• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.45-53
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• 2023

In this study, to analyze the correlation of surface chloride and corrosion amount level according to the installation location of steel members exposed to the marine environment, the surface chloride and mean corrosion depth were evaluated by member units for box girder members of the offshore steel bridge and box specimens. The surface chloride was measured monthly using the Bresle method for one year. The corrosion amount was evaluated by converting the weight loss due to corrosion products generated in the monitoring steel plate into mean corrosion depth. As a measurement result of the surface chloride and corrosion amount, relative differences in surface chloride and mean corrosion depth were appeared depending on the shape or installation location of the steel members. Moreover, even if members of the same shape were installed in the same bridge, it was confirmed that the corrosion amount was increased locally and rapidly. The tendency of corrosion amount depending on the surface chloride was evaluated to analyze the correlation between surface chloride and corrosion amount, and the relation equations that can asseses the corrosion amount depending on the surface chloride were analyzed. From the results of the correlation between surface chloride and corrosion amount, it was found that the corrosion amount of the steel member affected by the surface chloride was varied up to about 1.15 times depending on the structural detail.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.20-27
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• 2005

Solar radiation causes non-uniform temperature distribution in the structure, depending on the shape of the structure and its shadows. Especially in cases of curved steel box girder bridges, non-uniform temperature distribution due to solar radiation can reduce bridge life and serviceability when combined with another load combination. In this study, the method for predicting the temperature distribution of curved bridges developed by Kim et al., was used to predict the non-uniform temperature distribution which served as a basis for structural analysis of 3-D bridge behavior. In order to seek the most unfavorable conditions of solar radiation, observation data from the Korea Meteorological Administration for solar radiation were analyzed. The region of the most high solar radiation condition was selected and its one year variation of the solar radiation data was considered. From this analysis, the most unfavorable solar radiation condition with lower solar altitude and intense solar radiation was selected. Based on the selected solar radiation condition, structural behavior of curved bridges with diverse bridge direction, span length, radius and support conditions are analyzed.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.685-691
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• 2022

This study was based on the steel composite concrete box structure (Transfer girder) which was installed to support the skyscrapers directly above the subway line. In this study, it was analytically proved that the cause of cracks on the steel composite concrete box structure were the shrinkage cracks by comparing the results of crack investigation and numerical analysis. As the results, it was found that the internal temperature difference between concrete and steel members occurred according to the shape of the steel frame embedded in concrete, the location of vertical stiffener, and the closed section area. The narrower spacing of vertical stiffener was occurred the internal temperature concentration of the structure and the temperature difference increased. And the location of higher thermal strain and temperature were similar to the location of actual cracks by the visual inspection. Therefore, the internal temperature concentration parts were formed according to the presence and spacing of the vertical stiffeners and the inspection passage in the central part of the structure. The shrinkage cracks were occurred by the restrained of temperature expansion and contraction of the concrete. As the results of this study, it was important to separate and manage the non-structural cracks caused by shrinkage and the structural cracks in the maintenance of serviced steel-composite concrete structures.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.511-522
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• 2014

In this study, an innovative steel stair system is presented which enables rapid erection and high quality control in both residential and office building construction. This system features two lightweight steel stringers of box shape, bolted connections easy to absorb construction tolerance, and stair steps movable transversely (or sliding steps) such that the work space needed for concrete stairway wall could be easily provided. In this type of stairway system, other than providing robust connecting details, ensuring vibration performance is especially important since this system may be vibration-sensitive due to lightweight nature and/or probable low damping. To tackle these issues, a series of full-scale mock-up tests were conducted by using box-shape stringer members with or without concrete-fill. The connection system was shown to be sufficiently stiff and strong, or it remained elastic even under the 160% of service load level. Among the seven stringer alternatives, five exhibited satisfactory vibration performance according to the related North American and European acceptance criteria.

