Civil Engineering Reference
In-Depth Information
The other two symbols (L1, L2, L3, L4 and L5) correspond to the
loading. Five different combinations of top and bottom loads were used in
the tests as follows:
L1
uniformly distributed load on top of the wall-beam
L2
uniformly distributed load applied at the soffit of the wall-beam
L3
combination of top and soffit loads in a ratio 1:1
L4
combination of top and soffit loads in a ratio 2:1
L5
combination of top and soffit loads in a ratio 1:2
Thus, W1-L4 refers to a wall-beam with 1.06% of vertical reinforcement and
loaded under uniformly distributed load on top and soffit in the ratio 2:1.
A rig with two cross-heads and two independent hydraulic and
mechanical systems was used to apply the loads (Figure 6.4). These loads
were applied in constant increments up to failure; at each stage of loading
the strains at both surfaces were measured and the widths of cracks were
monitored with a hand microscope.
Figure 6.4
Test rig for Leeds tests on wall-beams.
6.5
Crack patterns
Despite differences in vertical reinforcement, crack patterns were similar for
walls W1, W2 and W3 under top loading. In general, the first cracks to
appear were small flexural cracks within the depth of the nib. The next
