• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.158-167
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• 2008

Reinforced earth wall system has been popularized since its introduction to Korean civil engineering society in early 1980's. Nowadays, the increased use of reinforced earth wall for the purpose of obtaining more land brings several additional demands such as environmental-friendly, better stable and constructible, and economical system. This paper introduces some recently developed reinforced earth wall systems with consideration of the current demands.

• Computers and Concrete
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• v.14 no.4
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• pp.387-403
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• 2014

The aim of this study is to assess the structural performance of deteriorated reinforced concrete bridge piers, and to provide method for developing improved evaluation method. For a deteriorated bridge piers, once the cover spalls off and bond between the reinforcement and concrete has been lost, compressed reinforcements are likely to buckle. By using a sophisticated nonlinear finite element analysis program, the accuracy and objectivity of the assessment process can be enhanced. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), is used to analyze reinforced concrete structures. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. Advanced deteriorated material models are developed to predict behaviors of deteriorated reinforced concrete. The proposed numerical method for the structural performance assessment of deteriorated reinforced concrete bridge piers is verified by comparing it with reliable experimental results. Additionally, the studies and discussions presented in this investigation provide an insight into the key behavioral aspects of deteriorated reinforced concrete bridge piers.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.321-326
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• 1998

Shear failure of reinforced concrete beams is serious problem due to sudden brittle failure and many experimental results proved that size effect in shear behavior is an important feature of reinforced concrete members. For this reason, the structural safety of the reinforced concrete beams for shear has been checked by applying empirical design formula, which includes the size-effect, derived from experimental data. However, as the sizes of reinforced concrete members become extremely large, experiments sometimes become very difficult so that the formula or the experimental data could not be obtained and size-effect analyses of shear behavior become significant. In this study, size-effect analysis of shear behavior in reinforced concrete beams is performed by modeling tension stiffening/shear stiffening on reinforced concrete and the tension softening/shear softening on plain concrete. Then, the influences of models in the size-effect analyses of shear behavior in reinforced concrete beams are analyzed.

• 기술발표회
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• s.2006
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• pp.156-161
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• 2006

Recently, construction of soil-reinforced segmental retaining walls which used geosynthetics are being increased day by day due to its construction efficiency, economic efficiency, and its aesthetic view. The conventional reinforced earth retaining wall has the connector system to fix the reinforcement and block However, this system may cause the crack of block and the rupture of reinforcement due to the stress concentration near the face of reinforced earth retaining wall In this study, the new connector system, which is able to allow the settlement of reinforcement, was applied to analyze the effect of connector system of reinforced earth retaining wall The connection strength tests and centrifugal tests for both the conventional reinforced earth retaining wall and the settlement reinforced earth retaining wall were performed to compare the results

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.301-313
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• 2001

Reinforced earth is a composite construction material in which the strength of engineering fill is enhanced by the addition of strong tensile reinforcement in variable types. The basic mechanism of reinforced earth involves the generation of frictional forces and bearing resistances between the soil and the reinforcement. The primitive structure of reinforced earth in Korean peninsula were found as the earth wall built around the old fort In about 3rd century Modern reinforced earth was introduced to Korea early 1980, and spreaded tremendously through the nation. Among them, not a few reinforced earth walls which were built ignored over all stabilities have been collapsed. In this paper basic concepts, economic benefits, design considerations and future applicable trends of reinforced earth are reviewed in simple manners.

• Structural Engineering and Mechanics
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• v.63 no.5
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• pp.629-637
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• 2017

Continuous concrete beams are commonly used as structural members in the reinforced concrete constructions. The use of fiber reinforced polymer (FRP) bars provide attractive solutions for these structures particularly for gaining corrosion resistance. This paper presents experimental results of eight two-span continuous concrete beams; two of them reinforced with pure glass fiber reinforced polymer (GFRP) bars and six of them reinforced with combinations of GFRP and steel bars. The continuous beams were tested under monotonically applied loading condition. The experimental load-deflection behavior and failure mode of the continuous beams were examined. In addition, the continuous beams were analyzed with a numerical method to predict the load-deflection curves and to compare them with the experimental results. Results show that there is a good agreement between the experimental and the theoretical load-deflection curves of continuous beams reinforced with pure GFRP bars and combinations of GFRP and steel bars.

