• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.39-52
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• 2011

This paper describes a new numerical analysis technique in stability analysis for a slope reinforced with pressure grouted soil nails. The installing effect of pressure grouted soil nails can be simulated in this method. Shear strength reduction method associated with finite element method is used for slope stability analysis. Factors of safety for a slope reinforced with pressure grouted soil nails are compared with those for a natural slope and a slope reinforced with gravity grouted soil nails in order to investigate their reinforcing effects. More than 50% increase in the factor of safety is obtained when the slope is reinforced with pressure grouted soil nails compared to the one with gravity grouted soil nails. The reinforcing effects of pressure grouted soil nails become obvious with increase in their length. The reinforcing mechanism of the pressure grouted soil nails for the slope stability can be explained by the slope failure surface expanding gradually toward the backfill. The increased stability of the slope reinforced with pressure grouted soil nails results mainly from their improved pull-out resistance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.517-528
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• 2008

This paper presents a hysteretic damage model for reinforced concrete (RC) joints that explicitly accounts for the bond-slip between the reinforcing bars and the surrounding concrete. A frame element whose displacement fields for the concrete and the reinforcing bars are different to permit slip is developed. From the fiber section concept, compatibility equations for concrete, rebar, and bond are defined. Modification of the hysteretic stress-strain curve of steel is conducted for partial unloading and reloading conditions. Local bond stress-slip relations for monotonic loads are updated at each slip reversal according to the damage factor. The numerical applications of the reinforcing bar embedded in the confined concrete block, the RC column anchored in the foundation, and the RC beam-column subassemblage validate the model accuracy and show how including the effects of bond-slip leads to a good assessment of the amount of energy dissipation during loading histories.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.466-469
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• 2006

This paper presents the structural characteristics of slab-column connections by using nonlinear finite element analysis. FEA considering material non-linearity was performed to investigate average column strain, failure mode, principal stress distribution, and steel yielding conditions for various slab-column members. In addition, to investigate alternative methods for improving the strength of interior column-slab joints, some specimens were provided with different reinforcing types of high-strength concrete puddling, high-strength column longitudinal steels, dowel bars, and high-strength concrete core. To make certain of the reliability of the analytical program, analysis results for concrete material model developed and two specimens with and without puddling were compared with experimental results. It was found that providing the alternative reinforcing methods in the slab-column joint results in a significant improvement in performance. This includes an increase in the axial compressive strength, greater loading stiffness, and ductility.

• Journal of Ocean Engineering and Technology
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• v.16 no.5
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• pp.49-55
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• 2002

The compression anchor is characterized by decrement of progressive failure, simple site work, economy and durability compared with tension anchor. In this paper, compression anchor is analysed through the laboratory element tests. The formula to be estimate the grout strength in fixed part of compression anchor and the effective reinforcement method for several types of soil were suggested. The following conclusions were made from this study : (1) A formula, which is able to calculate the grout strength in the fixed part of the compression anchor, is suggested. (2) The strength increment ratios( $R_{si}$) are 100％, 132％, 147％, 217％ according to the reinforcement method of grout. The reinforcement method is Non, Outside spiral, Inside-Outside spiral, Steel pipe, respectively. (3) The strength increment ratios( $R_{si}$) by reinforcing can be 8.23 times the strength increment effect according to the reinforcement types and ground confining pressure. (4) The steel pipe reinforcement is most effective in decomposed soil while, in the case of hard rock ground, high confining pressure is exerted on the grout, so there is no need to use reinforcements.

• Structural Engineering and Mechanics
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• v.34 no.6
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• pp.685-702
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• 2010

In this paper, a nonlinear finite element procedure is presented for the dynamic analysis of reinforced concrete shell structures. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), was used. A 4-node flat shell element with drilling rotational stiffness was used for spatial discretization. The layered approach was used to discretize the behavior of concrete and reinforcement in the thickness direction. Material nonlinearity was taken into account by using tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach was incorporated. The low-cycle fatigue of both concrete and reinforcing bars was also considered to predict a reliable dynamic behavior. The solution to the dynamic response of reinforced concrete shell structures was obtained by numerical integration of the nonlinear equations of motion using Hilber-Hughes-Taylor (HHT) algorithm. The proposed numerical method for the nonlinear dynamic analysis of reinforced concrete shell structures was verified by comparison of its results with reliable experimental and analytical results.

