캔틸레버식 교통신호 매스트암의 극한하중 시험

허광희,황충열 충북대학교 건설기술연구소 1997 建設技術論文集 Vol.16 No.1

Development of Viscoelastic Damper System to Improve Seismic Performance of Storage Racks

허광희,최형석,백은림,김충길 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.9

Storage racks are nonstructural components mainly designed to support the vertical load of goods. During strong external loads such as an earthquake, which acts in the lateral direction of the racks, stored goods become structurally vulnerable. To identify and reinforce the vulnerable parts of storage racks and improve their seismic performance, we developed a viscoelastic damper system with a capacity designed for storage racks. First, we performed an experiment to analyze the behavioral characteristics of a pallet rack — a representative storage rack used for large goods — under vibration. Based on the results of the experiment, we chose the members of storage racks that were vulnerable to vibration. For the proper seismic reinforcement of vulnerable members, we developed a viscoelastic damping system for storage racks by calculating the structural shear force on each floor of the rack and the capacity of the damper to distribute the shear force. First, three viscoelastic dampers of different capacities were fabricated using a viscoelastic material and subjected to cyclic loading tests to evaluate their mechanical performance. We determined the position on which the damper should be placed to improve the rack’s seismic performance by considering the shear force on each floor of the storage rack and its operational characteristics. Finally, we conducted a shaking table test to verify the new viscoelastic damper system. The system improves the seismic performance of storage racks by controlling their elastic and permanent deformations.

Steel Plate Girder교량의 동특성 분석을 위한 FE모델

허광희,이규,신형철,전준룡,김만구 한국구조물진단유지관리학회 2002 한국구조물진단학회 학술발표회논문집 Vol.- No.-

실시간 무선 진동제어 시스템 개발

허광희,안의종 청운대학교 건설환경연구소 2011 청운대학교 건설환경연구소 논문집 Vol.6 No.2

This paper aims to constitute a feedback vibration control system using wireless sensor networks and experiment it on a model structure to verify its effectiveness. The vibration control experiment was performed by shaking the 1/4 point of beam with a shaker. At the moment of shaking, we controled the vibration with MR damper which was placed vertically on the center of beam. Simultaneously, by acquiring acceleration response at the 2/4 point of beam, we evaluated the effectiveness of control capability. Although the realtime feedback vibration control system constituted in this paper is effective only within a limited command system, it has been proven that the system was able to effectively decrease the vibration of structure by generating a control command aimed for realtime purpose. The system also showed a possibility to be used as a structural response control system adapting a variety of semi-active control algorithm. 본 논문에서는 무선 진동제어 시스템을 구성하고, 모형 구조물을 대상으로 구성된 시스템의 진동제어효과를 실험적으로 검증하고자 하였다. 진동제어 실험은 가진기를 이용해 보의 1/4 등분점에서 일정하게 가진한 상태에서, 보 중앙점에 수직방향으로 설치된 MR 댐퍼를 이용해 진동을 제어하였으며, 보의 2/4 등분점에서의 가속도 응답을 획득하여 제어효과를 평가하였다. 최종적으로 본 논문에서 구성된 무선 센서 네트워크 기반의 실시간 피드백 진동제어 시스템은 비록 제한적인 명령 체계에서 검증되었지만, 실시간적으로 목적된 제어명령의 발생시킴으로써 구조물의 진동을 효과적으로 감소시키는 것을 확인하였고, 추후 다양한 준능동 제어 알고리즘을 적용한 구조적 응답 제어시스템으로의 활용 가능성을 제시하였다.

Application of Unified Lyapunov Control Algorithm and Mathematical Demonstration for Structure Control

허광희,전준용 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.3

This paper presents a new algorithm which is applicable in designing a smart damping system for vibration mitigation. The algorithm, which is extended into a unified system from Lyapunov stability theory, enables us to decrease the errors by its increased stability. The validity of this design method was proved in the experiment on a control model of three-storied building structure. Smart damper was used for MR (Magneto-Rheological fluid) damper in the experiment, and its control effectiveness was evaluated. In order to make a more accurate control model mathematically, we updated the model on the basis of the analysis of dynamic characteristics of structure and of the mathematical analysis of a lumped mass model, and then employed a state space model redefined by structural property matrix. Using this improved control model, control effect on structures that were under the influence of each different earthquake magnitude was analyzed with various performance indexes, and thus the algorithm presented here is proved to be valid.

A Smart Monitoring System Based on Ubiquitous Computing Technique for Infra-structural System: Centering on Identification of Dynamic Characteristics of Self-Anchored Suspension Bridge

허광희,전준용 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.5

In this paper, a smart monitoring system for infra-structure is developed with an integrated management system using ubiquitous computing techniques. This system is designed to enable to use TCP/IP network protocol, communicating the data measure by a wireless sensing unit based on Bluetooth technology. In order to verify this system, a randomly excited self-anchored suspension bridge is tested for real time monitoring by remote network user. Dynamic characteristics are identified to construct an integrity structure using the acquired data from the monitoring test. In this paper, a smart monitoring system for infra-structure is developed with an integrated management system using ubiquitous computing techniques. This system is designed to enable to use TCP/IP network protocol, communicating the data measure by a wireless sensing unit based on Bluetooth technology. In order to verify this system, a randomly excited self-anchored suspension bridge is tested for real time monitoring by remote network user. Dynamic characteristics are identified to construct an integrity structure using the acquired data from the monitoring test.

