• Proceedings of the KSR Conference
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• 2005.11a
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• pp.1261-1267
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• 2005

At this paper Dynamic respones of bridges for the Korean high-speed railway are analyzed by a modal analysis. To control vibration of bridges, Tuned Mass Damper(TMD) that is passive type control device is used. Opimize and prove it. Newmark method is used for a numerical analysis. In case of vehicle is modeled for moving mass that considers the effects of the moving. Also this paper is assumped as the simple supported Bernoulli-Euler beam and considered two dimensional Interaction motion between vehicle and bridge.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.399-408
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• 2000

IN analyzing earthquake response of structures important focus is on their diaplacements and shear forces. However seismic technology of passive energy dissipation makes focus on the seismic energy distribution of structures. The passive dampers enhance the capability of energy dissipation by their hysteretic behavior thus preventing the structural plastic deformation. In this paper the building structure with an active controller is analyzed with the view of earthquake energy distribution under elastic and plastic behaviors. The active control makes an effect of increasing damping capability which absorbs most of the earthquake input energy. Finally the different active gains resulting from the plastic deformation are applied to the active analysis and control forces and earthquake energy response are compared.

• Smart Structures and Systems
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• v.16 no.3
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• pp.459-478
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• 2015

The design of a passive control solution based on tuned mass dampers (TMD's) requires the estimation of the actual masses involved in the undesired vibration. This task may result not so straightforward as expected when the vibration resides in subsets of different structural components. This occurs, for instance, when the goal is to damp out vibrations on stays. The theoretical aspects are first discussed and a design process is formulated. For sake of exemplification, a multiple TMD's configurations is eventually conceived for an existing timber footbridge located in the municipality of Trasaghis (North-Eastern Italy). The bridge span is 83 m and the deck width is 3.82 m.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.360-367
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• 2003

This paper presents passive vibration control method to suppress train-induced vibration on a long-span steel arch bridge. According to the train load frequency analysis, undesirable resonance of a bridge will occur when the impact frequency of the train axles are close to the modal frequencies of the bridge. Because the first mode shape of the long-span steel arch bridge may take anti-symmetric shape along the bridge direction, however, the optimal control configuration for resonance suppression should be considered carefully In this study, bridge-vehicle element is used to estimate the bridge-train interaction precisely. From the numerical simulation of a loom steel arch bridge under TGV-K train loading, dynamic magnification influences are evaluated according to vehicle moving speed and efficient control system with passive dampers are presented in order to diminish the vertical displacement and vertical acceleration.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.453-460
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• 2006

Stay cables, such as used in cable-stayed bridges, are prone to vibration due to their low inherent damping characteristics. Recently some studies have shown that active and semiactive control system using MR damper can potentially achieve both higher performance levels than passive control system and adaptability with few of the detractions. However, a control system including a power supply, controller, and sensors is required to maximize the performance of the MR damper and this complicated control system is not effective to most of large civil structures. This paper proposes a smart complex damping system which consists of toggle system and MR dampers by introducing electromagnetic induction(EMI) system as an external power source to MR damper. The performance of the proposed damping device has been compared with that of the passive-type control systems employing a MR damper, a linear viscous damper, and EMI system.

• Structural Engineering and Mechanics
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• v.41 no.6
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• pp.791-803
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• 2012

Significant structural damages due to pounding between adjacent superstructures of multi-span reinforced concrete (RC) highway bridges have been observed in past earthquakes. Different methods have been proposed in the literature to mitigate the adverse seismic pounding effects. This paper presents an analytical investigation on the use of magnetorheological (MR) dampers in reducing seismic pounding effects of base-isolated multi-span RC highway bridges. It has been observed that MR damper can effectively reduce the seismic pounding effect. Three control strategies (passive off, passive on, and bang bang control) of MR damper have been investigated. Although all the control strategies are found to be effective, bang bang control has been observed to be the most effective.

