A STUDY OF THE USE OF TRUCK TIRE BEADS AS DRAINAGE PIPE AND ANALYSIS OF THE ECONOMICS OF TIRE DISPOSAL IN OKLAHOMA: PART 1 - CULVERTS

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A STUDY OF THE USE OF TRUCK TIRE BEADS

AS DRAINAGE PIPE AND ANALYSIS OF THE

ECONOMICS OF TIRE DISPOSAL IN OKLAHOMA:

PART 1
-

CULVERTS


MBTC FR 1025


Jess W. Everett and J. L. Gattis



I
Form
aGprnv
P C
1

REPORT DOCUMENTATION PAGE
FMS v0
PC1

0/040168

Pvoh
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:rep rtinq burden rnr rhis . .1i!."inn of :nform.lbon is estimated to aversgp
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hour oer response. .ndudinq the time for reviewing instructions . tear
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,sting
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, )ather,nq .end m.uni.umnq the 9 ro, npnded. and comptetmq and reviewing the :Olf!Rron of information ,end Comments re`] ard
inq this burden estimate
,~ iCIfCtuln.,t u,InrmaUi'n, mrl,ra,n f,,4gest,on%
for
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rectorate for Information
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peraOOns a^d ,Davit
H,ghw.ry. Suite t10a.Arnngtan /a12102 a 301.and t0 the Office of Management and Budget. Paperwork Reduction Project(0?04
-
0188),Washington,DC 20503

-

1 . AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED
July

1994 Final
July 1993
-

July 1994

4. TITLE AND SUBTITLE S. FUNDING NUMBERS

A Study of the Use of Truck Tire Beads as Drainage Pipe and Analysis of the
MBTC
0402
-
12003
-
21
-
1025

Economics of Tire Disposal in Oklahoma: Part I
-
Culverts

6. AUTHOR(S)

Jess W
. Everett and J. L. Gattis

7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) 8.
P
E
R
F
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M
I
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O
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9


Mack
-
Blackwell National Rural Transportation Study Center

University of Arkansas, Fayetteville, AR 72701


9. SPONSORING/MONITORING AGENCY NAME(S) AND ADORESS(ES) 10. SPONSORING/MONITORING
Oklahoma Alliance for Public Policy Research, Inc .
AGENCY
REPORT NU
MBER
2630 Northwest Expressway, Suite B Oklahoma
City, OK 73112 FR1025

Mack
-
Blackwell National Rural Transportation Study Center

University of Arkansas, Fayetteville, AR 72701


11. SUPPLEMENTARY NOTES

This project was conducted jointly between the Univer
sity of Oklahoma and thq
University of Arkansas ° Su portedby a grant from the U.S. Department of Transportation,
University Transport:atioh

Center Proaram. tt
12a. DISTRIBUTION /AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

NATIONAL TECHNICAL INFORMATIO
N SERVICE N/A

SPRINGFIELD VA 22161

13. ABSTRACT
(Maximum 200 words)

One of the effects of new state landfill regulations resulting from Subtitle D
of the Resource Conservation and Recovery Act (RCRA) has been a search for innovative
methods to divert ma
terials from landfills and find other ways to use or consume
them. Waste truck tires pose special disposal problems; truck tires have been
shredded to facilitate disposal, but the steel embedded in heavy truck tires
accelerates wear of shredding blades .

In an attempt to find alternate ways of dealing with waste truck tires, a private
tire recycling company developed a pipe from the tire bead and sidewall. This tire
-
pipe
has seen limited use as a roadway drainage culvert. To encourage wider use of this
pro
duct, an evaluation of pipe performance was performed . The evaluation consisted
of


(a) inspections of existing installations;



(b) structural tests; and



(c) leakage tests.

The study found that the majority of installations were performing well . Compared with corrugated
steel and fiberglass

pipes, the tire
-
pipe exhibited favorable structural performance . An individual tire
-
pipe section
was found to be

watertight. However, w
hen tested in the open
-
air (not in the ground), the tire
-
pipe joints were found
to leak.

Development of an improved end connection would improve the utility of the tire
-
pipe.



14
. SUBJECT TERMS
15. NUMBER OF PAGES

7
6 culverts, pipe, recycling, tires
16
.
PRICE CODE

N/A

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION
20
. LIMITATION OF ABSTRACT
OF REPORT OF THIS
PAGE OF ABSTRACT

none none
none
N/A

NSN 7540
-
01
-
280
-
5500
Prescribed by ANSI Std L39
-
18 298
-
102

1.
Report No.

2. Government Accession No. 3. Recipient's Catalog No .

4. Title and Subtitle 5. Report DateJuly 1994

A Study of the Use of Truck Tire Beads as Drainage Pipe and Analysis of the

Economics of Tire Disposal in Oklahoma: Part 1
-
Culverts
6. Perfor
ming Organization Code


8. Performing Organization Report
No .

7. Author(s) Jess W. Everett and J. L. Gattis
FR1025

9. Performlna Organization Name and Address10. Work Unit No.
(TRAIS) School of Civil Engineering and Environmental Science
University of O
klahoma, Norman, OK 73019 11 . Contract or Grant
No .

Mack
-
Blackwell National Rural Transportation Study Center

DTRS92
-
G
-
0013
UniversityofArkansas, Fayetteville,AR 72701
13. Type of Report and Period Covered

12. Sponsoring Agency Name and Address Oklahoma Alliance
for Public Policy Research, Inc. Final July 1993
-
July
1994 Oklahoma City, OK 73112

Mack
-
Blackwell National Rural Transportation Study Center

14. Sponsoring Agency Code

University of Arkansas, Fayet
teville, AR 72701


15. Supplementary Notes

T project w
-
as conducted mind the Unifve t~ of Okl htc~rna and re .Utuvet i of Arkansas
"Supported

by a grant trom the par nt o nspor a ions university ransportation

Center Program."


16. Abstract

One of the ef
fects of new state landfill regulations resulting from Subtitle D of the
Resource Conservation and Recovery Act (RCRA) has been a search for innovative methods to
divert materials from landfills and find other ways to use or consume them. Waste truck
tires

pose special disposal problems; truck tires have been shredded to facilitate disposal,
but the steel embedded in heavy truck tires accelerates wear of shredding blades.

In an attempt to find alternate ways of dealing with waste truck tires, a private tir
e
recycling company developed a pipe from the tire bead and sidewall. This tire
-
pipe has seen
limited use as a roadway drainage culvert . To encourage wider use of this product, an
evaluation of pipe performance was performed . The evaluation consisted of


(a) inspections of existing installations ;



(b) structural tests; and



(c) leakage tests.

The study found that the majority of installations were performing well . Compared with corrugated
steel and fiberglass

pipes, the tire
-
pipe exhibited favorable str
uctural performance. An individual tire
-
pipe section
was found to be

watertight. However, when tested in the open
-
air (not in the ground), the tire
-
pipe joints were
found to leak.

Development of an improved end connection would improve the utility of the t
ire
-
pipe.



17. Key Words

18. Distribution Statement

culverts, pipe, recycling, tires

NO RESTRICTIONS

19. Security Classic. (of this report) 20. Security Classif. (of this page) 21. No. of Pages
22. Price

none none
76


Form DOT F 1700.7 (8
-
72) Repro
duction of completed page authorized

' '

1
FINAL
REPORT

I

A STUDY OF THE USE OF TRUCK TIRE BEADS AS DRAINAGE PIPE AND ANALYSIS

OF THE ECONOMICS OF TIRE DISPOSAL IN OKLAHOMA


PART 1:
Culverts

JULY 1994

for the

Oklahoma Alliance:

Center for Resource Conservation and Environmental Research

and

Mack
-
Blackwell National Rural Transportation Study Center


University of Arkansas


by


Jess W. Everett, Ph.D. Assistant
Professor

School of Civil Engineering and Environmental Science

University of Oklahoma

202 West Boyd St., Room 334

Norman OK, 73019
-
0631


and


J. L. Gattis, Ph.D., P.E.
Associate Professor

Civil Engineering Department

University of Arkansas

4190 Bell Engineering Center

Fayettville, AR 72701


National Rund

Transportat
ion Study Center

1
Mac'`
-
Bell

M BTC

\


ACKNOWLEDGMENTS

This research was funded by the Oklahoma Alliance : Center for Resource Conservation
and Environmental Research and by the Mack
-
BlackwellNational Rural Transportation Study
Center, through a grant from

the U .S. Department of Transportation. The authors wish
to thank the elected countyofficials and the county road personnel in Arkansas and
Oklahoma who assisted with the studies and provided input .

