• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.121-126
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• 1994

In this thesis, a series of loading tests are conducted in order to investigate the fracture safety as structural materials of GFRP(Glass Fiber Reinforced Plastics) which we wifely used in the developed countries becauses of their natural of anticorrosion and lightweight etc.. In the fracture test, the mid-span displacement, the strain and the yield load of the GFRP pipes are measured for different number of laminates, and fracture energy is estimated. From this study, it is known that GFRP pipe could be used as structural materials in underground buried pipes if their ductility and strength are increased by controlling number of laminates. Furthermore, because of their merit of lightweight, they can contribute greatly to reduction of construe-tlon cost when they are employed.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.251-254
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• 2005

A number of studies have been conducted on FRP shear strengthening of RC beams during the past decade. The test results indicated. that the strengthened specimens failed predominantly by debonding of the FRP sheets before reaching the rupture strength of FRP sheets. For this reason, limits on the effective strain in FRP have been incorporated in ACI 440.2R recommendation considering debonding failure. This paper presents the test results of 7 small scale RC beams shear-strengthened with glass fiber sheets. Three types of FRP configurations, such as two sides bonded, U wrap and fiber shear-key embedded, were considered. GFRP sheet were bonded vertically to member axis along the shear span. From the test results, it was found that debonding strain of GFRP sheets at failure decreased with the number of layers. In addition, effective strain of FRP proposed by ACI 440.2R recommendation has been verified in this study.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.595-600
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• 2015

The implementation possibility of the flexible optical network configuration using the non-midway optical phase conjugator (OPC) in the dispersion-managed (DM) optical link for wavelength division multiplexed (WDM) transmission is demonstrated in this paper. It is confirmed that the implementation possibility of flexible link configuration is more increased, as number of fiber spans is more bigger and the residual dispersion per span (RDPS) is more large. It is also confirmed that the non-midway OPC link, in which RDPS of the latter half transmission section (after OPC) is decided by the averaged RDPS of the former half transmission section (before OPC), has more advantage for the flexible network configuration.

• Steel and Composite Structures
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• v.19 no.2
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• pp.441-465
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• 2015

This paper presents the experimental results of flexural and compression steel members strengthened with carbon fiber reinforced polymers (CFRP) sheets. In the flexural test, the five specimens were fabricated and the test parameters were the number of CFRP ply and the ratio of partial-length bonded CFRP sheets of specimen. The CFRP sheet strengthened steel beam had failure mode: CFRP sheet rupture at the mid span of steel beams. A maximum increase of 11.3% was achieved depending on the number of CFRP sheet ply and the length of CFRP sheet. In the compression test, the nine specimens were fabricated and the main parameters were: width-thickness ratio (b/t), the number of CFRP ply, and the length of the specimen. From the tests, for short columns it was observed that two sides would typically buckle outward and the other two sides would buckle inward. Also, for long columns, overall buckling was observed. A maximum increase of 57% was achieved in axial-load capacity when 3 layers of CFRP were used to wrap HSS columns of b/t = 60 transversely.

• Structural Monitoring and Maintenance
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• v.6 no.4
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• pp.269-289
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• 2019

This study investigated experimentally the response of thick reinforced concrete specimens having hollow cores with critical parameters. The investigation includes testing of twelve specimens that are solid and hollow-core slab models. Each specimen consists of two pieces, the piece dimensions are (1.2 m) length, (0.3 m) width and (20 cm) thickness tested under both monotonic and repeated loading. The test program is carried out to study the effects of load type, core diameters, core shape, number of cores, and steel fiber existence. Load versus deflection at mid span, failure modes, and crack patterns were obtained during the test. The test results showed that core shape and core number has remarkable influenced on cracking pattern, ultimate load, and failure mode. Also, when considering repeated loading protocol, the ultimate load capacity, load at yielding, and ductility is reduced.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.205-211
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• 2004

The purpose of this study is to investigate shear strengthening effects and behaviour of RC beams strengthened in shear by Carbon Fiber Mesh(CFM) and mortar for fixing CFM to concrete. Test parameters in experiment are shear span-to-depth ratio, layout of CFM and number of clip. From the test, it was shown that the governing failure patten was the bond failure between cover mortar and RC beam initiated at about 60% of maximum strength. And the strength of CFM was developed up to 19.6% of it's maximum tensile strength when the specimen reached to failure. The most effective enhancement using CFM and mortar were to attach CFM diagonally to concrete in a/d of 1.0 and increase the number of cilps in a/d of 1.5, respectively.