• International Journal of High-Rise Buildings
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• v.10 no.2
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• pp.99-107
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• 2021

This research investigates the potential of Adaptive TMDs for tall building damping. The Adaptive TMD under consideration is based on real-time controlled hydraulic dampers generating purely dissipative control forces. The control approach is designed to enhance the Adaptive TMD efficiency for moderate wind loads with return periods below 50 years. The resulting enhanced TMD efficiency is used to reduce the pendulum mass by 15% compared to the passive TMD while still guaranteeing the acceleration limits of the one and ten year return period winds. Furthermore, the adaptive control approach is designed to disproportionally increase the controlled damping force at wind loads with return periods of 50 years and more in order to reduce the maximum relative motion of the Adaptive TMD with only 85% pendulum mass. Compared to the passive TMD with 100% pendulum mass the maximum relative motion is reduced by 20%. Both the pendulum mass reduction and the maximum relative motion reduction significantly reduce the foot print of the Adaptive TMD which is highly desirable from the economic point of view.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.37-46
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• 2006

In this study, the efficacy of the newly developed smart passive control system to improve seismic performance of base isolated building structures is numerically verified. The smart passive control system consists of a magnetorheological (MR) damper and an electromagnetic induction (EMI) part. The damping characteristics of an MR damper can be controlled by the current generated in an EMI part according to the Faraday's law of electromagnetic induction. An EMI part consisting of a permanent magnet and a solenoid coil could substitute a control system including sensors, a controller and an external power supply in a conventional smart control system. The benchmark control problem for a base isolated building presented by the american society of civil engineers is considered for numerical simulation. The control performance of the smart passive control system is compared to that of the conventional smart control system using MR dampers. It is demonstrated from the numerical simulation results that the smart passive control system is useful to improve the seismic performance of base isolated buildings.

• Earthquakes and Structures
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• v.15 no.3
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• pp.227-241
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• 2018

The present paper deals with the optimum performance of the passive hybrid control system for the benchmark highway bridge under the six earthquakes ground motion. The investigation is carried out on a simplified finite element model of the 91/5 highway overcrossing located in Southern California. A viscous fluid damper (known as VFD) or non-linear fluid viscous spring damper has been used as a passive supplement device associated with polynomial friction pendulum isolator (known as PFPI) to form a passive hybrid control system. A parametric study is considered to find out the optimum parameters of the PFPI system for the optimal response of the bridge. The effect of the velocity exponent of the VFD and non-linear FV spring damper on the response of the bridge is carried out by considering different values of velocity exponent. Further, the influences of damping coefficient and vibration period of the dampers are also examined on the response of the bridge. To study the effectiveness of the passive hybrid system on the response of the isolated bridge, it is compared with the corresponding PFPI isolated bridges. The investigation showed that passive supplement damper such as VFD or non-linear FV spring damper associated with PFPI system is significantly reducing the seismic response of the benchmark highway bridge. Further, it is also observed that non-linear FV spring damper hybrid system is a more promising strategy in reducing the response of the bridge compared to the VFD associated hybrid system.

• Steel and Composite Structures
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• v.28 no.6
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• pp.691-708
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• 2018

An innovative Hybrid Passive Resistive configuration for Truss Girder Frames (HPR-TGFs) is introduced in the present study. The proposed system is principally consisting of Fluid Viscous Dampers (FVDs) and Buckling Restrained Braces (BRBs) as its seismic resistive components. Concurrent utilization of these devices will develop an efficient energy dissipating mechanism which is able to mitigate lateral displacements as well as the base shear, simultaneously. However, under certain circumstances which the presence of FVDs might not be essential, the proposed configuration has the potential to incorporate double BRBs in order to achieve the redundancy of alternative load bearing paths. This study is extending the modern Direct Displacement Based Design (DDBD) procedure as the design methodology for HPR-TGF systems. Based on a series of nonlinear time history analysis, it is demonstrated that the design outcomes are almost identical to the pre-assumed design criteria. This implies that the ultimate characteristics of HPR-TGFs such as lateral stiffness and inter-story drifts are well-proportioned through the proposed design procedure.