3.4. Ductility of confined concrete
The ductility of a structural member refers to its tendency to
deform to large strains without fracturing under the load applied
to it. This is most desirable attribute of any structural element that
provides warning prior to failure. The ductility of the tested specimens
is evaluated in terms of displacement ductility, which is
used by several researchers [15,25]. The displacement ductility is
the ratio of the axial displacements corresponding to the yield
and 0.85 ultimate loads (on the descending branch), respectively.
The computed ductility of the specimens is reported in Table 6.
Some of the specimens failed before reaching 85% of ultimate load
on the descending branch of the stress–strain curve. Therefore, for
those specimens, the ultimate displacement at failure load is considered
as the displacement at 85% of ultimate load. The results
shown that the ductility of all jacketed specimens is higher than
that of non-jacketed specimens. For LS and MS specimens, the ductility
of specimens jacketed with double layer wire mesh is higher
than that of specimens jacketed with single layer wire mesh. However,
in case of SS specimens, the ductility of both types of jacketed
specimens is almost similar