Polyethylene Pipe Testing Under 315000 Cars

8/9/2019 Polyethylene Pipe Testing Under 315000 Cars

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Corrugated Polyethylene Pipe Testing

under 315,000-Pound Ca rs at FAST

Letter Report No. P-09-052

Prepared for Plastic Pipe Institute

by Joseph A. LoPrestiTransporta tion Tec hnology Cente r, Inc .


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Disclaimer: This report w as prepa red for Plastic Pipe Institute (PPI) by Transporta tion Tec hno logyCe nter, Inc. (TTCI), a subsidia ry of the A ssoc iation o f America n Railroad s, Pueb lo, Co lorad o. It is

ba sed on investiga tions and tests c ond uc ted by TTCI with the d irec t p articipa tion of PPI to c riteria

ap prove d b y them . The c onte nts of this repo rt imply no end orsem ents wha tsoe ver by TTCI of

products, services or procedures, nor are they intended to suggest the applicability of the test

results und er circumstanc es other tha n those desc ribed in this report. The results and find ings

conta ined in this repo rt are the sole p rope rty of PPI. They may no t be relea sed by a nyone to a ny


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Table of Contents

1.0 Introduction ................................................................................................. 1

2.0 Test Preparation.......................................................................................... 1

2.1 Pipe Instrumentation ........................................................................ 1

2.2 Pipe Installation ................................................................................ 4

3.0 Testing ........................................................................................................ 8

3.1 Measuring Strains and Deflections ................................................... 8

3.1.1 Strains and Deflections From Construction Loads ................... 8

3.1.2 Strains and Deflections from Dynamic Loads after1 MGT of HAL Traffic ............................................................. 10

3.1.3 Strains and Deflections from Dynamic Loadsafter 96 MGT .......................................................................... 15

3.1.4 Results of Leaving Loaded Cars Parked Over thePipes for 6 Weeks .................................................................. 19

4.0 Summary ................................................................................................... 19

Appendix A. Instrumentation Photographs ......................................................... 21

Appendix B. Installation Photographs ................................................................ 23

Appendix C. Appendix B Time Histories, 1 MGT DynamicMeasurements, Lap 7 .................................................................... 29

Appendix D. Time Histories, 96 MGT Dynamic Measurements, Lap 7 .............. 37


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List of Figures

Figure 1. String Pot Locations ............................................................................. 2

Figure 2. Strain Gage Locations ......................................................................... 3

Figure 3. HTL at FAST ........................................................................................ 5

Figure 4. Cross Section Depicting As-Constructed Conditions atPipe Test Sites ..................................................................................... 5

Figure 5. Installation Plan View ........................................................................... 6

Figure 6. Installation Profile View ........................................................................ 7

Figure 7. Pipe Wall Strains from Backfill and Construction Loads ...................... 9

Figure 8. Pipe Deflections from Backfill and Construction Loads ........................ 9

Figure 9. Gage Orientation Relative to Train Direction ..................................... 10

Figure 10. Maximum Pipe Wall Strains Measured during 40 mph

Train Operations ................................................................................ 11Figure 11. Peak-to-peak Changes in Strains due to Dynamic Loads ................. 11

Figure 12. Maximum Pipe Deflections Measured during 40 mphTrain Operations ................................................................................ 12

Figure 13. Peak-to-peak Changes in Deflections due to Dynamic Loads .......... 12

Figure 14. Sample Dynamic Strain and Deflection Data during 40 mph

Train Operations ................................................................................ 13Figure 15. Dynamic Vertical Loads Measured under the Train at FAST ............ 13

Figure 16. Maximum Pipe Wall Strains Measured during 40 mphTrain Operations ................................................................................ 15

Figure 17. Peak-to-peak Changes in Strains due to Dynamic Loads ................. 16

Figure 18. Maximum Pipe Deflections Measured during 40 mph

Train Operations ................................................................................ 16Figure 19. Peak-to-peak Changes in Deflections due to Dynamic Loads .......... 17

Figure 20. Cars Parked over Pipes to Evaluate Long-term Pipe Response ....... 19


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List of Tables

Table 1. Measurement Description Summary .................................................... 3

Table 2. Statistics from Lap 7 Measurements during 40 mphTrain Operations after 1 MGT ............................................................ 14

Table 3. Statistics from Measurements during 40 mphTrain Operations after 96 MGT .......................................................... 18


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(blank page)