• Journal of Korean Society of Steel Construction
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• v.12 no.6
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• pp.671-680
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• 2000

This paper provides the results of the study on the structural behavior of the composite metal deck slab system. The experimental study on composite slabs with trapezoidal and inverse-triangle-top-flange deckplate result, it was found that the geometry of the cross-section was more important than any other factors to ensure the composite action of deck slabs. Hence the inverse-triangle-top-flange of closed box was more effective on the shear slip and deflection than the trapezoidal deck of open shape. These results show that the continuing development of composite deck plate must consider importantly the geometry of the deck. The experimental results were compared with established formulas and were analysed to advance a theory on composite slabs using deckplates.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.169-170
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• 2009

CFT structure has many advantages compared with the ordinary structural member made of steel or reinforced concrete. Because of increases in ductility, stiffness and load carrying capacity of overall structure owing to confinement effect of steel box and concrete, CFT structure is widely used to columns. Recently, the utilization of CFT member has been expanded to bridge structure as a girder member. The purpose of this study is to develop the analytical model and propose design method for CFTA girder bridge consisting of CFT structure, arch shape and tendons.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.613-618
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• 2008

As one way of cost innovation and weight saving of the automobile, the one-piece typed lower control arm was developed for the purpose of replacing the box typed lower control arm. In order to overcome less buckling strength of the one-piece typed lower control arm, the design parameters such as the high strength steel grade, the thickness and the shape of main panel were optimized based on Taguchi method.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.515-526
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• 2009

There are three main production processes in the manufacture of concrete-filled square steel columns. The first process is known as the 'box-type process' or 'four-seam method,' wherein four beams are welded together at the seams. The second is the 'cold-forming process' or 'two-seam method,' wherein the seams of two channel beams are welded together. The third is the 'pressing process' or 'one-seam method,' wherein a circular column is pressed until it becomes a square column. In calculating the production cost for the making of a steel tube, it is very important to consider the welding process to be used and the desiredthickness of the steel tube, such as a square column that was developed under a new method, formed through the four-seam flare welding method at the center of the steel column width, following the L-shape formation. Certain tests were suggested in this study to evaluate the welding amount of concrete-filled square steel columns. With the parameters of the production method of a square steel column, the thickness of the steel square columns, and the welding amount, six specimens were produced. A structural test and finite-element analysis were conducted to assess the behavior of the steel column according to the water pressure inside the steel columns.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.41-56
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• 2017

Recently, the necessity of deep and double-deck tunnels has been grown day by day due to the increase of traffic volume at metropolitans and thus the study on the divergence of those tunnels becomes required. Therefore sensitivity analyses were conducted with FLAC 2D program by selecting ground condition, coefficient of lateral pressure, support pattern, and depth of rock cover as parameters. Ultimately, this study is to find the optimal shape and support method of a diverged section. As the results of this study, it turned out that the box type gave higher stability of the section than arch type unlike the general thought. It can be explained that the arch type has about 30% bigger excavation area than the box type. When the ground conditions are poor, steel pipe grouting reinforcement gives higher stability than rockbolt reinforcement, but its thickness and range do not give a great influence on the stability of the enlarged section.

• Structural Engineering and Mechanics
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• v.47 no.1
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• pp.59-73
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• 2013

The Xiaolan channel super large bridge is unique in style and with greatest span in the world with a total length of 7686.57 m. The main bridge with spans arranged as 100m+220m+100m is a combined structure composed of prestressed concrete V-shape rigid frame and concrete-filled steel tubular flexible arch. First of all, the author compiles APDL command flow program by using the unit birth-death technique and establishes simulation calculation model in the whole construction process. The creep characteristics of concrete are also taken into account. The force ratio of the suspender, arch and beam is discussed. The authors conduct studies on the three-plate webs's rule of shear stress distribution, the box girder's longitudinal bending normal stress on every construction stage, meanwhile the distribution law of longitudinal bending normal stress and transverse bending normal stress of completed bridge's box girder. Results show that, as a new combined bridge, it is featured by: Girder and arch resist forces together; Moment effects of the structure are mainly presented as compressed arch and tensioned girder; The bridge type brings the girder and arch on resisting forces into full play; Great in vertical stiffness and slender in appearance.