• Transactions of Materials Processing
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• v.24 no.2
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• pp.130-137
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• 2015

This paper presents the development process of automotive side door impact beam for passenger cars. Weight reduction while maintaining functional requirements is one of the major goals in the automotive industry. In this study, thin-walled side door beam using quenchable boron steel was designed to reduce the weight of conventional side door tubular one. In order to estimate design for the proposed side door beams, the static side impact protection tests(FMVSS 214) were conducted using the finite element method. Based on the simulation results, geometry modification of the side door beam has been performed via creating new reinforcing ribs. Furthermore, the manufactured frontal impact beam was mounted on the real side door of a passenger car, and then static impact protection test carried out. It is concluded that the presented test results can provide significant contribution to the stiffness of side door impact beams and light-weighting door research.

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.389-396
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• 2001

This paper presents an analytical prediction of the fatigue behavior of reinforced concrete bridge piers under earthquake. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuous deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel. The proposed numerical method for fatigue behavior of reinforced concrete bridge piers under earthquake will be verified by comparison with reliable experimental results.

• Earthquakes and Structures
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• v.16 no.1
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• pp.83-96
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• 2019

The seismic behavior of PRC coupling beam-hybrid coupled shear wall system is analyzed by using the finite element software ABAQUS. The stress distribution of steel plate, reinforcing bar in coupling beam, reinforcing bar in slab and concrete is investigated. Meanwhile, the plastic hinges developing law of this hybrid coupled shear wall system is also studied. Further, the effect of coupling ratio, section dimensions of coupling beam, aspect ratio of single shear wall, total height of structure and the role of slab on the seismic behavior of the new structural system. A fitting formula of plate characteristic values for PRC coupling beams based on different displacement requirements is proposed through the experimental date regression analysis of PRC coupling beams at home and abroad. The seismic behavior control method for PRC coupling beam-hybrid coupled shear wall system is proposed based on the continuous connection method and through controlling the coupling ratio, the roof displacement, story drift angle of hybrid coupled shear wall system, displacement ductility of coupling beam.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.863-874
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• 2015

The use of pile reinforcement is considered as one of the most promising techniques for improving load carrying capacity of piles in offshore area. In this study, to consider the horizontal and uplift bearing capacity of submerged breakwater bearing pile, exclusive analysis on load-transfer behaviour of pile was conducted. First of all, check the reinforcing effect from the three-dimensional finite element method, and estimate load transfer curve (ground reaction force). Based on these results, the reinforcing effect was quantified by estimating the coefficients of horizontal and uplift reinforcement of reinforced piles. Load transfer function with consideration of the reinforcing effect was proposed from estimated coefficients. A comparison of the analysis using the proposed load transfer function with three-dimensional finite element analysis has resulted that the proposed load transfer function is displaying good accuracy of predicting behavior of the load transfer between the pile and soil reinforcement. Interpretation of the submerged structure by applying a load transfer function considering the reinforcing effect, has shown that the reinforced pile's shear, bending moment and displacement are less than that of non-reinforced piles, while the subgrade reaction modulus arises greater. Thus, it is expected to be relatively cost effective in terms of design.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.520-526
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• 2015

Reinforcing bar splices are inevitable in reinforced concrete structure. In these days, there are three main types of splices used in reinforced concrete construction site - lapped splice, mechanical splice and welded splice. Low cost, practicality in construction site, less time consuming and high performance make gas pressure welding become a favorable splice method. However, reinforcing bar splice experiences thermal loading history during the welding procedure. This may lead to the presence of residual stress in the vicinity of the splice which affects the fatigue life of the reinforcing bar. Therefore, residual stress analysis and tensile test of the gas pressure welded splice are carried out in order to verify the load bearing capacity of the gas pressure welded splice. The reinforcing bar used in this work is SD400, which is manufactured in accordance with KS D 3504. The results show that the residual stresses in welded splice is relatively small, thus not affecting the performance of the reinforcing bar. Moreover, the strength of the gas pressure welded splice is high enough for the development of yielding in the bar. As such, the reinforcing bar with gas pressure welded splice has enough capacity to behave as continuous bar.