Armoured Ford / Armoured Ford / Low Water Stream Crossing An alternative to constructing a bridge. Historically used since the beginning of mankind to cross a waterway. Bridges allow passage at all heights of water flows, but the cost and environmental impact of bridges with their abutments and approach causeways can be detrimental, liable to damage, loss of usage for a long period, expensive to build, expensive to maintain, expensive to replace as they come to the end of their service life and do not able to be upgraded to handle wider or heavier traffic. Benefits: a) short construction time b) much lower cost than a bridge Description: During normal stream low flows the water crossing is passable to vehicles and pedestrians. At periodic high flows vehicle passage is halted until water level drops(ie after a storm event). Endurance: The lack of stream restriction (such as bridge abutments and built up approaches) allows the high flows to pass without costly damage to the crossing structure such as bridge failure. High-water flows that carry debris such as trees that get hung up on bridges due to lack of height clearance are not impeded with the use of an armoured ford. Higher water volume streams: A modified armoured ford can handle larger normal water flows by the installation of one or a number of pipes underneath the armoured ford. Durability: The usage of geotextile underlayment and articulated concrete block allow for differential movements that cause premature destruction and failure of poured concrete or cemented ford structures. Modifiable: In the event that road usage changes such as wider vehicles or heavier loads or upgrading from one lane to two lanes is desired, the present armoured ford is able to be cheaply and quickly added to or re-built to accommodate. Longetivety: Armoured fords built by the Romans 2,000 yrs ago are still in user today. Environmental: A very low environmental impact compared to excavation and construction of abutments and building up of bridge approach causeways.

1. AArrmmoouurreedd FFoorrdd CCoonnssttrruucctteedd
wwiitthh AArrttiiccuullaatteedd CCoonnccrreettee BBlloocckk
Eric L Kay
KAY & ASSOCIATES

2. Eric L Kay and Associates Engineering and Training 2
FORD
.
 Shallow crossing with a firm bottom
 Simple effective crossing for a waterway
 In use by man since we first walked
 Romans were adept at designing and
constructing an armoured crossing
 Ensured passage in low and regular flows

3. reproduced from the
Stream Crossing Guidebook for Fish Streams
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4. Objections to fords
 Loss of access in high flows
 Generation of sediments
 Water contamination by users
 Negative values for aquatic life
 Loss of access thru site degradation by
users
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5. Long-term
successful
fords
 Well designed
 Expected water flows
 Expected traffic use
 Design shape ensures a fail-safe structure
 Well constructed
 Durable materials
 Concrete
 Rock
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6. Eric L Kay and Associates Engineering and Training 6
New
Concept
 New and novel use of a product that has been around for
many years in providing armour protection for small and
large waterways as a channel liner and on beachfronts
for wave protection.

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Flexibility
 Can withstand
changes in
ground (base)
materials from;
 Flexing
 Heaving from ground frost
 Loss of sub-surface material

8. Trilock System
 Trilock blocks have a diameter of 40cm
(16”) and weight of 10kg (30lb) and
20kg (60lb)
 Thickness of either 10cm (4”) or 15cm
(6”) readily available. 20cm (8”) and
30cm (12”) are used for higher loading
applications
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9. Design flexibility
 Trilock has a
working radius of
One Meter (3’) and
can flex in multiple
directions
 Openings can be
made for;
 Bridge pilings
 Trees
 Large obstructions
 Can withstand loss or breakage of individual
units with out serious threat to system
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10. Key design elements
Max 25% Max 25%
15% 15%
1.5 meter
stream bed
1.5 meter
apron
1.5 meter
apron
Armour to
above high
water mark
 Stream shape - ensure Fish passage at low flows
 Ensure passage shape for expected vehicle use
 Downstream splash apron for stream gradients over 5%
(Steeper gradient streams may require installation of a
culvert underneath to ensure fish passage in low flows)
 Extend approaches
 Above highest high water mark
 To a point where vehicle traffic will not adversely affect
(damage) road surface
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12. Mission Creek
 Crossing 399
Graystokes Forest
Service Road
 Penticton Forest
District, BC, CANADA
Community Watershed
High fish values
High use recreation area
Soon to be a Provincial Park
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13. Mission Creek
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14. Site Preparation
Excavation
Shape streambed
Shape approaches
Max 25% Max 25%
15% 15%
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15. Site Preparation
Streambed / Approaches
 Excavate upstream and
downstream “heel-in” for
stream bed and for approach
aprons (compact)
 Excavate “heel-in” at top of approaches (compact)
 Place suitable bedding material (compact)
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16. Site Preparation
Compaction / Fabric
 Compact to 90%
Density
24” plate tamper provides a firm base
 Geotextile (woven monofilament) fabric is used as
a base to;
Provide additional support
Prevent migration of fines
Provide bi-directional flow of water
 Strength and opening size (site specific)
Armtec AMF 245
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17. Placing of Blocks
 Line and right angle laid.
out to ensure alignment.
 Blocks are placed in unit .
pairs for ease of application .
 Blocks are laid rapidly .
Eric L 25 to Kay 40 and sq Associates meters/ hour Engineering for a crew and Training 17
of two .