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1.0 INTRODUCTION

Transportation Technology Center, Inc. (TTCI) conducted a test of corrugated high-

density polyethylene pipes for the Plastic Pipe Institute (PPI) at the Facility for

Accelerated Service Testing (FAST). The pipes were manufactured by Advanced

Drainage Systems, Inc. (ADS). FAST operates as a test bed for railroad track and

components, and for rail vehicles and components. The Federal Railroad Administration,

the Association of American Railroads, and individual railroads and railroad suppliers

(through in-kind contributions) have cooperatively funded the operations at FAST and its

test programs. The program has focused on increased axle loads and their implications for

track components, maintenance practices, and interaction of vehicles and track since

1988 when the nominal axle load of the train at FAST was increased from 33 tons to 39

tons. Typically, the train consist at FAST is four GP-40 locomotives and 80 315,000-

pound gross rail load (GRL) cars. Approximately 120 million gross tons (MGT) of heavy

axle load (HAL) traffic accumulate each year at FAST. Testing at FAST allows for safe,

controlled testing of components without incurring the risk of in-service evaluations.

The pipes were instrumented to allow data collection during train operations.Transducers were installed at various locations on the pipes to measure pipe wall strains

and lateral, vertical, diagonal, and circumferential deflections. Strains and deflections

were measured when the pipes were in place before the trenches were backfilled, after

backfill, during normal operations at FAST after accumulating 1 MGT of HAL traffic,

and after accumulating 96 MGT of HAL traffic. Also, the pipes were monitored visually

and with a video camera.

2.0 TEST PREPARATION

2.1 Pipe Instrumentation

Short (58-inch) sections of the pipes were instrumented inside, in a controlled

temperature environment prior to in-track installation. The 58-inch length was selected so

the joints would be nearly directly under the rails when the pipe was installed.

Representatives from the plastic pipe industry were at the Transportation Technology

Center (TTC) to observe and assist in the installation of the instrumentation. Theinstrumentation is described below.

String potentiometers (string pots) were installed to measure horizontal,

vertical, and diagonal deflections approximately 6 inches from the spigot end

of the watertight inline bell spigot joint and approximately 6 inches from the


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eyelets were attached to the interior pipe wall at approximately a 9.5-inch

spacing. The string was threaded through the eyelets around the

circumference of the pipe. Figure 1 shows the string pot locations.

Strain gages were installed to measure pipe wall strains at five circumferential

locations. Strains were measured at the crowns and valleys of the corrugations

at three locations and only at the valleys in two locations. Gages placed on the

inside crown of the pipes were placed through elliptical access ports cut

through the pipes smooth interior liner. Measurements were taken at clock

positions: 12:00 (crown and valley), 1:30 (valley), 3:00 (crown and valley),

6:00 (valley), and 9:00 (crown and valley). Strain gage locations areillustrated in Figure 2. The strain gages were placed as close to the deflection

gages as practicable. The strain gages were Vishay Measurements Group EP-

08-250BF-350 designed for high elongation measurements (crown) and

Vishay Measurements Group EP-08-500BL-350 (valley).

Internal wall temperatures were measured in each pipe, and ambient air

temperature was measured.

Instrumentation summary: two instrumentation locations at each of the two

test sites = a total of four instrumentation sites

Each instrumentation location:

Four deflection gages (4 x 4 = 16 deflection gages)

Eight strain gages (total 8 x 4 = 32 strain gages)

One circumferential shortening gage (total 1 x 4 = 4 circumferential

shortening gages)

String PotLocations


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Figure 2. Strain Gage Locations

Table 1 summarizes the measurement names and locations. Appendix A shows

photographs of the instrumentation.

Table 1. Measurement Description Summary

S or D 1 or 2 B or N 0, 45 0, 45 V or C

Name TypePipeSite

JointType

PipeLocation(degrees)

Pipe Location(clock

position)

Crown orValley

S1B0C Strain 1 WT 0 12:00 C

S1B0V Strain 1 WT 0 12:00 VS1B45V Strain 1 WT 45 1:30 VS1B90C Strain 1 WT 90 3:00 C

S1B90V Strain 1 WT 90 3:00 VS1B180V Strain 1 WT 180 6:00 V

S1B270C Strain 1 WT 270 9:00 CS1B270V Strain 1 WT 270 9:00 V

S1N0C Strain 1 Split 0 12:00 CS1N0V Strain 1 Split 0 12:00 VS1N45V Strain 1 Split 45 1:30 V

