1.0 DESCRIPTION - This work shall consist of PRO-TEC GABIONS™ welded wire mesh Gabions and rock filling instructions.
2.0 MATERIALS - Gabions shall be of a single unit construction. The base, ends, sides, and lid shall be either welded into a single unit or shall be connected in such a manner that strength and flexibility at the connection are at least equal to that of the wire mesh. The gabions shall be fabricated in such a manner that they can be assembled at the construction site with spiral binders or high tensile steel hog rings and pre-formed stiffeners into rectangular baskets of the specified size. Gabions shall be divided into cells of equal length, not more than 1 cubic yard by diaphragms made of the same wire mesh as used for the gabion body. Each gabion shall be fabricated with the necessary diaphragms secured in proper position on the base in such a manner that no additional tying at the base will be necessary.
3.0 WIRE - Wire for the manufacture and assembly of gabions shall meet or exceed any combination of the following requirements:
Description Requirement 3"x3" (7.62 cm x 7.62 cm),
9 Ga. - 0.144 in. min. (3.66 mm) Welded Wire Fabric ASTM A1064, A370 Exception: Weld Shear at 800 lbs of force min. Galvanization: (9 Ga. 0.90 oz/SF) ASTM A641, A90 9 Ga. Galvanized Pre-Formed Stiffener N/A 9 ga (0.148) Galvanized Spiral Binder - min. 0.144 in. (3.66 mm) ASTM A641, A90 13.5 Ga. Tie Wire - min. 0.086 in. (2.2 mm) Galvanized 0.70 oz/SF ASTM A641, A90 3.0
4.0 ROCK - Rock for filling the gabions shall be as listed: 100% passing 8 inches (20.3 cm), 0-5% passing 4 inches (10.2 cm)
4.1 CONSTRUCTION
Gabions shall first be assembled individually as empty units. Each gabion shall be manufactured with the necessary panels, properly spaced and secured, so they can be rotated into position at the construction site with no additional tying of the rotation joint. The panels and diaphragms shall be rotated into position and joined along vertical edges. When 13.5-gauge tie wire is used as the joint material, all vertical edges of each gabion panel shall first be constructed to form individual empty gabions. Simple spiraling (looping without locking) of 13.5-gauge tie wire is not permitted. For welded-mesh, the joint shall be constructed using alternating single and double half hitches (locked loops) in every mesh opening along the joint.
PRO-TEC I welded gabion specifications, Galvanized 9ga. When 9-gauge spiral binders are used, the spiral shall be screwed into position such that it passes through each mesh opening along the joint. Both ends of all spiral binders shall be crimped to secure the spiral in place. Temporary fasteners may be used to hold panels wherever gabion-to-gabion joints will be constructed. Temporary fasteners may remain in place.
4.2 Assembly of Successive Gabions (Gabion-to-Gabion Joints). Empty gabions shall be set in place. Individually constructed empty gabions shall be joined successively to the next empty gabion with 13.5-gauge tie wire or 9-gauge spirals, before filling with rock begins. The tie wire or spiral binders shall secure, in one pass, all selvage or end wires of panels of all the adjacent gabions along the joint.
4.3 Assembly of multiple layered gabions can be stepped and staggered as shown on the plans or as directed by the project engineer. When constructing multi-layered gabion configurations, each layer of gabions can be joined to the underlying layer along the front and ends.
4.4 Assembly of single-layered Gabions - Single-layered gabion configurations shall be butted and joined along the front, back, tops and bottoms of adjacent gabions.
4.5 Modified geometry to match the geometry of the planned gabion configuration, or to meet specific conditions panels shall be folded, cut, and/or re-tied to dimensions shown on the plans or as approved by the project engineer.
4.6 Filling with rocks- Rocks shall be placed in gabions to insure proper alignment, avoid bulges, and provide a minimum of voids. All exposed rock surfaces shall have a smooth and neat appearance. No sharp edges shall project through the wire mesh. When constructing with 1.5-foot high or 3-foot high gabions, pre-formed stiffeners shall be used to produce a flat, smooth external surface. Pre-formed Stiffeners shall be installed on the exposed face of the gabion prior to rock placement, two rows at 1/3 points on 3' high gabions, one row at 1/2 point in 1.5' high gabions. When filling 3-foot high gabions, rock shall be placed in 3 nominal 12-inch layers; when filling 1.5-foot high gabions, rock shall be placed in two 9-inch layers. The last layer of rock shall slightly overfill the gabions such that the lid will rest on rock when it is closed.
4.7 Closure of lids - Lids shall be tied along the front, ends, and diaphragms of individual gabions and to successive gabions with spiral binders in the same manner as specified elsewhere in this specification.