The authors also thank Dr. Ben Wallace, Salim Douglah,

Mike Schmitz,Karl Zimmerman,
and Adam Morton at the University of Oklahoma and Mark Kuss and Becky Collier at the
University of Arkansas for theirassistance.

DISCLAIMER

The contents of this report reflect the views of the authors, who are responsible fo
r
the facts and accuracy of the information presented herein . This Document is
disseminated under the sponsorship of the OklahomaAlliance, Center for Resource
Conservation and Environmental Research, and the Department of Transportation,
University Transp
ortation CentersProgram, in the interest of information exchange. The
U.S. Government assumes no liability for the contents or use thereof .

1

I


1


Tires Dumped along side of Road

TABLE OF CONTENTS

EXECUTIVE SUMMARY

1 Chapter 1:
INTRODUCTION AND OBJECTIVES

4

Chapter 2:

SUMMARYOFCURRENT EXPERIENCE: FABRICATIONTO FIELD PERFORMANCE

14
Chapter 3: TRUCK
-
TIRE PIPE EVALUATION RELATIVETO APPROPRIATE PIPE SPECIFICATIONS 23 Chapter
4: CONCLUSIONS AND RECOMMENDATIONS 48 REFER
ENCES 52

AppendixA:

TRUCK
-
TIRE PIPE SITE INSPECTION 53

AppendixB:

EXTERNAL LOADING CHARACTERISTICS BY PARALLEL
-
PLATE
LOADING

EXECUTIVE SUMMARY

Scrap tires pose special disposal problems . When deposited whole in
a landfill, ground vibration from heavy
equipment can cause tires to slowly
rise to the ground surface. Tires left exposed to rainfall at landfills or
illegal dump sites can collect rainwater and become potential mosquito
breeding sites . Large collections of tires represent fire hazards . If
sh
redded to facilitate disposal or as the first step towards recycling, high
grade steel present in the bead of large truck tires causes accelerated wear
of shredder hammers or blades .

One means devised to in part address the scrap tire problem is the
manufacture of drainage pipes from the bead and sidewall of large truck tires
. The manufacture of each eight foot truck
-
tire pipe section reuses the bead
and a large portion of the sidewal
l of approximately 40 waste truck tires.
In addition, the difficult
-
to
-
shred bead is removed before shredding occurs.
Thus, the manufacture of truck
-
tire pipes diverts waste material from
landfills and promotes recycling and reuse. Because waste truck tire
s can
usually be obtained at zero or negative cost, truck
-
tire pipes should sell
for a lower price compared to corrugated steel, fiberglass, and plastic pipes
. If truck
-
tire pipes perform well in applications, the manufacture of
truck
-
tire pipes will be a
n environmentally and economically sound activity.
However, the weight, short section length, and thickness of the pipe walls
will increase transportation and installations costs.

The major goal of the research presented here is to evaluate the
truck
-
tire

pipe and delineate its appropriate use. Information obtained
through conversations with pipe installers, site inspections of installed
pipes, experimental tests of pipes, and theoretical analyses conducted as part
of this research makes it possible to pre
sent a numberof conclusions and
recommendations concerning installation, expected performance, and
advantages and limitations of the truck
-
tire pipes.

Because the truck
-
tire pipe is made from a waste material with little
pre
-
processing, it does not presen
t the uniform appearance of pipes
manufactured using virgin materials. Furthermore, the diameters of truck
-
tire
pipes are limited to available truck tire sizes. The average inner diameters
for the nominal 20 and 22.5 inch truck
-
tire pipes currently made ar
e 19.5 and
22.6 inches, respectively (49.5 cm and 57.4 cm). The variability of the inner
diameter does not present a problem for pipe connections, because joint
connections can be made with a flexible wrap. The truck
-
tire pipes only come
in nominal eight f
oot lengths . 20" nominal truck tire pipes measured

had an average length of 97.6 inches (247.9 cm), while the 22.5" nominal truck
-
tire
pipes

measured had an average length of 98 .5 inches (250.2 cm). However, other lengths
can be made .

Truck
-
tire pipe
s have been installed at about 30 sites in Arkansas,
Oklahoma, and Texas. They have been used almost exclusively for surface
drainage under open channel flow conditions
.
Most of the tire
-
pipes observed
were installed in rural or small
-
town environments, ra
nging from a drive giving
access to a field to a rural subdivision road, most were on county roads. Traffic
volumes at most sites were relatively light. Most of the pipes were place under
dirt or gravel roads ; one was under a low
-
type asphalt pavement. Vi
sits to
26 of these sites gathered valuable information concerning the truck
-
tire pipes
.

The study found that truck
-
tire pipe installation is more
difficult than conventional thin
-
walled pipes because truck
-
tire
pipes:


are heavy, about 1200 pounds;


com
e in short sections, thus requiring many joints ;


require special care in maintaining a uniform and sufficient trench
-
bottom
slope ;


have 4 inch (10 cm) thick walls, requiring a trench that is approximately 8
inches (20 .3 cm)

deeper than conventional cu
lverts of equal inner diameter, and





require extra effort to get adequate joint connections. For these reasons
installation costs will somewhat higher for the truck
-
tire pipe than for galvanized
steel or fiberglass pipe. Pipe installers reported that to
tal installation time
for a galvanized steel pipe was roughly 1/2 day; users at different counties said
installation time was greater for the truck
-
tire pipe by anywhere from about 30
minutes to 3 hours. Thus, savings must be realized regarding purchase pr
ice, product
lifetime, or avoided disposal fees if truck
-
tire pipes are offer advantage over
conventional pipes.

The truck
-
tire pipes appear to work well in drainage applications.
Siltation in pipes was observed to be normal. The pipes work well with
litt
le cover soil and have been able to handle the traffic levels to which
they have been subjected, including heavyvehicles such as dump trucks.
None of the truck
-
tire pipes inspected to date have failed or required
replacement. Of approximately 90 joints ins
pected, three showed signs
of erosion through a joint, indicating that care must be taken to properly
wrap the joints . At most locations, joints were wrapped with a
six
inch
used conveyor belt; it may be necessary to use a wider belt to avoid
erosion in s
ome cases.

Pipe stiffness at 5 % deflection for 19.5 and 22.6 inches (49.5 and
57.4 cm) inner diameter pipes should be at least 38 and 35 psi,
respectively . Testing conducted at Fears Structural Laboratory on the
campus of the University of Oklahoma demo
nstrated that the truck
-
tire pipe
stiffness exceeds these requirements. However, one 22.5 inch culvert had
a stiffness at 5 % deflection of only 36 psi, just 1 psi greater than the
required value . The low stiffness value measured for that culvert
indicate
s a need for further tests with the 22 .5 inch inner diameter pipes
to (1) ensure that the required stiffness is always met, (2) determine
if manufacturing variability or testing error caused the low value, and
(3) suggest means to improve the 22 .5 inch p
ipes if necessary. However,
all of the truck
-
tire culverts exhibited higher stiffness values over a
wider range of deflection when compared to steel and polyethylene pipes
.. The truck
-
tire pipes were observed to rebound to original shape after
deflection
as high as 65 % . In the field, if an exposed end of a truck
-
tire
pipe is hit or run over by a vehicle, it will probably be able to regain
its former shape. This cannot be said of steel culverts.

Leakage tests were conducted at the Mack
-
Blackwell Transpor
tation Center
at the University of Arkansas. In the single
-
section pipe leakage test, the
one section tested did not leak between the sidewalls. When a joint between
two tire
-
pipe sections was tested, significant leakage at the joint was
observed. Both the

irregularity of the tire
-
pipe surface and the bridging
effect of the rebars appeared to make it practically impossible to completely
seal the joint with conveyor belt wrapping . The potential for the leakage to
cause a significant amount of erosion of soi
l around the pipe over time cannot
be ignored. However, it is important to note that this test was conducted
without any soil surrounding the joint. The apparent success of most truck
-
tire
pipe joints observed in the field suggests that in many situations
soil
surrounding the pipe can sufficiently seal joints.

It is hypothesized that an important method of failure will be 1, 2, or
3 rebars yielding on exterior pipe sections, i.e.,sections which protrude from
either side of a drivewayor roadway. A rebar wil
l fail when its cross
-
sectional
area is reduced beyond the minimum necessary to withstand the load placed on
the rebar by the bead
-
sidewalls and roadway traffic. Rough estimates based on
assumed corrosion models and values indicate that rebar failure can b
e expected
within 20 to 70 years in highly corrosive soils, 90 to 200 years in average
soils, and longer still in slightly corrosive soils. However, this does not
mean that truck
-
tire culverts will last 200 years or more. This claim cannot
be made because
the long
-
term behavior of the rubber bead
-
sidewalls in soil
is unknown. It appears that even without any of the measures listed above, the
truck
-
tire pipe should perform well in corrosive soils.