• Computers and Concrete
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• v.11 no.4
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• pp.351-364
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• 2013

This paper presents results from an analytical investigation of the behavior of steel reinforced concrete circular column sections with additional Glass Fiber Reinforced Polymers (GFRP) bars. The primary application of this composite section is to relocate the plastic hinge region from the column-footing joint where repair is difficult and expensive. Mainly, the study focuses on the development of the full nominal moment-axial load (M-P) interaction diagrams for hybrid concrete sections, reinforced with steel bars as primary reinforcement, and GFRP as auxiliary control bars. A large parametric study of circular steel reinforced concrete members were undertaken using a purpose-built MATLAB(c) code. The parameters considered were amount, location, dimensions and mechanical properties of steel, GFRP and concrete. The results indicate that the plastic hinge was indeed shifted to a less critical and congested region, thus facilitating cost-effective repair. Moreover, the reinforced concrete steel-GFRP section exhibited high strength and good ductility.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.364-371
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• 2009

This study was carried out to investigate the bending strength of the Larix glulam beams which were reinforced with CFRP (Carbon fiber reinforced plastic) of which the reinforcement ratios were 0.7% and 2.1% by volume. In the bending test, the rupture shape of the reinforced glulam shows that the reinforced glulam broke firstly in the lowest bottom layer on which tension was loaded, but did not in the upper part reinforced with the CFRP layer. The upper part of the reinforced layer kept strength and did not break when the reinforced glulam broke firstly at the bottom part of the reinforced layer, but broke secondly as loading was increased. In the glulam beams reinforced with CFRP of which the reinforcement ratio was 0.7% by volume, the bending strength of the reinforced beams was increased by 28% at the first break. When beams broke up to the upper part of the reinforced layer, the bending strength of the reinforced beams was increased by 55%, compared to those of control glulam beams. When the glulam beams were reinforced with CFRP of which the reinforcement ratio was 2.1% by volume, the bending strength of the reinforced beams was increased by 77%, compared to those of control glulam beams. The ratio of the height of calculated neutral axis using failure mode recommended by Romani and the height of actual neutral axis using strain gauge was 1.03 and agreed well.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.861-867
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• 2015

The Compact Tension (CT) type test was performed in order to evaluate the fracture toughness performance of glass fiber-reinforced laminated timber. Glass fiber textile and sheet Glass fiber reinforced plastic were used as reinforcement. The reinforced laminated timber was formed by inserting and laminating the reinforcement between laminated woods. Compact tension samples are produced under ASTM D5045. The sample length was determined by taking account of the end distance of 7D, and bolt holes (12 mm, 16 mm, 20 mm) had been made at the end of artificial notches in advance. The fracture toughness load of sheet fiberglass reinforced plastic reinforced laminated timber was increased 33 % in comparison to unreinforced laminated timber while the glass fiber textile reinforced laminated timber was increased 152 %. According to Double Cantilever Beam theory, the stress intensity factor was 1.08~1.38 for sheet glass fiber reinforced plastic reinforced laminated timber and 1.38~1.86 for glass fiber textile reinforced laminated timber, respectively. That was because, for the glass fiber textile reinforced laminated timber, the fiber array direction of glass fiber and laminated wood orthogonal to each other suppressed the split propagation in the wood.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.241-248
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• 2012

This paper presents a reinforced concrete composite column method in order to improve seismic performance of reinforced concrete column specimens by selectively applying steel fiber-reinforced mortars at the column plastic hinge region. In order to evaluate seismic improvement of the newly developed column method, a series of cyclic load test of column specimens under a constant axial load was investigated by manufacturing three specimens, two reinforced concrete composite columns by applying steel fiber-reinforced mortars at the column plastic hinge region and one conventional reinforced concrete column. Both concrete and steel fiber-reinforced mortar was cast-in placed type. From cyclic load test, it was found that the newly developed steel fiber-reinforced columns showed improved seismic performances than conventional reinforced concrete column in controlling bending and shear cracks as well as improving seismic lateral load-carrying capacities and lateral deformation capacities.