Modeling and seismic evaluation of nonstructural components: Testing frame for experimental evaluation of suspended ceiling systems
Ryu, Ki Pung
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In the last decades it was clear that suspended ceiling systems failing in earthquakes endanger safety and impede continuous operations of building structures. In order to evaluate the seismic performance of the suspended ceiling systems and provide better understanding in their seismic design, shaking table tests were conducted for more than a decade. The purpose of this thesis is developing a new testing facility for use with single or tandem shake tables for the evaluation of suspended ceilings and other components. A large reconfigurable frame of 20 ft. by 50 ft. was developed to test a continuous suspended ceiling of up to 1,000 ft 2 . The frame has dynamic characteristics with variable frequencies to match those typical to floors and roofs suspending of ceilings and typical to construction walls. Analytical models are developed using the structural analysis program SAP2000 in order to estimate the dynamic properties of the frame 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 deliver accurately a desired “floor motion” at a desired location in a structure. A special open loop procedure, which provides a compensated command “drive” signal to a shake table in order to obtain a “target floor motion spectrum” at the roof level, was proposed and verified experimentally. The combined designs of the physical frame and the shake table motion allow for testing a variety of suspended systems while simulating more realistic floor motions and eliminating side effects of wall distortions. This study describes the design of the frame and introduces the procedure for motion design which can be implemented also in other experimental facilities.