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Damage caused by earthquakes to buildings and their contents (e.g., sensitive equipment) can impact life safety and disrupt business operations following an event. Floor isolation systems (FISs) are a promising retrofit strategy for protecting vital building contents. In this study, real‐time hybrid simulation (RTHS) is utilized to experimentally incorporate multi‐scale (building–FIS–equipment) interactions. For this, an experimental setup representing one bearing of a rolling pendulum (RP) based FIS is studied—first through characterization tests and then through RTHS. A series of tests was conducted at the Natural Hazards Engineering Research Infrastructure (NHERI) Experimental Facility at Lehigh University. Multiple excitations were used to study the experimental setup under uni‐axial loading. Details of the experimental testbed and test protocols for the characterization and RTHS tests are presented, along with results from these tests, which focused on the effect of different rolling surface treatments for supplemental damping, the FIS–equipment and building–FIS interactions, and rigorous evaluation of different RP isolation bearing designs through RTHS.

 

Protecting both the essential building contents and the structural system—as well as facilitating and accelerating the post-event functionality of business operations—is a major concern during natural hazards. Floor isolation systems (FIS) with rolling pendulum bearings along with nonlinear fluid viscous dampers (NFVD) have been proposed to mitigate damage and enhance the resiliency of non-structural and structural systems, respectively. These devices are designed to decrease vibrations under dynamic loading conditions. In this poster, we introduce research using tridimensional nonlinear cyber-physical experimental testing (i.e., real-time hybrid simulations) to validate the performance of these response modification devices placed in structural systems under wind and earthquake loading conditions. The effects of soil-structure-foundation and fluid-structure interactions were also accounted for. The novelty of the project is the use of multi-directional large-scale real-time hybrid simulations of complex nonlinear systems under wind and earthquake demands to combine experimental structural modification passive devices with analytical multi-story buildings considering soil-foundation interaction via neural network. Results show that the FIS and NFVD can significantly reduce the demand on non-structural and structural systems of buildings subjected to natural hazards whose response can be also significantly affected by soil-foundation-structure interaction. A product of this research is the data (which is linked in Related Works), which can be used to compare with new studies using the same experimental techniques and structural modification devices or with alternative approaches. Researchers interested in multi-natural hazards resilience and mitigation, state-of-the-art structural experimental techniques, and the use of machine learning as a tool to improve modeling efficiency will benefit from its results. Also, companies dedicated to the commercial development of structural response modification devices, as well as policymakers working or with interest in economic and social resilience. 

Rolling-pendulum (RP) isolation bearings with different surface treatments were tested under quasi-static, harmonic, and simulated earthquake-induced motions. These tests were used to characterize the behavior of the RP bearings, including the gravitational restoring force and the rolling resistance associated with the elastomeric coatings of different thicknesses. The experimental data from analog sensors and cameras is archived here, as documented in the data report. 

This project provides an in-depth study into how floor isolation systems (FISs) perform when subjected to floor accelerations from a 3D building model of a special concentrically steel braced frame (SCSBF) building during real-time hybrid simulation (RTHS). The project details the creation and study of a 3D model of a SCSBF building using HyCoM-3D, a 3D modeling software created for use at the NHERI Lehigh Experimental Facility. Data in this project can be reused to further assess how FISs behave when subjected to accelerations and their ability to isolate large nonstructural components of buildings and lessen their damage when subjected to different accelerations due to different building configurations. This project is unique because it considers the multi-directional response of a FIS subjected to floor motions simulated from a 3D, nonlinear model of a SCSBF building. The main audience is researchers and professionals interested in learning more about how FISs can limit damage to nonstructural building components. 

Participated in a research project that involved multi-directional shake table preparation for future characterization testing of the rolling pendulum floor isolation system to understand its performance. This involved performing kinematics validation of the shake table to develop the actuator control system that will be used in future tests. The results of the future characterization tests will be used in the first multi-directional real-time hybrid simulation test for the rolling pendulum floor isolation system in the Lehigh University ATLSS Engineering Research Center. The efforts done contribute to the earthquake engineering community.