In the majority of the cases, the installer/owner appeared to be pleased with
the truck
-
tire

pipe. The field investigations indicated that the tire
-
pipe works well in many
rural road situations, but does have some limitations. The main limitations
are the

higher cost of installation and the potential for erosion through
joints. The greater difficulty of installation would hopefully be outweighed
by long
-
term performance and durability, but long term tire
-
pipe behavior will
not be

known for many years. Per
haps the erosion problem can be addressed by
carefully installing the joint wrap and, if necessary, using a wider wrap
. The lack of different sizes available is a

limitation; however, multiple parallel runs of thetruck
-
tire pipe can be, and indeed
are us
ed when

greater capacity is required. The main advantages include low cost and diversion
of waste from

disposal. An expected advantage will be long life, though this can only be proved
through

demonstration. Experience and laboratory tests suggest that
the exposed ends of
truck
-
tire pipes

will be able to sustain heavy loads and rebound without permanentdeformation. Field
inspection

also indicates that the truck
-
tire pipes perform well with little ground cover.
Overall, the inspected

truck
-
tire pipe cu
lverts appeared to be performing adequately.

CHAPTER 1

INTRODUCTION AND OBJECTIVES

As the effects of new state landfill regulations resulting from Subtitle D
of the Resource Conservation and Recovery Act (RCRA) are felt in the United States
of America,
the incentive to divert materials from landfills will increase. Already,
a significant number of landfills have closed rather than upgrade to meet the
requirements of the new regulations. These closures are expected to shorten the
life of remaining landfil
ls, increase waste haul distances for some communities,
and drive up disposal fees. Diversion of waste materials from landfills is one way
to reduce the impact of higher landfill disposal costs. Producing marketable
products from waste materials is one way

to divert waste materials.

Scrap tires pose special disposal problems . When deposited whole in a
landfill, ground vibration from heavy equipment can cause tires to slowly rise
to the ground surface . Tires left exposed to rainfall at landfills or illega
l
dump sites can collect rainwater and, thus, become potential mosquito breeding
sites. Finally, large collections of tires represent fire hazards .

In order to reduce problems associated with whole tire disposal, many states
have implemented programs to
either divert scrap tires from landfills or to ensure
that scrap tires deposited in landfills remain underground . An important step in
either program can be tire shredding. However, heavy truck tires can be difficult
to shred, because the bead (see Figure

1), in order to withstand the rigors of use
and to allow repeated retreading, contains a significant amount of high
-
grade steel.
The presence of this steel in heavy truck tires can represent a problem for shredding
operations, in that shredding of this ma
terial may result in accelerated wear of
the revolving hammers or blades used to shred tires. The result is increased costs
of hammer or blade maintenance, either from replacement or resurfacing.

In order to avoid the cost of shredding steel impregnated t
ire beads, the Mule
Rubber Company, located in Oklahoma, has developed a drainage pipe made from the
beads and sidewalls of scrap truck tires. The pipe material is produced by cutting
the bead and adjacent sidewall from a heavy truck tire, using a machine
which
operates similar to a can opener . Because truck
-
tires come in 20 and 22.5 inch
sizes, the process produces a disc with inner diameter of approximately 20 or

22.5 inches (50.8 or 55.9 cm), depending on the size of truck tire used, and wall
thickness

of 3 to 4 inches (76 to 10.2 cm), as shown in Figure 1 . The remainder
of the tire can then be shredded without undue hammer wear.

The pipes are made by using a large hydraulic press to compress more than 80
truck tire bead
-
sidewalls to a length of appro
ximately 8 feet . While the
bead
-
sidewalls are still compressed, four steel rebars, 3/8 inch (0.95 cm) in
diameter, are wrapped lengthwise around the pipe walls, 90 degrees apart, and
welded. Rebars are rough steel rods, commonly used in reinforcing concre
te .

1


1

1


bead and portion of
sidewall
(removed)

Bead

Side wall

(a)
(b)
(c)

Figure 1: Truck Tire Schematic

(a) truck tire terms

(b) material removed for truck
-
tire pipe

(c) bead
-
sidewall used to make truck
-
tire pipe

A schematic of the manufacturing process is shown in Figure 2. Pictures
of the process are shown in Figures 3 and 4. Field connections between
two end
-
to
-
end truck
-
tire pipe sections can be made with a flexible belt
which is wrapped around the two abutting

pipe ends and cinched in place
with a strap, as shown in Figure 5. Pipe installation is shown in Figure
6. Truck
-
tire pipes can be used as gravity flow drainage conduits where
soil provides support to the pipe walls. Several installations are shown
in Fig
ures 7 and 8 .

The product has been successfully used on a limited basis in
Arkansas, Oklahoma and Texas, costs less than other culverts, such as
those made of steel or plastic, and represents a diversion of materials
from disposal to recycling. The numbe
r of sites at which the truck tire
culverts have been used has been limited by reluctance of potential users
to install a pipe which is new to the marketplace and relatively untested.
It appears that wide
-
spread adoption in private, county, state and
feder
al projects must wait until specifications, indicating appropriate
uses for the product, have been developed by an independent testing
laboratory.

Wide
-
spread adoption of the truck
-
tire pipe can produce benefits
by providing an efficient reuse of a signif
icant portion of truck tires.
Adoption will be encouraged if the load
-
carrying capacity, durability,
and non
-
leakage potential of the truck
-
tire pipe are evaluated by an
independent research group and shown to be satisfactory. The goal of this
research pro
ject is to evaluate the truck
-
tire pipe and delineate
appropriate use. This has been done by investigating installation
requirements, field performance, load
-
carrying capacity, durability,
and joint leakage potential of the truck
-
tire pipe. Therefore, the
objectivesof this report are to:


present the results of inspections of truck
-
tire pipes that have been
installed in Oklahoma,

Arkansas, and Texas;



evaluate the merits of the truck
the
pipe relative to eight important pipe
characteristics: workmanship; pipe

dimensions; perforations; pipe stiffness; pipe
flattening, environmental stress cracking; brittleness; fitting requirements ; and
joint leakage; and
1


present conclusions and recommendations concerning appropriate use of the
truck
-
tire

culverts.



In the

next chapter observations gathered from inspections of installed
truck
-
tire pipes are discussed. Detailed site
-
by
-
site observations are presented
in Appendix A. In Chapter 3 the truck
-
1
tire pipe is evaluated relative to the
American Association of State
Highway and Transportation Official (AASHTO)
specification M 294
-
90, "Standard Specification for Corrugated Polyethylene Pipe,
12
-
36 in. Diameter." In that chapter the results of tests conducted at Fears
Structural Laboratory at the University of Oklahoma
and the Mack
-
Blackwell
Transportation Center at the University of Arkansas are presented. In the final
chapter, conclusions and recommendations are presented.

Downward Force

:O
-


Nmw_

imp

Rebar Welds

!
ZM


af~
-



(c)


Figure 2: Construction of Truck
-
Tire Pipe

(a) 80 truck tire
beads/sidewalls stacked
on form


(b) Beads/sidewalls compressed by piston to approximately
8 feet


(c) Beads/sidewalls are secured by 4 w
elded rebars set 90°
apart.



Figure 3: Manufacturing
Process: Placing Bead
-
sidewalls on Form

8

I


F
i
g
u
r
e

4
:

Form in Front of Hydraulic
Press

(
a
)


`
.
.
F
l
e
x
i
b
l
e

Belt

(b)

Cinch Straps






(c)


F
i
g
u
re 5: Connection of two truck
-
tire pipes

(a) two eight foots section of pipe laid end to end,
ready to be connected (b) flexible belt ready to be
wrapped tightly around adjacent pipe ends (c) tightly
wrapped flexible belt, cinched with strap



_r

a

I



CHAPTER 2 SUMMARY OF
CURRENT EXPERIENCE:
FABRICATION TO FIELD
PERFORMANCE

To date,
truck
-
tire pipes have been used at about 30 locations in
Oklahoma, Texas, and Arkansas. One of the project objectives
was to determine how the truck
-
tire pipe has performed in
the field. To determine what problems and benefits have been
encountere
d during installation and use, the project team
made field inspections of existing installations, and
queried the personnel who had installed and used the pipe.
In most cases
installations were
made by county road
departments, though
individual landowners
have installed pipes
and extensive
applications have
occurred at three tire
shredding facilities.
Each site inspection
is reported in detail
in Appendix A. Of the
26 pipe installations
inspected, one was
observed to be in fair
condition while all
others we
re
evaluateddas good.
Most installations
inspected consist of
one or two pipe runs of
3 or 4 pipes each. In
a few cases much
longer runs have been
installed . During the
process of inquiring
about performance,
field personnel made
remarks about aspects
oth
er than
performance, and
these remarks are
reported in this
section, where
appropriate .
OTHER
PIPE ALTERNATIVES

