• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.269-278
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• 2008

The primary object of the paper is to understand the compressive buckling characteristics of steel-concrete structures through the finite element analysis. The buckling pattern, compressive strength and stiffness of the steel plate concrete structures were investigated by the FEM analysis using the variations of B/t ratios and stud pitches. The investigation was focused on steel plate concrete structures with and without ribs placed on the surface of steel plates. The results of the FEM analysis were compared with the previous results from the theoretical equations. Conclusively, the buckling of the steel plate concrete structures occurred in the transverse direction of the loading direction. The stiffness of the steel plate concrete structure with ribs is greater than the one without the stiffened rib. The compressive strength in the FEM analysis is similar to that of JEAG 4681 and it showed 20% greater value than that of the proposed equations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.719-726
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• 2005

The optimal design was performed for the bridge superstructure composed of steel box girders and concrete deck considering life cycle cost. The service life of the superstructure was estimated, after load carry capacity curves for steel girder and concrete deck were derived on the basis of condition grade curves and maintenance histories. The object function was determined as life cycle cost, including initial cost, total maintenance cost, disposal cost and user cost, for a period of the estimated service life. The optimal design of the superstructure was performed for the various service lifes. The annual costs were used to compare calculated results and to get the most economical design. Also this paper presents reasonable idea for the use of user cost with uncertainty.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.965-970
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• 2001

The object of this research is to evaluate the seismic performance of existing RC bridge piers that were constructed before the adoption of the seismic design provision of Korea Bridge Design Specification in 1992. In this research, adopted test parameters were limited ductile design or non-seismic design, aspect ratio, confinement steel type, loading pattern, lap-spliced ratio for longitudinal reinforcement. This study has been performed to verify the effect of test parameter by quasi-static test. Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as lateral force-displacement hysteretic curve, envelope curve etc. It has been observed that seismic performance of lap-spliced test specimen, non-seismically designed specimens, was significantly reduced.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.471-476
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• 2003

The presence of voids under pavements or behind tunnel linings results in their deterioration. To detect these voids effectively by non-destructive tests, a method using radar was proposed. In this research, not only the detection of shape of voids, but also the location of reinforcing bars by radar image analysis is investigated. The experiments and image processing were conducted to detect voids and to locate reinforcing bars in or under concrete pavements (or tunnel linings) with reinforcing bars. From the results, the fundamental algorithm for tracing the reinforcing bars and voids, improving the horizontal resolution of the object image and detecting shape of objects, was verified.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.81-86
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• 1995

In order to apply to analysis methods of mechanism and cross tabulation methods for the influence factors by the accident types to the object of accidents which occurred in R.C and P.C methods among the accidents in construction work sites, the latent hazards in P.C method are evaluated from the data of accidents in H Company from Jan. 1, 1993 to Dec. 31, 1993. The relationship between accident types and unsafe acts, unsafe conditions are recognized and the hazards of R.C method and P.C method are compared from the data acquired by the analysis of causes for a kind of occurrence mechanism. In conclusions, the items such as causes of accidents, accidents types, occurrence time, and the characteristics, are concentrated on one side in the P.C method, which is quite different from R.C method. Therefore the control method for the accident causes is easily established with a lot of effective advantages. The frequency and severity of accidents in P.C method are so low in comparison with R.C method.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.281-286
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• 2003

This study presents the results of investigations with the object to determine the resistance to sulfuric acid for some kinds of cements containing 0%-70% of slag powder. The specimen is immersed 5% H$_2$SO$_4$ solution after the 28th days, is measured chemical analysis, XRD, SEM and etc after the immersed 35th days and is measured the erosion depth after the immersed 168th days. The results of experiment are founded out that alumina cement containing slag power was excellent at a point of view for the sulfuric acid resistance and the erosion depth was suitable to the evaluated method of the sulfuric acid resistance in the stead of the evaluated method of weight loss.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.375-380
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• 2001

Generally, countermeasures for the train-induced vibration are divided into the measures at the source, propagation path and receiving object. Among these measures the countermeasure at the source location is the most active and effective one in the field of railroad. In this study, the effectiveness of each anti-vibration measures at the track(source location) such as elastic rail fastener, ballast mat were evaluated through the comparison of acceleration level, insertion loss at the installed locations of each measures. As result of field measurement of vibration at the railroad track supporting structures and on the ground nearby the structures, elastic rail fastener showed vibration reduction effect of 4.5 ∼7.3㏈ on the concrete slab, 1.6∼3.7㏈ on the ground with the train operation speed of 80km/hr. In the case of ballast mat, the vibration reduction effect at the concrete slab and on the ground were 11.9∼13.3㏈ and 6.1∼7.6㏈, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1255-1260
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• 2000

The service life is defined as the period of the period of time, until repair becomes necessary to maintain the serviceability of structures. It is getting more common to specify the service life of a structure, particularly structures exposed to de-icing salt water. To accomplish this study, pier in the harbor was chosen as a experimental area. The service life of decks in marine environment was calculated as sum of three period ; initiation period, propagation period and cracking period. The object of this study is to indicate where and how measures can be adopted for checking relevant service lifes.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.4-5
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• 2020

The research presented in this paper is subject to RC frame that increases seismic capacity by attaching DT(Double T type) steel frame to reinforced concrete column. The object of this study is not only to build experimental database providing necessary information for retrofit column but also to formulate modeling parameters of RC frame retrofitted by DT steel frame through comparing analysis for analytical model predicting inelastic behavior of reinforced concrete members.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.47-52
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• 2001

Short reinforced concrete bridge piers are particularly susceptible to shear failure as a consequence of the high shear/moment ratio and conservatism in the flexural strength design of existing RC bridge pier, which were constructed before 1992. In addition, shear failure is brittle and involves rapid strength degradation. Inelastic shear deformation is thus unsuitable fur ductile seismic response. It is, however, believed that there are not many experimental research works fur shear failure of the existing RC bridge pier in Korean peninsula subjected to earthquake motions. The object of this research is to evaluate the seismic performance of existing circular RC bridge piers by the quasi-static test. Existing RC bridge piers were moderate seismically designed in accordance with the conventional provisions of Korea Highway Design Specification. This study has been performed to verify the effect of aspect ratio (column height-diameter ratio). Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as lateral force-displacement hysteric curve, envelope curve etc.