your solution to permanent hard armor erosion control armorform ® erosion control system utilizes...

The ARMORFORM® erosion

control system utilizes double-

layer woven geotextiles

engineered exclusively to serve

as forms for casting concrete

erosion control revetments and

linings. The forms are woven

from nylon and/or polyester

yarns and are designed with the

required mechanical and

hydraulic properties of a

superior textile form.

ARMORFORM, Inc.

PO Box 710

Jefferson, GA 30549

Ph/Fx (770) 237-0827

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Your Solution To Permanent Hard Armor Erosion Control

ARMORFORM Mat Being Pumped With Concrete

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ARMORFORM is positioned on the subgrade to be protected, where it is inflated with

pumpable fine aggregate concrete (structural grout) to form an erosion control mat.

ARMORFORM mats should be placed on a site-specific filter fabric.

ARMORFORM is available in various styles and thickness’. Uniform Section Mat

(USM), Filter Point Mat (FPM), Articulating Block Mat (ABM) and Armorbags are the

four standard styles of ARMORFORM. For the majority of applications, one of the

standard styles and thickness’ of ARMORFORM should prove adequate, however,

customized configurations and/or thickness’ can be manufactured. If required,

ARMORFORM mats can be produced to inflate to more than 24 inches thick or even

to allow revegetation of an eroded embankment.

CASE STUDIES

CONTACT US

ADVANTAGES

AVAILABLE

STYLES

FILTER POINT

MAT

UNIFORM

SECTION MAT

ARTICULATING

BLOCK MAT

ARMORBAGS

INSTALLATION

METHODS

CONCRETE

MIX DESIGN

grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete

blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch

lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion

mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete

pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm

ucs fp ab grout pumping grout mats grout bags concrete mats concrete blocks erosion control rip rap gabions ditch lining pond lining shoreline protection erosion mat mark torre concrete bags concrete pumping mirafi nicolon spillw ay usm fpm abm ucs fp ab grout pumping

O

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The ARMORFORMARMORFORMARMORFORMARMORFORM®®®® Advantage

ARMORFORM ARMORFORM ARMORFORM ARMORFORM is a unique product which has several advantages over more conventional methods of hard

armor, for instance:

U nlike conventional concrete, ARMORFORM ARMORFORM ARMORFORM ARMORFORM can be installed underwater.

U nlike rip rap, ARMORFORMARMORFORMARMORFORMARMORFORM is of consistent size and weight. ARMORFORMARMORFORMARMORFORMARMORFORM will also function as a mat

(with a fairly low Mannings “N” value) instead of individual units. This allows the designer to utilize an

ARMORFORMARMORFORMARMORFORMARMORFORM mat of considerably less thickness and weight to equal the performance of rip rap.

U nlike rip rap, gabions or precast concrete block mats, ARMORFORMARMORFORMARMORFORMARMORFORM can be installed without the use of

heavy equipment. Since the concrete is pumped into the mat through a hose, the trucks delivering the concrete

can also be parked up to several hundred feet away from the actual site. This allows for installations in even

the most inaccessible project sites.

U nlike most other hard armor systems, ARMORFORMARMORFORMARMORFORMARMORFORM is simply a form for concrete. Concrete is then

purchased from a local supplier of choice. By simply shipping the light-weight forms to the project site (and

not the actual armor unit itself) the client can save as much as 30% off of the overall cost of project simply due

to much lower freight costs. EXAMPLE: shipping 100,000 sq. ft. of 8 inch thick precast concrete block mats to

a project site would require over 200 flat-bed tractor-trailers at a cost $500.00 each, or more. That totals over

$100,000 simply to ship the units to the project. The same quantity of 8 inch ARMORFORMARMORFORMARMORFORMARMORFORM Articulating Block

Mat (ABM) would require less than 1 tractor-trailer.

W ith the introduction of our new ARMORFORMARMORFORMARMORFORMARMORFORM Vegetal Mat® (VGM) the system can be backfilled with

top soil and revegetated, providing a fully articulating hard armor system underneath.

