• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.119-126
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• 2006

The elastic budding strength of a GFRP pipe reinforced with ribs was evaluated. The height and thickness of a rib and the spacing between two adjacent ribs were considered as factors affecting tlje budding strength of the pipe. And also, the ratio of the longitudinal stiffness and transverse stiffness was considered as the parameter affecting on the budding strength because GFRP is orthotropic material. Buckling strengths of various GFRP pipe models with different shapes and stiffness ratio were evaluated by FE analyses and a formula to estimate the elastic buckling strength of a rib-reinforced pipe made of orthotropic material was suggested from the regression with FE analysis results. Analysis results show that a rib-reinforced pipe has superior buckling strength to a general flat pipe and the suggested formula estimates accurate buckling strength of the rib-reinforced pipe.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.737-746
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• 2006

The elastic buckling strength of a Glass Fiber Reinforced Plastic (GFRP) pipe reinforced with ribs was evaluated. The height and thickness of a rib and the spacing between two adjacent ribs were considered as factors affecting the buckling strength of the pipe. And also, the ratio of the longitudinal stiffness and transverse stiffness was considered as the parameter affecting the buckling strength as the GFRP is orthotropic material. Buckling strengths of various GFRP pipe models with different shapes and stiffness ratios were evaluated by FE analyses and a formula to estimate the elastic buckling strength of a rib-reinforced pipe made of orthotropic material was suggested from the regression with the results from the FE analysis. Analytical results show that a rib-reinforced pipe has a buckling strength superior to a general flat pipe and the suggested formula estimates accurate buckling strength of the rib-reinforced pipe.

• Journal of the Korean GEO-environmental Society
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• v.11 no.8
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• pp.73-82
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• 2010

The GFRP(Glass-Fiber Reinforced Plastic) pipe is designed to behave safely against the external forces and to secure stability of deformation and settlements of pipe, since it is laid under the ground. In this study, the evaluation for the pressure stability was carried out by performing the laboratory experiments to figure out the mechanical properties of Glass-Fiber Reinforced Plastic pipe, take a theoretical approach, and suggest the mechanical properties necessary for the analysis and design of GFRP. Numerical analysis is also conducted to evaluate on the field application through the comparison concerning relations between deformation and differential settlement in the GFRP and hume pipes when all and half sections are under the surcharge load.

• Journal of the Korean Geosynthetics Society
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• v.13 no.1
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• pp.33-40
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• 2014

In general, pipes buried underground can be classified into either rigid or flexible pipe. Glass fiber reinforced thermosetting polymer plastic (GFRP) pipe can be considered as one of typical flexible pipes for which the soil-pipe structure interaction must be taked into account in the design. In this paper, we present the result of an investigation pertaining to the short-term and long-term behavior of buried GFRP pipe. The mechanical properties of the GFRP pipe produced in the domestic manufacturer are determined and the results are reported in this paper. In addition, Ring deflection is measured by the field tests and the finite element analysis. Also, the extrapolation using these techniques typically extends the trend from data gathered over a period of approximately 5,232 hours, to a prediction of the property at 50 years, which is the typical maximum extrapolation time. Therefore, it was investigated that the long-term ring deflection of GFRP pipe estimated by methods for Monod-type.

• Journal of Korean Society of Steel Construction
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• v.26 no.3
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• pp.219-229
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• 2014

The experiment and FE analysis of ultimate behavior of GFRP cylindrical shell structure stiffened by steel pipe ring instead of rectangular cross-section ring was presented. Four kinds of test models were designed and flexural failure experiment was performed to investigate ultimate behavior characteristic according to the size of cross section of steel pipe ring and diameter of GFRP shell. Material properties of specimens were experimented by bending, tensile and compressive test. Displacements and strains were measured to evaluate failure behavior of steel pipe ring and GFRP shell structure. The experimental results were compared with the FEA results by commercial program ABAQUS. It is observed that GFRP shell structure stiffened by steel ring have enough ductility to bending failure, and an increase of bending rigidity of steel ring is very effective to increase of failure strength of GFRP shell structure.

• Journal of the Korean Society for Nondestructive Testing
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• v.9 no.1
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• pp.48-55
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• 1989

It is desirable to develop the effective NDT techniques to evaluate the strength of composite structures. In this study several of acoustic NDT techniques were applied to investigate useful parameters for evaluating the filament wound GFRP structures and following results were obtained. 1. Propagation velocity of stress wave to axial direction in the filament wound GFRP pipe depends on the effective modulus along the propagation direction and source location was parcticable from the a measured velocities. 2. By the application of acoustic emission techniques to GFRP pipe during hydraulic test, it was proven to be possible to detect the damage initiating pressure which could be evaluated nondestructively through the measuring of stress wave energy factor(SWEF). 3. The final failure pressure of GFRP was greatly influenced in the presence of pass through defects, and void-like defects were more dangerous than the laminar type defects.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1050-1059
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• 2010

The GFRP(Glass-Fiber Reinforced Plastic) Pipe is designed to behave safely against the external forces and to secure stability of deformation and settlements in pipe, Since it is laid under the ground. In this syudy, the evaluation for stability was carried out by performing the preliminary numerical analysis to decide the sclae effect in case of indoor model test. As a result of, strain of laying pipes is preponderantly reviewed. Numerical analysis is conducted to evaluate on the field application through the comparison concerning relations between deformation and differential settlement in the GFRP and hume pipes.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.3
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• pp.50-61
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• 2015

This paper presents on the structural behavior of the the methyl methacrylate monomer (MMA) double wide flanged the glass fiber-reinforced polymer(GFRP) pipe composite structures for the manhole raise. The evaluation of structural performance on this composite structure was conducted by the axial load, fatigue load, and ultimate load test. The assessment indicates that the MMA double wide flanged GFRP pipe composite structures was confirmed safety, durability and reliability in result as expected. It was found that this composite structure was able to short working times to around 30-50% and construction costs to around 10-23% with compare other construction methods. Also, environmental pollution and civil complaints will be prevented because there will be no longer any noises, vibrations, dust, or construction wastes.

• Journal of the Korean Society for Advanced Composite Structures
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• v.5 no.3
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• pp.23-31
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• 2014

Recently, sewer-pipe constructions replacing deteriorated pipes are currently underway in the downtown area. To resolve many problems in the conventional method of open-cut construction, lining-board system using light-weight GFRP panels is developed. The pultruded GFRP panels can be successfully used for the developed lining-board system as temporary decks and retaining walls in virtue of light weight, high strength and high durability. In this paper, the structural safety and serviceability of the lining-board system are examined through FE analyses and experiments. Further more, a field application of the lining-board system is presented. The field application shows that quality and environment of construction can be significantly improved.

• Composites Research
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• v.22 no.3
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• pp.1-8
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• 2009

In this paper, we present the results of experimental and analytical investigations on the structural behavior of GFRP pipes used in the water supply pipeline system. Cross-section of the pipe is consisted with two GFRP tubes and polymer mortar between the tubes. Due to the advantages such as light-weight, corrosion resistance, smooth surface, flexibility, etc., use of GFRP pipe in the water supply pipeline system is ever increasing trend. Therefore, more optimized structural design methodology should be developed. In the investigation, we conducted theoretical and analytical studies on the load versus radial deformation characteristics of GFRP pipes. In addition, ring stiffness test is also performed. Test results are compared with theoretical and analytical results and it was found that the results are agreed well within 5% of radial deformation. Finally, it was also found that the GFRP pipes used in the water supply pipeline system are strong enough to satisfy the industrial requirements.