• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.73-78
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• 1992

It would be much effective that single column type pier is used in concrete slab bridges rather than gravity type pier is used. To determine the longitudinal bonging moment in concrete slab bridges supported by single column type piers, the concept of effective width is applied. By elastic plate theory cooperated with finite element method, the distribution of the longitudinal moment of the slab supported by single column type piers is studied. The main variables are span, width, and thickness of the slab and column section size. Then the analytical results obtained are summarized and analysed to evaluate the maximum longitudinal negative moment by simple beam analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.1
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• pp.23-31
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• 2002

The purpose of this study is to investigate the size effect on inelastic behavior of reinforced concrete bridge piers. A computer program, named RCAHEST(reinforced concrete analysis in higher evaluation system technology), for the analysis for reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuous deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel. To determine the size effect on bridge pier inelastic behavior, a 1/4-scale replicate model was also loaded for comparison with the full-scale bridge pier behavior.

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.114-119
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• 2001

Goda formula (Goda, 1973) has been used in the determination of wave pressures acting on a large size caisson such as the pier of the cable stayed bridge at sea. Goda formula, however, is to evaluate the wave pressures acting the infinite vertical caisson of composite breakwater so that it can`t be applied to a large caisson with finite width and length because of diffraction effects. In the present study, three dimensional nonlinear frequence domain method based on perturbation method and boundary integral method is applied to the computation of the linear and nonlinear wave pressures acting on the front of a large size caisson under the variation of its width and length, and angle of incident wave. The numerical results are compared to Goda\`s ones, and then the characteristics of wave pressure distributions acting on a large size caisson are discussed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.2
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• pp.145-151
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• 2008

The research so far has primarily analyzed efficiency improvement but in this research, it analyzes the characteristics of earthquake behavior, with changed pier heights, through ordinary and seismic analysis. For this, the kind of bridge bearing has been changed against PSC I-shaped bridge, which is mostly used in practice, and at all times earthquake analysis has been performed with through height of pier. Especially considering sectional power resulting from earthquake analysis, displacement of PSC I-shaped bridge bearing, diameter of pier pillar by earthquake load, and upper spare gap have been analyzed. In case of high-pear, seismic isolated device is decided as proper for cars' driving and for management of bridge since it decreases movement of upper structure, than elastic bearing, reducing size of elastic connect device, and it's been analyzed it is effective for improvement of fine view and economic efficiency reducing section of lower bridge structure. Finally, when design PSC I-shaped bridge bearing, for the proper structure and high-pier side, applying seismic isolated device through precise inner analysis is proper than applying equal elastic bearing.

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.753-761
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• 2001

In this paper, the experiments to decide the riprap size for the local scour protection at bridge piers and the coefficients of attack angle were conducted. A formula for the decision of the riprap size and a figure for the coefficients of attack angle were suggested based upon the experimental results. The coefficients of attack angle indicate different values based on the variation of the length-width ratio of bridge pier and the coefficients are increased by the increment of the attack angle. In this paper, the experiments using the piers having the opening ratios of 90%, 92.86% and 95% were conducted. Also, the attack angles 0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and 60$^{\circ}$ as well as four different length-width ratios of the bridge pier were utilized. The suggested formula were compared with 6 different formulas and the riprap sizes calculated using the equation suggested in this paper indicate the similar patterns with the formula suggested by Richardson. The suggested formula in this paper can be widely applied in the riprap design for the local scour protection around the bridge pier with the consideration of the attack angle to the flow.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.4
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• pp.253-259
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• 2018

Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.

• Journal of the Korean Institute of Navigation
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• v.13 no.3
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• pp.37-44
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• 1989

Recently recognize the labor productivity of port physical distribution system in the port and shipping areas, Much Efforts for evaluating this productivity has been made continuously. BUt still there is little study, so far, on a systematic research for the management of port labor gangs, and even those were mainly depended on a rule of thumb. Especially the object of this study is to introduce the method of optimal allocation and assignment for the labor gangs per pier unit in the multiple ships berthed at an arbitary pier or port. In case the multiple ships have a homogeneous cargoes or do not have sufficient labor gangs to be assigned. The problem of optimal allocation and assignment of the labor gangs to be i) formalized with multi-state decision process in form of difference equation as the pattern which converted the independent multiple ships into a single ship with the intra-multiple ships, and ii) the optimal size of labor gangs could be obtained through the simple mathematical method instead of complicated dynamic programming, and iii) In case of shortage of labor gangs available the evaluation function considering the labor gangs available and total shift times was introduced, and iv) the optimal allocation and assignment of labor gangs was dealt at the point of minimizing the summation of the total shift times and at the point of minimizing the total cost charged for the extra waiting time except PHI time during port times for the multiple ships combinations.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.300-307
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• 2002

Bridge foundation failure considering the effect of local scour around pier foundations under hi-directional seismic excitations is examined in probabilistic perspectives. The seismic responses of bridges with deep foundations are evaluated with a simplified mechanical model, which can consider the local scour effect around the deep foundation in addition to many other components. The probabilistic characteristics of local scour depths are estimated by using the Monte Carlo simulation. The probabilistic characteristics of basic random variables used in the Monte Carlo simulation are determined from the actual hydraulic data collected in middle size streams in Korea. The failure condition of deep foundation is assumed as bearing capacity failure of the ground below the foundation base. The probability of foundation failure of a simply supported bridge with various scour conditions and hi-directional seismic excitations are examined. It is found that the local scour and the recovery duration are critical factors in evaluating the probability of foundation failure. Moreover, the probability of foundation failure under hi-directional seismic excitations is much higher than under uni-directional seismic excitations. Therefore, it is reasonable to consider hi-directional seismic excitations in evaluating the seismic safety of bridge systems scoured by a flood.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.94-105
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• 2013

Recently, the construction industry has been changed in such a way that the cost for bridge construction should be optimized or reduced. Therefore, bridges are required be cost-effective in terms of initial construction as well as in the maintenance during service stage. In order to reduce the cost for bridge construction, the Rahmen typed structure, in which the bridge components from superstructure to substructure are integral, has many advantages to reduce the size of structural members including girders, since the loadings from superstructure may be transferred to substructure through the connecting rebars such as stud, etc. This paper studied on the continuous Up and Down Prestressed Concrete (UD PSC) girder bridge in which the reinforced concrete pier cap is integral with the part of girders in superstructure. In previous studies, it is known that the structural behavior of continuous UD PSC girder bridge is quite different compared to the one of the bridges with conventional bearings or shoes to support the loading from girders. Nevertheless, it has hardly been studied about the structural behavior of bridge with UD PSC girder. Therefore, in this study, various dynamic behaviors of continuous UD PSC girder bridge with integral pier cap have been analyzed using numerical method. Furthermore, an equation to evaluate the impact factor is suggested for the UD PSC girder bridge which has two to three continuous spans.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.120-127
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• 1998

This paper deals with the dynamic responses of the multi-span continuous bridge with longitudinal shear keys. It is motivated by a need to understand the effects of longitudinal shear keys which may be used for the reduction of the longitudinal seismic force in continuous bridges. The results show that (1) The force reduction of fixed pier is proportional to the ratio of gap size and elastic maximum displacement of the bridges without shear keys ; (2) The thermal movement has little effect on the response of the continuous bridges with shear keys. Also the simplified equation is proposed to calculate the maximum response of the continuous bridges with longitudinal shear keys. The equation requires only the elastic analysis results of the bridge and the gap size between superstructure and shear keys.