• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.647-657
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• 2017

The main purpose of this study is to investigate the static & dynamic behavior of a precast bracket under precast road deck slab of double deck tunnel. In order to improve the construction speed, the field prefabricated bracket to connect the intermediate slab to the precast shield tunnel lining structure has been developed in the 'SPC (Steel Precast Concrete) bracket'. The experiments were performed for the full scale model in order to evaluate the performance of the 'SPC bracket', the structural stability was verified through the FEM analysis. The result of static loading test, no deformations or cracks of the bracket undergo the ultimate load was investigated. In addition, no pulling or deformation of the chemical anchor for fixing the bracket was measured. As a result of dynamic loading test, it was investigated that there is no problem in the chemical anchor for fixing the bracket. FEM analysis showed similar behavior to static load test and it was determined that there is no problem in serviceability and structural safety.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.47-54
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• 2016

In this study, the flexural capacity of fiber reinforced concrete floor slabs were evaluated using main design loads, racking and moving loads. Based on design standards and guidelines, the magnitude and loaded area of each load were determined, and its relationship was assessed. For the application of a single load, flexural capacity should be evaluated in the edge of a floor slab. In addition, the slab with thickness and concrete strength, greater than 180mm and 35MPa, respectively, sufficiently satisfied flexural capacity with a minimum of equivalent flexural strength ratio. The combination of racking loads required the largest equivalent flexural strength ratio to satisfy the flexural capacity of the floor slab. The combination of racking and moving loads showed equivalent flexural strength ratio smaller than the case of combination of racking loads, but larger than the application of single racking or moving loads. The results of this study indicated that the flexure of fiber reinforced concrete floor slabs should be designed using the combination of design loads.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.17-24
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• 1992

It would be much effective that single column type pier is used in concrete slab bridges rather than ${\Pi}$ or gravity type pire is used. To determine the longitudinal benging 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. thickness of the slab, and column section size. The analytical results obtained are summarized and analysed to evaluate the maximum longitudinal negative moment, then a simplified method for calculating the longitudinal moment is proposed.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.27-37
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• 2007

This research was conducted to determine the optimum lifting positions on precast concrete slabs for precast concrete pavement construction, based on the analysis of concrete stress distribution under various lifting conditions. To analyze stresses in concrete slabs, the finite element method was implemented and a numerical model of the precast slab that was going to be used in the experimental construction was developed. Changes in the stress distribution due to the lifting angle were investigated because slab lifting is not always performed in the perpendicular direction to the slab surface. In addition, the effect of the lifting level, the distance between the neutral axis of the slab and the lifting point, on the stress distribution was investigated since the lifting point is not always at the neutral axis of the slab. To consider the actual steel design of the precast slab, the effect of the reinforcement near the lifting point was also investigated. From this study, the optimum lifting positions of the precast slabs were determined according to the lifting angle and level, and the results were compared with the lifting positions used in the PCI standards.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.115-124
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• 2003

In this paper, the effects of vehicle loads on flat slab system are investigated on the basis of the previous studies for beam-gilder parking structural system. The influence surfaces of flat slab for a typical design section are constructed lot the purpose of obtaining maximum member forces under vehicle loads. In addition, the equivalent vehicle load factors for flat slab parking structures are suggested using artificial neural network. The network responses we compared with the results obtained by numerical analyses to verify the validation of Levenberg-Marquardt algorithm adopted as training method in this Paper. Many parameter studies for the flat slab structural system show dominant vehicle load effects at the center positive moments in both column and middle strips, like the beam-girder parking structural system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.1-15
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• 1992

A Practical and easily applicable methods for the numerical analysis and the optimum design of continuous and horizontally curved two-way slab systems with twelve possible edge conditions are presented. The proposed method for the numerical structural analysis is based on the use of design moment coefficients which are derived from the elastic theory of thin curved plates. The optimum values are selected from within the feasible region in the design space defined by the limit state requirements. The sequential linear programming is introduced as an analytical method of nonlinear optimization. The optimum design variables, including a effective depth and transformed steel ratios per unit width of middle and column strips of slabs, are then determined.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.331-340
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• 2021

The blast damage behavior of reinforced concrete (RC) structures exposed to unexpected extreme loading was investigated. To enhance the accuracy of numerical simulation for blast loading on RC structures with seven blast points, the calculation of blast loads using the Euler-flux-corrected-transport method, the proposed Euler-Lagrange coupling method for fluid-structure interaction, and the concrete dynamic damage constitutive model including the strain rate-dependent strength and failure models was implemented in the ANSYS-AUTODYN solver. In the analysis results, in the case of 20 kg TNT, only the slab member at three blast points showed moderate and light damage. In the case of 100 kg TNT, the slab and girder members at three blast points showed moderate damage, while the slab member at two blast points showed severe damage.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.39-49
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• 2007

The objective of this study was to investigate features of transverse crack occurrence and propagation in continuously reinforced concrete pavement(CRCP) when subjected to environmental loading. The finite element model of CRCP was developed and the element removal method was implemented to predict the crack propagation process. To investigate the effect of the type of environmental loading on the CRCP behavior and cracking aspects, the following three different cases were considered: (1) the temperature gradient between top and bottom of the slab does not vary and the constant temperature drop throughout the depth occurs; (2) the temperature at the slab bottom does not vary and the temperature gradient increases; and (3) the temperature between the mid-depth and the bottom of the slab is the same and does not vary and the temperature at the top decreases. The analysis results showed that the crack occurrence and propagation through the depth of the slab in CRCP were significantly affected by the type of environmental loading. The changes in stress distribution and displacements during the crack occurrence and propagation process could also be investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.59-64
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• 1993

The flexural and horizontal shear behavior of overlaid concrete slabs is investigated in the present study. An experimental program was set up and several series of overlaid concrete slabs have been tested to study the effect of different surface preparation ; and dowels between old slab and overlay under service load. The present study indicates that the overlaid concrete slabs behave integrally with existing bottom slabs up to yield range for rough and doweled joints.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.195-202
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• 1999

This study present the stability of middle slabs directly supporting train loads in the subway station. According to results of Quality confirmation, mixing and curing conditions are good. But, when effects of hydration heat are analyzed, cracks seems to take place because tensile stress is higher than tensile strength in several points of middle slabs. It is found that vibration by train running don't have an effect on cracks in the structure. The structural analysis shows that there is no problem on the stability of structural body, but the design through 3-dimensional analysis is need to consider columns and opening specially in the subway station structures.