Abstract:
..In the present study, an extensive experimental laboratory investigation has been carried
out to study the comparative in-plane cyclic behavior of brick infilled, isolated brick
infilled and bare reinforced concrete (RC) frames and to find an appropriate retrofit
measure for those frames against earthquakes.
Bangladesh is recognized to be an earthquake prone region where multistoried masonry
infilled reinforced concrete framed buildings are commonly seen. Burnt clay bricks are
the most common infill materials used as partition walls in those RC framed structures.
Lack of knowledge on the mechanical properties of the clay brick infills prevents the
local structural engineers from idealizing the seismic performances of such buildings in
Bangladesh. In this context, present study focuses on the experimental investigation of the
comparative in-plane cyclic response of the bare RC frames and the locally available
brick infilled RC frames. Moreover, in-plane cyclic behavior of a newly proposed
construction method of brick infilled RC frames where the infill is isolated from the
surrounding RC frames have also been evaluated and compared with the bare and the
conventional brick infilled RC frames.
In the present research, the increasing in-plane reverse cyclic loads in increasing
magnitude have been applied on six single bays, single story ½ scale models comprising
two bare RC frames; two brick infilled RC frames and two isolated brick infilled RC
frames till their ultimate capacities were reached accompanied by substantial deformation
and propagation of cracks. Behaviors of these frames were evaluated through the
observed strength and deformation characteristics along with hysteretic energy dissipation
capacity and ductility. Later, the damaged specimens were repaired with FC laminates
and tested following the same procedures as for the original frames.
The experimental results proved three times larger shear capacity as well as lower
ductility of brick infilled RC frames in comparison to bare RC frames. While, the isolated
brick infilled RC frames exhibited 40% lower shear capacity and comparatively large
energy dissipation capacity as compared to the brick infilled RC frame. Furthermore,
repair or retrofitting with ferrocement laminates confirmed improved performances of all
the damaged frames regarding shear capacity, stiffness degradation and energy
dissipations. Eventually more than the original strengths were achieved by repairing the
damaged frames with ferrocement laminates.