NEXT

ARMORFORMARMORFORMARMORFORMARMORFORM®®®® is a proven product with literally tens of millions of square feet installed over the past 20+

years. We firmly believe in ARMORFORM ARMORFORM ARMORFORM ARMORFORM and its ability to provide a unique and proven solution to

permanent hard armor erosion control. The design approach for ARMORFORMARMORFORMARMORFORMARMORFORM is nearly the same as that of

poured concrete.

BACK ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.

Available Styles

Articulating Block Mat (ABM) is formed with a double layer woven fabric,

joined together into a matrix of rectangular compartments each separated by a

narrow perimeter of interwoven fabric and containing interconnecting high

strength revetment cables. Relief of hydrostatic uplift pressure, caused by

entrapped and ground water, is provided through the narrow perimeter of

interwoven fabric.

Armor Bags are custom fabricated to fit job site requirements. Inlet valves,

attached by fabric flange to a slit in the surface of the bag, provide positive self

closure. Inlet tubes may be added to extend outside the bag if desired. Durable

nylon straps may be attached to the outside of Armor Bags to serve as

thickness controllers and to permit filling tapered or irregularly shaped bags.

BACK

Shown below are the standard syles of ARMORFORMARMORFORMARMORFORMARMORFORM available. “Click” on the

image to learn more about these specific styles.

ARMORFORM, Inc. ARMORFORM, Inc. ARMORFORM, Inc. ARMORFORM, Inc. NEXT

Filter Point Mat (FPM) fabric forms are constructed with spaced interwoven

filter points to form a lining of required average thickness, deeply cobbled

surface and specified weight to provide strength and erosion protection. Relief

of hydrostatic uplift pressure, caused by entrapped and ground water, is

provided by the woven filter points which are on 5”, 8” or 10” centers.

Uniform Section Mat (USM) fabric forms are constructed with spacer cords

on closely spaced centers to form a lining of required nominal thickness,

bonded cobbled surface and specified weight to provide strength and erosion

protection. Relief of hydrostatic uplift pressure, caused by entrapped and

ground water, may be provided by inserting plastic weep tubes through the mat

at specified centers.

Filter Point Mat (FPM)

Filter Point Mat (FPM) fabric forms are constructed with spaced interwoven filter points to form a lining

of required average thickness, deeply cobbled surface and specified weight to provide strength and erosion

protection. The design criterion for selection of lining thickness is the same as that used to determine the

thickness of conventional concrete slope paving. Relief of hydrostatic uplift pressure, caused by entrapped

and ground water, is provided by the woven filter points which are on 5”, 8” or 10” centers. Filter Point Mat

(FPM) is custom fabricated into multiple mill width panels, designed to fit actual site dimensions and

topography.

Filter Point Mat used to line a drainage ditch.

Filter Point Mat being pumped.

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. Available Styles BACK NEXT

FPM size Filter Point Spacing

Average Thickness

Weight/ sq. ft.

Coverage/ cu. yard of Concrete

5" FPM 5" 2.2" 26 lbs. 115 sq. ft.

8" FPM 8" 4.0" 47 lbs. 73 sq. ft.

10" FPM 10" 6.0" 70 lbs. 49 sq. ft.

FILTER POINT MAT (FPM)

DESIGN CONSIDERATIONS

FPM is used where velocities are

low, bedload and ice formations are

light and a roughness coefficient of

N= 0.025 to 0.030 is acceptable.

FPM is used where wave action is

light.

FPM is ideal for underwater

placement.

FPM should be installed on well

compacted soil conditions only.

Read interesting case studies of

ARMORFORM installations.

Uniform Section Mat (USM)

Uniform Section Mat (USM) fabric forms are constructed with spacer cords on closely spaced centers to

form a lining of required nominal thickness, bonded cobbled surface and specified weight to provide

strength and erosion protection. The design criterion for selection of lining thickness is the same as that

used to determine the thickness of conventional concrete slope paving. Relief of hydrostatic uplift pressure,

caused by entrapped and ground water, may be provided by inserting plastic weep tubes through the mat at

specified centers. Uniform Section Mat (USM) is custom fabricated into multiple mill width panels,

designed to fit actual site dimensions and topography.

Uniform Section Mat being pumped.

Uniform Section Mat used to line a high volume drainage ditch.


USM size Nominal Thickness

Weight/ sq. ft.


3" USM 3.0" 35 lbs. 97 sq. ft.

