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Pilot Implementation Using Geofoam for Repair of Bridge Approach Slabs
Anand J. Puppala, Ph.D., P.E., DGE, F.ASCE Distinguished Professor, Dept. of Civil Engineering
Director, Sustainable and Resilient Civil Infrastructure (SARCI) Center The University of Texas at Arlington (UTA)
www.uta.edu/sarci
SARCI
2
Courtesy: URETEK
Bump at the End of Bridge 40% TxDOT Bridges Have Bump Issues Annual Maintenance Costs - $7 Millions – Seo (2003)
Bump at the end of the bridge
3
SARCI
Foundation Soils Embankment backfill materials
1. Excavation and replacement 1. Geosynthetic reinforcement
2. Preloading surcharge loads 2. Use of MSE wall
3. Vertical drains 3. Grouting
4. Stone columns 4. Use of lightweight fill materials.
5. Deep soil mixing others
others
Lightweight Materials
4
SARCI
Use of lightweight fill materials for mitigating bridge approach settlement:
Lightweight Materials
5
SARCI
Densities and approximate costs of various lightweight fill materials (FHWA NHI-05-037)
Materials Density Approximate cost
kg/m3 lb/ft3 $/m3 $/ft3
EPS geofoam 12 to 46 0.75 to 2.85 40 to 85 1.2 to 2.4
Cellular (foamed) concrete 320 to 970 20.0 to 60.5 40 to 55 1.2 to 1.6
Shredded tires 600 to 900 37.5 to 56.2 20 to 30 0.6 to 0.8
Expanded shale and clay 600 to 1040 37.5 to 65.0 40 to 55 1.2 to 1.6
EPS Geofoam
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SARCI
Expanded Polystyrene (EPS) Geofoam:
ASTM D-4439: a block or planar rigid cellular foamed polymeric material used in geotechnical engineering applications.
It has been widely used around the world as a fill material for more than 30 years.
EPS Geofoam
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SARCI
Advantages of EPS Geofoam:
About 100 times lighter than soils.
At least 20 to 30 times lighter than other lightweight fill alternatives.
Easy to handle
Expedites construction process
Limited labor
EPS Geofoam
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SARCI
Advantages of EPS Geofoam:
About 100 times lighter than soils.
At least 20 to 30 times lighter than other lightweight fill alternatives.
Easy to handle
Expedites construction process
Limited labor
Implementation of EPS Geofoam
9
SARCI
Location: US 67 bridge over SH 174, Johnson County, Cleburne, Texas
Implementation of EPS Geofoam Bump at the end of the bridge:
• Test Section - US 67 over SH 174 in Johnson County, Texas
• Abutments supported by drilled shaft foundation
• More than 17 in. of settlement observed since
construction in 1995
10
SARCI
Geofoam Construction
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SARCI
EPS 22 geofoam blocks: top 6 ft depth
Geofoam installation period: 3-4 days
Test section construction period: January – February 2012
Geofoam Installation
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SARCI
Process of EPS geofoam installation
Geofoam – Lightweight Fill Material Instrumentation- Horizontal Inclinometers, Pressure Cells
13
PC #1 PC #2
PC #3 PC #4
SARCI
Site Visit and Data Collection
14
SARCI
The site visits have been conducted at least once a month from January 2012.
During the visit, the data from horizontal inclinometers and pressure cells are measured and recorded.
