• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1537-1542
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• 2007

In this study, based on a I-roll embedded steel composite deck, it is suggested a new type of simplified composite deck and analyzed under construction loading. Using ABAQUS, it's estimated effects of welding amount of steel plate and I-section, existence of a hole of I-section's flange, and a location of hole. For a reasonable verification of modeling, compare Euler-Beam theory with F.E.M models. In result, it is verified that change of welding amount increase more maximum bending tension stresses at the central part's section of span when elements are partial-welded. Also, verify that deflection is slightly increased when a hole existed compared with no hole.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.197-201
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• 2008

Conceptual cost estimates for domestic highway projects have generally been conducted using governmental unit-price references. Inaccuracies in governmental unit-price data has repeatedly addressed in the Korean construction industry which often lead to poor decision making and cost management practices. Thus, needs for developing a better way of conceptual cost estimating has been widely recognized. This research is considered as the first step in developing such model using real-world cost data based on actual construction activities. The data analyzed in this paper includes 41 P.S.C (Prestressed Concrete) Box bridges which broke into 4 categories based on construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). Actual design documents; including actual cost estimating documents, drawings and specifications were carefully reviewed to effectively break down cost structures for PSC girder bridges. Among more than 40 cost categories for each P.S.C girder bridge type, 7 of them were identified which accounted for more than 95% of total construction cost (ILM: 99.47%, MSS: 99.22%, FSM: 98.18%, and FCM: 98.12%). In order to validate the clustering of cost categories, the variation of each cost category has been investigated which resulted in between -1.16 % and 0.59%.

• Journal of Korean Society of Steel Construction
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• v.22 no.4
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• pp.377-388
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• 2010

The flexural behavior of composite HSB600 and HSB800 I-girders under a positive moment was investigated using the material non-linear moment-curvature analysis method. Three representative composite sections with different ductility properties were selected as the baseline sections in this study. Using these baseline sections, the moment-curvature program was verified by comparing the flexural strength and the moment-curvature curve obtained from the program with those obtained using the non-linear FE analysis of ABAQUS. In the FE analysis, the composite girders were modeled three-dimensionally with flanges, the web, and the concrete slab as thin shell elements, and initial imperfections and residual stresses were imposed on the FE model. In the moment-curvature and FE analyses, the 28-day compressive strength of the concrete slab was assumed to be 30-50 MPa, and the HSB600 and HSB800 steels were modeled as elasto-plastic strain-hardening materials, with the concrete as the CEB-FIP model. The effects of the ductility ratio of the composite girder, the type of steel, the compressive strength of the concrete deck, and the location of the plastic neutral axis on the flexural characteristics were analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.746-749
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• 2004

A new-type of FRP-concrete composite bridge deck system is proposed and its behaviors are experimentally studied. The new-typedeck consists of FRP as a permanent form and main tension resisting member and concrete as a compression resisting member. A suitable bonding method such as silica coating is applied to the interface between FRP and concrete to ensure composite behavior. The proposed deck system uses the box-shape FRP member, while a typical FRP-concrete composite deck uses the I-shape FRP member. Theproposed deck system has inherent advantages of a FRP-concrete composite deck like corrosion free and easy construction. The new-type deck shows the equal performances compared to a previous one, and has the advantage of reducing self-weight. In this study, the static tests on 3-span FRP-concrete decks in full scale are carried out, so that load-displacement relation, stress distribution, failure mode and design criteria are analyzed. The test results show that the deflection design criterion (L/800, L: span length) is satisfied at the service load state. No concrete tensile crack occurs in the negative moment region above the main girder, regardless of no tensile reinforcement at upper concrete portion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.81-94
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• 2010

This paper deals with the fracture simulation of UHPFRC girder with the interface type model. Based on the existing numerical simulation of quasi-brittle fracture in normal strength concrete, constitutive modeling for UHPFRC I-girder has been improved by including a tensile hardening at the failure surface. The finite element formulation is based on a triangular unit, constructed from constant strain triangles, with nodes along its sides and neither at the vertex nor the center of the unit. Fracture is simulated through a hardening/softening fracture constitutive law in tension, a softening fracture constitutive law in shear as well as in compression at the boundary nodes, with the material within the triangular unit remaining linear elastic. LCP is used to formulate the path-dependent hardening-softening behavior in non-holonomic rate form and a mathematical programming algorithm is employed to solve the LCP. The piece-wise linear inelastic yielding-failure/failure surface is modeled with two compressive caps, two Mohr-Coulomb failure surfaces, a tensile yielding surface and a tensile failure surface. The comparison between test results and numerical results indicates this method effectively simulates the deformation and failure of specimen.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1028-1033
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• 2004

The open deck steel bridge is the most common type in railway bridges. Steel I-shaped girders are connected with sleepers directly without ballast and moving train loads are transmitted directly to the girder, so this bridge has weak characteristics on impact. Therefore, considerable accelerations can cause unsatisfactory dynamic behavior of the open deck steel bridge. Especially, Impact created at rail joints can increase the dynamic response of the bridge and this phenomenon would be injurious to passenger comfort. In the present study, dynamic behavior of the open deck steel bridge which has a rail joint is estimated through experimental studies and bridge-train interaction analysis considering surface irregularities by rail joints.

