Near‐fault pulse‐type ground motions have characteristics that are substantially different from ordinary far‐field ground motions. It is essential to understand the unique effects of pulse‐type ground motions on structures and include the effects in seismic design. This paper investigates the effects of near‐fault pulse‐type ground motions on the structural response of a 3‐story steel structure with nonlinear viscous dampers using the real‐time hybrid simulation (RTHS) testing method. The structure is designed for 75% of the code‐specified design base shear strength. In the RTHS, the loop of action and reaction between the experimental and numerical partitions are executed in real time, accurately capturing the velocity pulse effects of pulse‐type ground motions. A set of 10 unscaled pulse‐type ground motions at the design basis earthquake (DBE) level is used for the RTHS. The test results validated that RTHS is a viable method for experimentally investigating the complicated structural behavior of structures with rate‐dependent damping devices, and showed that the dampers are essentially effective in earthquake hazard mitigation effects involving pulse‐type ground motions. The average peak story drift ratio under the set of pulse‐type ground motions is 1.08% radians with a COV value less than 0.3, which indicated that structural system would achieve the ASCE 7–10 seismic performance objective for Occupancy Category III structures under the DBE level pulse‐type ground motions. Additionally, a nonlinear Maxwell model for the nonlinear viscous dampers is validated for future structural reliability numerical studies involving pulse‐type ground motions.
Multi-directional Seismic Behavior Assessment of a Tall Building using Real-Time Hybrid Simulations
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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- Award ID(s):
- 2037771
- NSF-PAR ID:
- 10344047
- Date Published:
- Journal Name:
- 12th National Conference on Earthquake Engineering
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract -
This paper investigates the effects of near-fault pulse-type ground motions on the structural response of a 3-story steel structure with nonlinear viscous dampers using the real-time hybrid simulation (RTHS) testing method. The real time loop of action and reaction between the experimental and numerical partitions executed in the RTHS enabled the accurate capturing of the velocity pulse effects of pulse-type ground motions. An ensemble of 10 natural pulse-type ground motions at the design basis earthquake (DBE) level is used for the RTHS. The accuracy of RTHS under high velocity loading is demonstrated, and thereby, is a validated method for experimentally investigation of the complicated structural behavior of structures with rate-dependent damping devices. The test results showed that the dampers are essentially effective in earthquake hazard mitigation effects involving pulse-type ground motions. The average peak story drift ratio under the set of pulse-type ground motions is 1.08% radians with a COV value less than 0.3, which indicates that the investigated structure would achieve the ASCE 7-10 seismic performance objective for Occupancy Category III structures under the DBE level pulse-type ground motions.more » « less
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The system under investigation is a 2-story reinforced concrete building. Nonlinear viscous dampers were placed at the 1st and 2nd stories. The building was subjected to the maximum considered earthquake hazard levels. The outcome of the tests is to assess a newly developed explicit non-iterative formulation for the nonlinear viscous damper model and the ability of the unscented Kalman filter to identify and update the damper parameters in order to improve the model’s prediction of the damper force. The data collected from the tests can be reused by replaying the real-time hybrid simulation offline, where all of the response quantities of the building can be retrieved.more » « less
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The system under investigation is a 40 story building. Real-time hybrid simulations (RTHSs) were performed on the building, where the entire façade of the structure is subjected to wind loading over a 360 second duration. Nonlinear viscous dampers between the outrigger truss and perimeter columns are placed at stories 20th and 30th. The outcome of the tests is to assess the ability of the damped outrigger system to suppress undesirable floor accelerations. The data collected from the tests can be reused by replaying the real-time hybrid simulation offline, where all of the response quantities of the building can then be retrieved. The data can be reused to study the response of tall buildings with outriggers and passive dampers subjected to wind natural hazards.more » « less
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The system under investigation is a 40 story building. Real-time hybrid simulations (RTHSs) were performed on the building, where the structure is separately subjected to multi-natural hazards consisting of a 110 mph sustained wind storm and 43 second earthquake. Nonlinear viscous dampers between the outrigger truss and perimeter columns are placed at stories 20th and 30th. The outcome of the tests was to assess the ability of the damped outrigger system to suppress undesirable floor wind accelerations and reduce earthquake story drift and damage. The data collected from the tests can be reused by replaying the real-time hybrid simulation offline, where all of the response quantities of the building can be retrieved. The data can be reused to study the response of tall buildings with outriggers and passive dampers subjected to wind and earthquake natural hazards.more » « less
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Accepted Manuscript1.0
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