• Title/Summary/Keyword: cable-stayed bridge

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Vibration Control of a Benchmark Cable-Stayed Bridge using Maximum Eenergy Dissipation Algoritm (Maximum Energy Dissipation Algorithm을 이용한 벤치마크 사장교의 제어)

  • Cho, Sang Won;Jung, Hyung Jo;Han, La San
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.09a
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    • pp.435-441
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    • 2003
  • 본 논문에서는 Maximum Energy Dissipation Algorithm(MEDA) 사장교의 MR댐퍼제어에 적용하고자 한다 MR댐퍼의 제어를 위해서 여러 제어 이론들이 제안되었으나, 각각의 특성에도 불구하고 성능면에서는 큰 차이가 없다 MEDA는 Lyapunove 직접법을 바탕으로 군성되는 제어이론으로써, 15년전에 제안되었음에도 실제 토목구조물에는 적용된 바 없어 그 성능 및 장점이 제대로 검증되지 않았다. 따라서 본 논문에서는 벤치마크 사장교 수치예제를 통해서, MEDA의 토목구조물에의 적용성을 성능(performance)과 강인성(robustness) 측면에서 분석하려한다. 수치예제에서 다양한 지진에 대한 층간변위, 가속도, 그리고 상대변위의 각 제어기법에 의한 감소량은 벤치마크문제에 정의된 평가지수(evaluation criteria)를 사용하였다.

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Robust Hybrid Control System (강인 복합제어 시스템)

  • 박규식;정형조;오주원;이인원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.09a
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    • pp.442-449
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    • 2003
  • This paper presents a robust hybrid control system for seismic response control of a cable-stayed bridge. Because multiple control devices are operating, a hybrid control system could alleviate some of restirctions and limitations that exist when each system is acting alone. A LQG algorithm with on-off control scheme, H$_2$ and H$_{\infty}$ control algorithms with various frequency weighting filters are used to improve the controller robustness of the active control part in the hybrid control system. The numerital simulation results show that control performances of robust hybrid control systems are similar to those of the hybrid control system with LQG algorithm. Furthermore, it is verified that robust hybrid control systems are more robust than the hybrid control system with LQG algorithm and there are no signs of instabilities in the $\pm$5% stiffness matrix perturbed system. Therefore, the proposed hybrid control system have a good robustness for stiffness matrix perturbation without loss of control effectiveness.

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Analysis of a cable-stayed bridge with uncertainties in Young's modulus and load - A fuzzy finite element approach

  • Rama Rao, M.V.;Ramesh Reddy, R.
    • Structural Engineering and Mechanics
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    • v.27 no.3
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    • pp.263-276
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    • 2007
  • This paper presents a fuzzy finite element model for the analysis of structures in the presence of multiple uncertainties. A new methodology to evaluate the cumulative effect of multiple uncertainties on structural response is developed in the present work. This is done by modifying Muhanna's approach for handling single uncertainty. Uncertainty in load and material properties is defined by triangular membership functions with equal spread about the crisp value. Structural response is obtained in terms of fuzzy interval displacements and rotations. The results are further post-processed to obtain interval values of bending moment, shear force and axial forces. Membership functions are constructed to depict the uncertainty in structural response. Sensitivity analysis is performed to evaluate the relative sensitivity of displacements and forces to uncertainty in structural parameters. The present work demonstrates the effectiveness of fuzzy finite element model in establishing sharp bounds to the uncertain structural response in the presence of multiple uncertainties.

