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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Steel Construction
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Journal DOI :
Korean Society of Steel Construction
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Volume & Issues
Volume 18, Issue 6 - 00 2006
Volume 18, Issue 5 - 00 2006
Volume 18, Issue 4 - 00 2006
Volume 18, Issue 3 - 00 2006
Volume 18, Issue 2 - 00 2006
Volume 18, Issue 1 - 00 2006
Selecting the target year
The Model to Generate Optimum Maintenance Scenario for Steel Bridges considering Life-Cycle Cost and Performance
Park, Kyung Hoon ; Lee, Sang Yoon ; Kim, Jung Ho ; Cho, Hyo Nam ; Kong, Jung Sik ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 677~686
In this paper, a more practical and realistic method is proposed to establish the lifetime optimum maintenance strategies of the deteriorating bridges considering the life-cycle performance as well as life-cycle cost. The genetic algorithm is applied to generate the set of maintenance scenarios that is the multi-objective combinatorial optimization problem related to lifetime performance and cost as separate objective functions, and the technique to select optimum tradeoff maintenance scenario is presented. Optimum maintenance scenarios could be generated not only at the individual member level but also at the system level of the bridge. Through the analytical results of applying the proposed methodology to the existing bridge, it is expected that the methodology will be effectively used to determine the optimum maintenance strategy for introducing a real preventive maintenance system and overcoming the limits of existing maintenance methods.
Elasto-plastic Post-buckling Analysis of Spatial Framed Structures using Improved Plastic Hinge Theory
Kim, Sung Bo ; Ji, Tae Sug ; Jung, Kyoung Hwan ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 687~696
An efficient numerical method is developed to estimate the elasto-plastic post-buckling strength of space-framed structures. The inelastic ultimate strength of beam-columns and frames is evaluated by the parametric study. Applying the improved plastic hinge analysis that evaluate the gradual stiffness decrease effects due to spread of plasticity, elasto-plastic post-buckling behavior of steel frames is investigated considering the various residual stress distributions. Introducing the plastification parameter that represent pread of plasticity in the element and performing parametric study of equivalent element force and member idealization, finite-element solutions for the elasto-plastic analysis of space frames are compared with the results by plastic region analysis, shell elements and experimental results.
Wall Tie Member Force Curve for the Construction Tower Crane
Ko, Kwang IL ; Oh, W.H. ; Lee, E.T. ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 697~706
Tower crane's wall tie is generally used for extending of mast height according to rising of lifting height. In order to get wall tie member force this problem, this study concerning wall tie is based on load data described in manual book of 290HC model. This study made the equation of wall tie member force and computer programming for calculating wall tie member force and then get
curves(angle-wall tie force). After considering the
curves, optimum angle range (
) about wall ties (A), (C) members was obtained. Member force of wall tie (B) was changed from tension to compression or from compression to tension at
in service and
in out of service. When both horizontal force(
) and torsional moment (
) were varied from (+) to (-), wall tie force(A, B, C) were changed almost symmetrically about
-axis. Because this study was based on wall tie analysis conditions, wall tie members in symmetric and ideal geometry shape used for analizing wall tie of tower crane, it is necessary to have more careful verification in order to apply generally the results of this study.
Optimization of direct design system of semi-rigid steel frames using advanced analysis and genetic algorithm
Choi, Se Hyu ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 707~716
The optimization of the direct design system of semi-rigid steel frames using advanced analysis and genetic algorithm was presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. The genetic algorithm was used as the optimization technique. The objective function was assumed as the weight of the steel frame, with the constraint functions accounting for load-carrying capacities, deflections, inter-story drifts and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional method.