Inherent in the evaluation of a product
is a comparison with alternatives to the
product. Discussions with county
commissioners and with natur
al resource
companies in Oklahoma and Arkansas indicated
that the two predominate types of drainage pipe
currently being installed are

galvanized corrugated steel and fiberglass. When bought in
large quantities, some agencies obtain either type for
betwee
n $5.25 and $6.00 per linear foot; the cost may double
when bought in small quantities. Other county road districts
reported higherunit prices for these pipes. One natural
resource company representative stated that a galvanized
corrugated pipe may last 20

years, but they expect the newer
fiberglass pipes to last 50 years . One county employee said
galvanized pipe lasts about 25 years . In some areas, used
oil well pipe suitable for culverts is available for about
$7.00 per linear foot. Polyethylene piping
can be used, but
is more expensive and was not mentioned a being used by any
of the road crews.
TIRE PIPE MANUFACTURING

Decisions made concerning the truck tire
pipe manufacturing process
affect
the product's
performance in thefield. The current process
p
roduces a product with anundulating or uneven
end (when viewed perpendicular to the length or
"long" dimension of the pipe), because the rebars
"pinch" the bead
-
sidewallsasshown in Figure 7(a)
and8(a). A method that would produce a flat end
would be prefer
able . A future modification that
would produce an improved product involves

punching four holes through each
bead
-
sidewalls, "threading" rebars through
these holes, and fixing them to metal, rubber,
or fiberglass ends of similar shape and size
to the bea
d
-
sidewall .

1
4



1

1

1


F
I
N
A
L

R
E
P
O
R
T



This would result
in flat uniform
ends, and thus
would allow for
better joint
connections, but
at increased cost.

One issue raised
by users was whether
there would be any
benefits from using a
thicker reinforcing
bar (rebar) to bind
the separate
sidewalls

into a pipe
unit. The
manufacturer has
stated that the 3/8
inch (0.95 cm) size is
preferred, because it
is easier to bend than
the larger sizes . The
only benefit that
might be incurred by
increasing the
rebarsize would be
anincrease in the time
required
to rust
through the rebars.
Rusting through one or
two rebars is the most
likely failure mode
for the tire
-
pipes.
Currently, the rebars
are coated with a rust inhibiting paint. An alternative
would be to use fiberglass rebars, which are more expensive.
Reb
ar corrosion is discussed in greater detail in Chapter
3.
SHIPPING AND HANDLING

Before the pipe is installed in the ground, it must
be transported to and unloaded at the site. Product
durability and ease of handling during transport are
concerns. The pipe

is rather heavy ; the manufacturer
reports that a section weighs about 150 pounds per linear
foot, with the standard 8 foot section weighing 1200 pounds.
This makes shipping and handling more difficult for the tire
pipe than for a comparably
-
sized galvani
zed or fiberglass
pipe.

There were reported experiences with difficulty and
damage during transport and delivery . Some of the problems
may have occurred when the manufacturer made 10 foot
sections, before going exclusively to the 8 foot section.
A pictur
e of a 10 ft section which failed during
installation is shown in Figure 9. The manufacturer states
that the tire
-
pipe can be damaged by dragging one section
across another, or by dropping the tire pipe on its end
--
it
may buckle.

Because the pipe may be
damaged if it is flexed
laterally, care must be exercised when taking the pipe from
a truck and placing it in a ditch. Some use a back hoe to
hoist a chain slipped through the inside of the pipe. Even
with care, a few rebarwelds have been broken during
ins
tallation. Sometimes the bar was rewelded and the pipe
used, a couple of discarded tire
-
pipes with broken bars
were seen in county road yards . One county slipped a stout
rigid bar through the entire length of the pipe, and
attached a chain to each end of
the bar, this seems to be
the better method.

One county commissioner's office reported that "the
pipe is too heavy, awkward to handle . While unloading pipe
during delivery, one rebar on one pipe broke, the pipe came
apart slowly, with no
danger of hurtin
g
anyone." Despite some
problems, most pipes remained in good shape when care was
used while handling the pipe before installation.

1


1

I


1



Figure 9: Ten Foot Truck
-
Tire Which Failed During

Installation


INSTALLATION

Because the tire
-
pipe
is a relatively new
product, installation
procedures are still
evolving

and are
not
standard
ized. The
major
issues
related

to
installa
tion were

1
1 . what special site
preparation
procedures are
needed;

1

what type of
bedding, if any, is
desirable ;

2

what type of
jointing procedures
should be followed ;

3

how much cover
is needed over the top
of the pipe; and


5. what are the
installation cost and time
requirements .

Site Preparation Procedures


As to special site preparation, one county
field supervisor commented "to install
[the] tire
-

pipe, the pipe bed needs to dug with the proper
slope, because irregularities in pipe surfa
ce
make it

more difficult to tell what the pipe slope is
. You need a little smoother ditch to install
tire pipe than

you do for a galvanized pipe; [the] tire
-
pipe
is more difficult to install if the ditch bottom
is

muddy."

Due to the thicker walls, ti
re
-
pipes
require a slightlydeeper trench than
thin
-
walled culvert

pipe of similar inside diameter. Therefore, an
equivalent inside diameter tire
-
pipe requires
a greater

dimensio
n from
ditch
bottom to
top
-
of
-
p
ipe.
Where
ditches
must be
shallow,
a tire
pip
e may
not

work
well. In
a few
cases,
road
personne
l
reported
that they
had to
"build
the road
surface
up" to

clear the
top of
the pipe.
As an
alternat
ive to
building
up the
road
surface,
the
inverts
of some

truck
-
tire pipes were installed below the
stre
am flow line and there was subsequent
siltation in the

pipe bottom.

Bedding Procedures

The bedding procedures used on the pipes
observed ranged from none to elaborate.
Some

installed the pipe directly on the dirt surface
of a dug trench, others used crushed stone
bedding.

One county encased the pipe in concrete at a low
water crossing where galvanized pipe had washed

out. None of the bedding methods used resulted
in any pro
blems that the project personnel

observed. It appears that truck
-
tire pipes can
be bedded similarly to other types of culvert.

Joining Procedures,

Because the truck
-
tire pipes are only 8
feet (2.4 m) in length, at least 3 or 4
sections are

used to span

the typical driveway or
roadway. This results in two or three
joints, i.e.,places where two sections
ends meet. These joints need to be tight
enough to prevent water and/or
surrounding soil from flowing into the
pipe or to prevent outflowing water from
er
oding soil surrounding the pipe . A
variety of jointing procedures have been
used. Some of the pipe end connections had
been wrapped with strips of conveyor belt
or geotextile cloth. In some cases the
wrap was held in place with plastic ties.
At one locati
on, the crew spot
-
welded
rebar across the joint end. At other
sites, pipe were simply butted
together,with no wrap or physical
connection
.

1
7


1



Due to the
irregular shape of the
pipe ends, a
nd to pipe
weight, getting a
close joint is
1
difficult. Also,
installers have
difficulty getting
joints to butt
together, because to
lift the pipe they
install a chain
through the overt (the
inside, under to top)
and must leave room to
pull the chain out
a
fter the pipe has
been lowered into the
trench . After
observing
installation in
progress, a project
team member
recommended that the
installer rotate each
section 1/8 turn from
the previous section,
to get a better
end
-
to
-
end fit. This
is because with
eac
hpipe bound by four
rebars, the "rise and
fall" of each
end
-
undulation is on a
1/4 circumference
cycle ; the "out"
undulations mesh with
the "in" undulations by rotating a subsequent section by 1/8
the circumference. Joints will be discussed in more detail

in the next chapter. Pipe Cover

The tire pipes appear to perform well with
very little cover . Many of the pipes had cover
ranging from 1 to 4 inches deep . Because one pipe
section end under a road was protruding up into
the road, and appeared to have p
erhaps been "hung
up" by the blade of a road grader, it is suggested
that all installations have sufficient cover to
allow roads to be graded on a regular basis. Cost
and Time,

Installers agreed that installation costs
are higher for the tire
-
pipe than fo
r galvanized
steel or fiberglass pipe, because of the extra
time required . Total installation time for a
galvanized steel pipe was said to be roughly 12
day; users at different counties said
installation time was greater for the tire
-
pipe
by anywhere from

about 30 minutes to 3 hours. One
road maintenance supervisor, who was unimpressed
by the tire
-
pipe, claimed that it took about 2
-
3
times as long to install the tire
-
pipe culvert
compared to other types of culverts.

