• Journal of Korean Society of Steel Construction
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• v.27 no.4
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• pp.371-376
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• 2015

This study was conducted for the torsional behavior of catwalk system which is a temporary structure on a suspension bridge. The torsional deformation of the catwalk structure has a significant effect on the workability and safety of workers during main cable erection. For this reason, the torsional deformation of catwalk is controlled to be acceptable levels below by adjusting the cross bridge interval in design stage. This study analyzed the effect of separation between cross bridge associated with twist safety of catwalk system. For the analytical approach, a detailed analysis model was created including cross bridge. Both wind load within the wind velocity range that allows the construction and eccentric load of Prefabricated Parallel Wire Strand were analyzed by analysis model. Result of study shows that separation between cross bridges has a significant effect on the torsional behavior of the catwalk.

• Wind and Structures
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• v.12 no.6
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• pp.479-504
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• 2009

Structural health monitoring (SHM) systems have been recently embraced in long span cable-supported bridges, in which buffeting-induced stress monitoring is one of the tasks to ensure the safety of the bridge under strong winds. In line with this task, this paper presents a SHM-oriented finite element model (FEM) for the Tsing Ma suspension bridge in Hong Kong so that stresses/strains in important bridge components can be directly computed and compared with measured ones. A numerical procedure for buffeting induced stress analysis of the bridge based on the established FEM is then presented. Significant improvements of the present procedure are that the effects of the spatial distribution of both buffeting forces and self-excited forces on the bridge deck structure are taken into account and the local structural behaviour linked to strain/stress, which is prone to cause local damage, are estimated directly. The field measurement data including wind, acceleration and stress recorded by the wind and structural health monitoring system (WASHMS) installed on the bridge during Typhoon York are analyzed and compared with the numerical results. The results show that the proposed procedure has advantages over the typical equivalent beam finite element models.

• 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.

• Journal of Korean Society of Steel Construction
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• v.16 no.3 s.70
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• pp.355-363
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• 2004

In order to obtain the effective length factor of beam-column members of plane frames, this paper extensively used an alignment chart approach, based on the nomograph given in LRFD-AISC specification commentaries. However, it should be noted that various simplifications and assumptions were introduced in constructing the alignment chart. To overcome the practical limitations of the alignment chart, this paper proposes a simple but accurate procedure that determined the effective buckling length for stability design of main members of cable-supported bridges. This method requires the full system buckling analysis. The numerical examples showing the suitability of the present scheme are discussed and some conclusions are drawn.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.164-164
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• 2008

The beach-chair traction position is designed to allow the use of traction while allowing the surgeon to orient the shoulder in an upright position and convert to an open procedure, if necessary. The patient is placed in the beach-chair position under general anesthesia. A three-point shoulder holder (Arthrex, Naples, Florida) is attached to the rail of the operating table on the same side as the surgeon, whereas it is placed on the side opposite the surgeon in the lateral decubitus position. A shoulder traction and rotation sleeve (Arthrex) are affixed to the arm following the manufacturer's instructions. Positioning the thumb toward the closed side of the sleeve ensures a field for the anterior portion of the rotator cuff and prevents the tendency of the suspension apparatus to place the arm in internal rotation. The arm is maintained in 30 to 40 degree abduction and 30 to 40 degree flexion by controlling the length and height of the bar and the location of the universal clamp. The universal clamp allows multiple planes of adjustment to control abduction and forward movement of the arm. The sleeve is attached to the longitudinal traction cable using a sterile hook, and a lateral strap is secured around the proximal portion of the sleeve to the overhead traction cable to ensure a field for glenohumeral reconstruction. The use of a lateral strap permits ideal shoulder positioning for improved access to the anterior and inferior glenohumeral joint. The lateral strap can be released or removed to widen the subacromial space during subacromial decompression or rotator cuff repair. A 10-lb weight is attached to the longitudinal traction cable for an average-sized person.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.6
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• pp.11-20
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• 2002

