## 2 The Building, Temporary Instrumentation and Methodology
### Description of the Building and Sensor Layout  
The case study corresponds to a sixteen-story building office with three additional basement stories, where the first story is 3.42 in height and stories 2-16 are 3.24 in height. It is situated in Vina del Mar, located in the Chilean central coast area, where several buildings were damaged during the last Mw 8.8 Maule earthquake. A picture of the building and a typical plan view are depicted in Figure 1. The structure was built in 2008, following the 2004 Chilean Building Code, which refers to the ACI-318 concrete design provision [27]. It is designed and built as an RC dual system (i.e., core structural wall and perimeter moment frame-wall), which is a typical construction type for offices in Chile. The monitoring time is between 27 March 2010 and 19 April 2011. During the monitoring period, the building was equipped with 16 force-balance Digitexx uniaxial accelerometers model D-110U (see Table 2 for detailed specifications) distributed with the height and across the floor. Four (4) sensors were installed on the third underground level, three (3) on the ground surface level, and then three (3) sensors on the third, sixth, and top floor. It is worth mentioning that the two vertical sensors 3 and 4 in the 3 rd subterranean floor were not activated. The sensors \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Location** & **Date (MM-DD-YYYY)** & **Date** & **Depth (km)** & **Magnitude** \\ \hline Metropolitan Region & 04-05-2010 & 03:32-12 UTC & 58.6 & 4.5 (M\({}_{w}\)\({}^{(1)}\)) \\ \hline Offshore Valparaiso & 05-01-2010 & 14:41:08 UTC & 35.0 & 5.0 (M\({}_{w}\)) \\ \hline Coquimbo & 10-23-2010 & 01:38:14 UTC & 44.0 & 5.2 (m\({}_{b}\)\({}^{(2)}\)) \\ \hline Araucania & 01-02-2011 & 20:20:18 UTC & 25.1 & 7.2 (M\({}_{i}\)/M\({}_{wp}\)\({}^{(3)}\)) \\ \hline Libertador O’Higgins & 01-21-2011 & 15:36:11 UTC & 18.2 & 5.0 (m\({}_{b}\)) \\ \hline Offshore Maule & 02-14-2011 & 03:40:10 UTC & 25.4 & 6.6 (M\({}_{i}\)/M\({}_{wp}\)) \\ \hline \hline \end{tabular} \({}^{(1)}\) M\({}_{w}\) = Moment magnitude; \({}^{(2)}\) m\({}_{b}\) = Body wave magnitude; \({}^{(0)}\) M\({}_{i}\)/M\({}_{wp}\) = Integrated p-wave.  
\end{table} 
Table 1: List of seismic events recorded in the building (source: USGS). register accelerations along the two horizontal directions of the building, where one sensor measured in the EW direction and two sensors in the NS direction. The criteria followed for the chosen positions of the instruments was in such a way that torsional modes are identified, given that the distribution of walls and columns with non-coincidental mass and rigidity centers naturally is expected to cause torsional behavior. Additionally, this sensor distribution allowed for the monitoring of the structure's spatial motion, the partial capturing of its linear and nonlinear response features since no sensors were available on the intermediate floors (from the 7 th to the 16 th), The sampling rate for the sensors was 100 Hz. Figure 2 shows a diagram illustrating the array of 16 accelerometers temporarily deployed in the building. General information corresponding to the mounting of the accelerometer array can be found elsewhere [28]. \begin{table}
\begin{tabular}{c c} \hline \hline
**Specification** & **Parameter** \\ \hline Acceleration range & +/\(-\)3 (g) \\ Output & 1.2 (V/g) standard between 2000 (\(\Omega\)) or greater \\ Load capacitance & 10.000 (PF) maximum \\ Transverse axis & 0.005 (g/g) \\ Linear error & \(<\)\(\pm\)0.2\% F.S. \\ Noise threshold & \(<\)1 (ug/\(\surd\)Hz) (Band 0.05–1.500 (Hz)) \\ Dynamic interval & \(>\)110 (dB) \\ Bandwidth & DC–2.000 (Hz) to 3 (dB) \\ Power & \(+\)/\(-\)12 (Vdc), 9 (mA) \\ Operating temperature & \(-\)40 (\({}^{\circ}\)C) to +85 (\({}^{\circ}\)C) \\ Zero axis variation due to change & \(<\)200 (ug/\({}^{\circ}\)C) outside temperature range \\ Cover & Presurized hermetic aluminum housing \\ Dimensions & 108 \(\times\) 76 \(\times\) 57 (mm) \\ Mass & 0.5 (kg) \\ \hline \hline \end{tabular}
\end{table}