M 41-10 Page 9-137 Cribbing 9-279-27 Cribbing
9-27.1 Vacant
9-27.2 Vacant
9-27.3 Gabion Cribbing
9-27.3(1) Gabion Fabric
Gabions may be fabricated from either hexagonal twisted wire or from welded wire. Only one type of wire and protective coating shall be used throughout a structure. Baskets shall be furnished in the required dimensions with a dimensional tolerance of plus or minus 5 percent. Wire for construction of gabions shall be either galvanized steel wire conforming to ASTM A641, Class 3, Soft Temper, or aluminized steel wire conforming to ASTM A809, Soft Temper. The wire shall have a minimum tensile strength of 60,000 psi when tested in accordance with ASTM A370.
9-27.3(2) Gabion Baskets
Gabion baskets 1 foot or greater in the vertical dimension shall have openings with nominal dimensions not to exceed 4½ inches and the maximum area of any opening shall not exceed 10 square inches.
1.Hexagonal Twisted Wire
a.Wire for galvanized or aluminized hexagonal twisted welded wire shall be nominal sized 0.120 inch galvanized steel wire or aluminized steel wire.
b.Hexagonal twisted wire shall be formed from galvanized or aluminized wire in a uniform hexagonal pattern with nonraveling double twist. The perimeter edges of each panel shall be tied to a selvage wire of the same composition as the panel body and have a minimum diameter of 0.150 inch so that the selvage is at least the same strength as the body of the panel.
2.Welded Wire
a.Welded wire shall be fabricated from galvanized steel wire having a diameter of 0.106 inch. Wire shall be galvanized prior to fabrication.
b.Welded wire shall be formed in a uniform square pattern with openings 3 by 3 inches with a resistance weld at each connection in accordance with ASTM A1064.
c.If required, a PVC coating shall be fusion bonded onto the welded wire mesh to provide a nominal coating thickness of 0.0216 inch per side with a minimum of 0.0150 inch.
3.PVC Coating (For Welded Wire Only) Acceptance of PVC coating material shall be by certified test reports of an independent laboratory. The initial properties of PVC coating material shall have a demonstrated ability to conform to the following requirements:
a.Specific Gravity – In the range of 1.2 to 1.4, when tested according to ASTM D792.
b.Tensile Strength – Not less than 2,275 psi, when tested according to ASTM D638.
c.Modulus of Elasticity – Not less than 1,980 psi at 100 Strain, when testing according to ASTM D638.
d.Hardness – Shore “A” not less than 75 when tested according to ASTM D2240. Page 9-138 M 41-10
9-27 Cribbinge. Brittleness Temperature – Not higher than 15ºF when tested according to
ASTM D746.
f.Resistance to Abrasion – The percentage of the mass loss shall be less than 12 percent when tested according to ASTM D1242, Method B at 200 cycles, CSI-A Abrader Tape, 80 Grit.
g.Salt Spray Exposure and Ultraviolet Light Exposure – The PVC shall show no effect after 3,000 hours of salt spray exposure according to ASTM B117. The PVC shall show no effect of exposure to ultraviolet light with test exposure of 3,000 hours using apparatus Type E and 63°C, when tested according to Practice D1499 and Practice G 23. After the salt spray test and exposure to ultraviolet light as specified above, the PVC coating shall not show cracks, blister, split, nor show a noticeable change of color. In addition, the specific gravity, tensile strength, modulus of elasticity, and resistance to abrasion shall not change more than 6, 25, 25, and 10 percent respectively from their initial values.
9-27.3(3) Gabion Mattresses
Gabion baskets less than 1 foot in the vertical dimension shall have openings with nominal dimensions not to exceed 3.3 inches, and the maximum area of any opening shall not exceed 6 square inches.
1.Hexagonal Twisted Wire
a.Wire for galvanized or aluminized hexagonal twisted wire shall be nominal sized 0.086 inch galvanized steel wire or aluminized steel wire.
b.Hexagonal twisted wire shall be formed from galvanized or aluminized wire in a uniform hexagonal pattern with nonraveling double twisted. The perimeter edges of each panel shall be tied to a selvage wire of the same composition as the panel body and have a minimum diameter of 0.1062 inch so that the selvage is at least the same strength as the body of the panel.
2.Welded Wire
a.Welded wire shall be fabricated from galvanized steel wire having a diameter of 0.080 inch. Wire shall be galvanized prior to fabrication.
b.Welded wire shall be formed in a uniform rectangular pattern with openings 1½ by 3 inches with a resistance weld at each connection in accordance with ASTM A1064.
c.If required, a PVC coating shall be fusion bonded onto the welded wire to provide a nominal coating thickness of 0.0216 inch per side with a minimum of 0.0150 inch. The PVC coating shall be in conformance with Section 9-27.3(2) .
9-27.3(4) Fasteners for Basket Assembly
The lacing wire shall be a nominal sized 0.0866 inch galvanized steel wire or aluminized steel wire. Lacing wire shall have the same coating as the basket. Spiral binders, if used for joining welded wire panels shall be formed from 0.106 inch nominal diameter steel wire with a 3-inch pitch having the same Specifications and coating as the welded wire. Lacing wire may be used in lieu of spiral binders. Alternate fasteners for basket assembly shall remain closed when subjected to a 600 pound tensile force when confining the maximum number of wires to be confined. Installation procedures and test results for alternate fasteners shall be submitted for approval. Internal connecting wires shall be the same as required for lacing wire. Alternate stiffeners acceptable to the gabion manufacturer may be used. M 41-10 Page 9-139 Cribbing 9-279-27.3(5) Nonraveling Construction The gabion wire shall be fabricated in a manner to be nonraveling. This is defined as the ability to resist pulling apart at any of the connections forming the panel when a single strand in a section of panel is cut.
9-27.3(6) Stone
Stone for filling gabions shall have a Degradation Factor of at least 30. The stone shall be dense enough to pass the unit weight test described in Section 8-24.3(3)F . Stone shall meet the following requirements for gradation: Sieve Size Percent Passing 8″ 100 6″ 75-90 4″ 0-10 % Fracture 75 min. All percentages are by weight.
Source: Washington Standard Specifications for Road, Bridge, and Municipal Construction, 2024 Edition. Pages 1047–1049 of 1,151.