• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.503-506
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• 2005

The purpose of this study was the Development of Retrofit Method for Beam Using Steel Plate Reinforced by Fiber Sheet.1. Additional reinforcements are not needed in the joining area of slab and beam web.2. Beam using carbon fiber reinforced plastic displays low effects in shearing effect.3. Beams reinforced steel plate by epoxy effect the capacities of strength. But the capacities of strength are rapidly reduced when adhesive surface be omitted. Thus details are needed in this case.4.Retrofit method for beam using steel plate reinforced by fiber sheet with epoxy rosin improves the capacities of strength and the initial stiffness, shows a large transformation since the maximum load likewise may be excellent to the shearing reinforcement.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.811-816
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• 2002

An experimental work is performed to evaluate the retrofit method of damaged flexural walls. For two flexural walls damaged up to almost failure, reinforcements yielded and concrete below height of 1d are replaced with new reinforcements and steel fiber concrete, respectively. In order to evaluate the effectiveness of Aramid sheet for retrofitting walls, Aramid sheet is also, attached to longitudinal direction and rolled horizontal direction of one wall specimen. Horizontal cyclic loads are applied to the top of the specimen with constant axial load. Test result showed that retrofitting with steel fiber concrete after replacing reinforcements can not afford to recover 100% of the wall capacity before damage. However, the capacity of walls could be sufficiently strengthened by using Aramid sheet.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.709-712
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• 1999

This paper was aimed to investigate the shear strengthening effect of the pre-loaded reinforced concrete beams strengthened by carbon fiber sheet (CFS). Main tet parameters was the magnitude of pre-loading at the time of the retrofit and the strengthening method of carbon fiber sheet. A series of nine specimens was tested to evaluate the corresponding effect of each parameters such as maximum load capacity, load-deflection relationship, and failure mode. The results of this study showed that the failure mode is bonding failure between the concrete and the CFS before the tensile failure strain of the CFS is reached.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.787-792
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• 2002

The voided slab have many advantages, light weight, high load-distribution capacity, low cost and beautiful appearance, etc. But they have also many cracks due to difficulties in designs and construction, analysis, shrinkage, installation and rising force of voided tube. This paper presents the retrofit effects with steel plate(SP)/carbon fiber sheet(CFS) of RC voided slab. As a results of this study, it proved that the strip pattern has to be profitable than full-face pattern in performance such as crack, ultimate loads, stiffness. Retrofit length has many influence on retrofit effects, as the length increases, performance and stability of end blocks higher. Also, it proved that the retrofit on full-section has to be profitable than voided-section in performance, and the overlay length of CFS is desirable to extent approximately and welding(V-cut) has to be efficient than anchors in SP connection. But the kinds of end block and anchor has not influence on retrofit effects.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.781-784
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• 2004

Method of Steel plate reinforced by fiber sheet is advantageous in the secure loading facility. For this method are a light weight and a high strength, the thickness of steel can be reduced Effects of composite system are depreciated when the thickness of steel is thin. This is the result of the difference of ductility ratio with steel plate. Steel plate reinforced by fiber sheets confirms the ability of transformation. This is the result of the property of steel materials Steel plate reinforced by fiber sheet didn't display an enough performance when theadhesives are epoxy rosin. This is the result of the slide of the surface of stee1. The adhesive ability is varied by the number and span of anchor bolts. There wasn't happening the separation between steel and epoxy. Thus the method used in combination with anchor and epoxy is best excellent. This is the result of the upward of accumulation effects Shearing force is in proportion to the number of bolts. But the ability of shearing force per one bolt is reducing. Thickness of steel plate reinforced by fiber sheet must be designed so that steel is endure before concrete is wreck.

• Land and Housing Review
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• v.13 no.3
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• pp.83-102
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• 2022

After the earthquake in South Korea (Gyeongju and Pohang), interest in securing the seismic performance of piloti buildings was increasing. In this paper, a study was conducted to propose a seismic retrofit method for piloti building of LH. The proposed seismic retrofit method considers the priority of seismic retrofit and the type of core. To verify the effectiveness of the proposed seismic retrofit method, computational analysis was performed according to the type of core. As a result, it was confirmed that the seismic performance was improved when the proposed seismic retrofit method was used.

• Journal of the Korea Concrete Institute
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• v.25 no.6
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• pp.667-674
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• 2013

Improving the earthquake resistance of buildings through seismic retrofitting using steel braces can result in brittle failure at the connection between the brace and the building, as well as buckling failure of the braces. This paper proposes a new seismic retrofit methodology combined with glass fiber sheet (GFS) and non-compression X-brace system using carbon fiber (CFXB) for reinforced concrete buildings damaged in earthquakes. The GFS is used to improve the ductility of columns damaged in earthquake. The CFXB consists of carbon fiber bracing and anchors, to replace the conventional steel bracing and bolt connection. This paper reports the seismic resistance of a reinforced concrete frame strengthened using the GFS-CFXB system. Cyclic loading tests were carried out, and the hysteresis of the lateral load-drift relations as well as ductility capacities were investigated. Carbon fiber is less rigid than the conventional materials used for seismic retrofitting, resulting in some significant advantages: the strength of the structure increased markedly with the use of CF X-bracing, and no buckling failure of the bracing was observed.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.567-572
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• 2003

An experimental work is presented to evaluate the retrofit method for improving the flexural capacity of shear walls. Fives shear wall specimens are designed and retrofitted by using carbon fiber materials such as rod, sheet and plate. Cyclic horizontal loads are applied to the specimens under constant axial load, $0.1f_{ck}A_g$. Test result shows that specimens with additional flexural reinforcement have the increased initial stiffness and deformation capacity. However, the strength is not improved as much as expected. This is because that the flexural reinforcement is pulled out from the foundation at the latter half of cycles. In order to maximize the flexural retrofit, therefore, it is required to study the anchorage behavior of the flexural reinforcement for retrofit.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.55-62
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• 2012

Steel plate or FRP materials have been typically used for the seismic retrofit of civil infrastructures. In order to overcome the limitation of each retrofitting material, a composite material, which takes advantages from both metal and fiber polymer materials, has been developed. In the study herein, the composite retrofitting material consists of metal part(steel or aluminum) and FRP sheet part(glass or carbon fiber). The metal part can enhance the ductility and the FRP part the ultimate strength. As a preliminary study to investigate the fundamental mechanical characteristics of the metal-FRP laminated composite material this study performed the flexural fracture test with various experimental variables including the number, the angle and the combination of FRP laminates. From the aluminum-FRP composite tests no great increase in flexural strength and flexural toughness were observed. However, flexural toughness of steel-FRP laminate composite was increased so that its behavior can be considered in the retrofit design. In addition, the angle and the kind of fibers should be carefully considered in conjunction with the expected loading conditions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.51-61
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• 2007

A series of three shear wall specimens were tested under constant axial stress and reversed cyclic lateral loading to evaluate the capacity of seismic retrofit proposed for the shear wall with the opening induced by remodeling. One specimen was tested in the as-built condition and the others were retrofitted prior to testing. The retrofit involved the use of carbon fiber sheets and steel plates (thickness ; 3mm) over the entire face of the wall. Specimens were 1/2-scale representations of a one-story wall in a Korean apartment building that was built in 1980. The test results showed that failure mechanism of specimens governed by shear fracture and the strength of specimens was varied with according to the retrofitting strategies.