# Design Proposal for Masonry Infill Walls Subject to Seismic Actions
## 4 Comparison of the Experimental Results with Design Standards
### Demand  
In order to compute the design out-of-plane load according to the standards in Table 5 the maximum seismic input acceleration that is associated with the infill location on the structure must be considered, among other parameters. Given the fact that the PGA varied during the test, the PGA was not the same for each tested model, and that the measurements for the reinforced plaster infill seem to be unreliable, the value used in the equations proposed by each standard, see Table 5, was the maximum recorded acceleration at the foundation, for each tested model and each stage. This might not be necessarily the case for taller buildings, where more research seems to be needed. The out-of-plane design load variation, for each standard, was then plotted against the values recorded experimentally in each stage of the tested models, see Figures 10-12. As far as model 1 is concerned, see Figure 10, FEMA 302 [24], 306 [22] and 356 [25] presented a lower load than the experimental values during all the stages. FEMA 302 [24] and 306 [22] presented a load 46% and 60% lower on average, than the experimental values for the longitudinal and transversal infill walls, respectively, and FEMA 356 [25] presented design loads 48% and 62% lower in the same situation. As for NZS 1170.5 [26], in the longitudinal direction and until the second stage, the standard presented loads slightly higher than the experimental values for the exterior walls and lower values for the interior ones. In the last two stages, the standard presented loads 12% lower, on average for all infills, than the experimental values. In the transversal direction, the standard loads were lower in all stages, and 38% lower on average for all infills, in the last stage. EC8 [27], in the longitudinal direction presented design loads always higher than the experimental ones for the infill walls on the second floor (30% on stage 4) and always lower for the ground floor (20% on stage 4). In the transversal direction, the design loads were the same, on average, for all the infill walls on the second floor and always lower for the ground floor (46% on stage 4). As for model 1, FEMA 302 [24], 306 [22] and 356 [25] presented the highest differences in model 2, see Figure 11. In the longitudinal direction, FEMA 302 [24] and 306 [22] presented a load, on average (for all infills), 50% lower than the experimental results, in stage 3 and 267% lower in stage 4, while FEMA 356 [25] presented loads 74% lower in stage 3 and 87% lower in stage 4. \begin{table}
\begin{tabular}{c c} \hline \hline
**Standard** & **Analytical Solution** \\ \hline FEMA 302 [24] and 306 [22] & \(F_{p}=\frac{0.4\mu_{p}S_{0}S_{W_{p}}}{\frac{\mu_{p}}{\mu_{p}}}\big{(}1+2 \frac{\mu}{h}\big{)}\) \\ EC8 [27] & \(F_{a}=\frac{S_{W}S_{W}S_{a}}{\frac{\mu_{p}}{\mu_{p}}}\) \\ FEMA 356 [25] & \(F_{p}=\chi S_{S}SW\) \\ NZS 1170.5 [26] & \(F_{ph}=C_{p}\big{(}T_{p}\big{)}C_{ph}R_{p}R_{p}W_{p}<3.6W_{p}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Analytical solutions used to compute the out-of-plane demand of the infill walls. Figure 10: Standard and experimental out-of-plane load comparison for model 1. A similar situation was found in the transversal direction. NZS 1170.5 [26] presented very good results until the third stage, with load 14% and 9% lower in the longitudinal and transversal direction, respectively, but in stage 4, the load proposed by this standard is low, 57% and 23% for the longitudinal and transversal direction, respectively. This may be due to the nonlinear evolution of the experimental load due to damage accumulation in the infill walls and RC structure. As for the ECS [27], until the third stage the differences between the demand and experimental load was negligible (3% and 6% for the longitudinal and transversal directions, respectively, in stage 3), but in the last stage the load was 57% and 23% lower.