S1N90C Strain 1 Split 90 3:00 C


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Table 1. (Continued) Measurement Description Summary

S or D 1 or 2 B or N 0, 45 0, 45 V or C

Name TypePipeSite

JointType

PipeLocation(degrees)

Pipe Location(clock

position)

Crown orValley

S2B90C Strain 2 WT 90 3:00 CS2B90V Strain 2 WT 90 3:00 VS2B180V Strain 2 WT 180 6:00 V

S2B270C Strain 2 WT 270 9:00 CS2B270V Strain 2 WT 270 9:00 V

S2N0C Strain 2 Split 0 12:00 CS2N0V Strain 2 Split 0 12:00 V

S2N45V Strain 2 Split 45 1:30 VS2N90C Strain 2 Split 90 3:00 CS2N90V Strain 2 Split 90 3:00 V

S2N180V Strain 2 Split 180 6:00 VS2N270C Strain 2 Split 270 9:00 C

S2N270V Strain 2 Split 270 9:00 VD1B0 Displacement 1 WT 0 12:00-6:00 N/A

D1B45 Displacement 1 WT 45 1:30-7:30 N/AD1B270 Displacement 1 WT 270 3:00-9:00 N/A

D1B315 Displacement 1 WT 315 4:30-10:30 N/AD1BC Displacement 1 WT Circ. N/A N/AD1N0 Displacement 1 Split 0 12:00-6:00 N/A

D1N45 Displacement 1 Split 45 1:30-7:30 N/AD1N270 Displacement 1 Split 270 3:00-9:00 N/A

D1N315 Displacement 1 Split 315 4:30-10:30 N/AD1NC Displacement 1 Split Circ. N/A N/A

D2B0 Displacement 2 WT 0 12:00-6:00 N/AD2B45 Displacement 2 WT 45 1:30-7:30 N/AD2B270 Displacement 2 WT 270 3:00-9:00 N/A

D2B315 Displacement 2 WT 315 4:30-10:30 N/AD2BC Displacement 2 WT Circ. N/A N/A

D2N0 Displacement 2 Split 0 12:00-6:00 N/AD2N45 Displacement 2 Split 45 1:30-7:30 N/A

D2N270 Displacement 2 Split 270 3:00-9:00 N/AD2315 Displacement 2 Split 315 4:30-10:30 N/A

D2NC Displacement 2 Split Circ. N/A N/AT1A Temperature 1 N/A N/A N/A N/AT2A Temperature 2 N/A N/A N/A N/A

TEA Temperature Air N/A N/A N/A N/A

2 2 Pi I t ll ti


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pipes remained dry for the duration of the test. The pipes were installed 50 feet apart,

center-to-center. The variable between the two sites was the composition and preparation

of the backfill material, as Figure 4 shows.

Figure 3. HTL at FAST

5

HTL

PPIPipeTest


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Differences in composition and preparation of the backfill material between the

two pipe test sites are described as follows:

Site 1 Approximately 80 feet of 48-inch pipe was installed perpendicular to

the track beneath a 4-foot cover (Figure 5). The backfill was fractured rock

(No. 57 stone) wrapped with Geotex 1201 fabric manufactured by Propex.

The stone was vibrated in place. The soil above the pipes was compacted to

98 percent standard proctor density (SPD).

Site 2 Approximately 80 feet of 48-inch pipe was installed perpendicular to

the track beneath 4-foot cover (Figure 5). The backfill is native soil thatconforms to AASHTO M145 A-2-4 (ASTM D2321 class III) specifications.

The soil around the pipes was compacted to 94 percent SPD. The soil above

the pipes was compacted to 98 percent SPD.

Figure 5. Installation Plan View

The excavations were sloped to comply with OSHA regulations.

Cover depth was measured from the bottom of the tie to the outside top of the

pipe, and it included the thickness of the ballast layer. Native soil was used as


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The subballast depth of 6 inches and ballast depth of 12 inches below the

bottom of the tie are typical of the granular layer depth at FAST. The track

cross section, a 15- to 18-inch shoulder and 2:1 side slope, is representative ofthe typical cross section at FAST.

ADS constructed its standard watertight (WT) inline bell spigot joint, and its

standard fabric wrapped split coupler connection for each pipe. The

connections in each pipe were placed just outside the centerline of the rails

(Figure 6). Pipe installation followed standards outlined in ASTM D2321 and

in this document. Appendix B shows photographs of the installation.

