• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.5
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• pp.99-110
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• 2007

A single slab concrete pavement has been modeled and analyzed by ABAQUS program. The stress and displacement of the JCP slab under traffic load with frictionless contact interaction between slab and base calculated by ABAQUS program have been compared with the results obtained by KENSLABS program. The results of the stresses of the two modeling show similar tendency and the difference of the two modeling is very small however the results of the displacement of the two modeling show some dissimilarity. In order to analyze the effects of material and geometric properties on the responses of slab, some varying parameters were chosen as input for the modeling. The changing parameters include the thickness and elastic modulus of the concrete slab, the thickness and elastic modulus of base and the elastic modulus of the subgrade. The contact interaction between the slab and base layer had been also studied and different friction coefficient 0, 2.5, 6.6, 7.5, 8.9 had been used to simulate the different friction interface condition. The results of the analysis showed that the responses of the concrete slab vary with the material and geometric properties of the pavement structure and the slab-base friction condition.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1659-1663
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• 2011

Precast concrete slab track is a track structure to be installed by transporting and assembling precast concrete slabs manufactured at the factory. This method can improve concrete quality, provide easy maintenance and reduce construction time, compared with in-situ concrete track. However, the concrete slabs being continuously connected in longitudinal direction, due to the temperature change between summer and winter, the openings at slab joints have occurred. Thus, in this study, to identify the cause of this opening of slab joint, the joint opening caused by temperature drop in the longitudinally continuous precast concrete slab track has been predicted using three-dimensional finite element analysis, and compared with field measurements. Based on the proven model, the slab joint opening, and the stress pattern of concrete slab and steel reinforcement according to concrete slab-base friction properties, concrete-reinforcement bond properties, and prestressing were analyzed.

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.189-192
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• 2008

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.67-74
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• 2017

PURPOSES : In this study, a three-dimensional nonlinear finite element analysis (FEA) model for airport concrete pavement was developed using the commercial program ABAQUS. Users can select an analysis method and set the range of input parameters to reflect actual conditions such as environmental loading. METHODS : The geometrical shape of the FEA model was chosen by considering the concrete pavement located in the third-stage construction site of Incheon International Airport. Incompatible eight-node elements were used for the FEA model. Laboratory test results for the concrete specimens fabricated at the construction site were used as material properties of the concrete slab. The material properties of the cement-treated base suggested by the Federal Aviation Administration(FAA) manual were used as those of the lean concrete subbase. In addition, preceding studies and pavement evaluation reports of Incheon International Airport were referred for the material properties of asphalt base and subgrade. The kinetic friction coefficient between the concrete slab and asphalt base acquired from a preceding study was used for the friction coefficient between the layers. A nonlinear temperature gradient according to slab depth was used as an input parameter of environmental loading, and a quasistatic method was used to analyze traffic loading. The average load transfer efficiency obtained from an Heavy falling Weight Deflectomete(HWD) test was converted to a spring constant between adjacent slabs to be used as an input parameter. The reliability of the FEA model developed in this study was verified by comparing its analysis results to those of the FEAFAA model. RESULTS : A series of analyses were performed for environmental loading, traffic loading, and combined loading by using both the model developed in this study and the FEAFAA model under the same conditions. The stresses of the concrete slab obtained by both analysis models were almost the same. An HWD test was simulated and analyzed using the FEA model developed in this study. As a result, the actual deflections at the center, mid-edge, and corner of the slab caused by the HWD loading were similar to those obtained by the analysis. CONCLUSIONS : The FEA model developed in this study was judged to be utilized sufficiently in the prediction of behavior of airport concrete pavement.

• Journal of the Korean Geotechnical Society
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• v.34 no.10
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• pp.17-28
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• 2018

Important parameters for the stability checks of cantilever wall are the active earth pressure and the weight of soil above the heel of the base slab. If the heel length is so long enough that the shear zone bounded by the failure plane is not obstructed by the stem of the wall, the Rankine active condition is assumed to exist along the vertical plane which is located at the edge of the heel of the base slab. Then the Rankine active earth pressure equations may be theoretically used to calculate the lateral pressure on the vertical plane. However, in case of the cantilever wall with a short heel, the application of Rankine theory is not only theoretically incorrect but also makes the lateral earth pressure larger than the actual pressure and results in uneconomical design. In this study, for the cantilever wall with a short heel the limit analysis method is used to investigate the mechanism of development of the active earth pressure and then the magnitude and location of the resultants of the pressure and the weight of the soil above the heel are determined. The calculated results are compared with the existing methods for the stability check. In case of the cantilever wall with a short heel, the results by the Mohr circle method and Teng's method show max. 3.7% and 32% larger than those of the limit analysis method respectively.

