Steel is an important material for construction of bridges , rivets
have been traditionally used. The riveted connections have served us well for
over 150 years. With changing times, now
there is a replacement of the rivets
with some other type of connections and High Strength Friction Grip (HSFG)
bolts have been found suitable for the same.
Basics about HSFG Bolts :- Rivets have been used historically
for making field connections in steel girders subject to railway and highway
loadings. Rivets, however, require skilled workers and elaborate equipment/arrangements..
Also, rivets are difficult to make when the grip length increases as the uniform
heating of longer rivets and also ensuring that rivets do not cool down before
the same is driven becomes problematic in field. One option for substitute for
rivets, namely High Strength Friction Grip (HSFG) bolts is covered in these
guidelines. HSFG bolts are high strength structural bolts which have been
tightened such as to induce predefined tension in the. Due to the tension in
the bolt, the interface between the plies (steel members in a joint) cannot
move relative to each other because of the frictional resistance. The bolts act
differently than normal bolts or rivets