• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.150-151
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• 2013

Recently, the internal space organization of the building changes to the frame construction and flat slab construction in the wall type structure. And the use of light weight panel changing the internal joint use easily is increased. Therefore, in this research, the length change characteristic that the magnesium chloride addition rate reaches to the magnesium curing body tries to be studied. It could confirm according to the length change specific result that the magnesium chloride amount of addition reaches to the magnesium oxide curing body to expand. And the thing described below was the large-scale expansion the magnesium oxide addition rate 60%. And it showed up as 50, 40, 30, 20, and order of 10s (%). It could look at to form the hydrate of the SEM picture result needle-shaped of the Hardened.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.19-20
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• 2013

Green Frame is a column-beam system constructed by composite precast column and beam connected by embedded steel of their. From when the precast concrete beam of Green Frame is installed, until the concrete of slab and connection joint is cured, the self load of beam shall be supported by the embedded steel of it. Therefore, the concrete of beam could be separated from the embedded steel if the shear connector of beam of Green Frame is designed by the code on Structural standard. So, this study suggest an equation for the shear connection of composite precast concrete beams of Green Frame. The result of this study will be used as the main equation of the calculation model for shear connectors of composite precast concrete beams.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.1
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• pp.75-87
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• 1997

To study the behavior a deck when it was collide with the ship approaching to the deck to berth, it was analyzed the effect zone by the ship collision which consists of deck slab and PC piles of the quay. The numerical technique is used to simulate the behavior of the deck when the ship hit the expansion joint of deck between the deck slabs. The failure behavior and zone of the deck are determinated by the comprehensive numerical study. The impact energy by the ship is also evaluated. It is concluded that these numerical analysis gave a reasonable estimation of the remedial area of the deck damaged by ship collision.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.726-733
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• 2002

Shrinkage strip or separation strip is a temporary joint that is left open for a certain time during construction to allow a significant part of the shrinkage to take place without inducing stress. A shrinkage stress analysis method of shrinkage strip in concrete slab of multi-story building considering the relaxation effect of creep and construction sequence is proposed. The analysis results of 10-story example building show that the effect of shrinkage strip can be analyzed easily by the proposed method. And shrinkage strip installed in a particular floor makes the stress of that floor reduced and the stress of the other floors increased a little. The rate and amount of stress reduced with closing time mainly depends on the development of shrinkage with time of concrete model used. The amount of stress reduced is determined by the amount of shrinkage strain developed before the closing of shrinkage strip.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.25-32
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• 2006

Behavior of concrete pavement due to temperature gradient was investigated for 48 hours at test road using Falling Weight Deflectometer. The deflections at slab center changed similarly to those of ambient temperature and temperature gradients in the slab. And rapid variations in the deflections were observed between 8 to 12 in the morning. However, dynamic modulus of subgrade reaction and joint deflections showed reverse trends to the ambient temperature and temperature gradients. The dynamic modulus of subgrade reaction was significantly affected by temperature gradient when its value got higher. Backcalculated elastic moduli were obtained using AREA method and Method of Equivalent Thickness. The trends of the backcalculated elastic modulus were similar to those of dynamic modulus of subgrade reaction. Measured load transfer efficiencies showed maximum peak in the morning due to dowel locking. However, additional effort is necessary to verify the result.

• Geomechanics and Engineering
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• v.23 no.1
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• pp.39-50
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• 2020

In order to understand the shear mechanical properties of the interface between clay and structure and better serve the practical engineering projects, it is critical to conduct shear tests on the clay-structure interface. In this work, the direct shear test of clay-concrete slab with different joint roughness coefficient (JRC) of the interface and different normal stress is performed in the laboratory. Our experimental results show that (1) shear strength of the interface between clay and structure is greatly affected by the change of normal stress under the same condition of JRC and shear stress of the interface gradually increases with increasing normal stress; (2) there is a critical value JRC_cr in the roughness coefficient of the interface; (3) the relationship between shear strength and normal stress can be described by the Mohr Coulomb failure criterion, and the cohesion and friction angle of the interface under different roughness conditions can be calculated accordingly. We find that there also exists a critical value JRC_cr for cohesion and the cohesion of the interface increases first and then decreases as JRC increases. Moreover, the friction angle of the interface fluctuates with the change of JRC and it is always smaller than the internal friction angle of clay used in this experiment; (4) the failure type of the interface of the clay-concrete slab is type I sliding failure and does not change with varying JRC when the normal stress is small enough. When the normal stress increases to a certain extent, the failure type of the interface will gradually change from shear failure to type II sliding failure with the increment of JRC.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.122-129
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• 2015