4" USM 4.0" 47 lbs. 73 sq. ft.

6" USM 6.0" 70 lbs. 49 sq. ft.

8" USM 8.0" 93 lbs. 36 sq. ft.

UNIFORM SECTION MAT (USM)


USM is used where velocities are low

to high, bedload and ice formations are

light and a roughness coefficient of N

= 0.015 is required.

USM is used where wave action is

light.

USM reduces seepage losses in

reservoirs, ponds, holding basins and

channels.

USM is ideal for underwater

placement.

USM is recommended for drainage

flumes and spillways.

USM should be installed on well

compacted soil conditions only.



Articulating Block Mat (ABM)

Articulating Block Mat (ABM) is formed with a double layer woven fabric, joined together into a matrix

of rectangular compartments each separated by a narrow perimeter of interwoven fabric and containing

interconnecting high strength revetment cables. Articulating Block Mat forms are positioned on the area to

be protected, where they are filled with pumpable fine aggregate concrete (structural grout) to form a

mattress of individual blocks in a bonded block pattern. The high strength revetment cables become

embedded in the blocks to tie the blocks together and enable the revetment to resist tension in all directions.

Patented separate cable duct design assures that the revetment cables will be positioned securely in the

center of each block. Relief of hydrostatic uplift pressure, caused by entrapped and ground water, is

provided through the narrow perimeter of interwoven fabric after the grout has hardened. Articulating

Block Mat (ABM) is custom fabricated into multiple mill width panels, designed to fit actual site

Articulating Block Mat being pumped.

Articulating Block Mat used to protect a retaining wall.


ABM size Nominal Block

Dimensions

Weight/ Block

Weight/ sq. ft.


4" ABM 20" X 14" X 4" 90 lbs. 47 lbs. 73 sq. ft.



ARTICULATING BLOCK MAT (ABM)




ABM is used where velocities are low to

high, bedload and ice formations are

light to heavy and a roughness

coefficient of N = 0.045 to 0.050 is

acceptable.

ABM is used where wave action is light

to heavy.

ABM is ideal for underwater placement.

ABM is recommended where subgrade

deformation is expected.

ABM is available in custom sizes, other

than those shown on this web site.

Armor Bags

Armor Bags are custom fabricated to fit job site requirements. Inlet valves, attached by fabric flange to a

slit in the surface of the bag, provide positive self closure. Inlet tubes may be added to extend outside the

bag if desired. Durable nylon straps may be attached to the outside of Armor Bags to serve as thickness

controllers and to permit filling tapered or irregularly shaped bags.

Bags being used in conjunction with Articulating Block Mat

to prevent erosion of a steep slope.

Bags being used to absorb the energy of large waves at an off-

shore oil drilling island in the Arctic Circle.


ARMORBAG APPLICATIONS

Ideal for underwater placement.

Building groins and breakwaters.

Protecting shorelines against heavy

wave erosion.

Protecting buried pipelines against

scour.

Supporting and weighting underwater

pipelines.

Repairing stone jetties.

Installation Methods Once a contractor has been chosen there are four basic steps to

be taken in any ARMORFORM® erosion control installation.

They are: site preparation, panel placement and field

assembly, inspection before filling and structural grout

pumping.

SITE PREPARATION: Slope grading equipment is used to

excavate to required depths, contour the slopes to the specified

slope ratio and form the anchor, toe and terminal trenches

around the periphery of the installation. The area to be

protected must be free of rock, brush, roots or large soil clods.

ARMORFORM® should be placed on a compacted subgrade

and stable slope. The fabric forms are usually anchored into a

trench approximately two feet deep, by one foot wide, at the

top of the slope. The trench should be located one to three feet

from the top edge of the slope.

PANEL PLACEMENT AND FIELD ASSEMBLY: Once

the slope and other related excavation conforms to finished

grade and elevation specifications, installation of the filter

fabric and the ARMORFORM fabric forms may begin. After a

site specific filter fabric has been installed, the custom sized

ARMORFORM panels are rolled down the slope and

positioned for unfolding. The panels are positioned according

to prepared drawings where each panel is identified for

placement. The panel is then unfolded by a work crew and

pulled into position. The ARMORFORM panels should be

positioned loosely along the slope.

