# Performance Evaluation of Rigid Braced Indirect Suspended Ceiling with Steel Panels
## 3 Test results
### Performance Evaluation of the Indirect Suspended T-Bar Ceiling System with the Steel Panel  
Table 7 shows the performance levels of the two brace-applied specimens that were used in this study. This was achieved by using the damage state and the performance level of the indirect suspended ceiling system with a steel panel to which the anti-falling clip was applied, as shown in Table 4 in Section 3.2. In addition, the analysis was performed by comparing the results of a previous study [8] with the USD test. The maximum acceleration that could be checked was based on the input acceleration. In the case of the dislodged panel and hanging for the damage stages that are shown in Table 7, the steel panel is suspended from the ceiling. In addition, it is defined as stage I for the performance level since it does not directly affect the safety. In the case of the \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Damage Level**} & \multirow{2}{*}{**Input Acc. (g)**} & **Test 1** & **Test 2** & **Test 3** & **Test 4** & **Test 5** & **Test 6** & **Test 7** & **Test 8** \\  & & **(50\%)** & **(100\%)** & **(125\%)** & **(150\%)** & **(175\%)** & **(200\%)** & **(225\%)** & **(250\%)** \\ \hline \multirow{2}{*}{Panel dislodged and hanging} & USD & - & - & - & 5.56\% & 11.1\% & 19.4\% & 38.9\% & - \\  & SDB-2 & - & - & 2.0\% & 12.2\% & 28.6\% & 34.7\% & 16.3\% & 8.2\% \\  & SDB-3 & - & - & - & - & - & 4.1\% & 6.1\% & 10.2\% \\ \hline \multirow{2}{*}{Panel fell} & USD & - & - & - & - & - & 5.56\% & 13.9\% & - \\  & SDB-2 & - & - & - & 2.0\% & 6.1\% & 10.2\% & 32.7\% & 40.8\% \\  & SDB-3 & - & - & - & - & - & - & - & 4.1\% \\ \hline \multirow{2}{*}{Connection failure} & USD & - & - & - & - & - & - & - & 5 ea 1 \\  & SDB-2 & - & - & - & - & - & - & - & 4 ea 2 \\  & SDB-3 & - & - & - & - & - & - & - & - \\ \hline \multirow{2}{*}{System failure} & USD & - & - & - & - & - & - & - & - & Partial \\  & SDB-2 & - & - & - & - & - & - & - & - \\ \cline{1-1}  & SDB-3 & - & - & - & - & - & - & - & - \\ \hline \multirow{2}{*}{Performance Level} & USD & I & I & I & I & I & III & III & IV \\ \cline{1-1}  & SDB-2 & I & I & II & II & III & III & IV & IV \\ \cline{1-1}  & SDB-3 & I & I & I & I & I & I & I & II \\ \hline \hline \end{tabular}  
* Failure of the connection (C/T clip, hanger). 2 Failure of the cross T-bar connection (C/T clip, hanger has not dropped out).  
\end{table} 
Table 7: Percentage of the damaged panels and the performance level of the ceiling system. Figure 18: Cause of damage for the panel falling. (**a**) Panel dislodged and hanging because of the relative displacement of the grid member. (**b**) Failure of the anti-falling clip due to the impact. gypsum panels, which are widely used, a dropping rate of less than 5% may not affect the safety, but in the case of the steel panels, even if only one is dropped, it may cause personal injury. For Test 2 (0.864 g), which is 100% of the artificial seismic wave that is required by KDS 41 17 00, the performance level of all the ceiling systems was confirmed to satisfy the life safety level as I. In addition, the system did not completely collapse until the final stage of all the specimens. The 4 ea of SDB-2 that is shown in the connection failure section of Table 7 indicates that the cross T-bar has fallen off. This is different from the fact that the USD dropped from the C/T clip. SDB-3 is mechanically jointed between the main T-bar and the cross T-bar through a connection, but SDB-2 is only bonded with the clip that is attached to the cross T-bar. Figure 19 shows the connection failure of SDB-2 and the connection and mechanical joint that is used in SDB-3. In the USD in Test 8 (2.16 g), the joint was broken and some of the main T-bars were eliminated. In addition, the performance level was evaluated as IV. The performance level of SDB-2 was determined because the panel fell with a relatively lower level of acceleration than the other specimens.