In this study, a prediction model for the effective compressive strength of corner columns with intervening normal strength concrete slabs was developed. A structural analogy between high-strength concrete column-normal strength concrete slab joint and brick masonry was used to develop the prediction model. In addition, the aspect ratio of slab thickness to column dimension was considered in the models. The reliability of the new prediction model was evaluated by comparison with experimental results and its superiority was demonstrated by comparison with previous models proposed by design codes and other researchers. As a result, with average test-to-predicted ratios of 1.09, a standard deviation of 0.15, the newly developed equation provided superior predictions in terms of accuracy and consistency over all of the existing effective strength prediction approaches including KCI structural concrete design code (2012).

• International Journal of Highway Engineering
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• v.6 no.2 s.20
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• pp.47-59
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• 2004

The temperature variation of concrete pavement at early-age significantly affects the initiation and propagation of its early-age cracks. This implies that the measurement and analysis of early age temperature trend are necessary to examine the causes of early age cracks in the concrete pavement. In this study, it is investigated how the early age temperature trend in concrete pavement affects the random crack initiation and behaviors of saw-cut joints using the actual construction site which is located at the KHC test road. During 72 hours after placing the concrete pavement, the ambient air temperature and temperatures at the top, middle, and bottom in concrete pavement were measured and the random crack initiation in concrete slabs and early age behaviors in the joints were surveyed. The investigation results indicate that the first random crack was initiated at one of the slabs placed in the early morning which have higher temperature changes during early 72 hours. The movement of slab was influenced by the early-age crack in the joint. It suggested that the different occurrence time of the cracks in the joint had an influence on the behavior of the cracks. Besides, the slab constructed In the morning had higher possibility of crack initiation than that in the afternoon. The rarely occurred cracks had bigger gap than other cracks.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.515-527
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• 2013

Building energy simulations which are mainly used in Korea have evaluated the building energy performance with the different thermal conductivity of construction materials. In order to evaluate the energy consumption accurately, the difference in thermal conductivity of the wood used in stud for wooden structure was confirmed from the each simulation. In addition, the thermal transmission of building members and the thermal bridge at the conjunction of building members according to thermal conductivity from each simulation programs were researched. The thermal conductivity of pine that has the largest variation among the energy simulations was applied to the thermal properties of studs in wooden structure. The maximum error between the maximum and minimum thermal transmission of roof, wall, and floor slab was $0.023W/m^2{\cdot}K$. Plus, that thermal bridge at Rafter junction on the roof, roof-wall joint, and floor slab-wall joint was $0.025W/m{\cdot}K$. The heat transfer image for changes in temperature and the heat exchange were analyzed by HEAT2 program. The distorted temperature lines were found around the insufficient insulated connection parts. It was predicted that the temperature at the distorted parts in the analyzed image was lower than that of the other portion of the other structures.

• Steel and Composite Structures
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• v.37 no.3
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• pp.307-321
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• 2020

The slim-floor solution provides an efficient alternative to the classic slab-over-beam configuration due to architectural and structural benefits. Two deficiencies can be identified in the current state-of-art: (i) the technique is limited to nonseismic applications and (ii) the lack of information on moment-resisting slim-floor beam-to-column joints. In the seismic design of framed structures, continuous beam-to-column joints are required for plastic hinges to form at the ends of the beams. The present paper proposes a slim-floor technical solution capable of expanding the current application of slim-floor joints to seismic-resistant composite construction. The proposed solution relies on a moment-resisting connection with a thick end-plate and large-diameter bolts, which are used to fulfill the required strength and stiffness characteristics of continuous connections, while maintaining a reduced height of the configuration. Considering the proposed novel solution and the variety of parameters that could affect the behavior of the joint, experimental and numerical validations are compulsory. Consequently, the current paper presents the experimental and numerical investigation of two slim-floor beam-to-column joint assemblies. The results are discussed in terms of moment-rotation curves, available rotational capacity and failure modes. The study focuses on developing reliable slim-floor beam joints that are applicable to steel building frame structures located in seismic regions.