Site Visit and Data Collection
15
SARCI
0 2 4 6 8 10 12 14 16 18 20 22
Length of
inclinometer casing
in
feet
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
Cum
u la t
ive D
ispl
acem
ent (in
) from
1 /30
/201
2 01/30/1202/07/1202/14/1203/06/1204/18/1205/23/1206/20/1207/20/1208/29/1211/30/1212/21/1201/13/1302/17/1303/11/1304/13/1305/20/1306/18/1307/19/1308/21/1309/19/1310/18/1312/05/1301/16/1402/14/1403/21/1404/18/1405/23/1406/17/1407/18/1408/15/14
US 67_1
0 2 4 6 8 10 12 14 16 18 20 22
Len th of
inclinometer casin
in
feet
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
Cum
u la t
ive D
ispl
acem
ent (in
) from
1 /30
/201
2 01/30/1202/07/1202/14/1203/06/1204/18/1205/23/1206/20/1207/20/1208/29/1211/30/1201/13/1302/17/1303/11/1304/13/1305/20/1306/18/1307/19/1308/21/1309/19/1310/18/1306/17/1407/18/1408/15/14
US 67_2
0 2 4 6 8 10 12 14 16 18 20 22
Len th of
inclinometer casin
in
feet
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
Cum
u la t
ive D
ispl
acem
ent (in
) from
1 /30
/201
2 01/30/1202/07/1202/14/1203/06/1204/18/1205/23/1206/20/1207/20/1208/29/1211/30/1202/17/1303/11/1304/13/1305/20/1306/18/1307/19/1308/21/1309/19/1310/18/1312/05/1301/16/1402/14/1403/21/1404/18/1405/23/1406/17/1407/18/1408/15/14
US 67_3
0 2 4 6 8 10 12 14 16 18 20 22
Length of
inclinometer casing
in
feet
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75C
umu l
a tiv
e Dis
pla c
emen
t (in) fr
om 1 /
3 0/2
012 01/30/12
02/07/1202/14/1203/06/1204/18/1205/23/1206/20/1207/20/1208/29/1211/30/1201/13/1302/17/1303/11/1304/13/1305/20/1306/18/1307/19/1308/21/1309/19/1310/18/1312/05/1301/16/1402/14/1403/21/1404/18/1405/23/1406/17/1407/18/1408/15/14
US 67_4
Site Visit and Data Collection
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SARCI
• PC #1 and PC #2 were installed horizontally at 2 ft. (0.6 m) and 8 ft. (2.4 m) under the pavement surface.
• The data presented in the plots was collected from March 2015 Time (Month-Year)
0
2
4
6
8
Pres
sure
(psi
)
PC #1PC #2
Mar-15 Apr-15 May-15 Jun-15 Jul-15 Aug-15
Prediction of a Long Term Settlement of the Test Embankment: Predicted from the collected field data. Using Hyperbolic method (Lin and Wong, 1999). The hyperbolic relationship between the settlement and time:
𝒕 = time from the start of embankment fill (days); 𝑺 = measured settlement as any specific time (mm);
𝜷 = gradient of the straight line between 𝒕 and 𝒕𝑺 ; and
𝜶 = intersection of the straight line on the 𝒕𝑺 axis.
𝒕𝑺 = 𝜶 + 𝜷(𝒕) or 𝑺 = 𝒕
(𝜶+ 𝜷𝒕)
17
Analysis of Field Data
Prediction of a Long Term Settlement of the Test Embankment: By plotting the data with the function of time-settlement ratio,
the values of 𝜷 and 𝜶 can be determined.
0 100 200 300 400 500 600 700 800 900 1000
Time da s
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Tim
e /Se
ttlem
ent (d
a ys /
mm
)
Substituting 𝜷 and 𝜶 back
into the Equation 𝑺 = 𝒕(𝜶+ 𝜷𝒕)
,
the settlement at several times can be calculate and the plot between the settlement and time can be provided.
18
Analysis of Field Data
Prediction of Long Term Settlement
19
SARCI The total settlements of 1.42 in. and 1.50 in. are
predicted to occur at 10 year and 20-years intervals.
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Settl
emen
t (in. )
0 100 200 300 400 500 600 700 800 900 1000Time
(days)
40
35
30
25
20
15
10
5
0
mm
Numerical Modeling of Geofoam Embankment
Geometry of the Test Embankment Section:
Material Properties: • Properties of the embankment fill and foundation soil were derived
from the laboratory test results.
