Guidelines for the Tri-Lock System

  • 1.0 Typical Installation Area
  • 2.0 Typical Tri-Lock Draft Specification
  • 3.0 Typical Tri-Lock Specifications
  • 3.1 Typical Tri-Lock Installation Specifications
  • 3.2 Installation
  • 3.3 Standard and Optional Block Laying Methods
  • 3.4 Trenches | Vegetation
  • 3.5 Up Stream and Down Stream Flanks
  • 3.6 90-Degree Corner
  • 3.7 Slope Protection
  • 3.8 Toe/Top Protection
  • 3.9 Channel Lining Cross Section
  • 3.10 Installation Rate
  • 4.0 Guidelines for Selection of Tri-Lock System
  • 5.0 Geotextile Specifications
  • 6.0 Stability Chart and Disclaimer

1.0 Typical Installation Areas

  • Shore Line Protection from Wave Action
  • Bank Protection from Flow or Wake Action
  • Reservoir Embankment Protection
  • Channel Lining
  • Culvert Inlet or Outfall Protection
  • Drainage Ditch Lining
  • Pipeline Watercourse Crossing Protection
  • Bridge Apron
  • Slope Protection
  • Boat Launching Ramps
  • Parking Areas
Tri-Lock can be used as an alternative to the following products:
  • Concrete Ditch and Slope Lining
  • Rock Rip-Rap
  • Gabions and Reno Mattress
  • Grouted Mattress
  • Cable Block Systems
NOTE: Tri-Lock is not a retaining wall.

All slopes must be stable before Tri-Lock can be installed.

2.0 Typical Tri-Lock Draft Specification

Articulating Cellular Concrete Block Erosion Control System

1. The interlocking cellular concrete block system shall be as described herein, or approved equal design. Any alternative system submitted for approval must include' complete design and hydraulic data including test evidence of compliance to the essential design parameters of this specification.

2. Compressive strength testing of wet cast blocks shall be performed on cylinders, in accordance with ASTM C-31 and C-39. Compressive strength testing of dry cast blocks shall be performed on cubes cut from random block samples,
inaccordance with ASTM C-140.

Design Parameters

Concrete: The unit weight of the concrete used shall not be less than 125 Ibs. percubic foot on an oven dried basis. Pre-cast concrete and machine made blocks shall have a compressive strength of 4,000 psi minimum. Machine made concrete blocks strength shall be determined by testing random cubes, cut from the body of the block. The cementitious materials shall conform to ASTM designation C-33, except that the grading requirement shall not necessarily apply.

Cellular Concrete Blocks: The Cellular concrete blocks shall be interlocking components dimensioned within a 1611 module. Each component shall lock into a minimum of three adjacent components in a manner which inhibits horizontal movement.

Permeability: The assembled cellular block system shall have voids at ground/block interface of a minimum of 16% and shall provide, when required, adequate channels between cells below the top level of the blocks for the migration of
vegetation from cell to cell.

Flexibility: The assembled cellular concrete block system shall flex to a minimum of 31:0011 (three foot) radius in any two directions a minimum of 60 degrees apart without separation of the blocks at the base. The interlock must remain securely fastened
at this radius.

3.0 Typical Tri-Lock Specification

Tri-Lock Specification Drawing

Tri-Lock Specification Drawing

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3.1 Typical Tri-Lock Installation Specification

Site Preparation

The Slope must be stable independent of the erosion control system and filled slope shall be compacted to not less than 900/0 density.

Before placing either the concrete block system or the underlaying filter fabric, the slope shall be inspected to insure that it is free from obstructions, such as tree roots projecting stones or other foreign matter. Voids or soft areas should be filled with suitable material and well compacted. Although some variation in contour will be permitted, no sudden changes in level can be accepted. The maximum difference in level between any cuts will be 1.511• Hand dress where necessary.

3.2 Installation

Installation

The entire perimeter of the cellular concrete block erosion control system shall be turned into, and buried beneath the adjacent ground level to a depth of not less than three (3) feet, or as shown on the drawings. Any junction with other structures shall be made as noted on drawings, but shall always provide a permanent soiltight joint to prevent the migration of soil between the structures. Grouting if necessary.

Penetrations through the erosion control system may be made by omitting sufficient blocks to provide space for the penetration. It will be necessary to provide extra filter fabric in the form of a tightly fitting flange around the pipe or device so that it may be overlaid with the erosion control system filter fabric. (Minimum overlap 18".) Any voids around the penetration should be filled with grout and floated smooth.