Figure 6. Installation Profile View


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3.0 TESTING

3.1 Measuring Strains and DeflectionsThe instrumented sections of the pipes were moved to the HTL after the instrumentation

was completed and the functionality of the transducers had been verified. The pipes were

placed in their respective trenches, and the sections of pipe were coupled together. The

transducers were zeroed, and the readings at this point were designated as the starting

(zero) condition. Strains and deflections were measured:

Statically, when backfill and track construction was complete

Statically, after accumulating 1 MGT of HAL traffic

Dynamically, during 10 laps of train operations after accumulating 1 MGT of

HAL traffic

Statically, prior to train operations after accumulating 96 MGT of HAL traffic

Dynamically, during 10 laps of train operations after accumulating 96 MGT of

HAL traffic

3.1.1 Strains and Deflections From Construction LoadsThe transducers had been set to zero after the pipes were set in place, but before

backfilling began. Values from all transducers were recorded again after the trenches had

been filled, the native soil placed and compacted, and the ballast and track installed. This

subsection describes those results. Figure 7 shows measured strains that were induced by

the backfill. Maximum strain was about 7,300 microstrain (compressive) at the site 1

pipe, 0 degree (top of pipe), split joint, in the valley of a corrugation. Most of the other

strains were also compressive; however, tensile strains were measured at four locations in

the site 2 pipe. The strains at the split joint were generally higher than the corresponding

strains at the WT bell joint.


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10000

8000

6000

4000

2000

0

2000

0Cr

own

0Va

lley

45V

all

ey

90C

rown

90V

all

ey

180

Va

lley

270C

rown

270

Va

lley

WallStrain(m

icrostrain)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint

Figure 7. Pipe Wall Strains from Backfill and Construction Loads

Figure 8 shows the deflections. Lateral compression of the pipes produced the

highest deflections. The distances between the 3:00 and 9:00 clock positions (270

degrees) decreased by 0.4 inch to 0.7 inch. The heights of the pipes tended to increase as

the sides of the pipes were squeezed in.

1

0.8

0.60.4

0.2

0

0.2

0.4

0.6

0.8

1

gree

gree

gree

gree

nti

al

Displacements(in)

Site1WTJoint

Site1Split

Joint

Site2WTJoint

Site2SplitJoint


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3.1.2 Strains and Deflections from Dynamic Loads after 1 MGT of HALTraffic

One MGT of HAL traffic (approximately one night of train operations at FAST) wasaccumulated to consolidate and settle the fills and track. Strains and deflections were then

measured during 10 laps of train operations. Speed during the first lap was approximately

5 mph. Train speed had increased to 40 mph, typical operating speed at FAST, by the

fourth lap. Train speed for laps for 4 to 10 was 40 mph. There was little difference in

strains or deflections within the range of test speeds, though the higher speeds produced

slightly higher values. Train direction during testing was counterclockwise. Travel was

from the 90-degree side (3:00 clock position) toward the 270-degree side (9:00 clockposition), as Figure 9 shows.

Figure 9. Gage Orientation Relative to Train Direction

Figure 10 shows maximum strains (compared to pre-backfill conditions)

measured during lap 7 (lap 7 was chosen arbitrarily and is representative of the other

40 mph laps) Maximum strains tended to increase compared to those resulting from

TrainDirection

2

2 2

1

1


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10000

8000

6000

4000

2000

0

2000

0C

rown

0Va

lley

45

Va

lley

90C

rown

90V

all

ey

180

V

all

ey

270

Crown

270

V

all

ey

Strain(microstrain)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint

Figure 10. Maximum Pipe Wall Strains Measured during 40 mph Train Operations

1500

1300

1100

900

700

500

300

100

100

300

500

0C

rown

0V

all

ey

45V

all

ey

90C

rown

90V

all

ey

180V

alley

270C

rown

270V

alley

Strain(microstrain)

Site1WTJoint

Site1SplitJoint

Site2WT

Joint

Site2SplitJoint

Figure 11. Peak-to-peak Changes in Strains due to Dynamic Loads

Figure 12 shows maximum deflections (compared to pre-backfill conditions) for

lap 7. Figure 13 shows peak-to-peak changes in deflections due to dynamic loads.


