Seismic isolation is widely used in the structures to dissipate the destructive energy of an earthquake by decoupling the superstructure from the ground. High-damping rubber (HDR) devices, as a type of energy dissipat...
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Seismic isolation is widely used in the structures to dissipate the destructive energy of an earthquake by decoupling the superstructure from the ground. High-damping rubber (HDR) devices, as a type of energy dissipating device, used in structural systems to control the structural response under energetic excitations such as earthquakes. This paper uses the Weakening and Damping (WeD) scheme to realize a modified approach in reducing all of the structural responses simultaneously. By this modification, Negative Stiffness Devices (NSDs) are used for the weakening phase to lessen lateral strength. The HDR device is used as a part of NSDs components. HDR generates a high damping force to establish a modified "Weakening and High Damping" (WeHD) concept and gain optimal performance in the overall structural responses. Use of the HDR in seismic base isolation not only prevents permanent deformation under strong motions but also works as an energy dissipating device even during the small ambient vibrations. Since the structure could be unstable by using NSDs, MR dampers are added to preserve stability. An inverse model is employed to command MR dampers by adjusting the voltage and generating the desired control forces. To further verify the proposed WeHD device, a smart base-isolated benchmark building framework is used. Based on the results, the proposed Weakening and High Damping (WeHD) approach not only reduces base displacements, accelerations, and shear but also leads to a reduction in the accelerations and inter-story drifts of the superstructure.
Strong seismic events commonly cause large drift and deformation, and functionality failures in the superstructures. One way to prevent functionality failures is to design structures which are ductile and flexible thr...
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Strong seismic events commonly cause large drift and deformation, and functionality failures in the superstructures. One way to prevent functionality failures is to design structures which are ductile and flexible through yielding when subjected to strong ground excitations. By developing forces that assist motion as "negative stiffness forces", yielding can be achieved. In this paper, we adopt the weakening and damping method to achieve a new approach to reduce all of the structural responses by further adjusting damping phase. A semi-active control system is adopted to perform the experiments. In this adaptation, negative stiffness forces through certain devices are used in weakening phase to reduce structural strength. Magneto-rheological (MR) dampers are then added to preserve stability of the structure. To adjust the voltage in MR dampers, an inverse model is employed in the control system to command MR dampers and generate the desired control forces, where a velocity control algorithm produces initial required control force. An extensive numerical study is conducted to evaluate proposed methodology by using the smart base-isolated benchmark building. Totally, nine control systems are examined to study proposed strategy. Based on the numerical results of seven earthquakes, the use of proposed strategy not only reduces base displacements, base accelerations and base shear but also leads to reduction of accelerations and inter story drifts of the superstructure. Numerical results shows that the usage of inverse model produces the desired regulated damping, thus improving the stability of the structure.
High-damping rubber bearing isolator (HDR) has become as an effective device to enhance the seismic resistance for ridge, the lead rubber isolators (LRB) as well. However, the dynamic characteristics of the HDR isolat...
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ISBN:
(纸本)9787030357878
High-damping rubber bearing isolator (HDR) has become as an effective device to enhance the seismic resistance for ridge, the lead rubber isolators (LRB) as well. However, the dynamic characteristics of the HDR isolators have not always been clarified so far because of their scatter nature of mechanical properties and the lack of reliable test data. In this study, new type of HDR isolator is tested dynamically under different conditions. Using the test results, the relationships between the equivalent stiffness, damping ratio and number of cycles as well as the magnitude of shear strain were examined.
In this study, the developed real-time substructure hybrid earthquake loading test system for verification tests of rubber bearings for highway bridges and viaducts is studied. A series of the fast/real time substruct...
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ISBN:
(纸本)9787030357878
In this study, the developed real-time substructure hybrid earthquake loading test system for verification tests of rubber bearings for highway bridges and viaducts is studied. A series of the fast/real time substructure hybrid earthquake loading tests on NR (natural rubber), HDR (high-damping rubber), and HDR-S (super-high-damping rubber) bearings specimens are presented. The test system utilizes the concepts of the real-time pseudodynamic test method and the substructure technique to combine the loading process of rubber bearing specimens and numerical modeling of bridge column and girders. The objective of the development of the test system is to pursue accurate prediction of the seismic response and investigate the isolation effects of rubber bearings considering the loading rate effects subject to earthquake ground motion.
In this study,the developed real-time substructure hybrid earthquake loading test system for verification tests of rubber bearings for highway bridges and viaducts is studied.A series of the fast/real-time substructur...
详细信息
ISBN:
(纸本)9787030357878
In this study,the developed real-time substructure hybrid earthquake loading test system for verification tests of rubber bearings for highway bridges and viaducts is studied.A series of the fast/real-time substructure hybrid earthquake loading tests on NR(natural rubber),HDR (high-damping rubber),and HDR-S(super-high-damping rubber) bearings specimens are presented. The test system utilizes the concepts of the real-time pseudodynamic test method and the substructure technique to combine the loading process of rubber bearing specimens and numerical modeling of bridge column and *** objective of the development of the test system is to pursue accurate prediction of the seismic response and investigate the isolation effects of rubber bearings considering the loading rate effects subject to earthquake ground motion.
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