Dress the entire revetment with topsoil. Apply fertilizer and seed with native grass as approved by the engineer. If the drawings do not indicate that revegetation is required, then dress with ~" crushed rock as approved by the engineer.

3.3 Standard and Optional Block Laying Methods

Standard Block Lay Method

Standard Block Lay Method

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To initiate block lay, start with a straight line perpendicular to direction of lay.

Maintain straight line block lay proceeds across slope. Watch orientation or rotation of individual units as a small error in laying can progress in severity as lay block proceeds. To maintain straight lines it is best to lay no more than two rows at a time.

Block pairs are generally easiest to install by placing lock block into key block then rotating block pair until key fits into adjoining lock block. Always lay towards an open area and not toward a point of fixity.

Optional Block Lay Method

Standard Block Lay Method

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If laying adjacent to a pavement or similar structure this option may be pursed to achieve a more aesthetic appearance.

Schematic View Block Lay Operation

Standard Block Lay Method

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Tri-Lock blocks are normally delivered to Job site on pallets with blocks stacked in pairs.

Block lay can proceed equally as well In either direction. To negotiate tums or curves in the slope step the blocks up or down as required. Maintain continuity of straight lines.

If unevenness of slope or other circumstances prevents the block from interlocking, a new block line may be started. The resulting joint or seam should be grouted with concrete.

3.4 Trenches | Vegetation

The key trench depth should increase with site-job conditions such as length of slope, degree of grade, soil conditions, etc. While a general rule on the key trench depth is not available, Southwest Erosion Control will assist and advise as needed.

THE TOE TRENCH: (Bottom Trench) is needed under most conditions. While some site circumstances do not allow the toe trench, such as certain shallow water installations, it is necessary where conditions are dry to utilize the toe trench at a depth of 12" - 18" minimum with geotextile being "back-wrapped" over the top of block in the toe trench. For site specific recommendations, Southwest Erosion Control should be contacted.

LATERAL OR FLANK TRENCHES: (Diagram C-S) should be utilized on all Tri-Lock installations. The lateral trench prevents extreme lateral stress on the revetment system during unusually heavy flow. Lateral trench also allows modules to "knuckle" at interlock points providing added strength.

EXCEPTIONS: and alterations are sometimes necessary due to site specific conditions. Shallow or deep water installations and installations which involve joining of Trl-Look to a fixed object at the top, bottom, or lateral points of the Tri-Lock System are just a few circumstances. These situations are easily reconciled without loss of the flexibility or integrity of the Tri-Lock System.

90 DEGREE CORNER: Due to the flexibility of the Tri-Lock System, 90 degree corners may be installed without incurring a grout line, While it may be necessary to step up or down some block modules to maintain straight lines, this is normally a minor process. A joint may be avoided at the angle, but a reorientation of the leading edge of the block will occur.

COMPLETION OF INSTALLATION: Upon completion of installation, all key, toe, and lateral trenches should be backfilled.

FOR VEGETATION ESTABLISHMENT: for areas to be revegetated as identified on Drawings, backfill openings flush with the top surface of the blocks using topsoil at approximately one cubic yard per 45 square yards of surface area for 4 inch thick blocks, per 33 square yards of surface area for 6 inch thick blocks and per 22.5 square yards of surface area for 8 inch thick blocks.

NON-VEGETATED INSTALLATIONS: for areas not requiring revegetation as identified on Drawings, backfill openings with ½ inch nominal size crushed rock to a minimum depth of 2 inches, regardless of block thickness, or approximately one cubic yard of backfill per 90 square yards of surface area.

3.5 Up Stream and Down Stream Flanks

Down Stream Flank

Down Stream Flank

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Up Stream Flank

Up Stream Flank

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3.6 90-Degree Corner

90-Degree Corner

Up Stream Flank

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3.7 Slope Protection

Rip-Rap Cross Section
Rip-Rap

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Tri-Lock Cross Section
Tri-Lock Cross Section

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Rip-Rap vs Trilock Rip-Rap vs Trilock Tri-Lock Slope Protection Slope Protection Tri-Lock Tangential Forces Tangential Forces

3.8 Toe/Top Protection

Tri-Lock Top Protection
Top Protection 1

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Top Protection 2

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Top Protection 3

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Toe Protection 4

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Tri-Lock Toe Protection
Toe Protection 1

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Toe Protection 2

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Toe Protection 3

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Toe Protection 4

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3.9 Channel Lining Cross Section

Tri-Lock Channel Lining Cross Section
Tri-Lock Channel Cross Section

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3.10 Installation Rate

The extreme versatility of Tri-Lock provides a variety of site-specific conditions which affect installation in subtle manners.

