# Performance Evaluation of Rigid Braced Indirect Suspended Ceiling with Steel Panels
## 1 Introduction
As shown in Figure 2, the brace system has a strut-tie system that uses wires and a rigid brace with high-rigidity members. In the ASTM E580/E580M, both the strut-tie brace and rigid brace that are shown in Figure 2 are presented. In Figure 2a, the hanging member and brace are mainly constructed to respond to the tensile forces by using wires and to take charge of the compression force by using vertical struts. In Figure 2b, when considering a suspended member, the load in the gravitational direction of the ceiling is in charge, and the brace is responsible for the tensile and compressive forces. In countries that use direct suspended ceilings, such as the United States, most braces use wires. Meanwhile, for Japan, which mostly uses indirect suspended ceilings, rigid braces are often used. However, for all brace systems overseas, the end clearance and separation distances of the braces for the installation are not provided in detail. Research cases for ceiling systems that apply braces are also extremely rare. In addition, the exact construction methods, such as the above standards and specifications, have not been presented. The representative studies of the ceiling systems that apply braces are described as follows. Figure 1: Damage case of ceiling system due to Pohang earthquake in Pohang Station. [PERSON] et al. [5] analyzed the existing earthquake damage cases and the criteria that are applied to the ceiling, and compared them to prior case studies. In addition, a shaking table experiment was performed according to the brace installation method that was suggested by the Ceilings & Interior Systems Construction Association (CISCA) and ASCE7, and a fragility curve was prepared. From the experimental results, it was confirmed that the acceleration was amplified more than the acceleration in the vertical direction that was suggested by the standard. It was also confirmed that it is different from the damage pattern for earthquake damage. [PERSON] et al. [6] analyzed a ceiling system in which a brace was applied in a quasi-static experiment through repeated loading. For different vibration periods depending on the ceiling installation height, the elastic displacement and acceleration that used the displacement base were evaluated. A brace system and its accessories were introduced, and these can be directly applied to the suspension. [PERSON] et al. [7] studied steel-panel suspended ceilings, conducting tests with steel and gypsum panels while varying the application of perimeter clips and the thickness of the suspension wires. The results of their tests showed the definition of the performance level of the ceiling system. These research cases that were previously described are similar to the T-bar products in Korea; however, most of them use direct suspended ceilings and, as shown in Figure 3a, the method of installing finishing materials is different. As a result, it is difficult to apply them in practice. In addition, there is a paucity of studies on ceiling systems with braces. Similarly, studies on the actual application method and behavior of the rigid brace as suggested in the standards are also scant. In this study, a shaking table test was performed. This was achieved by applying a brace to a ceiling system of steel panels of which the indirect suspended ceiling is mainly used in Korea. The test specimens were subjected to different end clearances, joints, and brace installation intervals. These specimens were analyzed and compared to the experimental results from a previous study [8], which describes the non-seismic ceiling system. The basis for this study is the KDS 41 17 00 in Korea, which is similar to ASCE7-16 in the United States. In addition, a rigid brace-based seismic ceiling system that is suitable for the Korean situation is proposed, and its performance is evaluated by performing a shaking table test. As shown in Figure 3c, the specimens used