Modeling and Seismic Evaluation of Nonstructural Components: Testing Frame for Experimental Evaluation of Suspended Ceiling Systems

In the last few decades, it has become clear that failure of suspended ceiling systems in earthquakes endangers safety and impedes continuous operation of a building. In order to evaluate the seismic performance of suspended ceiling systems and provide a better understanding of their seismic design, many shaking table tests have been conducted. However, there were many limitations in these tests, due to the size, frequency limits and work limitations of currently used testing frames. The purpose of this report is to describe the development of a new testing facility for use with single or tandem shake tables to evaluate suspended ceilings and other nonstructural components. A large reconfigurable frame of 20 ft. by 50 ft. was developed to test a continuous suspended ceiling of up to 1,000 ft2. The frame has dynamic characteristics with variable frequencies to match those typical of floors and roofs with suspended ceilings. Analytical models were developed using the structural analysis program SAP2000 to estimate the dynamic properties and complete the design of the frame. Since a test frame has flexibilities and a test system is not perfect, the frame as built cannot accurately deliver a desired “floor motion” at a specific location in a structure. A special open loop procedure, which provides a compensated command “drive” signal to a shake table to obtain a “target floor motion spectrum” at the roof level of the test frame, was proposed and verified experimentally. The combined designs of the physical frame and the shake table motion allow for testing of a variety of suspended systems while simulating more realistic floor motions and eliminating side effects caused by wall distortions. This study describes the design of the frame and introduces the procedure for motion design which can also be implemented in other experimental facilities.