• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.5
• /
• pp.531-542
• /
• 2011

The time-dependent temperature distribution across the section in bridges is determined on the basis of the three-dimensional finite element analyses and numerical time integration in this study. The material properties which change with time and thermal stress of concrete are taken into account to effectively trace the early-age structural responses. Since the temperature distribution is nonlinear and depends upon many material constants such as the thermal conductivity, specific heat, hydration heat of concrete, heat transfer coefficients and solar radiation, three representative influencing factors of the construction season, wind velocity and bridge pavement are considered at the parametric studies. The validity of the introduced numerical model is established by comparing the analytical predictions with results from previous analytical studies. On the basis of parametric studies for four different bridge sections, it is found that the creep deformation in concrete bridges must be considered to reach more reasonable design results and the temperature distribution proposed in the Korean bridge design specification need to be improved.

• Journal of Korean Society of Steel Construction
• /
• v.9 no.3 s.32
• /
• pp.351-362
• /
• 1997

In designing short to medium-span bridges, continuous composite bridges are becoming popular due to their advantages. However, if the concrete slab in continuous composite bridge is not prestressed, negative moment occurs in the mid-support and creates problems such as cracks in the concrete slab. Therefore. it must be considered in design. Two methods of arrangement of shear connectors were conducted using finite element elastic plastic analysis. Partial interaction theory was introduced and an analytical solution based on this theory was derived. The differences in the degree of interaction were investigated using analytical solutions and finite element analyses of simple composite beam and continuous composite beams. The results of the analyses were used to determine the advantage and disadvantages as well as any precaution when necessary using partial composite during actual design and construction.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.2
• /
• pp.34-39
• /
• 2016

Structural behaviour of PSC box bridge, on which KTX train runs, is analysed up to 500 km/h speed considering 12 stages track irregularity and interaction between bridge and vehicle. To evaluate wheel forces and rotations of vehicle, lateral wheel forces, derail factor and offload factor calculated on the track combining the bridge and 170 m normal track are compared with existing allowed limits. Maximum longitudinal displacement and accumulated sliding distance of the brige bearings for simply supported and 2 span continuous PSC bridges are presented by each running speeds. Long-term friction tests based on EN-1337-2 are conducted between PTFE and DP-mate plates. Finally, the long-term friction tests are proposed to consider the increasing speed of next generation high-speed train.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.1
• /
• pp.165-174
• /
• 2010

In this paper, a two-phase structural health monitoring system using acceleration response signatures are presented to firstly alarm the change in structural condition and to secondly detect the changed location for full-scale concrete girder bridges. Firstly, Mihocheon Bridge which is a two-span continuous concrete girder bridge is selected as the target structure. The dynamic response features of Mihocheon Bridge are extracted by forced vibration test using bowling ball. Secondly, the damage alarming occurrence and the damage localization techniques are selected to design two-phase structural health monitoring system for Mihocheon Bridge. As the damage alarming techniques, auto-regressive model using time-domain signatures, correlation coefficient of frequency response function and frequency response ratio assurance criterion are selected. As the damage localization technique, modal strain energy-based damage index method is selected. Finally, the feasibility of two-phase structural health monitoring systems is evaluated from static loading tests using a dump truck.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.4
• /
• pp.127-134
• /
• 2005

Design and construction of long-span bridge are recently increasing by development of computer technology. Specially, cable stayed bridge and suspension bridge having cable component are representative of long-span bridge may do. Therefore, this paper a present a methodology for cable tension force monitoring in cable-stayed bridge under construction using acceleration data acquired by the vibration method. To improve accuracy construction, all stay cables are measured, according to 4-step construction stage and change of temperature.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.13 no.1
• /
• pp.25-35
• /
• 2000

The superstructure of general bridge like slab bridge and slab on girder bridge is composed of elastically supported isotropic plate. The objective of this study is to develop the new analysis method for elastically supported plate with general edge beam or girder(boundaries) under arbitrary out of plane loading. The displacement solutions for the macro-element of plate and beam are obtained by solving for the unknown interactive forces and moments at the beam or nodal line locations after satisfying equilibrium equation along the nodal line. The displacement functions for macro-elements ate proposed in single Fourier series using harmonic analysis, and the equilibrium equations of nodal line are composed by using slope-deflection method. The proposed analysis method is programmed by MS-Fortran and can be applied to all types of isotropic decks with bridge-type boundaries. Numerical examples involving elastically supported plates with various aspect ratio, loading cases, and bridge-type boundary conditions are presented to demonstrate the accuracy of this program. The major advantage of this new analysis method is the development of a simple solution algorithm, leads to obtain rapidly responses of bridge deck system. This proposed method can be used in parametric study of behavior of bridge decks.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.13 no.1
• /
• pp.13-24
• /
• 2000

Current specification prescribes that upper and lower reinforcement mat is required in the same amount to resist negative and positive moment in bridge decks. But the negative moment is much smaller than positive moment because the actual behavior of decks consists of local deflection of slab and global deflection of girder. From this study, the analysis method based on harmonic analysis and slope-deflection method was developed and verified by finite element method. The negative moment, obtained from this method, were smaller than those computed based on the KHBDC specifications as much as 40∼50% in the middle of bridge. The amount of reduction of the design negative moment was shown herein to be dependent on variable parameters as shape factor(S/L) of slab, relative stiffness ratio of girder and deck slab, and so on. This investigations indicate that the upper reinforcement mat to resist negative moment can be removed. But further experimental study is required to consider durability and serviceability. From this new design concept, the construction expense can be reduced and the problem of decreasing durability resulting from corrosion of upper reinforcement steel settled.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.174-177
• /
• 2011

비선형 정적 해석법(NSPs)은 최근 구조물의 지진해석방법으로서 그 사용성을 인정받고 있다. 비선형 정적 해석법은 직관적으로 구조물의 지진해석을 수행할 수 있는 등의 장점으로 빌딩구조물의 지진해석법으로 널리 사용되고 있지만, 기본 진동모드에 의해서 구조물의 거동이 지배되지 않는 구조물의 경우에는 그 사용성에 대한 연구가 매우 제한적이다. 이를 개선하기 위한 고차모드의 기여분을 반영할 수 있는 비선형 정적 해석법들이 제시 되었지만, 교량 구조물에 사용함에 있어서는 여전히 지진의 특성에 따라 그 사용성 및 신뢰성이 크게 변화하는 문제가 발생한다. 이 논문에서는 지진의 특성을 고려할 수 있는 두가지 지수를 제시하고, 이를 이용하여 비선형정적 해석법의 적용성을 사용단계에서 알아 낼 수 있는지에 대한 연구를 진행하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.05a
• /
• pp.758-759
• /
• 2010

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.448-455
• /
• 2007

In 1992, the first design standard of quake proof bridge was established. However, most bridge structures which were constructed without considering earthquake in former times need performance of quakeproof property. Quakeproof analysis in current bridges, is based on analysis of load base which just has strength over the load of simple structures but is not checked through simple comparison of strength performance of structures so that we would like to check that ADRS method is reasonable or not using ADRS method(Accleration-Displacement Response Spectrum Method), a analysis method based on displacement of object of performance test. As the result of that, the capacity spectrum method can avoid complex dynamic analysis in analysis based on loads and it efficiently applies to design verification with normal checking for quakeproof performance and aimed performance of new structures. However we can not consider effects of high modes and it has problem that does not consider falling of performance in structures by repeated load.