The major component by mass of truck
-
ti
re pipes is
waste truck tires. This material can generally be obtained
at zero or negative cost to the truck
-
tire manufacturer. For
this reason, the purchase price of truck
-
tires pipes should
be about $3 to $5 per linear foot, less than other types of
pipe
s.
FIELD PERFORMANCE

Pipe users may have a number of questions
about the performance of the truck
-
tire pipe,
regarding:

1 . water carrying capacity, and debris accumulation
potential inside the pipe due to the

rough surface;


1

erosion, especially at joints, and ability to
withstand flooding;

2

ability to carry the weight of vehicles passing over
the pipe;

3

potential for continuous and excessive flexure,
causing deterioration
of the road above

the pipe;



5 . failure of rebars fro
m corrosion, resulting in pipe
failure; and

6. susceptibility to fire damage.

1
8



1

1

1


1


1


1


F
I
N
A
L

R
E
P
O
R
T



The field inspec
tions
gave insight into some
of these and other
issues .

The tire
-
pipes
observed had all been
installed in rural or
small
-
town
environments, ranging from a drive giving access to a field
to a rural subdivision road ; most were on county roads.
Traffic vol
umes at most sites were relatively light. A few
of the pipe installation sites had endured some heavy
-
weight
vehicle traffic, associated with nearby construction
projects . Most of the pipes were place under dirt or gravel
roads; one was under a low
-
typeas
phalt pavement. Water Flow

Even though the surface inside the pipe is irregular,
deposits observed inside the pipe were few and generally
small. Many of the pipes had r
ather "clean" insides after
a few months to more than 2 years of service. The bottom
of some culverts had
accumulated
sedimentation
material, but no more
than would be
expected with any
type of culvert . At
the few sites where
extensive siltation
had occur
red, it
appeared to be due to
the pipe flow
-
line
being too low or to
upstream erosion,
not due to erosion at
the joints . It is
important to note
that the truck
-
tire
pipe is not
corrugated, as are
steel and plastic
drainage pipe. The
truck
-
tire pipe's 4
in
ch (10 cm) thick
walls make
corrugation
unnecessary . Thus,
the truck
-
tire pipe
inner surface, though rough, provides fewer opportunities
for the collection of soil and detritus than typical
corrugated culverts. Erosion

In some cases erosion of the road e
mbankment near
a pipe
-
end was observed. This may have been caused by
insufficient compaction of the backfill on the embankment
slope, and subsequent surface erosion on the side of the
embankment. This type of erosion could happen with any
type of drainage
pipe .

Out of 90 joints observed during site inspections,
three cases of erosion were observed in the road surface near
a pipe joint. Two examples areshown in Figure 10. This
suggests erosion into or out of the pipe, caused by gaps at
a joint . Perhaps th
is problem can be eliminated by better
installation of the joint wrap and/or using a wider wrap.
Truck
-
tire pipe connections are discussed in greater detail
in the next chapter.

At one county, users indicated that the tire pipe has
been more resistant to
flood damage. One run of truck
-
tire
pipes stayed in place when comparable metal pipes washed
out. One possible explanation is that the truck
-
tire pipe's
extra weight keeps it anchored in place under situations
that

can wash
-
out light culverts. However, Co
manche County
personnel stated that one tire
-
pipe culvert washed out the
night after installation due to a heavy rain that same night
; it was re
-
installed and they have not experienced a problem
with it since.


= =


=
-

-

-

=
-

= =
-

w
-

=

O

N


1
-
1


Loads and
Deflecti
on

The
truck
-
ti
re pipes
appear to
be strong
enough
for typical culvert duty. Several pipes served
roads which had carried earth moving trucks
during near
-
by construction projects. However,
the project team observed two instances of pipe
deflection, i.e., pipe
s which noticeably
deviated from a round cross
-
section. Though
deflection was noticeable, it was not excessive
. In one case the cause was not known. In the
other case a county commissioner suspected than
an
overweig
ht
(120,000
lb.)
off
-
road
vehicle
operat
in
g nearby
had
driven on
the
county
road.
Another
explanat
ion for
truck
-
ti
re pipe
deformat
ion could
be
improper
back
filling
procedur
es, which
can lead
to
deflecti
on in any
drainage
culvert .
One of
the dirt
roads was
observed
to have a
slight
dip in it
di
rectly
above a
truck
-
tire culvert. This also could be due to
insufficient compaction of the soil during
installation. Load versus deflectiontests,
presented in the next chapter, indicate that the
truck
-
tire pipe is stiff enough for culvert duty
. Cover and

Flexure,

Rather small "hairline" cracks in the
surface over the pipe were noted at a number of
sites. It is hypothesized that this might be
caused by vibration of the truck
-
tire pipe
whenever traffic crosses it. There were no
observable problems resultin
g from the limited
cracking observed, even at sites where pipes had
been in place for approximately 2.5 years. There
were no cracks observed in the surface of the
single low
-
type asphalt road (which appeared
tobe crushed stone covered with chip seal)
insta
llation, although a small hairline crack
was noted in the dirt cover past the edge of the
asphalt. However, the asphalt had been in place
less than 9 months. Rebar Durability

At one county, the long
-
term
performance of the tire
-
pipe in its current
form wa
s raised concerning the potential
for rebars to give and cause entire pipes
to split apart. At one 10 ft.
-
long section
installation, several of the sidewalls
near the one end have been displaced out of
shape (pushed inward and outward). This
happened durin
g installation of the
culvert. At one end a rebar had snapped,
apparently some time after installation.
It may be that the rebar weld was inadequate
.

1
However, the manufacturer of the
tire
-
pipe no longer
makes the 10 foot
sections, because
some sections
experienced
excessive flexure and
deformed when lifted.
I
t

a
p
p
e
a
r
s

t
h
a
t

t
h
e

m
o
s
t

l
i
k
ely cause of pipe
failure will be rebar
yield, brought on by
rebar co
rrosion,
especially in
corrosive soils. One
county commissioner
stated that overall,
he preferred
galvanized steel pipe
because it is quicker
and easiertoinstall,
but would use the tire
pipe in
alkali

spots, due to better corrosion resistance . It
is cert
ainly true that the four inch thick
rubber walls of the truck
-
tire culvert afford
greater protection fromcorrosion. However,
the end section, i.e.,the
1
sections that
protrude out of the roadway, may fail when one
or two rebars fail. Failure of truck
-
tire
pipes by rebar failure is discussed in greater
detailin the next chapter.

Fire Damage,


No instances of
damage to the rubber
truck
-
tire culverts
caused by fire damage
were noted . However,
the

potential for
damage due to fires
caused by vandalism or
accidents cannot be
ignored. It is not
known at this time how
much effort would be
required on the part
of vandal to cause a damaging fire.
COMMENTS

In the majority of the cases, the installer/owne
r
appeared to be pleased with the truck
-
tire pipe. The field
investigations indicated that the tire
-
pipe works well in
many rural road situations, but does have some limitations
. The greater difficulty of installation would hopefully be
outweighed by long
-
term performance and durability, but
long term tire
-
pipe behavior will not be known for many
years. Of course, the lack of different sizes available is
a limitation, however, multiple parallel runs of the
truck
-
tire pipe can be, and indeed are, used when
greater
capacity is required. The joining method is very important.
If the observed holes in roadways were in fact due to erosion
through a joint
opening, then the
jointing problem will
have to be addressed .
One simple solution is to use a wider wrap. To
data,
only
six
inch (15.3 cm) wide wrap has been used. The use of
10 or 12 inch (25.4 or 30.5) wraps would be expected to solve
this problem.


