A substructural shake table testing method for full-scale nonstructural elements

The seismic performance of nonstructural elements is crucial for buildings to remain functional during and after earthquakes. Since the seismic damage to many nonstructural elements is sensitive to their acceleration and/or velocity responses, dynamic testing becomes inevitable in assessing their seismic performance. We propose a novel experimental method that enables the dynamic testing of various layouts of nonstructural elements through a passively controlled and adaptable testbed mounted on and driven by a shake table. The testbed is made of three consecutive floors of steel structure. The bottom two floors provide a space to accommodate a full-scale room. The third floor on top adds additional degrees of freedom for the ease of tuning the dynamic properties of the testbed. The input motion of the shake table is generated by an offline control algorithm to drive the testbed so that its bottom two floors trace the time histories of target floor motions of the building of interest. This paper introduces the key aspects of the new method, including the derivation of the desired structural properties of the testbed, and the control algorithm that generates the necessary input motion of the shake table. An example of simulating the motions of two consecutive floors in the middle of a 42-story tall building is adopted to assist illustrating and validating the method by numerical simulation and experimental demonstration.