## 5 Conclusions  
This work investigated the use of post-embedded piezoceramic-based sensors to estimate the applied force on an RC column under seismic loading. Generally, in the damage-controlling design of an RC building structure, the details of the process by which each column member is damaged, including the curves of force vs. deformation, force vs. residual crack width, damage level vs. residual crack width, and damage level vs. deformation relationships, are simulated. In other words, based  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Specimen** & **FF-155-II** & **FF-155-IV** & **FSF-155-II** & **FF-155-IV** & **SF-305-II** & **SF-305-III** \\ \hline F\({}_{\text{max}}\) & 191.69 kN & 209.44 kN & 193.87 kN & 212.22 kN & 199.31 kN & 210.28 kN \\ (v\({}_{\text{si}}\))\({}_{\text{max}}\) & 0.47 mV & 0.59 mV & 0.46 mV & 0.83 mV & 0.73 mV & 0.53 mV \\ F\({}_{\text{max}}\)/(v\({}_{\text{si}}\))\({}_{\text{max}}\) & 408.25 & 357.27 & 421.05 & 255.32 & 273.51 & 393.09 \\ \hline \end{tabular}
\end{table}
Table 7: Ratio between maximum force applied to a specimen and maximum voltage signal of Sensor 4.  
Figure 13: Regression graphs of normalized force from specimens and normalized signal from sensors. (**a**) FF-155-II (Sensor 3 and Sensor 4); (**b**) FF-155-IV (Sensor 4); (**c**) FSF-155-II (Sensor 3 and Sensor 4); (**d**) SF-305-III (Sensor 3 and Sensor 4).  
on the details of the damage process of a column member, post-embedded piezoceramic sensors can be used to detect the maximum force during an earthquake to quantify damage that is caused by the earthquake. The experimental results herein reveal that signal voltages that are measured by piezoceramic sensors are very strongly correlated with the forces that are applied to a specimen. However, since the number of specimens was limited, the issue related to the sensor position was not included in this work. For practical use, how to determine the appropriate sensor position for measuring the maximum applied force under an earthquake should be included in follow-up research.  
In the future, piezoceramic transducers can be used to measure the maximum applied force on an RC column member in an earthquake and to determine the maximum crack width following that earthquake. Moreover, these two pieces of information can be used to determine the damage level and the corresponding reduction factors of strength, stiffness, and energy dissipation capacity. For practical use in post-earthquake damage assessment of RC structures, in addition to durability, the wireless transmission and remote data storage of PZT transducers should be developed.  
Conceptualization, C.-K.C. and W.-I.L.; methodology, C.-K.C.; software, C.-H.W.; validation, C.-K.C., W.-I.L., and C.-H.L.; data curation, C.-H.W. and H.-F.S.; writing--original draft preparation, C.-K.C.; writing--review and editing, W.-I.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Minister of Science and Technology (MOST), Taiwan (MOST: 107-2221-E-011 -012 -MY3).  
The authors gratefully acknowledge the financial support granted by the Minister of Science and Technology (MOST), Taiwan (MOST: 107-2221-E-011 -012 -MY3). The facilities for research provided by the National Center for Research on Earthquake Engineering (NCRE), Taiwan, are also highly appreciated.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.