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lower strains and deflections at the beginning of the train are from the locomotives that

have lighter axle loads than the test cars. The lower strains and deflections at the end of

the train are from the cars loaded to 286,000 pounds (compared to the 315,000-poundcars in the rest of the train). Most channels show similar differences. Table 2 shows

statistics for each channel. Appendix C shows time histories for all channels from lap 7.

1

0.8

0.6

0.4

0.2

0

0.2

0.4

0.6

0.8

1

0Degree

45

Degree

270

Degree

315D

egree

Cir

cumfr

enti

al

Displacement

(in)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint

Figure 12. Maximum Pipe Deflections Measured during 40 mph Train Operations

0.06

0.04

0.02

0

0.02

0Degree

45

Degree

270

Degree

315

Degree

Cir

cumfr

enti

al

Displacement(in)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint


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Figure 14. Sample Dynamic Strain and Deflection Data during 40 mph Train Operations

Figure 15 shows the distribution of dynamic vertical loads for the train at FAST.

These loads were measured with rail mounted strain gages in a section of tangent track

with track geometry similar to the geometry at the pipe test. Average vertical load was38,000 pounds, 99

thpercentile load was 52,000 pounds, and maximum load was 83,000

pounds.

2000

3000

4000

5000

6000

7000

umberofOccuran

ces


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Table 2. Statistics from Lap 7 Measurements during 40 mph Train Operations after 1 MGT

Channel Name Average Maximum Minimum

S1B0C -794.1 -581.7 -1066.5S1B0V -2438.2 -2326.8 -2710.8S1B45V -4597.5 -4337.3 -5052.7S1B90C -4238.5 -3982.7 -4609.2S1B90V -2358.5 -2048.2 -2816.3S1B180V -4813.1 -4698.8 -4939.8S1B270C -2704.7 -2461.2 -3072.8S1B270V -1999.5 -1709.3 -2492.5S1N0C -2465.7 -2200.2 -2864.0S1N0V -7562.4 -7379.5 -7808.7S1N45V -5761.4 -5406.6 -6370.5

S1N90C -4721.0 -4474.9 -5086.5S1N90V -2442.1 -2146.1 -2921.7S1N180V -6038.6 -5911.1 -6174.7S1N270C -2576.4 -2327.0 -2923.6S1N270V -1641.2 -1347.9 -2146.1S2B0C -3479.4 -3289.1 -3773.9S2B0V -2742.5 -2560.2 -3019.6S2B45V -7213.6 -6852.4 -7906.6S2B90C -4988.0 -4706.1 -5444.5S2B90V -209.0 128.0 -760.5

S2B180V -457.4 -361.4 -564.8S2B270C -4010.3 -3729.1 -4482.4S2B270V -414.3 -82.8 -948.8S2N0C -5360.8 -5079.1 -5839.8S2N0V -3853.6 -3667.2 -4164.2S2N45V -7381.4 -6988.0 -8162.7S2N90C -5916.1 -5638.4 -6376.8S2N90V -816.0 -459.3 -1453.3S2N180V 287.8 376.5 158.1S2N270C -4186.2 -3893.2 -4653.9S2N270V -650.1 -316.3 -1212.3

D1B0 0.5 0.5 0.5D1B45 -0.2 -0.1 -0.2D1B270 -0.6 -0.5 -0.6D1B315 -0.1 -0.1 -0.2D1BC -0.2 -0.2 -0.2D1N0 0.5 0.6 0.5D1N45 -0.2 -0.2 -0.2D1N270 -0.7 -0.7 -0.7D1N315 -0.2 -0.2 -0.3D1NC -0.5 -0.5 -0.5

D2B0 0.1 0.1 0.1D2B45 0.3 0.3 0.2D2B270 -0.6 -0.6 -0.6D2B315 -0.1 -0.1 -0.1D2BC -0.2 -0.2 -0.2D2N0 -0.2 -0.2 -0.3D2N45 0.2 0.2 0.2D2N270 -0 4 -0 4 -0 4


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3.1.3 Strains and Deflections from Dynamic Loads after 96 MGTThe measurements taken after accumulating 1 MGT of HAL traffic were repeated after

accumulating 96 MGT of HAL traffic (8 months). Data was collected during 10 laps oftrain operations. Train speed increased from approximately 5 mph to 40 mph. Again,

there was little difference in strains or deflections within the range of test speeds, though

the higher speeds produced slightly higher values.

