Experimental and Analytical Research into the In-Plane Behaviour of Calcium Silicate Piers, Retrofitted with Unbounded Steel Bars

In a building, some masonry piers may receive relatively low axial
loads. These piers can be toppled over, and consequently, their contribution to
the lateral stability of the building will be smaller. A previous paper dealt with
the possibility of activating low-loaded, and therefore passive, one-storey high
piers by using unbonded reinforcement. This paper describes the research into
the behaviour of two-storey high walls, six metres high, performed to check the
developed model. Rectangular walls with lengths of 600 mm and 1200 mm, and
walls with a 1000 mm long T-section were tested in duplicate. All six tested piers
were reinforced with unbonded threaded bars, anchored at each of the three floors.
Load was applied at the centre of the first and second storey floor.
Horizontal floor displacements, forces in the reinforcement and deformations
in the floor wall contact areas were measured. The results allowed, together with
the dimensions of the test set-up, for a relatively accurate establishment of the
position and magnitude of the axial forces in the critical sections of the wall and
in the reinforcement. Like in the one-storey walls, the critical section was at the
bottom of the walls. One of the T-section wall systems failed suddenly in tension-
shear. The shorter wall systems were aborted when the reinforcement started to
behave non-linearly or when the masonry at the toe started to crush. The findings
from the experiments and those from an earlier developed mode