• 연구논문집
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• s.29
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• pp.57-67
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• 1999

This paper presents the status quo of the development of a piecewise bendable switch system for the urban transit MagLev. MagLev system as well as railroad requires switch systems to reach its destination. Requirements of the switch system for commercial lines are high speed operation satisfying about 2-3 minute headway and system reliability, etc. Parallel moving type switch system was installed on the test track of urban transit MagLev in KIMM. In this system, switch operation from one position to another can be done in about 90 seconds. Therefore, we concluded that this system can not satisfy the headway for the commercial lines. We decided to develop a high speed piecewise bendable switch system in which switching can be done in 20 seconds. Designed switch system is very complicated in view of operating mechanism. It consists of 11 segmented girder beams driven by hydraulic cylinders. To gain the idea of a piecewise bendable switch system, we manufactured and tested a 1/5 scale switch model. We are going to construct a full scale piecewise bendable switch system next year.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.722-728
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• 2000

This study of field control machine in the recycled vinyl rail is gantry crane type and promoting agricultural automatization through self-controlled spraying, harvesting and conveyance. In addition to, that control machine could get a cost and labor reduction effect through automatization and make better environment by preventing farmers from agrichemical damage, accidents and recycling wasted vinyl. That machine is able to be divided as traveling, spraying, harvesting and conveyance sections. In driving section consists of girder frame, carrier, rail, control system, driving system, working machine, rail and loading device for working machine. This machine has following advantages to be able to bring a big innovation in the agricultural industry. I) Accurate performance is able to be done by proper positioning due to based on the rails. 2) The soil is not made hard like heavy tractor 3) The wheel is not sank into the soil and slipped well under rain like heavy tractor. Therefore, weather and soil situation could not affect working condition. 4) Complete unmanned control and 24hours-working are available due to traveling on the rails. 5) It could use various energy resources like not only liquid fuel but also solar, common electronic power due to traveling on the rails.

• Steel and Composite Structures
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• v.51 no.6
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• pp.647-659
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• 2024

Given the increased interest in enhancing structural sustainability, the current study sought to apply multiobjective optimization to a footbridge with a steel-concrete composite I-girder structure. It was considered as objectives minimizing the cost for building the structure, the environmental impact assessed by CO2 emissions, and the vertical accelerations created by human-induced vibrations, with the goal of ensuring pedestrian comfort. Spans ranging from 15 to 25 meters were investigated. The resistance of the slab's concrete, the thickness of the slab, the dimensions of the welded steel I-profile, and the composite beam interaction degree were all evaluated as design variables. The optimization problem was handled using the Multiobjective Harmony Search (MOHS) metaheuristic algorithm. The optimization results were used to generate a Pareto front for each span, allowing us to assess the correlations between different objectives. By evaluating the values of design variables in relation to different levels of pedestrian comfort, it was identified optimal values that can be employed as a starting point in predimensioning of the type of structure analyzed. Based on the findings analysis, it is possible to highlight the relationship between the structure's cost and CO2 emission objectives, indicating that cost-effective solutions are also environmentally efficient. Pedestrian comfort improvement is especially feasible in smaller spans and from a medium to a maximum level of comfort, but it becomes expensive for larger spans or for increasing comfort from minimum to medium level.

• Journal of the Korea Concrete Institute
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• v.29 no.4
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• pp.371-378
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• 2017

In this study, the flexural behavior of the RC Arch Deck under static loading was evaluated. Flexural test was carried out using an actual size RC Arch Deck with a length of 2.5 m, a center thickness of 100 mm and an end thickness of 160 mm. The test results showed that it's ultimate load was 1.74 times higher than the ultimate design load. On the other hand, it showed that the flexural behavior has different behaviors (i.e. different stiffness). This type of structural behavior indicates that it has inter-dependency between the deck and the supporting girder. Therefore, it is necessary to confirm the precise behavior by the static loading test of the RC Arch Deck, excluding the girder effect in the future study. The overall results showed that RC Arch Deck has excellent structural performance due to the structural advantages of the arch shape. In the future, the RC Arch Deck can be applied as a long span slab.