A versatile software architecture for civil structure monitoring with wireless sensor networks

  • Flouri, Kallirroi;Saukh, Olga;Sauter, Robert;Jalsan, Khash Erdene;Bischoff, Reinhard;Meyer, Jonas;Feltrin, Glauco
    • Smart Structures and Systems
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    • v.10 no.3
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    • pp.209-228
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    • 2012
  • Structural health monitoring with wireless sensor networks has received much attention in recent years due to the ease of sensor installation and low deployment and maintenance costs. However, sensor network technology needs to solve numerous challenges in order to substitute conventional systems: large amounts of data, remote configuration of measurement parameters, on-site calibration of sensors and robust networking functionality for long-term deployments. We present a structural health monitoring network that addresses these challenges and is used in several deployments for monitoring of bridges and buildings. Our system supports a diverse set of sensors, a library of highly optimized processing algorithms and a lightweight solution to support a wide range of network runtime configurations. This allows flexible partitioning of the application between the sensor network and the backend software. We present an analysis of this partitioning and evaluate the performance of our system in three experimental network deployments on civil structures.

The aerodynamic characteristics of twin column, high rise bridge towers

  • Ricciardelli, Francesco;Vickery, Barry J.
    • Wind and Structures
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    • v.1 no.3
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    • pp.225-241
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    • 1998
  • The high-rise supporting towers of long-span suspension and cable-stayed bridges commonly comprise a pair of slender prisms of roughly square cross-section with a center-to-centre spacing of from perhaps 2 to 6 widths and connected by one or more cross-ties. The tower columns may have a constant spacing as common for suspension bridges or the spacing may reduce towards the top of the tower. The present paper is concerned with the aerodynamics of such towers and describes an experimental investigation of the overall aerodynamic forces acting on a pair of square cylinders in two-dimensional flow. Wind tunnel pressure measurements were carried out in smooth flow and with a longitudinal intensity of turbulence 0.10. Different angles of attack were considered between $0^{\circ}$ and $90^{\circ}$, and separations between the two columns from twice to 13 times the side width of the column. The mean values of the overall forces proved to be related to the bias introduced in the flow by the interaction between the two cylinders; the overall rms forces are related to the level of coherence between the shedding-induced forces on the two cylinders and to their phase. Plots showing the variation of the force coefficients and Strouhal number as a function of the separation, together with the force coefficients spectra and lift cross-correlation functions are presented in the paper.

Experimental and numerical study on generation and mitigation of vortex-induced vibration of open-cross-section composite beam

  • Zhou, Zhiyong;Zhan, Qingliang;Ge, Yaojun
    • Wind and Structures
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    • v.23 no.1
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    • pp.45-57
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    • 2016
  • Open-cross-section composite beam (OCB) tends to suffer vortex-induced vibration (VIV) due to its bluff aerodynamic shape. A cable-stayed bridge equipped with typical OCB is taken as an example in this paper to conduct sectional model wind tunnel test. Vortex-induced vibration is observed and maximum vibration amplitudes are obtained. CFD approach is employed to calculate the flow field around original cross sections in service stage and construction stage, as well as sections added with three different countermeasures: splitters, slabs and wind fairings. Results show that flow separate on the upstream edge and cause vortex shedding on original section. Splitters can only smooth the flow field on the upper surface, while slabs cannot smooth flow field on the upper or lower surface too much. Thus, splitters or slabs cannot serve as valid aerodynamic means. Wind tunnel test results show that VIV can only be mitigated when wind fairings are mounted, by which the flow field above and below the bridge deck are accelerated simultaneously.

Wind power spectra for coastal area of East Jiangsu Province based on SHMS

  • Wang, Hao;Tao, Tianyou;Wu, Teng
    • Wind and Structures
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    • v.22 no.2
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    • pp.235-252
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    • 2016
  • A wind velocity power spectrum (WVPS) with high fidelity is extremely important for accurate prediction of structural buffeting response. WVPS heavily depends on the geographical locations, local terrains and topographies. Hence, field measurement of wind characteristics may be the unique way to obtain the accurate WVPS for a specific region. In this paper, a systematic analysis and discussions of existing WVPSs were performed. Six recorded strong wind data from the structural health monitoring systems (SHMS) of Runyang Suspension Bridge (RSB) and Sutong Cable-stayed Bridge (SCB) in Jiangsu Province of China were selected for analysis. The measured and pre-processed wind velocity data was first transformed from time domain to frequency domain to obtain the measured spectrum. The spectrum for each strong wind was then fitted using the nonlinear least square method and compared with both the fitted spectrum from statistical analysis and the recommended spectrum in specifications. The modified Kaimal spectrum was proved to be the "best" choice for the coastal area of East Jiangsu Province. Finally, a suitable WVPS formula fit for the coastal area of East Jiangsu Province was presented based on the modified Kaimal spectrum. Results in this study provide a more accurate and reliable WVPS for wind-resistant design of engineering structures in the coastal area of East Jiangsu Province.