This study aims to discover the landscape image of bridges and their harmonization wish surrounding sceneries. This research utilized the basic study tool of psycho-physics and processed the case study of five types of bridges on the Han-River, Seoul. Twenty-one bridges on Han-River were classified into five categories ; the cable stayed bridge, the arch bridge, the girder bridge, the trust bridge and the suspension bridge. Also, aesthetic elements of the bridges including the form the texture, the color, the scale and the harmony were examined. The questionaires to analysis the image and harmonization with surrounding sceneries were designed using semantic differential scale and 5 point Likert scale. The results of the research were as follows. First, components representing the images of bridge landscape are classified into three types, ‘beauty’, ‘weightfulness’ and ‘friendliness’. Second, the image of each bridge as a whole turns out not to be different from each other but to be different in the context of neighboring sceneries. It was also determined that both the Cable Stayed Bridge type and the Arch Bridge type are the most attractive. But, the former does have a more masculine image, and the latter has a m[n feminine image. Third, the Cable Stayed Bridge and the Arch Bridge were evaluated highly in terms of harmonization with surrounding landscapes, while the Girder Bridge received the lowest evaluation. All of the above results suggest that the bridges should be constructed not only for beauty itself in form, color, texture and scale, but also in harmonization with the surrounding landscape. Lastly, it is desirable to do further research to find out sort specific design principles that exist between bridges and tangible surrounding landscape types.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.79-88
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• 2022

Cable-supported bridges, as important large infrastructures, require a long-term and systematic maintenance strategy. In particular, various methods have been proposed to secure safety for the bridges, such as installing various types of sensor on members in the bridges, and setting management thresholds. It is evidently necessary to propose a strategic plan to efficiently manage increasing number of cable-supported bridges and data collected from a number of sensors. This study aims to develop an analysis tool that can automatically remove abnormal signals and calculate statistical results for the purpose of efficiently analyzing a wide range of data collected from a long span bridge measurement system. To develop the tool, basic information such as the types and quantity of sensors installed in long span bridges and signal characteristics of the collected data were analyzed. Thereafter, the Humpel filtering method was used to determine the presence or absence of an abnormality in the signal and then filtered. The statistical results with filtered data were shown. Finally, one cable-stayed bridge and one suspension bridge currently in use were chosen as the target bridges to verify the performance of the developed tool. Signal processing and statistical analysis with the tool were performed. The results are similar to the results reported in the existing work.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.127-134
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• 2001

Wire ropes are widely used in cable car, suspension bridge and elevator, etc. and composed of single or multi-layer strands. It is difficult to find out the characteristics of a strand or wire rope because of complicated geometry and contact condition. In this study, the axial stiffness is evaluated using finite element method and reliable finite element analysis model is presented, taking into consideration the convergence on the length. The axial stiffness predictive equation of a strand is developed using analysis of variance, which can be applicable for characterizing the relationship between load and displacement when the strand configuration is determined.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.148-157
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• 1999

Dynamic structural behavior in long span bridges, especially cable structures, is very sophisticated due to their flexibility and structural members are sequentially erected in each construction step. In this study, the consistent mass matrix for dynamic analysis is formulated and computational program considering construction sequences is developed where structural members can be builded or removed by command language and automatically reanalyzed in the moment when structural system is changed. The dynamic analysis, i.e. eigenvalue and time series analysis and the geometrically nonlinear analysis considering construction sequence are conducted to the Namhae Bridge. The analytical results are satisfactory compared with measuring values and the developed computational program can successfully be applied to design and safety check.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1246-1253
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• 2000

Wire ropes are widely used in cable car, suspension bridge and elevator, etc. and there has been a growing need for ropes of large diameter. The theoretical procedures to obtain the stiffness coefficients of wire ropes, using previously reported theory, are programmed and the verification of the program is made. The effects of lay angle on the stiffness of strand are researched and comparisons on stiffness of rope are made according to the lay type. Axial stiffness optimization problems with coupling and torsional stiffness constraints are formulated and the effects of constraints on other stiffness coefficients on axial stiffness optimization are investigated.