• Advances in materials Research
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• v.8 no.4
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• pp.337-359
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• 2019

Shape Memory Polymer Composites (SMPC) have gained popularity over the last few decades due to its flexible shape memory behaviour over wide range of strains and temperatures. In this paper, non-linear bending analysis has been carried out for SMPC beam under the application of uniformly distributed transverse load (UDL). Simplified C⁰ continuity Finite Element Method (FEM) based on Higher Order Shear Deformation Theory (HSDT) has been adopted for flexural analysis of SMPC. The numerical solutions are obtained by iterative Newton Raphson method. Material properties of SMPC with Shape Memory Polymer (SMP) as matrix and carbon fibre as reinforcements, have been calculated by theory of volume averaging. Effect of temperature on SMPC has been evaluated for numerous parameters for instance number of layers, aspect ratio, boundary conditions, volume fraction of carbon fiber and laminate stacking orientation. Moreover, deflection profile over unit length and behavior of stresses across thickness are also presented to elaborate the effect of glass transition temperature (T_g). Present study provides detailed explanation on effect of different parameters on the bending of SMPC beam for large strain over a broad span of temperature from 273-373K, which encompasses glass transition region of SMPC.

• Steel and Composite Structures
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• v.24 no.5
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• pp.561-568
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• 2017

Steel frames are widely used in steel structures. Exiting steel structures may be needed to strengthen for various reasons. Carbon Fiber Reinforced Polymers (CFRP) is one of the materials that are used to strengthen steel structures. Most studies on strengthening steel structures have been done on beams and steel columns. No independent study, to the researcher's knowledge, has studied the effect of CFRP strengthening on steel frames. This study explored the use of CFRP composite on retrofitting square hollow section (SHS) steel frames, using numerical investigations. Ten Finite Element (FE) models, which were strengthened with CFRP sheets, were analyzed under different coverage length, number of layers, and location of CFRP composite. One FE model without strengthening was analyzed as a control FE model to determine the increase of the ultimate load in the strengthened steel frames. ANSYS software was used to analyze the SHS steel frames. The results showed that the coverage length and the number of layers of CFRP composite have a significant effect on increasing the ultimate load of the SHS steel frames. The results also showed that the location of CFRP composite had no similar effect on increasing the ultimate load and the amount of mid span deflection of the SHS steel frames.

• Magazine of the Korea Concrete Institute
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• v.7 no.5
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• pp.179-188
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• 1995

SFRC overcomes brittleness of concrete and has increases strength due to the action of confmement, crack arrestmg mechan~sm and pull out resistances of steel f~bers ~ n s ~ d e the concrete. These lead also to the increased strength and ductility under the shear stress. It has been reported that the secondary remforcement effect of steel fibers IS more pronounced In shear than flexure. Addition of hooked stee!, fibers into the cementitious materials enhanced shear resistance and consequently improves structural behavior and shear strength of Reinforced Hooked-Steel-Fiber Concrete Ream(RHSFCI3) under the shear forces. Experimental observations were made on the main parameters effecting structural behavior of RHSFCB in this study. The volume fractions of fibers, shear span to depth ratios, and spaclngs of stlrrups were taken into account as the mam parameters. Some eyuatlons reported in the literatures, regardmg the predict~ons of the shear strength of RHSFCB have been evaluated stdtlst~cdlly based on the tot a1 number of 95 test results on RHSFCB faded In shear on shear flexu~al mode.

• Earthquakes and Structures
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• v.8 no.6
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• pp.1453-1461
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• 2015

In this article the non-linear behavior of the shear wall with low yield stress retrofitted with Glass Fiber Reinforced Polymer (GFRP) is investigated under pushover loading. The models used in this study are in ${\frac{1}{2}}$ scale of one story frame and simple steel plates with low yield stress filled the frame span. The models used were simulated and analyzed using finite elements method based on experimental data. After verification of the experimental model, various parameters of the model including the number of GFRP layers, fibers positioning in one or two sides of the wall, GFRP angles in respect to the wall and thickness of the steel plate were studied. The results have shown that adding the GFRP layers, the ultimate shear capacity is increased and the amount of energy absorbed is decreased. Besides, the results showed that using these fibers in low-thickness plates is effective and if the positioning angle of the fibers on the wall is diagonal, its behavior will improve.