Study on Design of Hydraulic Pump with High Temperature and High Pressure Resistance for Cable-Stayed Bridge (케이블 사장교용 내고온·내고압 유압 펌프의 설계에 관한 연구)

  • Qin, Zhen;Wu, Yu-Ting;Kim, Dong-Seon;Kim, Sang-Bae;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.11
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    • pp.109-114
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    • 2019
  • Hydraulic pumps are widely used in fields such as machinery manufacturing, engineering and construction. Although the research on hydraulic engineering is mature, it is still necessary to examine various performance aspects in detail for specific applications. This paper will focus on the hydraulic pump used in special construction machinery that needs high temperature and high pressure resistance. It will analyze the theoretical design, structure and thermal characteristics of the pump system using the Fundamentals of Engineering (FE) method, and will measure the key tolerance parameters of the hydraulic pump to ensure the accuracy of the machining. Through this research, a good design method for the linear reciprocating type of hydraulic pump can be summarized.

Development of Shape Determination Program for Suspension Bridge Using Digital Image Processing (디지털 화상처리기법을 이용한 현수교의 형상결정기법 개발)

  • Cheung, Jin-Hwan;Kang, Choong-Hyun;Kim, Nam-Shik;Park, Yong-Myoung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.1
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    • pp.117-126
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    • 2008
  • In this paper, it is presented a digital image processing method and the program (Visual C++) to determine the shape of the suspension bridge. To investigate the precision of this method, a suspension bridge is divided into 5, 13 and 19 images, respectively, by using the 6.3M pixels digital camera with 300mm zoom lens. Obtained results of the Kwang-Ahn Grand Bridge by using this method are fairly close to the real precision surveyed data. The accuracy is more improved by increasing the number of divided images of the structure. The total cost, man power and time of field survey by this method presented in this study could be much more reduced and the developed program could be applied with little modification for other structures like cable-stayed bridges, if lens compensation algorithms and program access capabilities are improved.

Design of Large-scale Drilled Shaft (대구경 현장타설말뚝의 설계 사례)

  • Im, Chul-O;Choi, Young-Seok;Kwak, Ki-Seok;Jang, Hak-Sung
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.545-553
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    • 2009
  • A lot of long-span marine bridge, which connects land to island or island to island, are being designed and constructed lately in south-west coast in South Korea. In the past, caisson foundations in marine were mainly adopted in construction and stability aspect, however, nowadays with development of pile construction technology, drilled shaft foundations are mainly adopted. As the long span cable stayed bridge and suspension bridge applied with lots of loads are being designed, the scale of pile foundations are getting larger. As the construction cost of substructure including foundation in marine bridges is too high, the appropriate evaluation of the axial bearing capacity of pile becomes a core factor to decide the construction cost of foundation if the drilled shaft is adopted as foundation type of bridge. The evaluation values of skin friction and end bearing capacity of drilled shaft in weathered rock suggested in south Korea are only to introduce the foreign specifications, and most of them are designed in a kind of hard soil layer. Also the allowable load of pile section is less than the expected bearing capacity of pile in the soil condition since the allowable capacity of pile is undervalued. Recently in order to improve this factor the bi-axial hydraulic load test of pile was taken, the data of load transfer analysis of pile, unit of skin friction and end bearing capacity are accumulated. In our country, the design of piles are made with ASD, however, LRFD considering service, strength and extreme state was adopted in Incheon Grand Bridge implemented with BTL, and the research to systematize the resistance coefficient appropriate at home country are being progressed.

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