Bolts and Washers

Fastening systems with bolts and washers are used on the radial and circumferential joints of the lining segments in the tunnel; they increase shear and pull-out resistance on the connecting joints. A complete range of bolts coupled with FAMA threaded sockets withstand tensile stresses from 70 to 400 kN.

• The length of the bolt fits design specification.
• The thread length on the bolts ranges from 115 to 155 mm according to socket type.
• Bolts are available in different diameters (20/25/28 mm).
• The thread pitch ranges from 5 mm to 12.5 mm (rail bolts).
• The bolts are made of C40/C45 steel and, at the customer’s request, also of 316L stainless steel or any other grade.
• FAMA fasteners are available in different strength grades (ASTM A325, 10.9, 12.9).

When they can be removed, the bolts and washers are supplied raw or electrolytically galvanized while permanent bolts are treated with the hot-dip galvanizing process or made of stainless steel. Additional accessories such as HDPE washers, washers with grommet and plain grommets are also available in the range.