Once positioned, the upper edge of the panel is folded into the

anchor trench atop the slope. The extra fabric provided for

contraction during pumping should be accumulated and held

at the top of the slope and gradually released as the panel is

filled. Adjacent panels are joined by field sewing or zippering

the double-layer fabric forms, bottom edge to bottom edge,

INSPECTION BEFORE FILLING: When inspecting the

panels prior to pumping, wrinkles and loose fabric should be

expected as they are necessary to compensate for form

contraction. As much as 10% contraction in each direction

may be expected during the filling process. ARMORFORM

Incorporated should be contacted to determine the appropriate

contraction factor for your site conditions. All field sewn

seams, zipper connections and lap joints must be carefully

inspected to assure that no holes in the forms are present.

Colored thread is advised for all field sewn seams to facilitate

inspection. For detailed installation guidelines contact

ARMORFORM Incorporated.

STRUCTURAL GROUT PUMPING: The upper edge of

the ARMORFORM panel that has been placed into the anchor

trench should be weighted down with sandbags to prevent the

panel from sliding down the slope as it is pumped with grout.

Grout should then be injected into the lower mat area first,

proceeding gradually up the slope and into the upper anchor

trench until the entire panel has been filled. Structural grout is

injected into the ARMORFORM panels by inserting a 3”

diameter grout hose through a small slit cut in the upper layer

of fabric near the top of the slope. A grout-tight seal is formed

by wrapping the injection hose with burlap, or similar

material, while the grout is being injected. When the hose is

withdrawn, the burlap is stuffed into the hole where it remains

until the grout is no longer fluid. The burlap is then removed

and the concrete surface at the hole is smoothed by hand.

and top edge to top edge. When installing Articulating Block

Mat (ABM), transverse revetment cables should be spliced

together prior to joining of the top layers of fabric.

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. BACK NEXT

Concrete Mix Design


CONCRETE MIX DESIGN: A pumpable fine aggregate concrete (structural grout) is utilized in the

construction of all ARMORFORM revetments. As an aid to pumpability, a pozzolan grade fly ash may be

substituted for up to 35% of the cement. Mixes designed with 5% to 8% air content will have improved

pumpability and resistance to freeze-thaw. A retarding admixture may be used in hot weather.

Excess mixing water expelled through the permeable ARMORFORM fabric will reduce the volume of

fluid structural grout from 27 cu. ft. to approximately 25 cu. ft. of hardened grout and also reduce the

water / cement ratio from approximately 0.7 to approximately 0.4..

Fine aggregate concrete consistency should be in the 9-11 second range when passed though the 3/4”

orifice of the standard flow cone described in ASTM C-939-93. Tests utilizing a concrete slump cone are

not appropriate.

Material Mix Proportions Lbs./cu. Yd.

After Placement Lbs./cu. Yd.

Cement 750-850 810-920

Sand (FM 2.60) 2030-2120 2195-2290

Water 485-555 360-430

Air as required

Typical Range of Mix Proportions (approx. 3,000 psi)

ARMORFORMARMORFORMARMORFORMARMORFORM is pumped and formed

under pressure. This method provides

superior strength and durability when

compared to conventional concrete

forming. Tests show that structural grout

pumped into ARMORFORM is 1.5 to 1.75

times stronger, plus it absorbs 5% less

water.

The ARMORFORM system is ideal for

situations requiring resistance to mild

concentration of acid, alkali, salt or

petrochemicals. With minimal water

absorption, ARMORFORM also resists

freeze - thaw action.

Concrete that is pumped into ARMORFORM is 1.5 to 1.75 times

stronger than conventionally formed concrete.

Case Studies

PIPELINE PROTECTION A once buried pipeline that is now exposed can be of serious

concern. When Colonial Pipeline found out that a 16” diameter

pipeline that had once been buried well beneath Raccoon

Creek in North Georgia was now exposed they required

immediate action. Find out how ARMORFORM® Articulating

Block Mat was utilized to control the erosive forces of the

creek so that the pipeline would not be re exposed.

ARMORFORM has been utilized in many different applications. Wherever erosion is a

problem or of concern ARMORFORM can help. Here are just a few projects in which

ARMORFORM was selected as the solution to a serious erosion control problem.