• Properties of EPS 22 geofoam provided in ASTM D 6817-07 were used.
20
• The vertical displacement – time plots at points A, B, C, D, and E.
Results of the Numerical Modeling:
• Contours of the total vertical displacement on the EPS geofoam embankment model after full dissipation of pore pressure.
Numerical Modeling of Geofoam Embankment System
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Ver t
ica l
Dis
plac
emen
t (inc h
)
0 200 400 600 800 1000 1200Time
(days)
40
35
30
25
20
15
10
5
0
Ver t
ica l
Dis
lace
men
t mm
21
Design charts to evaluate minimum thickness of EPS geofoam layer
250 500 750 1,000 1,250 1,500 1,750 2,000 2,250 2,500 2,750
Undrained Shear Stren th, Su
psf
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
Min
imum
Thic
knes
s o f EP
S Geo
foam
Laye
r (ft) 10 20 30 40 50 60 70 80 90 100 110 120 130
Undrained Shear Strength, Su
(kPa)
0.0
1.0
2.03.0
4.0
5.06.0
7.08.09.0
10.0
11.0
12.0
13.0
14.0
15.0
Min
imum
Thic
kne s
s o f E P
S Geo
foam
Laer
m
FS =
1.5FS
= 2.0
FS =
2.5FS
= 3.0
Embakment Height
= 50
ft
Top Width
of Embankment
= 76
ft
22
Development of Design Charts
𝑺𝒖 =𝑭𝑺𝟓.𝟏𝟏
[∆𝝈𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒕 + ∆𝝈𝒕𝒕𝒑𝒕𝒕𝒕𝒕 + ∆𝝈𝒕𝒕𝒇𝒇 𝒑𝒑𝒎𝒎]
∆𝝈𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒕 = 𝝈𝒐, 𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒕 𝑾𝑾+ 𝑯𝑬𝒑𝑬.
∆𝝈𝒕𝒕𝒑𝒕𝒕𝒕𝒕 = 𝝈𝒐, 𝒕𝒕𝒑𝒕𝒕𝒕𝒕 𝑾𝑾+ 𝑯𝑬𝒑𝑬.
∆𝝈𝒕𝒕𝒇𝒇 𝒑𝒑𝒎𝒎 = 𝜸𝑬𝑬𝑺 𝑨𝑬𝑬𝑺 + 𝜸𝒕𝒕𝒇𝒇 𝒎𝒐𝒕𝒇 𝑨𝒕𝒕𝒇𝒇 𝒎𝒐𝒕𝒇
𝑾+𝟐 𝑺𝒇𝒐𝒑𝒑 𝑯𝑬𝒑𝑬.
𝑨𝑬𝑬𝑺 = 𝑾 + 𝑺𝒇𝒐𝒑𝒑 𝑯𝑬𝑬𝑺 𝑯𝑬𝑬𝑺
𝑨𝒘𝒘𝒐𝒇𝒑 𝒑𝒑𝑬. = 𝑾 + 𝟐 𝑺𝒇𝒐𝒑𝒑 𝑯𝒑𝒑𝒑𝒑. + 𝑺𝒇𝒐𝒑𝒑 𝑯𝑬𝒑𝑬. 𝑯𝑬𝒑𝑬.
𝑨𝒕𝒕𝒇𝒇 𝒎𝒐𝒕𝒇 = 𝑨𝒘𝒘𝒐𝒇𝒑 𝒑𝒑𝑬. − 𝑨𝑬𝑬𝑺
Design charts to evaluate minimum thickness of EPS geofoam layer (Bearing capacity controls the height of Geofoam)
23
Development of Design Charts
Comparisons of the thickness of EPS geofoam layer
24
Long Term Assessments
25
Long Term Assessments
Acknowledgements • TxDOT: Richard
Williammee, Jimmy Si, Wade Blackmon
• RTI Office – Joe Adams, Sonya Badgely and Wade Odell
• UTA Geotech Research Group
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SARCI