Certain procedures are constant in the proper installation of Tri-Lock.

General Installation Rate

4010 Tri-Lock
  • 3:1 Slope
  • 4 Person Crew
  • Dry Terrain
  • Prepared Slope (Graded Dressed)
  • 2,000 - 3,000 SQ. FT. Per Day
4110 Tri-Lock
  • 3:1 Slope
  • 4 Person Crew
  • Dry Terrain
  • Prepared Slope (Graded Dressed)
  • 2,800 - 3,800 SQ. FT. Per Day
4015 Tri-Lock
  • 3:1 Slope
  • 4 Person Crew
  • Dry Terrain
  • Prepared Slope (Graded Dressed)
  • 1,500 - 2,000 SQ. FT. Per Day

4.0 Guidelines for Selection of Tri-Lock System

The selection of the proper Tri-Lock System, 4" or 6" is affected by site or project conditions such as soil permeability, flow or wave intensity, soil compaction and slope or grade conditions.

Generally Acceptable Guidelines Are:

  • 4010 (Nominal 4" Tri-Lock)
  • Flow: 10 - 16 fps
  • Wave: 4'-0" Height
  • 4015 (Nominal 6" Tri-Lock)
  • Flow: 16 - 20 fps
  • Wave: 7'-0" Height

5.0 Geotextile Specifications

Tri-Lock and Geotextile Specifications

Tri-Lock Geotextile Specifications

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Filter Fabric: The cellular concrete block erosion control system shall be laid over a plastic filter fabric as herein specified. The characteristics of the woven filter fabric will be not less than the following:

Filter fabric shall be free of defects, rips, holes or flaws and shall be either overlapped by a minimum of 18" or sewn into panels to suit the application. Sewn seams shall have strength at least equal to that specified for the fabric.

Soil samples shall be analyzed to assure that the soil particle size is compatible with the specification above. Generally, if 100/0 of the particle analysis is bigger than the AOS, a graded filter will develop under the fabric capable of filtering much smaller particles Should the percentage of particles larger than the AOS be less than 100/0, then it will be necessary to install a supplementary filter, either with fabric or sand.

Tri-Lock and Geotextile Chart
TYPE ASTM SPECIFICATIONS
Tensile Strength ASTM 0-4632 330x400 lbs.
Burst Strength ASTM D-3786 805 PSI
Puncture Strength ASTM 0-4833 165 lbs.
Trapezoid Tear Strength ASTM 0-4533 120 lbs. x 120 lbs.
Abrasion Resistance ASTM 0-3884 580/0 x 810/0
Apparent Opening Size ASTM 0-4751 40 U.S. std. sieve
Permeability ASTM 0-4491 .12em/Sec
Tri-Lock and Geotextile Specifications

6.0 Stability Chart and Disclaimer

Tri-Lock Hydraulic Stability Curves
Tri-Lock Stability Chart 1

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Tri-Lock Hydraulic Stability Curves
Tri-Lock Stability Chart 2

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Shear Stress and Velocity Reduction Factors K1
Revetment Type 5H:1V 4H:1V 3H:1V 2H:1V
Class 4010 0.953 0.938 0.912 0.854
Class 4015 0.934 0.914 0.879 0.803
Sideslope Reduction Factors for Tri-Lock Revetment

Tri-Lock is a revetment system for minimizing erosion. Although in some circumstances Tri-Lock may enhance the stability for a slope, Tri-Lock is not sold or intended to be used as a structural component of a slope stability design. The slopes on which the Tri-Lock system is placed must be stable, and should be designed by a registered Engineer pursuant to a slope stability analysis performed by a qualified Geotechnical Engineer.

Tri-Lock is not sold or intended to be used when design hydraulic conditions exceed the threshold stabilities established by Charts 1 and 2, in conjunction with Table 1, or when hydraulic pressures are created due to substantial changes in grades or flow directions. Additionally, Tri-Lock systems must be installed in accordance with the Tri-Lock Design Manual.

To the extent Tri-Lock is misused in applications for which the product was not sold or intended to be used, Midwest Construction Products and Tri-Lock disclaim any liability arising out of or related to the product's misuse.