C
HAPTER 3
TRUCK
-
TIRE PIPE EVALUATION RELATIVE
TO
APP
ROPRIATE PIPE

SPECIFICATIONS


Some
standard
specifications
and test methods
for pipes are
listed in Table
1. The most
appropriate
specification
for application
to the truck
-
tire
pipe culvert i
s
AASHTO M 294
-
90,
"Standard
Specification
for Corrugated
Polyethylene
Pipe,
12
-
36
in.
Diameter."
This
ASSHTO
specification is
for pipes from
12
to
36
inches in
diameter, used
for " ...surface
and subsurface
drainage
applications
where soil
provides support
to

its flexible
walls"
(AASHTO M
294
-
90,
section 1
.1). The major use of corrugated polyethylene pipe is
to ". . .collect or convey drainage water by open gravity
flow, as culverts, storm drains, etc."
(AASHTO M 294
-
90,
section 1 .1). The size range and use
are applicable to
the truck
-
tire pipe. Section
7 of AASHTO M 294
-
90
states the
requirements that corrugated polyethylene pipe must
meet concerning workmanship, pipe dimensions,
perforations, pipe stiffness, pipe flattening,
environmental stress cracking, b
rittleness, and
fitting requirements. Most are important to truck tire
drainage pipe quality, and is considered in this
Chapter. In addition, rebar corrosion will be discussed
at the end of this chapter.
WORKMANSHIP

Because the truck
-
tire pipe is made fro
m a waste
material with little pre
-
processing, it does not present the
uniform appearance
of
pipesmanufacturedusing virgin
materials. However, acceptable workmanship can be
delineated . The pipe should not have visible gaps between
tire bead
-
sidewalls, nor s
hould bead
-
sidewalls be split.
Four rebars should be used to hold the bead
-
sidewall
together, each should have an intact weld, and weld lengths
should be
sufficient
to hold
6,000
pounds
(22,300
Newtons)
of
tensile
force. This amount is based on strain analyses
performed on
truck
-
tire pipe rebars, discussed later in this chapter.
This will provide a factor
of
safety
of
approximately
2,
but is
based on a limited number of tests .Rebarsshould be
positioned at approximately
90°
intervals about the pipe
circumference .
PIPE DIMENSIONS

Truck
-
tire pipe sizes are limited to truck tire sizes,
and currently are made using
20
and

22.5
inch
(50.8 or 55.9
cm) inner diameter tires. Because truck
tires are made to very strict

re
quirements, the inner circumference of each
bead
-
sidewall in a given truck
-
tire pipe is uniform.
However, due to the truck
-
tire pipe structure, i .e.,
separate discs
held together by
rebars,
truck
-
tire pipe
inner diameters
vary for a given
pipe,
bead
-
sidew
all,
or orientation,
i.e., the pipe
bead
-
sidewalls are not perfect circles . In Tables
2
and
3
multiple measurements of truck
-
tire inner
diameters and lengths are presented . The average inner
diameters for the 20 and
22.5"
truck
-
tire pipes
are
19.5
and
22.6
i
nches, respectively
(49.5 cm
and
57.4 cm).
The
variability shown in Table
2
regarding inner diameter
does not present a problem for pipe connections, as it
is accommodatedby the flexible joint connection

2
3



Table 1: Standard
Specifications and
Test Methods For Pipes

T
e
s
t

DescriptionIdentifica
tion

(1)

(2)

(a) Standard Specifications


AASHTO M 36 Standard
Specific
ation for
Corrugated Steel Pipe,
Metallic
-
Coated,AASHTO M 36M
-
90 for Sewers and Drains ASTM A
760 ASTM A 760M
-
86

AASHTO M 196M Standard Specification for Corrugated Aluminum
Pipe for Sewers

AASHTO M 196M
-
90 and Drains

ASTM
B 745

ASTM B 745M
-
90


A
A
S
H
T
O

M

2
9
4
-
9
0

S
t
a
n
d
a
r
d

S
p
e
c
i
f
i
c
a
t
i
o
n

f
o
r

C
o
r
r
u
g
a
t
e
d

P
o
l
y
e
t
h
y
l
e
n
e

P
i
p
e
,

1
2
-
3
6

i
n
.

D
i
a
m
e
t
e
r

A
A
S
H
T
O

M

3
0
4
M
-
8
9

S
t
a
n
d
a
r
d

S
p
e
c
i
f
i
c
a
t
i
o
n

f
o
r

P
o
l
y

(
V
i
n
y
l

C
h
l
o
r
i
d
e
)

(
P
V
C
)

R
i
b
b
e
d

D
r
a
i
n

P
i
p
e

&

F
i
t
t
i
n
g
s

B
a
s
e
d

o
n

C
o
n
t
r
o
l
l
e
d

I
n
s
i
d
e

D
i
a
m
e
t
e
r
A
S
T
M

F

4
0
5

S
p
e
c
i
f
i
c
a
t
i
o
n

f
o
r

C
o
r
r
u
g
a
t
e
d

P
o
l
y
e
t
h
y
l
e
n
e

(
P
E
)

T
u
b
i
n
g

a
n
d
F
i
t
t
i
n
g
s


(b) Standard Test Methods


A
S
T
M

D

2
4
1
2

D
e
t
e
r
m
i
n
a
t
i
o
n

o
f

E
x
t
e
r
n
a
l

L
o
a
d
i
n
g

C
h
a
r
a
c
t
e
r
i
s
t
i
c
s

o
f

P
l
a
s
t
i
c

P
i
p
e
b
y

P
a
r
a
l
l
e
l
-
P
l
a
t
e

L
o
a
d
i
n
g
A
S
T
M

D

2
4
4
4

T
e
s
t

f
o
r

I
m
p
a
c
t

R
e
s
i
s
t
a
n
c
e

o
f

T
h
e
r
m
o
p
l
a
s
t
i
c

P
i
p
e

a
n
d

F
i
t
t
i
n
g
s

b
y
M
e
a
n
s

o
f

a

T
u
p

(
F
a
l
l
i
n
g

W
e
i
g
h
t
)
A
S
T
M

D

6
9
5

T
e
s
t

M
e
t
h
o
d
f
o
r

C
o
m
p
r
e
s
s
i
v
e

S
t
r
e
n
g
t
h

o
f

R
i

'

P
l
a
s
t
i
c
s

A
S
T
M

D

2
1
2
2

T
e
s
t

M
e
t
h
o
d

f
o
r

D
e
t
e
r
m
i
n
i
n
g

D
i
m
e
n
s
i
o
n
s

o

T
h
e
r
m
o
p
l
a
s
t
i
c

P
i
p
e
a
n
d

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i
t
t
i
n

s

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S
T
M

F

7
2
5

P
r
a
c
t
i
c
e

o
r

D
r
a
f
t
i
n
g

I
m
p
a
c
t

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e
s
t

R
e
q
u
i
r
e
m
e
n
t
s

i
n
T
h
e
r
m
o
p
l
a
s
t
i
c
p
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e

a
n
d

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i
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t
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n
g

S
t
a
n
d
a
r
d
s


ASTM
-
American Society for Testing and MaterialsAASHTO
-
American Association of State Highway and Transportation
Officials


Table 2: Variation in
20 inch Diameter
Truck
-
Tire Pipe
Dimensions

Pipe
Sampl
e
Numbe
r Average of FourMeasurements

Diameter (inches)

Length (inches)

(1)

(2)

(3)


20.0

97.0


19.7

96.9


19.0

98.5


19.7

95.7


19.4

97.3


19.1

99.3


19.2

98.1


19.0

98.9


19.8

97.9


19.8

96.4



T
a
b
l
e

3
:

V
a
r
i
a
t
i
o
n

i
n

2
2
.
5

i
n
c
h

D
i
a
m
e
t
e
r

T
r
u
c
k
-
Tire Pipe Dimensions

Pipe Sample Number
(1) 1

Average of Four Measurements Diameter (inches) Length
(inches) (2) (3) 21.3 99.6

2

22.5

98.5

3

21.8

98.1

4

22.9

97.6

5 6

22.7 23.5

99.1 98.3




㜠㠠

㈳⸰′㈮㜠

㤸⸶‹㤮㐠

Ⱜ,



㈲⸵2

㤸⸱9


10

23.0

97.7


11

22.1

98.5


12

20.9

99.9

'

13

230

97.3


14

22.6

97.1

'

15

23.1

98.8


16

23.2

99.0


17

22.6

98.9

'

18

22.8

98.8


19

23.1

98.7

'

20

23.2

97.4




curren
tly in
use. It does in
dicate that 20 and 22.5 inches
should be considered nominal dimensions,
thus
the
truck
-
tires
will
be
referr
ed to
as 20
and 22
.5
inch
nomina
l
truck
-
tire
pipes.

