• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.177-186
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• 1999

Dynamic Characteristics of the bridge motions under seismic excitations are analyzed by adopting multi degree - of - freedom system to estimate the effect of restrainers. The applied restrainer is assumed to be a dead - band - system, which has the force clearance and the linear elastic force. The inelastic behaviors of pier and foundation motions are also considered in the study. It is found that the major effect of restrainer is to remarkably decrease the relative displacement between adjacent girders. It is found that restrainers placed on the parts of the bridge system rather than the whole system may increase the unseating failure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.203-209
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• 2004

Recently, various and new special methods of construction about steel bridges have been tried, and the study about local buckling under this methods have been performed too. But because of various cases, structural analysis is performed to check safety for each step of construction, and this is not efficient and economical method for time and manpower. So, for solution of this problems, general method about checking safety needs to he developed. In this study, local buckiling of web of girder due to various load cases under construction by ILM(Incremental Launching Method) will be studio considering various parameters such as forces, aspect ratio, boundary condition and so on. Also interaction curve will he plotted for each case.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.373-387
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• 2010

This study is intended to assess low frequency sound radiated from a viaduct under normal traffic. The bridge comprises steel box girders and wide cantilever decks on which vehicles pass. The low frequency sound and the acceleration response of the bridge under normal traffic are measured to investigate how bridge vibrations affect the low frequency sound observed near the bridge. Observations demonstrate that strong relationships exist between frequency characteristic of bridge's acceleration response and the sound pressure level of low frequency sound. A noteworthy point is that the dynamic feature of the sound pressure level is mostly affected by dynamic feature of the span locating near the observation point.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.721-726
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• 1999

Diverse strengthening methods for reinforced concrete are applied to real structures with a variety of materials. On the other hand, only external prestressing is used for strengthening damaged prestressed concrete girders. But the end brackets for external prestressing are hard to design and to manufacture, the magnitude of prestressing is limited when applied to real structures. The current end brackets are not clearly understood in load transmitting mechanisms and they may damage the original girder by drilling during construction. And also the designed welding area of the current bracket is insufficient to support the high load. The problems of current end bracket are solved in this study. And a new and improved end bracket is proposed and tested. The tested end bracket is similar to the end bearing bracket, but many supportting plates are addded to increase its welding length of the weakest point of the bracket. The increased welding length finally increases its load carrying capacity significantly.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.223-228
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• 1999

The state of the current design practice in designing the so-called hybrid structures with the upper shear-wall and lower frame systems are reviewed through the investigation of the 43 design examples. In particular, the trend in the design of the transfer system between upper wall and lower frame systems are analyzed with respect to the depth, the length and the number of spans of transfer deep girders and the number of upper stories. Finally the most critical portions in this conventional transfer system, which should be studied in depth in the future, are pointed out to improve the current design and analysis practice.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.165-166
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• 2009

This paper is to research for construction of the longest open toped steel box girder composite bridge using precast concrete deck in the country. This type bridge can bring down the construction costs by reducing the steel's weight used it's girders. And, it also can reduce working hours for construction over 6months by applying the precast deck system. I will introduce the process of construction the longest this type bridge within the country named Seochon Bridge

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.173-176
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• 2003

Progressive failure analysis of steel composite double T-beam is performed to investigate the mechanical effects of steel composite fabricated in the webs of double-T beam to replace concrete placing forms. The analysis is based on nonlinear finite element scheme considering material nonlinearities of concrete, reinforcing bar and PS steel. Four-parameter strength envelope defines the hardening and softening phenomena of concrete with consideration of the various levels of confining pressures. Rankine maximum strength criterion defines the elasto-plasticity of PS steel and reinforcing bar, and Von Mises $J_2$ failure criterion for steel plate which wraps the concrete webs of double T-beam. A 6m long two-span steel composite double T-beam is analyzed and compared with the experimental results.

• Composites Research
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• v.27 no.1
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• pp.1-6
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• 2014

Theories for composite material structures are too difficult for such design engineers for construction and some simple but accurate enough methods are necessary. The author has reported that some laminate orientations have decreasing values of $D_{16}$, $B_{16}$, $D_{26}$ and $B_{26}$ stiffnesses as the ply number increases. For such plates, the fiber orientations given above behave as specially orthotropic plates and simple formulas developed by the author. Most of the bridge deck structures on girders have large aspect ratios. For such cases further simplification is possible by neglecting the effect of the longitudinal moment terms $M_x$ on the relevant partial differential equations of equilibrium. In this paper, the result of the study on the subject problem is presented.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.427-436
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• 2017

This paper presents an experimental and analytical investigation on the behavior of a U-shaped girder subjected to operation, cracking and ultimate loads. A full-scale destructive test was conducted on a U-shaped girder to study the cracking process, load-carrying capacity, failure mechanism and load-deformation relationships. Accordingly, the tested U-shaped girder was modeled using ANSYS and a non-linear element analysis was conducted. The investigation shows that the U-shaped girder meets the specified requirements of vertical stiffness, cracking and ultimate load capacity. Unfavorable torsional effect is tolerable during operation. However, compared with box girders, the U-shaped girder has a more transverse mechanical effect and longitudinal cracks are apt to occur in the bottom slab.

• Steel and Composite Structures
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• v.29 no.2
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• pp.161-173
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• 2018

Point bending is often used for cambering and curving structural steel girders. An analytical solution, applicable in the elasto-plastic range only, that relates applied loads to the desired curve was recently developed for inducing horizontal curves using four-point bending. This solution does not account for initial residual stresses and geometric imperfections built-in hot-rolled sections. This paper presents results from a full-scale test on a hot-rolled steel section curved using four-point bending. In parallel, a numerical analysis, accounting for both initial geometric imperfections and initial residual stresses, was carried out. The models were validated against the experimental results and a good agreement for lateral offset and for strain in the elasto-plastic and post-plastic ranges was achieved. The results show that the effect of initial residual stresses on deformation and strain is minimal. Finally, residual stresses due to cold bending calculated from the numerical analysis were assessed and a revised stress value for the service load design of the curved girder is proposed.