# Reinforced Concrete Building with IED Detonation: Test and Simulation
## 4 Results and Discussion
### Acceleration Signals  
Peak acceleration values comparing all the simulations performed and the measurements with the different sensors (A1-A4, Figure 1 and Table 2) can be found in Table 5. A filter was applied to the acceleration signals to eliminate noise and electrical peaks. The filtering applied was the Butterworth low-pass type of order 4; in addition, if the signal \begin{table}
\begin{tabular}{c c c c c} \hline
**Test** & **Explosive** & **Sensor** & **P\({}_{\textbf{r}}\) (kPa)** & **P\({}_{\textbf{r}}\) (LS-DYNA) (kPa)** & **Relative Dif. (\%)** \\ \hline T0 & PG-2 & P1 & 88.72 & 99.67 & \(-\)12.34 \\ T0 & PG-2 & P2 & 129.80 & 136.02 & \(-\)4.79 \\ T1 & Black Powder & P1 & 193.11 & 181.21 & 6.71 \\ T2 & Black Powder & P1 & 195.38 & 181.21 & 6.71 \\ T1 & Black Powder & P2 & 372.27 & & \\ T2 & Black Powder & P2 & 382.36 & 309.64 & 17.93 \\ \hline \end{tabular}
\end{table} 
Table 4: Pressure sensor results. Friedlander adjustment. Figure 7: Sequence of images obtained with HSC in trial T7: PG2. Time in milliseconds; the reference time is the first frame of the video where the detonation is observed. presented an offset, it was also corrected. Sensors that were not measured in the field are not reflected in Table 5, which is used to show the differences between measured and simulated values. Measurement failures were sometimes due to poor sensor coupling, failures in the trigger system or measurements that did not make sense because of the extreme (high/low) values obtained. Figure 8: Pressure isovalues (view from the inner door) on the interior faces of the room where the detonations were carried out for the T0 test. The color scale is the pressure values in Pa.  
Figure 9: Pressure signals (P1 and P2) for tests T1 and T2: black powder, and the simulated signal with LS-DYNA. As can be seen in Table 5 for sensors A1 to A4, the acceleration data obtained are quite large for the ANFO, AN/AL and PG2 tests, with values between 1000 and 5000 g, while in the black powder tests, the acceleration values are around 400 g. This clearly indicates that accelerations increase with the use of more powerful charges, as expected. Given the non-linear nature of the phenomenon, as well as the limitations of the simulation itself, the differences between the model and the real data are quite good with an average absolute value of 20%. Therefore, the model can reproduce with some reliability the acceleration peaks. The highest difference is found in the only useful measurement of sensor A2 and sensor A3 in test T1. On the other hand, the lowest value is also found at sensor A3 in test T7, followed by sensor A4 in tests T5 and T6. The lowest values are generally found in sensor A4, but it is also the sensor that shows the largest deviations from the mean value. The highest mean values are found in sensor A1 but with the smallest deviations. Considering the results obtained, it can be deduced that the differences between measured and simulated values on sensor A1 are the most important. This may be since the behavior of this interior wall is not well reproduced, being more rigid in the model than it should be. The opposite is true for the outer wall where sensor A4 is located, where the model reproduces quite faithfully the behavior of sensor A4. However, sensor A5, located on the roof of the structure (see Figure 1), shows somewhat different results (see Table 5 and Figure 10). In general, the model can reproduce the results measured in the field with errors averaging (and in absolute value) around 25%. Figure 10 shows how the accelerations look similar in all cases. In the T2 test, the peak accelerations were not recorded with the first arrival of the wave as in the other cases, as always happens in the modeling. Therefore, in this test, the acceleration peaks between LS-DYNA and the tests do not coincide in time, although they do coincide in peak values.