• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.163-176
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• 2006

The paper proposes rating equations for main components such as girders, towers and cables in cable-stayed bridges. Load rating equations for girders and towers are proposed using stress and stability equations and load rating equation for cables is presented. A moving load analysis is performed and distribution types of live loads are determined for the cases of a maximum axial tensile force, a maximum axial compressive force, a maximum positive and a negative moment for each component. The Dolsan Grand bridge is used to verify a validity of proposed equations, The conventional rating equation overestimates rating factors of girders and towers in the Dolsan Grand bridge, whereas proposed rating equations properly reflect the axial-flexural interaction behavior of girders and towers in cable-stayed bridges.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.114-122
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• 2018

This study presents the emergency assessment method about seismic safety of cable-supported bridges using seismic acceleration sensors installed on the primary structural elements of them. The structural models of bridges are updated iteratively to make their dynamic characteristics to be similar to those of real bridges based on the comparison of their natural frequencies with those of real bridges estimated from acceleration data measured at ordinary times by the seismic acceleration sensor. The displacement at the location of each seismic acceleration sensor is derived by seismic analysis using design earthquake, and the peak value of them is determined as the disaster management criteria in advance. The displacement time history is calculated by the double integration of the acceleration time history which is recorded at each seismic acceleration sensor and filtered by high cut(low pass) and low cut(high pass) filters. Finally, the seismic safety is evaluated by the comparison of the peak value in calculated displacement time history with the disaster management criteria determined in advance. The applicability of proposed methodology is verified by performing the seismic safety assessment of 12 cable-supported bridges using the acceleration data recorded during Gyeongju earthquake.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.127-135
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• 2018

With the nation showing increasing concern for earthquakes, there have been several methods for the analysis of earthquakes and evaluation of damage. Nevertheless, there is no clear standard to assess the seismic damage to structures quantitatively. Accordingly, this study conducted seismic analysis of several forms of seismic waves and actual seismic load, targeting the cable stayed bridge, which is supported by a cable and proposes a method for evaluating the damage based on the results. The damage index was calculated based on the tilting of the pylon of the cable-stayed bridge and the characteristics of physical seismic damage was suggested with 4 levels, such as A, B, C, and D. In addition, it is not proper to simply judge that the seismic damage index is obtained as large or small at all times depending on the seismic analysis method. Although this study focused on the proposal seismic damage index and an evaluation of the damage targeting the cable stayed bridge, the result was applied to a structure with a similar maximum displacement response.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.711-721
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• 2014

PPWS, a large number of which a main cable of a suspension bridge consists of, must be precisely erected at a target location under construction considering the differences among design conditions. The absolute sag is measured for several PPWSs, which are reference strands and the relative sag is surveyed from them to other PPWSs, which are divided into several groups. And the adjustment of PPWS length is performed to erect it at target configuration. When PPWS is being under erection in a real bridge site, the procedures are as follows; evaluate sag sensitivities according to sag variation factors, calculate an adjustment length of PPWS corresponding to them and adjust a sag of PPWS by controlling the calculated amount of PPWS length. In this study, the differential-related equations of sag sensitivity were proposed for support movement of PPWS. Before site demonstration study of a series of them, we established a catenary model system and accomplished verification tests of them. From test results, the validation of them was done.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.199.1-199.1
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• 2012

TRIO-CINEMA(TRiplet Ionospheric Observatory-Cubesat for Ion, Neutron, Electron & MAgnetic field)는 지구근접공간에서의 미세 자기장 변화 및 중성입자의 검출을 목적으로 경희대학교와 UC Berkeley가 공동 개발하는 초소형위성이다. 초소형위성은 내부 공간이 협소하여 효율적인 공간배치 및 위성체발사 시 진동에도 견딜 수 있도록 harness가 제작되어야 한다. CINEMA는 OBC, EPS, 배터리, 수신기, IIB(Instrument Interface Board), MAGIC(MAGnetometer Imperial College) board, HVPS(High Voltage Power Supply)로 구성된 avionics bus와 MAGIC, STEIN(Supra Thermal Electron, Ion, Neutral)의 payload, Solar panel, UHF와 S-band 안테나로 구성되어 있다. Solar panel에서 생산된 전력은 EPS를 통해 배터리에 저장되고 PC104를 통해 avionics stack의 각 board로 전력이 분배된다. IIB는 탑재체 파트와 연결되어 이를 제어하고 HVPS에서 STEIN에 공급되는 고전압은 특수 와이어를 통해 연결되며 UHF 안테나와 S-band 안테나는 RF 케이블로 수신기와 송신기가 연결되어 있다. 각각의 harness는 케이블타이와 lacing tape로 위성체와 고정되며 커넥터는 고정 지지대를 제작하여 나사로 체결하였다. CINEMA에 적용된 harness는 진동시험과 열진공시험을 통해 harness와 시스템의 안정성이 검증 되었다.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.84-92
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• 2012