COMING SOON LANDFILL CAPS

Providing erosion protection on steep landfill caps and

surrounding drainage channels.

OVERFLOW SPILLWAY

In the summer of 1995, a large coal company in West Virginia,

was in the process of upgrading an overflow spillway at their

coal refuse slurry impoundment facility in Boone County,

West Virginia. The new spillway would need to be constructed

directly over coarse coal refuse, and provide a safe means of

transporting large volumes of water over a distance of

approximately 1,700 feet (520 meters).

COMING SOON

ARMORFORM FPM helps to remove flood waters in a

suburban Atlanta neighborhood.


Exposed Pipeline is Once Again Protected

Thanks to ARMORFORM

A once buried pipeline that is now exposed can

be of serious concern. When Colonial Pipeline

found out that a 16” diameter pipeline that had once

been buried well beneath Raccoon Creek in North

Georgia was now exposed they required immediate

action.

In December of 1995, shortly after the exposed

pipeline was discovered, Colonial Pipeline had a

crucial decision to make. The pipeline obviously

needed to be re buried. The options were to close

the pipe, refit it and re bury it below the now

relocated creek bottom or to simply move the creek

back to its original position. The first option

appeared to be the easiest thing to do, however,

shutting down the pipeline would cause serious

down time and there was no guarantee that the creek

would not relocate itself again and cause the

pipeline to be re exposed. Upon further inspection

of the site it was discovered that the outer bank of

the creek was now less than 20 feet away from a

500,000 volt electrical tower! It was obvious that

the creek would have to be moved.

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. CASE STUDIES BACK NEXT

It was decided to relocate a 250 feet long curved

section of the creek in order to re bury the exposed

pipeline and to protect the electrical tower. The

creek would have to be moved over 40 feet thus

creating a much sharper bend than that which was

formed naturally, and there was evidence in the

surrounding terrain that the creek frequently

overtopped its banks. It was obvious that there was

the potential for a serious erosion problem. Hard

armoring of the creek’s embankments would be

necessary.

Once it was decided what needed to be done

Colonial Pipeline was faced with another problem.

The application of the hard armor system would

have to be done without dewatering the site. Since

it was an active creek, flow conditions of 2 feet

deep at velocities of 5 fps were expected during

the construction. Any type of poured concrete or

shotcrete was immediately ruled out. Rip rap

seemed to be the obvious solution, but very large

stones would be needed and it was feared that the

sized of the stone would lower the capacity of the

creek and cause more water to spill out of its

banks. It was decided that an articulated concrete

block mat, or ACB, would be the best possible

solution. ARMORFORM® Articulating Block

Mat (ABM)

A preconstruction meeting was held at the project

site with Colonial Pipeline and ARMORFORM

representatives present. It was determined that the

creek should retain its current sectional area. The

creek would be relocated by cutting from the inside

embankment and filling the outside embankment.

Final geometry would be trapezoidal with a bottom

width of 20 feet, a depth of 12 feet, 1.5:1 side slopes

and a bed slope of approximately 1%. It was also

estimated that a discharge of 7,000 cfs would be

experienced frequently. This volume of water

equates to a unit discharge of over 180 cfs/ft at a

velocity of over 16 fps. Since the application area is

in a sharp curve, additional shear stresses can also

be expected. The size of ARMORFORM ABM that

was chosen is a 6” thick mat.

CONTINUED

Exposed 16” diameter pipeline caused by the

natural relocation of Raccoon Creek.

A 500,000 volt electrical ower is dangerously close to the the edge of the

creek’s outer embankment.

Pipeline case study (continued)

Since time was a critical issue the custom fabricated

ABM panels were assembled immediately and the

dirt work was commenced. Just a few days after the

preconstruction meeting the custom fabricated

ABM panels were delivered to the job site, and the

now relocated creek was ready for armoring.

After grading was completed the creek was effectively “moved” to re bury the

exposed pipeline. Also note that the electrical tower is now far away enough

from the outer embankment to be out of the photograph.