Figure 16 shows maximum strains measured during lap 7 (lap 7 was chosen to

match the 1 MGT data; it is representative of the other 40 mph laps). Figure 17 shows

peak-to-peak changes in strains due to dynamic loads. Figure 18 shows maximum

deflections (compared to pre-backfill conditions) for lap 7. Figure 19 shows peak-to-peak

changes in deflections due to dynamic loads. The general trends measured after 1 MGT

of HAL traffic accumulation continued after accumulating 96 MGT of HAL traffic;

however, there were moderate increases in maximum strains and deflections. Maximum

strain increased from approximately 8,200 microstrain to approximately 8,800

microstrain. The pipes tended to flatten vertically during the period. The shortening

between the 12:00 and 6:00 clock positions increased from about 0.3 inch to about 0.5

inch during the period. Maximum circumferential shortening increased from about 0.5

inch to nearly 0.8 inch. Dynamic strains and deflections were similar to those measured

after accumulating 1 MGT of HAL traffic. Table 3 shows statistics for each channel.

Appendix D shows time histories for all channels from lap 7.

8000

6000

4000

2000

0

2000

0Cro

wn

0Vall

ey

45V

all

ey

90C

rown

90V

all

ey

180

Va

lley

270

Crown

270

Va

lley

Strain(microstrain)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2Split

Joint


22/49

1500

1300

1100

900

700

500

300

100

100

300

500

0Cr

own

0Va

lley

45V

all

ey

90C

rown

90V

all

ey

180

Va

lley

270

Crown

270

Va

lley

Strain(m

icrostrain)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint

Figure 17. Peak-to-peak Changes in Strains due to Dynamic Loads

1

0.8

0.6

0.40.2

0

0.2

0.4

0.6

0.8

1

0Degree

45

Degree

270

Degree

315D

egree

Cir

cum

frenti

al

Displacement(in)

Site1WT

Joint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint

Figure 18. Maximum Pipe Deflections Measured during 40 mph Train Operations


23/49

0.1

0.08

0.06

0.04

0.02

0

0.02

0Degr

ee

45

Degree

270

Degree

315

Degree

Cir

cumfr

enti

al

Displacem

ent(in)

Site1WTJoint

Site1SplitJoint

Site2WTJoint

Site2SplitJoint

Figure 19. Peak-to-peak Changes in Deflections due to Dynamic Loads


24/49

Table 3. Statistics from Measurements during 40 mph Train Operations after 96 MGT

Channel Name Average Maximum Minimum

S1B0C -2811.5 -2602.9 -3072.8S1B0V -1687.2 -1513.6 -1867.5

S1B45V -7456.3 -7191.3 -7936.7

S1B90C -6155.3 -5906.9 -6533.4

S1B90V -5461.1 -5173.2 -5926.2

S1B180V -6551.0 -6423.2 -6679.2

S1B270C -4786.8 -4534.6 -5153.6

S1B270V -6528.0 -6219.9 -7033.1

S1N0C -5661.5 -5422.1 -6018.8

S1N0V -8385.7 -8177.7 -8659.6S1N45V -5677.8 -5436.7 -6031.6

S1N90C -7553.2 -7279.2 -8025.1

S1N90V -6111.9 -5813.3 -6603.9

S1N180V -6449.3 -6325.3 -6603.9

S1N270C -4130.9 -3908.1 -4445.1

S1N270V -3693.3 -3433.7 -4119.0

S2B0C -3060.6 -2916.2 -3274.2

S2B0V -2943.0 -2793.7 -3140.1

S2B45V -8386.1 -8170.2 -8795.2S2B90C -4230.2 -4049.8 -4489.9

S2B90V -1213.9 -1001.5 -1536.1

S2B180V -32.2 45.2 -113.0

S2B270C -4581.1 -4400.4 -4855.3

S2B270V -1173.5 -956.3 -1506.0

S2N0C -6772.2 -6563.2 -7085.3

S2N0V -4067.5 -3900.6 -4307.2

S2N45V -8276.0 -8004.5 -8704.8

S2N90C -6547.7 -6339.5 -6831.7

S2N90V -2030.6 -1784.6 -2409.6

S2N180V 1389.0 1468.4 1310.2

S2N270C -5200.7 -5019.4 -5466.9

S2N270V -1335.2 -1122.0 -1664.2

D1B0 0.1 0.2 0.1

D1B45 -0.2 -0.2 -0.3

D1B270 -0.4 -0.3 -0.4

D1B315 -0.2 -0.2 -0.3

D1BC -0.5 -0.5 -0.5

D1N0 0.2 0.2 0.1

D1N45 -0.2 -0.2 -0.2

D1N270 -0.6 -0.6 -0.6

D1N315 -0.4 -0.4 -0.4

D1NC -0.8 -0.8 -0.8

D2B0 0.0 0.0 -0.1


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3.1.4 Results of Leaving Loaded Cars Parked over the Pipes for 6 WeeksOne of the unknowns at the start of the test was the response of the pipes to long-term