A Study on Strengthening of Steel Girder Bridge using Multi-Stepwise Thermal Prestressing Method
Kim, Sang Hyo ; Kim, Jun Hwan ; Ahn, Jin Hee ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 717~726
Traditional external post-tensioning method using either steel bars or tendons is commonly used as a retrofitting method for steel composite bridges. However, the method has some disadvantages such as stress concentration at anchorages and inefficient load-carrying capability of live loads. Multi-stepwise prestressing method using thermal expanded coverplate is a newly proposed prestressing method, which was originally developed for prestressing steel structures. A new retrofitting method for steel girder bridges founded on a simple concept of thermal expansion and contraction of cover plate, the method is a hybrid of and combines the advantages of external post-tensioning and thermal prestressing. In this paper, basic concepts of the method are presented and an illustrative experiment is introduced. From actual experimental data, the thermal prestressing effect was substantiated and the FEM approach for its analysis was verified. The retrofitting effects ofa single-span bridge were analyzed and the feasibility of the developed method was examined.
Geometric nonlinear analysis of steel structures with external pretension using the multi-noded cable element
Lee, Jun Seok ; Kim, Moon Young ; Han, Man Yop ; Kim, Sung Bo ; Kim, Nak Kyung ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 727~735
In this paper, a geometric nonlinear analysis procedure of the beam-column element including multi-noded cable element in extension of companion paper (Kim et al., 2005) is presented. First, a stiffness matrix was derived about the beam-column element that considers the second effect of the initial force supposing the curved shape at each time-step, with Hermitian polynomials as the shape function. Second, the multi-noded cable element was also subjected to the tangent stiffness matrix. To verify the geometric nonlinearity of this newly developed multi-noded cable-truss element, the Innovative Prestressed Support (IPS) system using this theory was analysed by geometric nonlinear method and the results were compared with those produced by linear analysis.
Elastic Behavior Characteristics of GFRP Pipes Reinforced Ribs
Han, Taek Hee ; Seo, Joo Hyung ; Youm, Eung Jun ; Kang, Young Jong ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 737~746
The elastic buckling strength of a Glass Fiber Reinforced Plastic (GFRP) pipe reinforced with ribs was evaluated. The height and thickness of a rib and the spacing between two adjacent ribs were considered as factors affecting the buckling strength of the pipe. And also, the ratio of the longitudinal stiffness and transverse stiffness was considered as the parameter affecting the buckling strength as the GFRP is orthotropic material. Buckling strengths of various GFRP pipe models with different shapes and stiffness ratios were evaluated by FE analyses and a formula to estimate the elastic buckling strength of a rib-reinforced pipe made of orthotropic material was suggested from the regression with the results from the FE analysis. Analytical results show that a rib-reinforced pipe has a buckling strength superior to a general flat pipe and the suggested formula estimates accurate buckling strength of the rib-reinforced pipe.
The Methodology of Determination of the Allotment Ratio in Maintenance Cost on the Multi-Purpose Steel Bridge
Kim, Kyoung Nam ; Lee, Seong Haeng ; Jung, Kyoung Sup ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 747~758
With the growth of economy, the esthetic values of bridges become significant points in the decision process of a type of new bridges. So, it is common that a long-span bridge or a multi-purpose bridge are selected as the type of new bridges. Also, the economic growth derives increase in traffic and then the increased traffic derives multi purpose bridges from the decision process of bridge types. In the multi-purpose bridges with private fund, the construction cost is simply alloted to several organizations according to the percentage of participation and usage. But the allotment of the maintenance cost is not simple. Because the loads and safety factors in design are different between the criterion of design of highway bridges and that of railway bridges. In this study, we verify the possible problems in case of allotment method of maintenance cost in foreign examples as well as domestic example. As one of the method of determination of allotment ratio in maintenance cost, the method based on the stress of structural analysis is presented and it can be an example in the similar problem later.
Development of a Tensile Force Measurement Device for Long-term
Shin, Kyung Jae ; Lee, Swoo Heon ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 759~768
The turn-buckle inserted between tension members is a device adjusting a tensile force in tension member. However, the measurement of designed tensile force is impossible and the tensile force is determined based on the experience of field workers. The conventional turn-buckle might be used without any adjustment even though the tensile force has been changed for long term. To improve the disadvantages of conventional turn-buckles a turn-buckle which is measurable the tensile force is developed. In this study, the displacement to the lateral direction is induced by the deformation of curved elements if the tensile force is applied to the new type of turn-buckle that the straight elements are slightly curved. The total lateral displacement could be measured by using the micrometer or vernier-calipers. Trial devices for a measurable turn-buckle were made and tested. An theoretical study was also conducted to show the applicability, and parametric studies were conducted. The appropriate shape and capacity were determined by the parametric study.
