Gabions shall be constructed with PVC coated wire mesh boxes rectangular in shape filled with clean and approved types of rocks larger than the mesh openings in accordance with the design, standard and latest Specifications.
PVC Coated Wire mesh shall consist of galvanized steel fabricated in double twist woven hexagonal shape with the following requirements:
-WIRE DIAMETER MESH SIZE
Boxes 2.7mm 8 cm x 10 cm
Mattresses 2.2 mm 6 cm x 8 cm
The rocks shall consist of clean solid rock non-friable and resistant to weathering and frost action meeting the following requirements:
-Bulk Specific Gravity (ASTM C128/C127) Min. 2.6
Absorption (ASTM C128/C127) Max. 2%
Soundness by Magnesium Sulphate Max. 12% (ASTM C88)
Excavation required for the placement of gabions shall be made in accordance with the dimensions as shown on drawings or as directed. Gabions shall be constructed in units to the dimensions indicated on the drawings.
The sides, ends, and diaphragms of the gabions shall be lifted into a vertical position, and located together with binding wire to form the base.
The binding shall be carried out in a continuous lacing operation, the wire being passed through each mesh and around both selvedges which must be tied together with two round of turns after every second mesh.
Assembled gabions may be placed in position for filling singly, or wired together in groups suitable for man-handling. The baskets shall be securely wired together at all comers and edges in the same manner as described above. Where there are more than one course of gabions, the one in the upper course must be laced to those below. Gabions shall be slightly over-filled to allow for subsequent settlement.