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Bio-engineering
 20% interspacing provides
many opportunities for
establishment of mature
vegetation
 Shade and nutrition
 Management of water energy
 Use vegetation as a tool to
assist stability
 Soil Plugs – local grasses,
herbs and forbs, associated
microbes, enzymes, and soil
building organisms
 Live-staking - Willow whips
(through the blocks)
 Planting rooted stock –
Softwoods / hardwoods

19. Backfilling
 Back-fill stream channel and approach ramp flanks with suitable
well-graded cobble material and compact to 90%
 Infill blocks with well-graded material within the wetted
perimeter
 Infill blocks on the approaches with native sands and soils (or
gravels)
 Compacting of infill material – optional – dependant on
materials and engineering objectives
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20. Articulated Concrete
Block (ACB) also
known as Flexible
Concrete Revetment
 Designed to be hand-placed or machine placed
 Provides protection from erosive water energy
 Conforms to changes in grade while remaining
interlocked
 Allows bi-directional water flows (will not build up static
pressure)
 Provides a secure crossing structure for traffic
 Abrasive resistance for transported bedload material
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21. ACB’s are suitable for
placing over many
different soil types
 Suitable for placement over
fine-textured materials such
as sands and silts
 The system employs a Geotextile
(woven monofilament fabric) as a base (site-specific)
(Armtec AMF 245 was chosen for Mission Creek installation)
(Nilex non-woven geotextile 2016 chosen for 18 mile creek)
 Geotextile overlain with interlocking concrete blocks
(Trilock System was chosen for these installations for its multi-directional
installation flexibility values)
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23. When to use ACB’s
 When traditional Poured Concrete
or Rock Armour is not easily available
 When costs are excessive for;
Mobilization / Demobilization
 Transport (trucking access / distance)
 Generate rock (drilling and blasting)
Flow
 When heavy equipment or truck access is difficult or denied.
Eg. The materials can be transported by smaller vehicle or by
helicopter to remote sites
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24. Long-term solution
with ACB’s
 Can be cost effective
 Easy to install by semi-skilled
workers
 Permanent
 Fish friendly
 No maintenance
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25. Cattle Crossing Solution
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26. CONTACT INFORMATION
Eric L Kay - Forest and Industrial Road Consultant
250 337-5096 erickay@kayassociates.com
Daryl Hunt, A.ScT - Ministry of Forests, Penticton District
250 490-2219 Daryl.Hunt@gems8.gov.bc.ca
Bruce Stickney / Ernie Bone - Coast Masonry, CCI Industries
604 270-8411 Bruce bstickney@cci-industries.com
Ernie ebone@cci-industries.com
David Campbell, P.Eng - Campbell Engineering Inc.
250 658-4276 dcamp@mail.islandnet.com
Ken Langedyk, P.Eng - Dobson Engineering Ltd.
250 861-5595 langedyk@dobsoneng.com
Phil Carroll, P.Eng – Armtec Industries Ltd.
604 278-3881 pcarroll@armtec.com
Doug Bennett, M.Sc. R.P.F. P.Eng. - FERIC
604 228-1555 dbennett@vcr.feric.ca
Eric L Kay and Associates Engineering and Training 26

27. www.kayassociates.com
www.dobsoneng.com
www.cci-industries.com
www.trilock.com
www.armtec.com
www.gov.bc.ca/for/
www.feric.ca
Eric L Kay and Associates Engineering and Training 27 Thank you