Pi
pes used
as
culverts
are
typicall
y sold in
any
length,
up to a
maximum,
dependen
t on
material
. The
truck
-
ti
re pipe
only
comes in
nominal
eight
foot
lengths
. Ten
foot
lengths have been constructed and used, but
present handling problems due to lateral
instability during installation (i.e.,when
not supported by soil). Shorter lengths can be
made, h
owever, if desired. The 20" nominal
truck tire pipes measured had an average length
of 97 .6 inches (247.9 cm), while the 22.5"
nominal truck
-
tire pipes measured had an
average length of 98 .5 inches(250.2cm). Thus,
truck
-
tire pipe sections, as currently
m
anufactured, tend to be slightly longer than
8 feet .
PERFORATIONS

Truck
-
tire pipe will not be perforated,
and thus cannot be used in situations where
perforated pipe is required.
PIPE STIFFNESS

AASHTO M 294
-
90 (section 7.4) specifies
that corrugated pol
yethylene pipe shall have
at least the minimum pipe stiffness at five
percent deflection listed in Table 4 when
tested in accordance with ASTM D 2412. Because
the truck
-
tire pipes are not of standard size,
it is necessary to interpolate the required
stiffn
ess . The information in Table 4 is
plotted in Figure 11, and a straight line fit
to the data results in the equation

RPS = 57.0
-
0.96 ID


(1) where: RPS =
required pipe stiffness at 5 % deflection, psi;
and ID = inner diameter, in . The line fits the
data well, with an R2of 0.99. Using equation
(1) the required pipe stiffness at 5 %
deflection for 19.5 and 22.6 inches (49.5 and
57.4 cm) inn
er diameter pipes is 38 and 35 psi,

respectiv
ely.
Test
ing
cond
ucte
d at
Fear
s
Stru
c
t
u
r
a
l

L
a
b
o
r
a
t
o
r
y

o
n

t
h
e

c
a
m
p
u
s

o
f

t
h
e

U
n
i
v
ersi
ty
of
Okla
homa
demo
nstr
ated
that
the
truc
k
-
ti
re
pipe
stif
fnes
s
exce
eds
the
requ
irem
ents
show
n in
Tabl
e

4. A schematic of the t
esting apparatus is
shown in Figure 12 . A picture of a pipe at
near maximum deflection is shown in Figure 13
. During the tests, eight foot truck
-
tire
pipe sections were subjected to uniformly
applied lateral forces up to and in some cases
exceeding 60,00
0

pounds. Results for all 12 culverts tested are
presented in Appendix B . Figure 14 is a plot
of pipe stiffness versus deflection for a 20
inch (50 .8 cm) truck
-
tire pipe. At 5 %
deflection the pipe stiffness is 97 psi, 2.6
times greater than the require
d amount . During
the particular test shown in

Figure 13, the culvert was deflected well past
5 % . At 65 % deflection the culvert's
stiffne
ss was
over 90
psi.

FINAL REPORT

Table 4: AASHTO M 294
-
90 Specification for Pipe Stiffness

Diameter (inches)

Pipe Stiffness (psi)

12 (305 mm)

45 (310 kPa)

15 (381 mm)

42 (289 kPa)

18 (458 mm)

40 (276kPa)


,

21 (533 mm)

38 (262 kPa)



24 (610 mm)

34 (235 kPa)


'

30 (760 mm)

28 (193 kPa)



36 (915 mm)

22 (152 kPa)




C

O

M


0


0


M


0


o

c
ML

r
-


N

0


a


F
L


c
c


Inner Diameter
(Inch)


F
i
g
u
r
e 11: Required Pipe Stiffness
Versus Inner Diameter .


Lateral Brace
Angles

t
-

r
Loading Platen


Lateral ~r Brace

Angles

Hydraulic
Cylinder Wire
Potentiometer


C
1

1

Hydraulic Cylinder Wire
Potentiometer

1

Reaction
Floor








Directional Flow Valve






Figure 12: Load Versus Deflection
Apparatus





30

1


m _
-

= _ mm
-
m__


1

2

3

4

5

6

7

8 9 10 11 12 13 14
Deflection (Inches)

Figure 14: Load Deflection Diagram for 20 inch Inner Diameter
Truck
-
Tire Pipe (Culvert #8)

32

1


Pip
e
sti
ffn
ess
es
at 5 percent deflection for the 20 inch and
22.5 inch nominal truck
-
tire

pipes tested are shown in Table 5. The average
values are 86 psi and 47 psi respectively, which

exceed the AASHTO requirements. The 22.5 inch
nominal culvert, as expected, exhibited lower

stiffness at 5 % deflection than the 20 inch
nominal
culvert.
Howe
ver,
culvert
10 had a
stiffnes
s at

5 %
deflecti
on of
only 36
psi, just
1 psi
greater
than the
required
value.
Inspecti
on of the
stiffnes
s

versus
deflecti
on
relation
ship
recorded
for
culvert
10 (see
Appendix
B) shows
that the
culvert

maintain
ed
stiffnes
s

at 36
psi or
greater
at all
deflecti
onsunder
45 %. The
low
stiffnes
s value
for

culvert
10
indicate
s a need
for
further
tests
with the
22.5 inch
inner
diameter pipes to ensure that

(1) the required stiffness is always met, (2)
to determine if manufacturi
ng variability or
testing error caused the low value, and (3)
to suggest means to improve the 22.5 inch
pipes if necessary.

Two conventional eight foot culvert
sections were also tested, made of
corrugated

galvanized steel and corrugated polyethylene,
an
d theresults presented in Table 5. In Figure
15

pipe stiffness versus deflection curves for
typical 20 and 22.5 inch nominal truck
-
tire, 21
inch

steel, and 18 inch plastic pipe are shown . It
is clear from the Figure that the Truck
-
Tire
Pipes

behave dif
ferently from the other pipes. The
truck
-
tire pipes tend to reach maximum
stiffness later,

generally after 10 to 15 % deflection, while the
steel and plastic pipes reached maximum
stiffness

at about 5 % deflection . Furthermore, the
truck
-
tire pipes rema
in stiffer for much higher

deflections, general to deflections of 40 % or
higher, while the steel and plastic culverts
lose

stiffness rapidly after 5 % deflection. The
steel pipe did not retain its original shape
after the load

in test, as shown in Figure 16. All of the
truck
-
tire pipes tested regained their original
shape after

testing, as did the polyethylene pipe. The
ability to rebound indicates that truck
-
tire
and

polyethylene pipe
-
ends, i.e.,the portion
protruding from ei
ther side of the road, will
be able to

regain their original shape if run over by
errant
vehicles.

PIPE FLATTENING


AAS
HTO
M29
4
-
9
0
(se
cti
on
7.5
)
spe
cif
ies
tha
t it
sha
ll
be
pos
sib
let
o
fla
tten corrugated

polyethylene pipe until the vertical inner
diameter is reduced by 20 percent without the
occurrence

of cracking, splitting, delamination, or wall
buckling . Delaminatio
n refers to the
separation into

constituent layers, for example, a piece of
plywood separating into each wood layer.
Testing

conducted at Fears Structural Laboratory on the
campus of the University of Oklahoma

demonstrated that the truck
-
tire pipe does
not
crack, split, delaminate, or exhibit wall
buckling

behavior even at deflections nearing 50 % .
A truck
-
tire pipe, flattened to near 50
percent of its initial diameter but still
able to withstand more load, is shown in
Figure 13. These observations wer
e made
during the load deflection tests described
above.


Table 5: Measured Pipe
Stiffness

RebarS

(in/in)

Pipe Specimen
Number

Pipe Stiffness at
5Percent
Deflection

At No Deflection

At 5 Percent
Deflection


(~~~)




(
1
)



(a) 20 inch diameter
Truck
-
Tire Pipe
(5 %deflection =
0.05 x 19.5 = 0
.98
in (2.5 cm))
1 74
0.00014 0.00015

2 83 0.00004 0.00006

3 90 NM NM 4 101 0.00071 0.00073 6 73 0.00027 0.00031 8 97
NM
NM

Average = 86

(b) 22.5 inch diameter Truck
-
Tire Pipe(5 % deflection = 0.05
x 22.6 =1.13 in (2.9 cm)) 7 0.00037 0.00040 9 NM NM

10 NM
NM

(c
) 18 inch diameter
corrugated
polyethylene pipe

(5 % deflection
= 0.05 x 18 = 0.9 in
(2.3 cm))



11
I
46NA
NA


(d) 21 inch diameter corrugated steel pipe (5 % deflection = 0 .05 x 21 = 1.05 in (2.7 cm)) NA

12

I

106

I

NA

NA = Not Applicable
NM = Not Measured



Plastic, 18"





Steel, 21' 100 o Culvert 1, 20'

+

C
u
lvert 7, 22"

20


0
1111III11

0 123 4 56789

Deflection (Inches)


Figure 15: Stiffness Versus Deflection for 20 and 22.5 inch
Truck
-
Tire, 21 inch Steel, and 18 inch Plastic pipes


F
i
g
u
r
e

1
6: Permanently deflected steel
pipe


ENVIRONMENTAL STRESS
CRACKING
The
environmental stress
cracking requirement
is specific to
ethylene plastics and
therefore


is not
applicable to
truck
-
tire pipes.
BRITTLENESS
AASHTO M
294
-
90 (section
7.7) specifies that
corrugated
polyethylene pipe
shall not crack or
split when tested,
ac
cording to ASTM D
2444, by dropping a
5.5 pound (2.5 Kg)
tup a vertical
distance of at least
10 feet onto a pipe
specimen . A tup is
a weight of
specified shape, in
this case a blunt
rod with a two inch
d
i
a
m
e
t
e
r

(
T
u
p

B
,

d
e
s
c
r
i
b
e
d
i
n

A
S
T
M

D

2
4
4
4
)
.

