceleration = 0.15 g, per Regulations)
Results:
- See table below.
- Safety factors meet requirements of Regulations.
- Foundation bearing pressures are less than allowable bearing pressure.
TABLE: SLIDING AND BEARING PRESSURE RESULTS FOR ALL LOAD CASES
Bearing pressure (ksf)
Spillway Discharge Impoundment Tailwater El. FS Sliding
Load Case Required Bridge Bridge Spillway
(cfs) Water El. (ft.) (ft.)
Required Estimated (allowable) Toe Heel Heel
Normal 10 113.5 105.4 3.0 4.8 2.2 0.8 0.4
100 114.8 106.5 4.0 2.2 0.7 0.2
200 115.6 107.1 3.6 2.2 0.6 0.2
Flood Discharge
400 116.3 107.8 2.0 3.3 < 3 ksf 2.3 0.6 0.1
610 116.5 108.4 3.3 2.2 0.6 0.1
Ice 10 113.5 105.4 2.3 2.9 0.4 -0.4
Earthquake 10 113.5 105.4 1.0 2.0 2.7 0.5 -0.2
Page 1 of 13Source page 78
Old Shepard Street Dam, NID No. MA03104 SA Project No. 052-15-022
Canton, MA Stephens Associates Consulting Engineers, LLC
Stability Evaluation - Spillway
Sketch ofDam Plan and Cross-Sections
i V3" 22'-6" [et 18'-3g =|
I | rd
Downstream bridge toe (x = 0) °
c
c c * a
s & 3 9
6 = | rs] dow
is ® oN
a o % 5
3 g 5 t | %
a ow a i
an a ° a
° 6 2 a
2 2 rs)
cs) So c
xo > [s) wm
3 o oO
2 2 2
5 = + a
Q _ a
. oO
$ [Upstream spillway heel (x = 29.4) | o
4% :
a) T ne} =
T T TL_it ©
nS Neen i 4
=
70°
l | lf ; |
EL. 120 FT. Spillway cross-section
4 TOP conc.
eS 7] DESIGN 100-vEsR FLOW Pool EL uisso | FL TISS FT. ROAD SURFACE EL. £116
Se. 1s|. 4 fate Strack £1 att
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Stephens Associates
Consulting Engineers
Structural
Page 2 of 13
Hydrology & Hydraulics
[Original embedded text, retained for comparison]
Old Shepard Street Dam, NID No. MA03104 SA Project No. 052-15-022
Canton, MA Stephens Associates Consulting Engineers, LLC
Stability Evaluation - Spillway
Sketch of Dam Plan and Cross-Sections
Downstream bridge toe (x = 0)
Bridge approach cross-section
Bridge approach cross-section
Spillway cross-section
Upstream spillway heel (x = 29.4)
Upstream bridge approach heel (x = 22.5)
Spillway cross-section
Bridge approach cross-section
Page 2 of 13Source page 79
Old Shepard Street Dam, NID No. MA03104
Canton, MA
Stability Evaluation - Spillway
SA Project No. 052-15-022
Stephens Associates Consulting Engineers, LLC
SpreadsheetProgram Variables Defined:
DOWNSTREAM SIDE UPSTREAM SIDE
YZ
a (Ground Surface
Arching Effects
H| [Assumed Tension
Crack at Base, L.
Assumed Slope of Base
Stephens Rasectates:
paver ‘Structural
Page 3 of 13 Siete Hydrology & Hydeautcs
[Original embedded text, retained for comparison]
Old Shepard Street Dam, NID No. MA03104 SA Project No. 052-15-022
Canton, MA Stephens Associates Consulting Engineers, LLC
Stability Evaluation - Spillway
Spreadsheet Program Variables Defined:
Page 3 of 13Source page 80
Old Shepard Street Dam, NID No. MA03104 SA Project No. 052-15-022
Canton, MA Stephens Associates Consulting Engineers, LLC
Stability Evaluation - Spillway
Wall/Dam and Problem Geometry:
Location
Point El. Position Batter
Desig. Description (Y) (X) Length Vert.: Angle Factors
(feet) 1 Horiz. (deg.) Remarks
D Crest Front: 116.75 24.9
E Back: 116.75 27.9 0.0 0.0
B Base Front: Top 105.0 11.9
A Bottom 101.0 11.9
G Back: Top 105.0 29.4 17.5 Width of base
H Bottom 101.0 29.4 0.0 0.0 Batter of foundation surface
C Toe meets stem 105.0 22.4 10.5 4.7 12.0 Stem front batter
F Heel meets stem 105.0 27.9 1.5 0.0 Stem back batter
Water elevation at back 113.5
Water elevation at toe/face 105.4
Anchor Number 1 Force Loc. 0.0 0.0 0.0 Angle from horizontal, deg.
Anchor Number 1 Force Magnitude 0 Anchor force, kips
Anchor Number 2 Force Loc. 0.0 0.0 0.0 Angle from horizontal, deg.
Anchor Number 2 Force Magnitude 0 Anchor force, kips
Reduction factor for piezometric head at toe = 1.00 x head to account for losses
Reduction factor for piezometric head at heel = 1.00 x head to account for losses
Length of Tension Crack on Dam Base at heel = ft.
Unit weight of Wall = 150.00 pcf
Arching Effects of Wall as percent reduction of driving forces= 0.00 x 100 = % reduction
Earthquake Effects? no Yes or No
Earthquake effects calculated using Mass Bld. Code (MBC) or AASHTO Other - See separate sheet
Ice Force on Reservoir side of Wall (per foot of Wall) = -4.70 Kips 0.94 ft thick
Subsurface Profile:
Top Top Unit Wt. Wall Friction Rankine Earth Pressure
Layer Elevation Depth Phi Su (pcf) Srchrg. Factors Coefficient
Layer Number (feet) (feet) (degrees) (psf) Tot. (psf) Delta/PhiSu alpha Ka Ko Kp
Back of Wall/Dam:
Soil 1B 107.0 0.0 27 0 100 0 1 0.38 0.55 2.66
Rock 2B 101.0 6.0 27 0 100 0 0.38 0.55 2.66
At Wall Bottom 101.0 6.0 37 0 0 0.25 0.40 4.02
At Water Elevation 113.5 -6.5 0 0 62.4 0 NA NA NA
Front of Wall/Dam:
Rockfill 1F 105.0 0.0 35 0 135 0 0.27 0.43 3.69
Rock 2F 101.0 4.0 35 0 135 0 0.27 0.43 3.69
At Wall Bottom 101.0 4.0 37 0 0 1 0.25 0.40 4.02
At Water Elevation 105.4 -0.4 62.4 62.4 62.4 0 0.06 0.11 16.58
Page 4 of 13