The right choice of steel – according to the Eurocode - Economical Bridge Solutions based on Innovative Composite Dowels and Integrated Abutments - page 18

growth direction and thus energy is dissipated. Consequently, fine grained steels are
more resistant to brittle failure.
Cold forming
With an increase in cold forming, the yield strength increases with decreasing ductility
(“Fig. 13”).
Material thickness
In the two dimensional stress state, steel plastic deformation starts at the yield point. In
the three-dimensional stress state, the crystal lattice of the steel is compacted from all
sides and therefore the steel yield strength is increased significantly. Thus, thinner plates
with a higher share of material in the two-dimensional stress state do have more ductility
than thicker plates (“Fig. 14”).

The material toughness is in general experimentally investigated by the Charpy impact
test with the resulting impact energy - temperature curve.
Further relevant factors which have also an influence on the resistance of members to
brittle fracture are:

Notch detail
Crack initiation highly depends on the notch detail and the resulting stress, crack posi-
tion and crack shape expressed by the notch intensity factors (“Fig. 15”).
Load utilisation level of member
The higher the tension in the member, the higher the failure probability (“Fig. 16”).

Figure 10: Impact energy A v - temperature

T curve

Figure 11: Stress intensity factor -

temperature curve for quasi-
static and dynamic loading