대피 공간 확보를 위한 이상물검출 시스템 및 모니터링 시스템 개발

허광희,전승곤,김기완,이재훈,김대혁 한국재난정보학회 2021 한국재난정보학회 학술대회 Vol.2021 No.11

고층 아파트와 같은 공동주택은 저층의 단독주택과는 달리 화재 발생 시 신속하고 안전한 대피가 어렵다. 따라서 이러한 공 동주택은 거주자들이 신속하게 대피할 수 있는 별도의 대피공간을 의무적으로 설치하도록 규정하고 있다. 그러나 안전 불감증 으로 인하여 일부 거주자들은 대피공간에 평상 시 이상물을 적재함으로써 상시 안전공간으로 확보되어야 하는 대피공간이 창 고역할을 하면서 제 기능을 발휘하지 못하고 있다. 따라서 본 연구에서는 평상시 대피공간의 확보를 통하여 화재발생 시 신속한 대응을 할 수 있도록 대피공간 내의 이상물 검출시스템 및 모니터링 시스템을 개발하였다. 또한, 개발된 시스템은 대피공간을 모형화한 구조물에 적용하여 이상물 검출 및 모니터링 성능을 검증하였다.

진동 제어 방향에 따른 MR-damper의 제어 성능 비교

허광희,김충길,전승곤,안의종 한국구조물진단유지관리학회 2012 한국구조물진단학회 학술발표회논문집 Vol.2012 No.1

In this paper, an experimental research was carried out to compare the capability to control a MR-damper attached structure, which turned out to differ according to its vibration control direction whether vertical or horizontal. The target structure for the experimental test was a real size asymmetrical cable-stayed bridge. The MR-damper for vibration control was designed 30KN to fit into the target bridge. For the performance experiment of the MR-damper, the el-centro earthquake wave using three shaking table was inflicted on the model bridge structure, once horizontally and then vertically. Finally, each control capability, different according to its direction, was compared and evaluated. The experiment proved that the MR-damper was able to damp in a different way according to its control direction(horizontal or vertical) and also to work effectively damping the acceleration responses of the structure.

A Dynamic Characterization of Long Span Bridge Using Mean FRF

허광희,최만용,안병익,Heo, Gwang-Hee,Choi, Man-Yong,An, Byung-lk 한국구조물진단유지관리공학회 2000 한국구조물진단유지관리공학회 논문집 Vol.4 No.1

구조물의 동특성은 대형구조물을 상시감시 할 수 있는 장점으로 인하여 널리 활용된다. 상시감시를 위해 계측된 랜덤 데이터는 FFT를 통한 구조물의 동적 고유특성을 분석함으로써 이루어진다. 이 과정에서 Input Data와 Response Data사이에서 FFT Analyzer를 통하여 FRF가 측정된다. 특히 랜덤 데이터의 계측은 여건과 환경에 따라 발생하는 Noise로부터 가능한 정확한 FRF를 계측해야만 성공적인 구조물의 고유의 동적특성을 파악하게 된다. 랜덤 데이터에서 발생할 가능성이 높은 입력, 출력 Noise를 동시에 최소화 할 수 있는 새로운 개념의 FRF측정 알고리즘을 제안한다. 이 알고리즘에 의하여 장대형 모형교량으로부터 Modal 실험을 수행하여 계측된 동특성을 FE 해석 결과와 비교 평가하여 유용성을 제시한다.

비대칭사장교의 동특성 분석을 위한 FE 모델링

허광희,전승곤,김충길,안의종 한국구조물진단유지관리학회 2011 한국구조물진단학회 학술발표회논문집 Vol.2011 No.9

Asymmetrical Cable-stayed bridges are often built asymmetrically due to their circumstances around them. Such asymmetrical bridges keep their structural equilibrium generally by transmitting their load from the central longer span into their main tower and the other side foundation piles. This unusual asymmetrical structure has unique dynamic characteristics when it vibrates due to random load. The asymmetrical bridge concerned here is composed of a main tower and a upper deck of steel composite structure, in which the cables are tied along the center line of the longer span, and again connected to the other side of foundation piles through the main tower. For the exact analysis of its dynamic characteristics, which is essential to the monitoring for bridge maintenance, this paper developed its three-dimensional FE modelling which turn out to be appropriate FE analyses by solving the problems involved in transforming the different size of sections and their center of the mass. For evaluation, we first measured structural vibration using ambient vibration, then obtained cross correlation function by the FFT of cross power spectrum, and finally analyzed the dynamic characteristics of the bridge structure. As results, the FE modelling suggested here was proven effective.