• Proceedings of the KSR Conference
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• 2011.05a
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• pp.707-716
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• 2011

It has been applied using cranes or insertion methods to install heavy structures to strengthen existing railway bridges. These methods are uneconomical because of two reasons. The first one is it is required to construct approach roads for heavy equipment and/or working yard. The second one is the electric lines shall be cutoff during construction. Both require additional construction cost and duration. In this study, new transport equipment was developed which can be applied to heavy structures up to 100 ton. Using this method, the heavy structure can be loaded into the new transport equipment at working yard and transported to the working site. This method can be applied, but not limited to railway bridge or roadbed rehabilitation. It was found that the precious construction can be achieved to install heavy structure using this method. The experimental construction to make non-ballast girder bridge composite with new pc deck slab using this method was carried out for Jewon bridge. The example bridge is in extreme condition because it locates above national road #38 within extreme transition curve and has 10 ‰ slope and skew. The experimental construction results were satisfactory both for safety and construction precision.

• Journal of the Korea Institute of Building Construction
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• v.2 no.2
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• pp.157-164
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• 2002

In this study, attempts to analyze the case study of production design were carried out through: 1) exploration of the factors influencing the interface between architectural and production design phases; 2)application of precast technologies. Building design and construction planning in Japan may be characterized by ample use of Production Design which extends over the whole projects phases. Taking a composite construction system for apartment buildings which allow for alternative combination of different technologies as a case study object, three projects have been chosen to analyze actual process of determining product sub-system and their specification. And the expectancies of this paper are that it can be used as efficient data for improvement of system to systematize Constructability(Buildability) in korea.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.577-587
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• 1998

The influences of high speed train on the dynamic responses of steel composite railway bridges are investigated. The bridge system which has two I-girder and several cross beams is modeled with plate and frame elements. With assumption of concrete slabs are fully connected with steel girders, the offset between slabs and girders is modeled using constraint equation. The track system is modeled using beams on elastic foundation theory. And, the TGV train model is developed in 2-dimension considering bouncing and pitching motion. And braking action of vehicle is considered using speed dependent braking function. To investigate the behavior of bridges due to moving trains, parametric studies on the variation of natural frequency of bridge, speed parameter, vehicle modeling method, braking action of train, etc are performed.

• Steel and Composite Structures
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• v.39 no.1
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• pp.109-123
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• 2021

This research endeavor intends to use the implicit finite element method to investigate the structural response of steel shear walls with partial plate-column connection. To this end, comprehensive verification studies are initially performed by comparing the numerical predictions with several reported experimental results in order to demonstrate the reliability and accuracy of the implicit analysis method. Comparison is made between the hysteresis curves, failure modes, and base shear capacities predicted numerically using ABAQUS software and obtained/observed experimentally. Following the validation of the finite element analysis approach, the effects of partial plate-column connection on the strength and stiffness performances of steel shear wall systems with different web-plate slenderness and aspect ratios under monotonic loading are investigated through a parametric study. While removal of the connection between the web-plate and columns can be beneficial by decreasing the overall system demand on the vertical boundary members, based on the results and findings of this study such detachment can lower the stiffness and strength capacities of steel shear walls by about 25%, on average.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.18-28
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• 2015

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of U-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D, agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.105-117
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• 2015

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were experimentally performed on one unreinforced beam-column specimen and two reinforced specimens with L-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of L-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D except for the equation to predict the concrete breakout failure strength at the concrete side, principally agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2153-2166
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• 2017

Web apps have a problem that they cause same data to be repetitively retrieved, processed, and displayed when web browsers load different web pages. To resolve the problem, this paper presents and evaluates a new method for restructuring of Java web apps. This approach dynamically analyzes Java web apps from the MVC (Model-View-Controller) architecture point of view and identifies redundant data by using the composite view pattern. Then the input apps are restructured in order not to load the redundant data when users make requests for new pages. This restructuring generates new web apps that conform to the MVC architecture and improve the performance of input web apps. The experimental results showed that when compared to legacy web apps, the restructured apps' response time was reduced on desktop PCs and mobile devices by 38% and 55%, respectively. In addition, case studies using open-source web apps showed the applicability of the proposed approach.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.697-705
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• 1997

The conventional preflex beams are designed by the method of paritial prestressing and allow the tensile stresses at the lower concrete of beams. As a consequence, most of preflex beams experience the tensile cracks under the service loads. This study was conducted to develop the most effective preflex beams, which do not allow tensile stress under the service load, by introducing additional prestressing called 'represtressing' at the lower concrete of beams. The objective of the study was accomplished by developing a computer analysis and design program and conducting experiments. Using the developed computer program, standard sections of the represtressed preflex beams were determined by computer modeling. In the experiment, two actual size of represtressed beams were tested under the imitated service loads. The results of test have shown that the performance of the represtressed preflex beams is generally excellent. A remarkable improvement was made in the design of preflex composite beams. Since the represtressed preflex beams(RPF) do not experience the tensile cracks under the service loads, the use of this beam for the bridge structures will lead to easy bridge maintenance and management. Furthermore, due to the low beam depth, high clearance and economical design can be realized in the bridge design using RPF.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.277-286
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• 2010

Derrick or caterpillar crane is generally used for the long-span/cable-stayed bridge construction by pre-cast segment lifting from over-land or water transportation. The heavy weight of them, however, could make defects on unstable under-construction structure and, furthermore a method of conventional segment transportation is also able to occur additional time and cost. In this study, in order to improve conventional construction method, the newly developed derrick crane is mainly considered. It could be not only eccentrically loadable on constructing girder but having rotatable boom for segment transportation from back-side. A series of construction stage using developed derrick crane is defined and also its numerical analysis is conducted. To reflect load characteristics of developed derrick crane on construction stage analysis, on/out of service load is separately calculated by considering vertical/lateral rotation range of boom and it is loaded on 4 fixed positions of crane. The derrick crane on this study could be time and cost saving solution for cable-stayed bridge construction and also make contributions to construction load reduction in its process.

• Advances in Energy Research
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• v.5 no.3
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• pp.219-226
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• 2017

Electrochemical double layer capacitors (EDLCs) have received a tremendous interest due to their suitability for diverse applications. They have been fabricated using different carbon based electrodes including activated carbons, single walled/multi walled carbon nano tubes. But, graphite which is one of the natural resources in Sri Lanka has not been given a considerable attention towards using for EDLCs though it is a famous carbon material. On the other hand, EDLCs are well reported with various liquid electrolytes which are associated with numerous drawbacks. Gel polymer electrolytes (GPE) are well known alternative for liquid electrolytes. In this paper, it is reported about an EDLC fabricated with a nano composite polyethylene oxide based GPE and two Sri Lankan graphite based electrodes. The composition of the GPE was [{(10PEO: $NaClO_4$) molar ratio}: 75wt.% PC] : 5 wt.% $TiO_2$. GPE was prepared using the solvent casting method. Two graphite electrodes were prepared by mixing 85% graphite and 15% polyvinylidenefluoride (PVdF) in acetone and casting n fluorine doped tin oxide glass plates. GPE film was sandwiched in between the two graphite electrodes. A non faradaic charge discharge mechanism was observed from the Cyclic Voltammetry study. GPE was stable in the potential windows from (-0.8 V-0.8 V) to (-1.5 V-1.5 V). By increasing the width of the potential window, single electrode specific capacity increased. Impedance plots confirmed the capacitive behavior at low frequency region. Galvanostatic charge discharge test yielded an average discharge capacity of $0.60Fg^{-1}$.