• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1003-1008
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• 2001

It is recently reported that bond failure can be initiated in the region where maximum bending moment and shear force is acted by accompanying shear deformation after flexural crack in full-scale RC beams strengthened by CFRP. Such a shear deformation effect causing bond failure is relatively little in the case of small-scale specimens. So, additional reinforcing details to the critical beam section where maximum moment and shear were acted is required to prevent the bond failure caused by the shear deformations. The U-type wrapping methods by CFRP to the critical beam section is proposed and tested in this paper. Also, the applicability of design bond strength derived from the tests of small-scale beam was investigated by the full-scale RC beam strengthened by CFRP.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.428-434
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• 2015

The objective of the present study is to analyze the results of the trial-test for the full-scale driving pump, which is arranged in the LCT (Large Cavitation Tunnel). Firstly, the reasons of selecting the final design pump are introduced in terms of the performance analysis in model tests. The trial-test items for the full-scale driving pump are measurements of output current/voltage at the inverter of the main motor and the flow velocity in the LCT test section. The test results show the increase in flow rate of about 10.7% and the decrease in pump head of about 26%, compared with those of final design-pump specification. The motor power has the margin of about 22%. The performance analysis for the full-scale pump is conducted using the commercial code (CFX-10). The delivered power calculated with CFX-10 shows good agreement with that extracted from the full-scale pump test. It is found that CFX-10 is useful to analyze a full-scale pump.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.101-110
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• 2007

Recently, rudder erosion due to cavitation frequently has occurred at large high speed container carriers. Especially, in the case of a horn-type rudder, the rudder erosion is severe around a gap. The gap-flow characteristics are investigated through a computational method to understand the effects of a gap on the cavitation and rudder efficiency. A viscous flow theory utilizing a cavitation model is applied to calculate the flow around idealized 2-dimensional rudder sections in a full scale. The effects of gap clearance and flow-control projection are also investigated. From the computational results, the mass flow rate through a gap is found to be one of the important parameters to affect the cavitation and rudder efficiency.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.867-873
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• 2004

It has been known that debonding failures between CFS(Carbon Fiber Sheet) and concrete in the strengthened RC beams are initiated by the peeling of the sheets in the region of combined large moment and shear forces, being accompanied by the large shear deformation after flexural cracks. These shear deformation effects are seldom occurred in small-scale model tests, but debondings due to the large shear deformation effects are often observed in a full-scale model tests. The premature debonding failure of CFS, therefore, must be avoided to confirm the design strength of full-scale RC beam in strengthening designs. The reinforcing details, so- called 'U-Shape fiber wrap at mid-span' which wrapped the RC flexural members around the webs and tension face at critical section with CFS additionally, were proposed in this study to prevent the debonding of CFS. Other reinforcing detail, so called 'U-Shape fiber wrap at beam end' were included in this tests and comparisons were made between them.

• Wind and Structures
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• v.28 no.4
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• pp.203-213
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• 2019

The topography and geomorphology are complex and changeable in western China, so the railway transition section is common. To investigate the aerodynamic effect of the subgrade-tunnel transition section, including a cutting-tunnel transition section, an embankment-tunnel transition section and two typical scenarios for rail infrastructures, is selected as research objects. In this paper, models of standard cutting, embankment and CRH2 high-speed train with the scale of 1:20 were established in wind tunnel tests. The wind speed profiles above the railway and the aerodynamic forces of the vehicles at different positions along the railway were measured by using Cobra probe and dynamometric balance respectively. The test results show: The influence range of cutting-tunnel transition section is larger than that of the embankment-tunnel transition section, and the maximum impact height exceeds 320mm (corresponding to 6.4m in full scale). The wind speed profile at the railway junction is greatly affected by the tunnel. Under the condition of the double track, the side force coefficient on the leeward side is negative. For embankment-tunnel transition section, the lift force coefficient of the vehicle is positive which is unsafe for operation when the vehicle is at the railway line junction.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.222-225
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• 2008

To prove a lot of technical difficulties related to the safety management of a railroad fire effectively, we design for the full-scale fire test facility of the railroad vehicle. It will be consist of major 3 part - duct system with smoke cleaning system, measuring section and gas analysis system. The CFD simulation was also carried out to design of the hood and duct system optimization. The results will be help for basic research of the railroad fire safety.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.357-364
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• 2002

This paper describes the feasibility of compacting subgrade layer in thicker lifts than currently permitted as 20 cm. This project involved constructing and testing a full scale test section in highway. Soil stiffness in field was evaluated by a nondestructive testing method, called Geogage. Quality control tests and FE Analysis were also conducted. Typical dynamic compaction roller of 11ton weight is applied for full scale test and a Mohr-Coulomb model and Plane strain condition are used for FE Analysis. The results showed that compaction-induced stress and dissipated energy are mainly depend on depth of soil and it could be possible to increase thickness of a lift.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.306-316
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• 2002

This paper summarizes the results of full-scale cyclic seismic testing on four RBS (reduced beam section) steel moment connections. Key test variables were web bolting vs. welding and strong vs. medium PZ (panel zone) strength. The specimen with medium PZ strength was specially designed to mobilize energy dissipation from both the PZ and RBS region in a balanced way; the aim was to reduce the requirement of expensive doubler plates. Both strong and medium PZ specimens with web-welding were able to provide sufficient connection rotation capacity required of special moment frames, whereas specimens with web-bolting showed inferior performance due to the premature brittle fracture of the beam flange across the weld access hole. In contrast to the case of web-welded specimens, the web-bolted specimens could not transfer the actual plastic moment of the original (or unreduced) beam section to the column. If a quality welding for the beam-to-column joint is made as in this study, the fracture-prone area tends to move into the beam flange base metal within the weld access hole. Analytical study was also conducted to understand the observed base metal fracture from the engineering mechanics point of view.

• Magazine of the Korea Concrete Institute
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• v.2 no.1
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• pp.79-90
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• 1990

The purpose of this paper is to study on the effect of cutting off tension bars in reinforced concrete beams. that is, the ultimate strength, the failure mode and thl} tension stress distribution through the span. To achieve this purpose, a full-scale frame and seven small scale model beams (five rectangular and two T-section beams) were tested. The four main model specimens and two speciml}ns without cutting off tension bars 1,'{ere analyzed as plane stmss element with package program ADINA. As a result of test and analysis, the shorter' distance bet ween the reaction point and the cutting off point, the higher the ultimate strength of a bl}am will be when other physical properties are equal.

• Wind and Structures
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• v.38 no.2
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• pp.93-107
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• 2024

A π-shaped composite deck in the form of an open section is a type of blunt body that is highly susceptible to wind loads. To investigate its vortex-induced vibration (VIV) performance, a large-scale (1/20) section model of a cable-stayed bridge with a main span of 650 m was tested in a wind tunnel. The vibration suppression mechanism of the countermeasures was analyzed using computational fluid dynamic. Experimental results demonstrate that the vertical and torsional VIVs of the original section can be suppressed by combining guide plates with a tilt angle of 35° and bottom central stabilizing plates as aerodynamic countermeasures. Numerical results indicate that the large-scale vortex under the deck separates into smaller vortices, resulting in the disappearance of the von Kármán vortex street in the wake zone because the countermeasures effectively suppress the VIVs. Furthermore, a full-bridge aeroelastic model with a scale of 1/100 was constructed and tested to evaluate the wind resistance performance and validate the effectiveness of the proposed countermeasures.