Once the side slopes were graded to the desired

angle, an “anchor” trench was cut at the top of each

slope. This trench is located approximately 1 foot

back from the top of the slope and its purpose is to

provide an anchor or “toe-in” for the

ARMORFORM mats. This anchor will help reduce

the possibility of the mat from sliding down the

slope, however, its primary function is to prevent

scour at the top of the slope caused by water

flowing outside of the creek’s banks when a flood

occurs. A geotextile filter fabric supplied by Mirafi

was installed directly over the subgrade to prevent

the loss of fines when water passes through the open

areas of the concrete mat. The ARMORFORM

panels were then placed on top of the geotextile and

temporarily held in place by placing sandbags

around the edges. During the inflation process the

sandbags are simply pushed off of the ABM as the

injected grout thickens the mat.

The ARMORFORM panels were installed starting

at the downstream end first. By working

downstream to upstream, panels could be

overlapped onto one another in the flow direction so

that water could not infiltrate the system. Access to

the project site was limited to 1 side of the creek,

however, the armoring was required on both

embankments. The work crews simply carried the

light weight ABM panels across the creek and

unrolled them into place. The grout was then

pumped through a hose and into the ABM from the

opposite side of the creek where the pump and the

trucks delivering the concrete were located.

ABM panels being inflated on the inside embankment. Note the geotextile filter

fabric on the slopes of the outer embankment in the foreground.

The installation of the ARMORFORM panels

continued into its second day with just under half of

the project completed. While the inflation of the

panels continued, a dozier backfilled the anchor

trenches of the mats that were installed the previous

day. The second day of installation proved to be

much more productive, and the project was

completed in the early hours of the evening. The

installation of the ARMORFORM panels went

without a single glitch. Over 400 cubic yards of fine

aggregate concrete was injected into the ABM

panels in just 2 days, and the project was completed

substantially under the amount budgeted by

Colonial Pipeline.

As the inflation of the ARMORFORM mats continues into the second day a

dozier can be seen in the background filling in the anchor trench of the mats

installed the previous day. Note the change in the color of the concrete. The freshly pumped concrete in the foreground is dark gray, while the concrete

that was installed the previous day has turned to a whitish color.

CONTINUED

NEXT BACK CASE STUDIES ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.

Pipeline case study (continued)

Nearly four years after the installation of the 6”

Articulating Block Mat the creek still flows between

the ARMORFORM protected embankments with no

apparent damage to the system. The mats are

completely intact and are providing the necessary

protection to the creek’s embankments to insure that

the pipeline will not be re exposed.

Completed ARMORFORM 6” ABM installation (looking downstream)

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. Case Studies BACK NEXT

Other Installations

ARMORFORM has been utilized to protect a

pipeline or fiber optic cable in several projects.

If the pipeline or fiber optic cable crosses a

creek the potential for erosion of the creek bed

to expose the pipeline or cable is imminent.

Shown here are photographs of just a couple of

projects in which ARMORFORM was utilized

to protect these crossings.

ARMORFORM ABM being installed over a fiber optic cable

crossing in a shallow creek.

ARMORFORM ABM mat being installed over a

restored pipeline crossing

ABM mat before concrete injection

(looking upstream)

ABM Mat after concrete injection

(looking downstream)

ARMORFORM Protects Steep Landfill

Slopes Against Erosion.

SORRY, THIS PAGE IS STILL

UNDER CONSTRUCTION.

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. Case Studies BACK NEXT

ARMORFORM is Chosen to Protect

a High Volume Spillway

In the summer of 1995, A large coal company in

West Virginia was in the process of upgrading an

overflow spillway at their coal refuse slurry

impoundment facility. The new spillway would

need to be constructed directly over coarse coal

refuse, and provide a safe means of transporting

large volumes of water over a distance of

approximately 1,700 feet. The bed slope of the

spillway would vary from 1% to 10% with the 10%

section generating flow velocity of over 20 feet per

second and a corresponding shear stress of nearly 40

pounds per square foot during a severe storm event.

It was obvious that a substantial form of erosion

protection would be necessary to combat the

potentially destructive forces that would be present

during these hydraulic conditions.

