Civil Engineering Reference
In-Depth Information
Comparison of Figures 6.34(a) and (b) shows an important difference in the deformation
characteristics of panels CA3 (
45
◦
) and CE3 (
0
◦
). In panels CA3 (
45
◦
) Figure
α
1
=
α
1
=
α
1
=
6.34(a) shows that under positive shear stress (Figure 6.33a), the vertical strain
ε
V
reaches the
compression region in every cycle, meaning that the horizontal cracks are fully closed and
vertical concrete struts are formed to resist the vertical compression. Under negative shear
stress (Figure 6.33b), the horizontal strain
ε
H
reaches the compression region in every cycle,
meaning that the vertical cracks are fully closed and horizontal concrete struts are formed to
resist the horizontal compression.
In contrast, in panels CE3 (
0
◦
) Figure 6.34(b) shows that under positive shear stress
α
1
=
ε
V
do not reach the compression region and the end strains are further
away from the compression region with every cycle. Physically, this means that the horizontal
cracks remain open, and widen with each cycle. The vertical compressive stresses are resisted
by the vertical steel bars in compression, rather than concrete. Under negative shear stress, the
horizontal strains
the vertical strains
ε
H
do not reach the compression region and the end strains are further away
from the compression region with every cycle. Physically, this means that the vertical cracks
remain open and widen with each cycle. The horizontal compressive stresses are resisted by
the horizontal steel bars in compression, rather than concrete.
Figure 6.34
Predicted and experimental horizontal-strain versus vertical-strain curves of panels CA3
and CE3 (dotted curves show predicted results, solid curves show experimental results.)