• Earthquakes and Structures
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• v.10 no.4
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• pp.939-963
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• 2016

According to the new directives about the rational and efficient use of energy, thermal bridges in buildings have to be avoided, and the thermal insulation (TI) layer should run without interruptions all around the building - even under its foundations. The paper deals with the seismic response of multi-storeyed reinforced concrete (RC) frame building structures founded on an extruded polystyrene (XPS) layer placed beneath the foundation slab. The purpose of the paper is to elucidate the problem of buildings founded on a TI layer from the seismic resistance point of view, to assess the seismic behaviour of such buildings, and to search for the critical parameters which can affect the structural and XPS layer response. Nonlinear dynamic and static analyses were performed, and the seismic response of fixed-base (FB) and thermally insulated (TI) variants of nonlinear RC building models were compared. Soil-structure interaction was also taken into account for different types of soil. The results showed that the use of a TI layer beneath the foundation slab of a superstructure generally induces a higher peak response compared to that of a corresponding system without TI beneath the foundation slab. In the case of stiff structures located on firm soil, amplification of the response might be substantial and could result in exceedance of the superstructure's moment-rotation plastic hinge capacities or allowable lateral roof and interstorey drift displacements. In the case of heavier, slenderer, and higher buildings subjected to stronger seismic excitations, the overall response is governed by the rocking mode of oscillation, and as a consequence the compressive strength of the XPS could be insufficient. On the other hand, in the case of low-rise and light-weight buildings, the friction capacity between the layers of the applied TI foundation set might be exceeded so that sliding could occur.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.15-20
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• 2019

This paper evaluated the construction costs of 11 design cases to decrease the horizontal forces applied to the abutment. They include two abutment types, which are to improve backfill materials for a reversed T-shaped abutment and geosynthetic Reinforced Abutment for Railways (RAR). The first type of economic analysis was that the internal friction angles of backfill materials were increased from Φ=35° to Φ=40° and 50° for a reversed T-shaped abutment. In addition, the second type was the cases with the design of geosynthetic RAR. When friction angles of 40° or 50° were applied through the improvement of the backfill material, the decrease in construction cost of the abutment was not large (2.0~3.9%), even though the horizontal forces applied to the abutment had decreased to 18~48%. In the case of applying the RAR, however, a maximum 30% cost reduction was evaluated by the decrease in horizontal force to "0" theoretically. The cost reduction resulted from the decrease in wall thickness, base slab size, and number and material change of pile foundation for the abutment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.87-98
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• 1990

The present Study dealt with the earthquake-resistant design of cantilever retaining walls supporting cohesionless soils. With design examples of three different types of cantilever retaining walls, the factors of safety against sliding were computed at various values of horizontal acceleration coefficient and compared with each other. The horizontal inertia effect due to the weights of concrete wall itself and a portion of backfill was taken into account in the analyses, and also Mononobe-Okabe pseudo-static solution method was modified to deal with various states different from limiting equilibrium state. From the analyses of safety against sliding, it was found that a cantilever retaining wall with sloped base was the most efficient type in earthquake resistant design. It was also found that by sloping the base, the width of the base slab could be reduced, resulting in the least volume of concrete, excavation and backfill as compared to the other types of walls. In the case of a cantilever retaining wall with sloped feel, the efficiency similar to that of a wall with sloped base could be expected under static loading as well as at relatively low level of earthquake loading. However, this efficiency became vanished with the increase of horizontal acceleration coefficient, since the rate of reduction in developed earth pressures on the heel became smaller. In addition, the design charts with different soil friction angles as well as with different earthquake resistant design criteria of safety factor against sliding were presented for the design of cantilever retaining walls sith sloped base.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.508-517
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• 2018

This study evaluated the construction costs of 11 design cases to decrease the horizontal forces applied to an abutment. They include two kinds of abutment types, which are used to improve the backfill materials for reversed T-shaped abutment and geosynthehtic reinforced abutment for railways (RAR). In the first economic analysis, the internal friction angles of the backfill materials were increased from ${\Phi}=35^{\circ}$ to ${\Phi}=40^{\circ}$ and $50^{\circ}$ for a reversed T-shaped abutment. The second analysis examined cases with the design of a geosynthehtic RAR. When the friction angles were $40^{\circ}$ or $50^{\circ}$ after improvement of the backfill material, the reduction in the construction cost of the abutment was not as large (2.0-3.9%), even though the horizontal forces on the abutment were decreased by 18-48%. However, in the case of applying the RAR, a maximum cost reduction of 30% was achieved by decreasing the horizontal force to zero. The cost reduction results from the decreased wall thickness, base slab size, and the number of pile foundations for the abutment, as well as changing the material.