T
h
i
s

t
e
s
t

w
a
s

n
o
t attempted because
it is obvious that
the truck
-
tire
pipe, with 4 inch
thick rubber walls,
can withstand a far
greater impact
without cracking or
splitting.
FITTING
REQUIREMENTS
AASHTO
M294
-
90 (section
7.8) specifies that
fittings for
corrugated
pol
yethylene pipe
shall not reduce or
impair the overall
integrity or
function of the
pipeline. Two
truck
-
tire pipes
can be joined with a
flexible belt
wrapped around the
two abutting pipe
ends and cinched in
place with straps,
as shown in Figure 3
and 4 . Ma
ny pipes
installed to date
have been joined
with 6 inch

wide used conveyor belt material. However, any
rubber or plastic flexible material at least 6
inches

(15.2 cm) wide and with length greater
than 120 inches (3 m) can be used. It is
recommended, howe
ver, that wraps of
greater width, perhaps 10 inches (25.4
cm) or more, be used. In a few cases,
poured concrete joints were used.

O
ne
con
cer
n
rel
ate
d to
the
tru
ck
-
tir
e
pip
e
fit
tin
gs
is
the
abi
lit
y of
the
fle
xib
le
bel
t
con
nec
tio
n to
imp
ede
the
flow of wate
r into or out of the pipe at
joints . Thus, one study objective was to
assess leakage potential (both
infiltration and exfiltration) of the
tire
-
pipe. Infiltration can cause soil at
the outside surface of the pipe to seep
into the pipe, while exfiltration
can lead
to erosion of soil away from the outside
pipe surface . Either can eventually
result in sufficient loss of soil around
the outside of the pipe so that holes or
cavities in the soil around the pipe occur.
If enough erosion occurs, cave
-
ins can
resu
lt . Leakage tests were conducted at
the Mack
-
Blackwell Transportation Center
at the University of Arkansas .

Existing specifications that are to
some degree related to the situation of
a tire
-
pipe culvert include ASTM C
443
-
85a(concrete culverts) andASTM

C969
-
82 (longer sections of pipe).

ASTMC443
-
85a reads in part :
"10.1 .1 Pipes in
Straight Alignment
-
Hydrostatic pressure
tests on joints shall be made on an
assembly of two sections of pipe...
Suitable bulkheads may be provided within
the pipe

adjacent to and on either side of the
joint, or the outer ends of the two
joined pipe sections may be
bulkheaded...Moisture or beads of
waterappearing on the surface of the
joint will not beconsidered
leakage.. ."

3
7



Two
types of
test were
scheduled for the tire
-
pipe . First, a single
section was
tested to
check for leakage from
between the sidewalls . Then, a test of joint
leakage was conducted. Test methods for the
tire
-
pipe
were
impro
vise
d, but
were based
on
establish
ed tests.

Single
-
Section
Leakage Test

Single
-
section
pipe
leakage
tests were
conducted
outdoors in
May, 1994 .
The weather
was dry,
with
daytime
highs
around 800
and the
nighttime
lows in the
50s°. The
ends of a
nominall
y 8
foot long
(actually
100 inches)
single tire
pipe
section
were sealed
with 3/4
inch
plywood
plugs at
each end
(Figure
17). Both plugs were recessed approximately 3.5
to 6 inches from the end. They were nailed into
the pipe wall and sealed with silicon c
aulk . An
initial attempt had been made to seal the pipe with
plywood plugs over the ends, but a satisfactory
seal could not be made due to the size of the
undulations in the plane of the pipe
-
end. The
inside diameter of the pipe varied from 23
to
24
inches.

The variation was due
to
undulations of the
tire ridges. The inside distance

between the end plugs was about 90 inches.

An improvised manometer made from flexible
tubing was inserted into one end plug, a ruler
had been affixed to the plug surface, next to

the
tubing. At the opposite end plug, a hole had been
cut near the top to allow a garden hose end
to
be
inserted for filling. Because of the filling
hole, it was impossible to fill the pipe to the
top .

The pipe section was laid horizontally on
level gro
und . The filling began, and leakage at
both end plugs was observed. Leaking was noted at
both the seams between the plug and the pipe wall,
and in imperfections in the plywood itself.
However, the leakage rate was insignificant when

compared to the filli
ng rate, so the filling
proceeded. The system was tight enough that the
flow from the garden hose caused about 1 .5 inches
of air
-
pressure head inside the pipe (as read from
the manometer), so the rate of filling was
decreased to minimize air pressure insi
de the
tire
-
pipe section. The pipe was filled to the
point that the manometer read 21
-
7/16 . At this
point, the amount leaking at each end was
collected over a known time period. The pipe walls
were inspected for signs of leaking; an almost
imperceptible a
nd immeasurable amount of moisture
was observed at one tire
-
wall joint. Because no
sign of flow was observable, it could not be
determined if the wall was seeping or if the
moisture came from another source . The pipe was
left to sit overnight.


-

~~ ~i~~
-
_
-
:~e17

~~
_~_~wr~'Sec~on Leakage Test

-
~~~


The pipe
was
inspected
the next
morning.
The
manometer
level was
holding
constant at
17

7/8 inches. No leaking
was observable at
either end, or in the
side walls . It was
hypothesized that
over time, the water
confined inside the
pipe had caused the
plywoo
d plugs to
swell, and
self
-
sealed leaks.
The hose was again
inserted to fill the
pipe backto the
21
-
7/16 level. As the
pipe was filling, no
leaking occurred at
the "hole" end
-
plug,
but the manometer
end
-
plug resumed
leaking. This time,
the leaking seemed t
o
come from one plywood
split near the top,
where a nail had been
driven through the
plywood into the tire wall . Leakage at this end was
measured. No leaking was observed in the side wall. The pipe
was again lefttosit overnight. Additional inspections wer
e
made on following days. No leaking or seeping from the
tire
-
pipe walls was observed. Data recorded during the test
are presented in Table 6 . The results of the single
-
section
leakage test indicate that leakage through the sides of
truck
-
tire pipes does
not occur at measurable rates under
open channel flow conditions, even when the pipe is not
surrounded by soil. Two
-
Section Joint
-
Leakage Test

In June, 1994, two tire
-
pipes were placed end
-
to
-
end,
while resting on wooden pallets, to prepare for the joint
leakage test (Figure 18) . The test site was outdoors .
The weather was dry, with daytime highs around 90°.

The dimensions of the tire
-
pipes were as described in
the single
-
section test. The endjoint was wrapped with a
36 inch wide piece of conveyor belti
ng. The belting was
cinched
-
down with four separate lengths of aircraft
-
cable,
two on each side of the joint . This cinching was done in
an attempt to simulate the effect of banding placed around
joints in the field. The far (or opposite) ends of the two
t
ire
-
pipe sections were plugged with caulked plywood
disks, as in the single
-
section test.

Even with the four separate cinches or bands around the
joint wrap, water escaped from the joint as fast as it came
in through the hose, so no rate of escape could b
e
established . A close inspection of the tire
-
pipes' surface
reveals considerable surface irregularity, with successive
sidewall sections having somewhat different outer diameter,
and the irregularity causing the rebar to span or bridge some
of the indivi
dual sidewall edge
-
surfaces . This surface
irregularity and rebar bridging makes it nearly impossible
to make a tight connection with a conveyor belt strip.

The results of the two
-
section joint
-
leakage test
indicate that significant leakage will occur whe
n the
pipes are not
surrounded by soil,
even when a 36 inch
belt is used,
cinched in four
places. It should be noted that there was no soil
surrounding the pipe or the joint. At actual tire
-
pipe
installations, the ability of surrounding soil to act as
a mu
d
-
seal around the joint could vary from site to site.

FINAL REPORT


Table 6: Leakage Data
from Test of
Bead
-
sidewall Test

D
a
t
e

T
i
m
e

A
c
t
i
v
i
t
y

W
a
t
e
r

L
e
v
e
l

L
e
a
k

r
a
t
e

l
e
a
k

r
a
t
e
1
(inches)
through

plug,
through plug,
fill end
manometer end

(1) (2) (3) (4) (5) (6)

5/16/94 3:30 PM initial fill 21
-
7/16 28 ml / 20
7
0