static loads. Two loaded cars at FAST were parked over the pipes for 6 weeks. One set ofwheels from each car was directly over one of the pipes (Figure 20). There were slight

depressions in the rails under the wheels at the end of the 6-week period. The rails

rebounded when the cars were moved, and no track geometry maintenance was needed.

Figure 20. Cars Parked over Pipes to Evaluate Long-Term Pipe Response

4.0 SUMMARY

Transportation Technology Center, Inc. conducted a test of corrugated high-density

polyethylene pipe for PPI in the HTL at FAST. The pipes were supplied by ADS. Two

pipes were installed 50 feet apart under tangent track in a fill on the HTL. There was a

4-foot cover, including the typical granular layer at FAST, between the pipes and the

bottoms of the ties. The backfill for one pipe was fractured rock; it was native soil for the

other pipe. The pipes were instrumented to allow data collection before and during trainoperations. Gages were installed at various locations on the pipes to measure lateral,

vertical, diagonal, and circumferential deflections; and pipe wall strains. Measurements

were taken at the following times:

Statically, when backfill and track construction was complete


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The train that was operated over the pipes typically consists of three to four

locomotives and approximately 80 315,000-pound GRL cars.

Results of testing are summarized below:

The pipes performed acceptably through 96 MGT.

No track geometry maintenance was required at the test site due to pipe deflectionor fill settlement.

Locomotive engineers who operated the FAST train during the test periodreported that ride quality over the pipes was satisfactory.

A locomotive-mounted, accelerometer-based, ride quality measurement system

recorded no exceptions over the pipes during the test period. One loaded car was parked over each of the pipes continuously for six weeks

during a scheduled pause in train operations. The minor track settlement that

occurred did not require track geometry maintenance.

The maximum strain (compressive) from construction loads was 7,300microstrain.

The maximum horizontal deflection from construction loads was 0.7-inchhorizontal shortening.

The maximum vertical shortening from construction loads was less than 0.1 inch.

The maximum circumferential shortening from construction loads was 0.4 inch.

The maximum strain (compressive) from the combination of construction loadsand dynamic train loading after 96 MGT was 8,800 microstrain.

The maximum horizontal deflection from the combination of construction loadsand dynamic train loading after 96 MGT was 0.6-inch horizontal shortening

The maximum vertical deflection from the combination of construction loads and

dynamic train loading after 96 MGT was 0.5-inch vertical shortening. The maximum circumferential shortening from the combination of construction

loads and dynamic train loading after 96 MGT was 0.8 inch. The portion of the

shortening caused by the dynamic loads was inconsequential.

The maximum measured deflection in any direction caused by dynamic loads wasless than 0.065 inch.

Acknowledgment

ADS Regional Engineer Shawn Coombs was the project engineer representing PPI;

Joseph LoPresti was the project engineer for TTCI; David Williams led the

instrumentation and data collection effort for TTCI. They were supported by many


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Appendix A: Instrumentation Photographs

Figure A1. Installation of Valley and Crown Mounted Strain Gages

Held in Place with Vacuum Cups


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Figure A3. Pipe Section being Instrumented


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Appendix B: Installation Photographs

Figure B1. Track Fill Excavated for Pipe Installation


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Figure B3. Pipes Being Aligned so Joints are under Rails


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Figure B4. Site 1, Crushed River Rock Backfill Vibrated with Jumping Jack


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Figure B6. Initial Compaction of Native Soil Cover Material


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Figure B8. Track Surfacing at Test Site


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Figure B10. Preparation for Data Collection


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Appendix C: Time Histories, 1 MGT Dynamic Measurements, Lap 7


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Appendix D: Time Histories, 96 MGT Dynamic Measurements, Lap 7


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Polyethylene Pipe Testing Under 315000 Cars

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