Tri-Lock 4010 Typical Installation

Tri-Lock 4010

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The Slope must be stable independent of the erosion control system and filled slope shall be compacted to not less than 900/0 density. Before placing either the concrete block system or the underlaying filter fabric, the slope shall be inspected to insure that it is free from obstructions, such as tree roots projecting stones or other foreign matter.

Voids or soft areas should be filled with suitable material and well compacted. Although some variation in contour will be permitted, no sudden changes in level can be accepted. The maximum difference in level between any cuts will be 1.511• Hand dress where necessary.


Tri-Lock 4010 General Installation Rate

  • 3:1 SLOPE
  • 4 PERSON CREW
  • PREPARED SLOPE (GRADED-DRESSED)
  • 2000 - 3000 SQ. FT. PER DAY
Installation

The entire perimeter of the cellular concrete block erosion control system shall be turned into, and buried beneath the adjacent ground level to a depth of not less than three (3) feet, or as shown on the drawings. Any junction with other structures shall be made as noted on drawings, but shall always provide a permanent soiltight joint to prevent the migration of soil between the structures. Grouting if necessary.

Penetrations through the erosion control system may be made by omitting sufficient blocks to provide space for the penetration. It will be necessary to provide extra filter fabric in the form of a tightly fitting flange around the pipe or device so that it may be overlaid with the erosion control system filter fabric.(Minimum overlap 18".) Any voids around the penetration should be filled with grout and floated smooth.

"crushed rock as approved the engineer.

Tri-Lock 4110 Typical Installation

Tri-Lock 4110

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The Slope must be stable independent of the erosion control system and filled slope shall be compacted to not less than 900/0 density. Before placing either the concrete block system or the underlaying filter fabric, the slope shall be inspected to insure that it is free from obstructions, such as tree roots projecting stones or other foreign matter.

Voids or soft areas should be filled with suitable material and well compacted. Although some variation in contour will be permitted, no sudden changes in level can be accepted. The maximum difference in level between any cuts will be 1.511• Hand dress where necessary.


Tri-Lock 4110 General Installation Rate

  • 3:1 SLOPE
  • 4 PERSON CREW
  • PREPARED SLOPE (GRADED-DRESSED)
  • 2800 - 3800 SQ. FT. PER DAY
Installation

The entire perimeter of the cellular concrete block erosion control system shall be turned into, and buried beneath the adjacent ground level to a depth of not less than three (3) feet, or as shown on the drawings. Any junction with other structures shall be made as noted on drawings, but shall always provide a permanent soiltight joint to prevent the migration of soil between the structures. Grouting if necessary.

Penetrations through the erosion control system may be made by omitting sufficient blocks to provide space for the penetration. It will be necessary to provide extra filter fabric in the form of a tightly fitting flange around the pipe or device so that it may be overlaid with the erosion control system filter fabric.(Minimum overlap 18".) Any voids around the penetration should be filled with grout and floated smooth.

"crushed rock as approved the engineer.

Tri-Lock 4015 Typical Installation

Tri-Lock 4010

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The Slope must be stable independent of the erosion control system and filled slope shall be compacted to not less than 900/0 density. Before placing either the concrete block system or the underlaying filter fabric, the slope shall be inspected to insure that it is free from obstructions, such as tree roots projecting stones or other foreign matter.

Voids or soft areas should be filled with suitable material and well compacted. Although some variation in contour will be permitted, no sudden changes in level can be accepted. The maximum difference in level between any cuts will be 1.511• Hand dress where necessary.


Tri-Lock General Installation Rate

  • 3:1 SLOPE
  • 4 PERSON CREW
  • PREPARED SLOPE (GRADED-DRESSED)
  • 1500 - 2000 SQ. FT. PER DAY
Installation

The entire perimeter of the cellular concrete block erosion control system shall be turned into, and buried beneath the adjacent ground level to a depth of not less than three (3) feet, or as shown on the drawings. Any junction with other structures shall be made as noted on drawings, but shall always provide a permanent soiltight joint to prevent the migration of soil between the structures. Grouting if necessary.

Penetrations through the erosion control system may be made by omitting sufficient blocks to provide space for the penetration. It will be necessary to provide extra filter fabric in the form of a tightly fitting flange around the pipe or device so that it may be overlaid with the erosion control system filter fabric.(Minimum overlap 18".) Any voids around the penetration should be filled with grout and floated smooth.

"crushed rock as approved the engineer.