The coal company enlisted the services of a local

consulting engineering firm to design the spillway

and confirm that the selected form of erosion

protection would be adequate. Rock riprap was

almost immediately ruled-out due to the large

diameter required to resist the expected flow

conditions, and the designer wanted a system that

was less restrictive than large boulders. Although a

properly installed (i.e. reinforced, freeze/thaw

resistant, expansion joints, etc.) poured concrete

spillway would provide sufficient hydraulic

stability, it was believed that the cost would be

higher than desired. With numerous, successful

spillway projects under their belt, the engineering

firm felt most comfortable in selecting

ARMORFORM Articulating Block Mat (ABM).

Product Selection and Design

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. CASE STUDIES BACK NEXT

Due to the flow conditions that would be present at

the coal refuse facility, the engineering firm

determined that the ABM erosion protection would

be required for the 40 foot wide bottom and both

side slopes of the trapezoidal spillway. The

“finished” average thickness requirement of the

ABM will be 8 inches to produce individual block

sizes of approximately 24 inches x 24 inches and a

weight of 95 pounds per square foot. High strength,

3/8 inch diameter polyester cables, exhibiting a

nominal breaking strength of 10,000 pounds will be

inserted into the ABM at the factory. These cables

will provide additional tensile strength to the

system, as well as reinforcement during

articulation.

Entrance point of the spillway. ABM mat is buried in a 10 feet deep

trench at this location.

Completed spillway, looking downstream.

CONTINUED

ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc.ARMORFORM, Inc. CASE STUDIES BACK

Spillway case study (continued)

In prior applications, 8 inch thick ABM has

successfully withstood unit discharges in excess of

100 cubic feet per second/per foot, which is the

approximate equivalent to the expected discharge of

the spillway at this project site, however, as an

added factor of safety, it was decided that

intermediate anchoring would be necessary every

120 feet along the 10% slope section of the spillway

to resist drag forces. A poured concrete “deadman”

anchor, constructed approximately 5.5 feet below

grade, will secure each 120 foot long section of

ABM. Each subsequent ABM panel would then be

positioned to provide a 5 foot minimum overlap of

the previous panel to serve as an “expansion” joint.

The panels along the sides of the spillway would be

installed in a 3 feet deep terminal trench and

subsequently buried to provide additional

anchoring. The design analysis concluded that the 8

inch ABM, utilizing these methods of installation,

would produce a factor of safety greater than the

targeted 1.5 to 1.

referencing each panel, identified numerically, with a

panel layout plan prepared by ARMORFORM, Inc.

Construction

A local contractor, McGraw & Son Construction

Company, Inc., Glen Daniel, West Virginia, was

chosen to construct the spillway and install the ABM.

The installation of the ABM panels commenced at the

bottom of the spillway and proceeded upwards. This

“reverse-order” of installation was necessary to

properly construct the intermediate anchor trenches

and overlaps. More than 70 custom made panels of

ABM were shipped to the project via motor freight.

Each panel, up to 3,500 sq. feet in size, was fabricated

to fit a specific section of the spillway. Proper

placement of the panels was facilitated by cross-

ABM panels were unrolled into position and joined

together with a portable sewing machine prior to

filling with concrete. The ABM was installed directly

over a site specific geotextile filter to prevent the loss

of underlying material through the openings around

the perimeter of the blocks. For this project, a 5 ounce

per square yard nonwoven geotextile was selected. A

nonwoven geotextile was selected because it exhibited

a higher angle of friction and greater hydraulic

characteristics when compared to a woven geotextile.

The fine aggregate concrete, supplied by a local ready

mix plant, was injected into the panels, through a 3

inch diameter hose, utilizing a conventional grout

pump. Once the ABM was filled with concrete to the

required thickness and allowed to cure, coal refuse

was utilized to backfill the terminal trenches along the

sides of the spillway. The entire project required

approximately 45 days to complete with more than

5,000 cubic yards of concrete being injected into the

ABM panels.

For this high volume spillway, ARMORFORM ABM

appeared to be the only practical solution. Riprap was

not a viable option due to the extremely large diameter

stone that would be required, and to properly install a

poured concrete spillway would have been far too

costly. This coal company is just one of several end

users who have discovered the advantages of

ARMORFORM. Coal refuse facilities operated by

other firms have also benefited from this technology,

as have the owners/operators of landfills and

embankment dams.

This case study is a summarized version of an article “High

Tech for High Volume” which appeared in the May 1998 issue

of GFR magazine.

Summary

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