Dynamic Characteristics of Railway Plate Girder Bridges with Increase of Diesel Locomotive Speed
Cho, Eun Sang ; Kim, Hyun Min ; Hwang, Won Sup ; Oh, Ji Taek ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 769~782
As the ambient vibration test (AVT) of railway bridges has a limited range of speed, it has a limitation in examining the dynamic behavior of bridges accordingto speed. Thus, in order to analyze the correlation between the speed of a train passing over a bridge and the bridge's dynamic response, we conducted a speed-increasing experiment using a real diesel locomotive. To analyze the acceleration response characteristics, we attached seven vertical accelerometers at equal intervals throughout the entire section of the bridge except the supports, and one horizontal accelerometer to the middle span. Linear variable differential transformers (LVDT) were installed at the bridge's center in both vertical and horizontal directions to investigate the vertical and horizontal behaviors. The test train was statically loaded at the center and at the end of the bridge. And its speed was increased from 5 km/h to 90 km/h. With data obtained from the experiment, the vibration level was evaluated in each direction by the filtering frequency, and the level of horizontal vibration was examined in comparison with vertical vibration. The displacement and wheel load variation was analyzed by speed.
Multi-Stepwise Prestressing Method of Steel Structure Using Thermal-Expanded Cover-plate
Kim, Sang Hyo ; An, Jin Hee ; Kim, Jun Hwan ; Kim, Hyung Ju ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 783~792
This study investigates developments in a prestressing method using the thermal-expanded cover-plates that increases the load-carrying capacity of structures by installing it on upper or lower flanges in case that huge flexural stiffness according to the increase in span length or load are required of steel structure, such as rolled H-beam or built-up beam. This method applies multi-stepwise contraction forces generated by the contraction of cover plates as prestressing forces after joining the cover plate applied by multi-stepwise thermal expansion that was applied to induce prestressing to structures. To perform a theoretical investigation of the prestressing force applied to a structure due to the thermal expansion and induce a multi-stepwise prestressing method using multi-stepwise thermal distribution, this study proposes a theoretical heat transfer solution for the multi-stepwise thermal distribution of cover plates and analyzes the effect of a multi-stepwise prestressing method using the multi-stepwise thermal expansion.
Dynamic Behavior of the Prestressed Composite Girder by Modal Tests and Moving Train Analysis
Kim, Sung Il ; Lee, Pil Goo ; Lee, Jung Whee ; Yeo, In Ho ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 793~804
Various PSC and steel-concrete composite railway bridges are being developed for short-medium spans with structural and economic efficiency. According to the design concept, the prestressed composite girder bridge has the advantages of being lightweight and having low girder depth, with the capacity for long spans. However, the dynamic behavior under a passing train is one of the critical issues concerning these railway bridges designed with more flexibility. Therefore, it is very important to evaluate the modal parameters before performing dynamic analyses. In this paper, real-scale prestressed composite girders were fabricated as a test model and modal testing was carried out to evaluate modal parameters including natural frequency and modal damping ratio. During the modal testing, a digitally controlled vibration exciter as well as an impact hammer was applied to obtain frequency-response functions, and the modal parameters were also evaluated after the fracture of test models. With application of reliable properties from modal tests, the estimation of dynamic performances of prestressed composite girder railway bridges can be obtained from various parametric studies on dynamic behavior under the passage of a moving train.
Initial Stiffness Evaluation of T-stub Connection
Lee, Myung Jae ;
Journal of Korean Society of Steel Construction, volume 18, issue 6, 2006, Pages 805~813
The objective of this study is to ascertain the applicability of T-stub connection for rigid connections. Tests and analysis are focused on the initial stiffness and their results are compared with the case of general rigid connections. Influential factors are investigated from the analysis results.