## 3 Experimental Results  
### Failure Models and Load-Displacement Hysteresis Diagrams  
Figure 6 illustrates SCMSW specimens cracking pattern at the end of testing for all walls. In general, all SCMSW specimens, except WS1, showed predominantly flexural behavior as expected. The flexural mode of failure is defined by the presence of horizontal cracks at the bottom layers of the wall due to the tensile bond strength between the unit and mortar. The strain gauges located in first and fifth course of SCMSW specimens recorded no significant strain, meaning that only negligible strains developed in these bars. On the other hand, the outermost vertical steel bars of the walls yielded due to the relatively insufficient amount of the flexural reinforcement. The load degradation can be attributed to the buckling of the vertical steel bars in the toe regions of the walls as shown in Figure 7, which is very significant in the final stage of the test. The ultimate strength of the walls is governed by the flexural yielding of the vertical reinforcement and the compressive crushing of the toe regions in the masonry wall.  
Figure 4: Typical testing protocol.  
Figure 5: Self-insulating concrete masonry shear wall (SW1) ready for testing.  
Although SW1 was expected to fail in shear, it did not show sudden strength degradation after the maximum wall strength was reached. Also, the strain gauges connected to the outermost vertical steel bars measured significant strains, meaning that yielding in those bars had occurred. Consequently, it showed a flexural/shear failure. This type of failure usually takes place when using a small amount of axial loading and the horizontal reinforcement distributed closely with bars of small diameters; similar observations for this behavior were reported by [PERSON] and [PERSON] [11]. The initial diagonal cracks did not widen significantly as the lateral load was increased. However, new sets of diagonal cards appeared gradually over the wall diagonals as shown in Figure 6a, thus leading to high energy dissipation and ductile behavior. The shaded areas illustrated in Figure 6 show the crushing in the masonry walls.  
General wall behavior is summarized in Table 4. The load-displacement hysteresis diagram for each SCMSW specimen is presented in Figure 8, concerning the lateral displacement and the lateral load along with theoretical flexural capacities, which were determined from moment curvature analysis. The theoretical flexural capacity was based on the rectangular masonry compression stress block using the measured material strength. The effective thickness of the compression stress block was 220 mm after deducting the area covered by the insulation material. On average, the observed capacities decreased from the theoretical capacities by a factor of 0.94, which confirms the use of moment curvature analysis to predict the flexural strength for the newly-developed type of self-insulating concrete masonry shear walls. The predicted capacity for SW2, which was subjected to an axial stress of 0.5 N/mm\({}^{2}\) and had an aspect ratio of 2.0, was overestimated by 18%. This could be due to the fact that the cyclic loading test created residual stresses in the reinforcement and resulted in increased damage to the masonry [4].  
Figure 6: SCMSW specimen cracking patterns: (**a**) SW1; (**b**) SW2; (**c**) SW3; (**d**) SW4; (**e**) SW5; and (**f**) SW6.  
Figure 7: Extent of damage at end of test: (**a**) for wall SW2; and (**b**) for wall SW4.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \
\begin{tabular}{c} **Theoretical** \\ **Flexural** \\ **Capacity** \\ **(kN)** \\ \end{tabular} &
\begin{tabular}{c} **Average** \\ **Observed** \\ **Capacity to** \\ **Capacity to** \\ **Theoretical** \\ **Elevental Capacity** \\ **Ele