• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.353-359
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• 2005

To evaluate the proposed shear strength models developed in a companion paper, the shear strengths of test specimens strengthened with FRP were predicted by ACl specification, and elsewhere. The advantage and disadvantage of the models were investigated by the comparisons with the test results. The characteristics and limitations of the existing model were investigated with respect to FRP types, strengthening methods, shear span to depth ratio and effective strength of FRP. The results of this parametric study showed that the proposed shear strength model is more accurate than other models.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.136-145
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• 2013

Social interest in the seismic retrofit of the structure is growing massive earthquake that occurred recently. The brittle fracture of Non-seismically designed Columns lead to full collapse of the building. In the past, cross-sectional expansion method, a steel plate reinforcing method is applied mainly in recent years, fiber-reinforced method utilizing the advantages of the composite material are preferred. However, the reinforcement methods such as this, there is a drawback to induce physical damage to structures, and time consuming work space is large. IIn this study, FRP seismic reinforcement was developed using the Aluminum connector and the composite material (Glass Fiber Reinforced Polymer). Then, the optimum quantities of FRP seismic reinforcement was determined using a nonlinear finite element analysis program. Finally, the quantity decision process through the design and analysis of FRP reinforcement was suggested.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.37-45
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• 2021

This paper is a basic study to evaluate the possibility of earthquake-resistant reinforcement by reinforcing engineered cementitious composite in masonry members. In order to examine the performance according to the fiber mixing rate of the engineered cementitious composite, a test specimen was prepared according to the formulation design, and flow ability, compressive strength, flexural strength, length change rate, and direct tensile strain were measured. In addition, non-reinforced masonry members, masonry members reinforced with engineered cementitious composite, and masonry members in which glass fibers and wire mesh were separately reinforced with engineered cementitious composites were manufactured, and flexural strength and maximum displacement were measured. All specimens reinforced with engineered cementitious composite showed more than 16 times the effect of maximal strength compared to that of no reinforcement, and as a result of examining the crack shape, the energy dissipation ability was excellent, confirming the possibility of seismic reinforcement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.141-148
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• 2008

In the recent construction industry, Carbon Fiber Reinforced Polymers(CFRPs) have been highly considered as innovative strengthening materials for civil structures due to their superior material properties. This paper is to offer design data and strengthening efficiency of reinforced concrete beams strengthened with CFRP Plate. Static tests were carried out to evaluate failure modes and strengthening capacity. Displacements and strains of steel and CFRP plates were obtained and analyzed through a series of fatigue tests. Also, Those evaluated the energy dissipation. Results of the tests showed increase in strengthening ratios caused debonding failure at the end of beams. For the beams wrapped with CFRP sheets around the end of the plates, debonding failure mode that was induced from flexural cracks was indicated. Through the fatigue tests, it was observed that displacements, strains of steel and CFRP plates converged into certain values. It is also proved that the beams strengthened with CFRP plates are able to resist fatigue loading under serviceability.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.337-349
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• 2001

This study present an optimum deck and girder system design for minimizing the life-cycle cost (LCC) of orthotropic steel deck bridges. The problem of optimum LCC design of orthotropic steel deck bridges is formulated as that of minimization of the expected total LCC that consists of initial cost, maintenance cost, expected retrofit costs for strength, deflection, and fatigue. To demonstrate the effect of LCC optimum design of orthotropic steel deck bridges, the proposed optimum LCC design is compared with the conventional method for orthotropic steel deck bridges design. From the numerical investigations, it may be positively stated that the proposed optimum design procedure for orthotropic steel deck bridges based on the LCC will lead to more rational, economical and safer design.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.311-318
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• 2009

An experimental investigation was conducted to examine the hysteretic behaviors of ultra-high strength concrete tied columns. The purpose of this study is to propose the volumetric ratio of transverse reinforcement for ultra-high strength concrete tied columns with 100 MPa compressive strength. Nineteen 1/3 scaled columns were fabricated to simulate an 1/2 story of actual structural members with the main variables of axial load ratio, configurations and volumetric ratios of transverse reinforcement. The results show that the deformability of columns are affected by the configurations and volumetric ratios of transverse reinforcement. Especially, it has been found that the behavior of columns are affected by axial load ratio rather than the amounts and the configurations of transverse reinforcement. To improve the ductility behavior of RC column using ultra high strength concrete in a seismic region, We suggested the amount of transverse reinforcement for all data that satisfy the required displacement ductility ratio over 4. It is means that the lateral confining reduction factor (${\lambda}^c$) considering the effective legs, configuration and spacing of transverse reinforcement and axial load ratio was reflected for the volumetric ratio of transverse reinforcement.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.137-144
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• 2013

The use of fiber-reinforced polymer (FRP) reinforcing bars in concrete structures has been increased as an alternative of steel reinforcement which has shown greater vulnerability to corrosion problem. However, the long-term performance of concrete members with FRP reinforcement is still questioned in comparison to the used of steel reinforcement. This study presents the results of an experimental study on the long-term behaviors of GFRP (glass fiber reinforced polymer) bar reinforced concrete beams after exposed to accelerated aging in an environmental chamber with temperature of $46^{\circ}C$ ($115^{\circ}F$) and 80% of relative humidity up to 300 days. The objectives of this research was to compare strength degradation and change of ductility between GFRP reinforced concrete beams and steel reinforcement beams after accelerated aging. Two types (wrapped and sand-coated surface) of GFRP bars and steel were reinforced. in concrete beams. Test results show that the failure modes of GFRP bar reinforced concrete beams are very similar with traditional RC beams, and the change of load-carrying capacity of steel reinforcing concrete beam is greater than that of GFRP bar reinforcing concrete beam under the accelerated aging. Test result also shows that the use of GFRP reinforcing in concrete could be introduced more brittle failure than that of steel reinforcing for practical application. The deformability factor up to compression failures indicates no significant variation before and after exposure of accelerated aging.

• Fire Science and Engineering
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• v.26 no.1
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• pp.23-30
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• 2012

The temperature development of a structural element is dependent on section factor, which is estimated as a ratio of the fire-exposed perimeter to the cross-section area. Hence, with the higher section factor, the faster temperature development of the section os observed. Composite beam member, partially embedded asymmetry H beam, has a good fire resistance to the cross-section. The study was intended to conduct with change with section factor. The experimental result of section type which the Slim Beam Floor is bottom flange reinforced method.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.129-139
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• 2000

The liquefaction of reclaimed land generally caused the harbor facilities to hazards. In Korea, the major harbor quay walls are gravity type and the gravity quay wall is not a good earthquake resistant structure. Recently, various earthquake resistant quay walls have been suggested, but the study on the efficiency of reinforced quay wall was not much performed. In this study, numerical analysis is carried out for performance evaluation of easily adoptable earthquake resistant quay walls. The results of numerical analysis are compared with shaking table test that is performed at the same cross-section.

• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.32-40
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• 2000

This paper presents the results of a parametric study on the behavior of tunnel face reinforced with horizontal pipes. A series of reduced-scale model tests was carried out to in an attempt to verify previously performed three-dimensional numerical modeling and to investigate effects of reinforcement layout on the tunnel face deformation behavior. The results of model tests indicate that the tunnel face deformation can significantly reduced by pre-reinforcing the tunnel face with longitudinal members and thus enhancing the tunnel stability. In addition, the model tests results compare fairly well with those from the previously performed three-dimensional finite element analysis. Therefore, a properly calibrated three dimensional model may effectively be used in the study of tunnel face reinforcing technique.