Abstract:
Reinforced concrete (RC) columns are the most crucial building component in
concrete buildings, resisting both gravity and lateral loads. Therefore, their
effective retrofitting technique is a burning topic in the scientific community. This
research investigates the performance of prefabricated ferrocement angles (PFAs)
as a retrofitting solution for damaged RC columns. A total of 18 scaled-down
square columns of three different concrete strengths of 36.40 MPa, 34.20 MPa and
31.40 MPa were experimentally investigated. The strength of the ferrocement
used to make the PFAs was 39 MPa. Each concrete strength group consists of 6
columns: 1 control, 1 control pre-cracked, 2 retrofitted with single-layer wire
mesh PFAs and 2 retrofitted with double-layer wire mesh PFAs. The complete
retrofitting procedures involved the external application of PFAs at the column
corners with bonding agents, joining the PFAs with each other by sewing wire
meshes and filling the voids between PFAs with high-strength mortar. The
specimens were tested under displacement-controlled axial loading and
performance in regard to ultimate load capacity, stiffness, energy absorption,
ductility and failure patterns were evaluated.
The application of PFAs significantly increased the axial load capacity of the pre-
cracked RC columns. Increasing the layer of wire mesh also increased the gain of
axial load capacity by almost 50%. This increase was found to be more for RC
columns of the higher concrete strength group, indicating the dependence of the
axial load capacity increase after PFA jacketing on the actual concrete strength of
the RC columns. PFA jacketing also helped to retain the stiffness of the pre-
cracked samples while allowing greater lateral and axial deformation. Jacketing
the pre-cracked columns with PFAs increased their energy absorption capacity
by more than 100%. The proposed jacketing method of RC columns with PFAs
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also improved their ductility via the confinement effect, ensuring higher plastic
deformation and preventing brittle failure.
