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Large-scale multi-directional real-time hybrid simulations (RTHS) are used to assess the maximum considered earthquake (MCE) seismic performance of a 40-story steel building equipped with supplemental nonlinear viscous dampers. These dampers are placed between outrigger trusses and the perimeter columns of a building that was part of the inventory for the California Tall Building Initiative (TBI) PEER study. The analytical substructure for the RTHS consists of a 3-D nonlinear model of the building while the experimental substructure consists of a full scale nonlinear viscous damper. Other dampers in the structure are analytically modelled using an online explicit model updating scheme where the physical damper is used to obtain the parameters of the analytical damper models during the RTHS. The displacement, residual drift, and ductility demand are found to be reduced by adding the dampers to the outrigger, but only in the direction of the plane of the outriggers. Higher modes, including torsional modes, contribute to the 3-D seismic response.
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REAL TIME HYBRID SIMULATION (RTHS) OF A 2-STORY BUILDING EQUIPPED WITH NOVEL BASE ISOLATION SYSTEMS
A new friction device using band brake technology, termed the Banded Rotary Friction Damper (BRFD), has been fabricated at the NHERI Lehigh Experimental Facility. The damping mechanism is based on band brake technology and leverages a self-energizing mechanism to produce large damping forces with low input energy. The device is a second-generation BRFD, where the friction mechanism is achieved using two electric actuators. The BRFD generates a damping force as a function of the input force provided by the electric actuators, where the ratio of BRFD force output-to-electric actuator force input is equal to about 112. The paper presents the results of a study using real-time hybrid simulations (RTHS) to investigate the performance of the BRFD’s in mitigating seismic hazards of a two-story reinforced concrete building. The building has two and three special moment resisting frames (SMRFs) in the east-west and north-south directions, respectively. In order to perform the RTHS, the north south SMRF is considered and the BRFD along with a parallel elastic member is used as a base isolation system to mitigate the effects of earthquake hazards by reducing story drift and floor accelerations of the structure. For the RTHS the building and the elastic component of the isolator are part of the analytical substructure while the experimental substructure is comprised of the BRFD. The response of the structure is investigated involving six Maximum Considered Earthquake (MCE) hazard level events that includes three near-field and three far-field ground motions. The explicit, unconditionally stable dissipative Modified KR-α integration algorithm is used to accurately integrate the equations of motion during the RTHS. The model for the reinforced concrete building is created using explicit non-linear force-based fiber elements to discretely model each member of the structure. First, the details of the prototype of the BRFD are presented. Second, the details of the isolator system consisting of a linear spring element and the BRFD are discussed. Finally, the details of the RTHS study and the results are presented. The building’s inter-story peak and residual story drift from base-isolated and fixed-based conditions are compared. Results show that the proposed isolator system produces a significant reduction in both maximum inter-story drift and residual drift, and reduces the damage developed in the structure during the MCE.
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- Award ID(s):
- 2037771
- PAR ID:
- 10562140
- Publisher / Repository:
- WCEE2024
- Date Published:
- Journal Name:
- World Conference on Earthquake Engineering proceedings
- ISSN:
- 3006-5933
- ISBN:
- 978-1-119-61942-0
- Format(s):
- Medium: X
- Location:
- Milan, Italy
- Sponsoring Org:
- National Science Foundation
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