Anchorage zone in prestressed concrete cable stayed bridges is very important area due to the more accurate analysis is needed to estimate the behavior. In the study, since the cable anchorage zone in the prestressed concrete cable-stayed bridge is subject to a large amount of concentrated tendon forces, it shows very complicated stress distributions and causes a serious local cracks. Accordingly, It is necessary to investigate the parameters of affecting the stress properties, such as the cable inclination, the position of anchor plate, the modeling method and the three dimensional effect. The tensile stress distribution of anchorage zone is compared to the actual design condition by varing the stiffness of spring element in the local modeling and an appropriate position of anchor plate is determined. These results would be elementary data to the stress state of anchorage zone and more efficient design.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.205-213
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• 2019

Recently, because of the global recession of the offshore plant industry and low-cost orders, there has been increasing interest in strengthening the competitiveness of domestic companies for the design and production technologies of offshore plants. However, in the offshore plant design field, the Plant Design Management System (PDMS), which is a 3D CAD program for plant layout developed by AVEVA Marine, is already commonly used as offshore plant design software and widely used in large domestic shipyards and cooperative design companies. Under this background, we have been thinking about ways to design better with the existing software. In this study, we developed a parametric design program to maximize the efficiency and reduce the working time for offshore plant electrical outfit production design based on the Programmable Macro Language (PML) of PDMS. We also examined its performance. By applying the developed program to the offshore plant module selected as an application example, it was confirmed that a 50% improvement in the work efficiency of cable tray design could be obtained compared with the existing method, with work efficiency improvements of 80% or more in other field design work.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.485-498
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• 2014

In this paper, vehicle-bridge interaction analysis under a series of moving vehicles to simulate a lane load was performed to estimate impact factor of the main cable, hanger and girder for the selected suspension bridges with 404m and 1545m main span. Korea Bridge Design Code(Limit State Design) was selected for the live model in which KL-510 truck was modeled 6-d.o.f. vehicle and a lane load was simulated by a series of single-axle vehicles. For the 404m main span bridge, hinge-type and floating-type girders at the tower were considered to examine the impact factor according to the connection and supporting type of the girders. The parameters considered herein are the types of live load-a truck only and a truck plus lane load, eccentricity of moving vehicles, road surface roughness and vehicle speed. The road surface roughness was randomly generated based on ISO 8608 and it was applied to the truck only. The impact factors were also evaluated by using the influence line method that is commonly used in cable-supported bridges and compared with those from vehicle-bridge interaction analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.167-174
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• 2008

Number of long-span bridge construction has been increased recently so that seismic consideration of design has become significant. To adapt such significance to design, seismic design in the newly revised 'Cable Steel Bridge Design Handbook' specifies some of wave travelling effect and local site effect. In this study, a cable-stayed bridge with main span of 500m is analysed having variables of uniform excitation, wave travelling effect, and wave travelling effect plus local site effect. Result shows that wave travelling effect in cable-stayed bridge affects considerably to its seismic response under weak soil condition even though the span length is relatively short. What's more, regardless of soil type, the seismic response has become higher for analysis with wave travelling effect and local site effect than with wave travelling effect only. Consequently, in seismic response analysis of long-span bridge, consideration should be given to application of wave travelling effect and local site effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.664-668
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• 2018

Free-standing structures that are especially high are more likely to receive brain attacks caused by lightning. Since special structures are generally part of national industrial structures, lightning strikes mostly cause socio-economic damage. Lightning protection facilities are installed to prevent such lightning damage, but in 2015, support cables on West Sea bridges were hit by lightning, causing a lot of economic damage. Accordingly, the design of a lightning protection system shall establish protective measures after analyzing the risk of debris falling onto the structure. In this thesis, lightning strikes are analyzed directly in relation to the modeling system that operates the actual information collection system for lightning strikes, depending on the location of the tall, free-standing structures, and practical lightning hazard information is provided by a meteorological station. In addition, we propose monitoring and applying a probability correction rate to the calculation of the lightning risk based on the number of lightning strikes directly reaching the ground in order to obtain an effective lightning risk assessment.