• Structural Engineering and Mechanics
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• v.50 no.6
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• pp.741-754
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• 2014

The conventional PHC pile-footing connection is the weak part because the surface area and stiffness are sharply changed. The Composite PHC pile reinforced with the transverse shear reinforcing bars and infilled-concrete, hereafter ICP pile, has been developed for improving the flexural and shear performance. This paper investigates the cyclic behavior and performance of the ICP pile-footing connection. To investigate the behavior of the connection, one PHC and two ICP specimens were manufactured and then a series of cyclic loading tests were performed. From the test results, it was found that the ICP pile-footing connection exhibited higher cyclic behavior and connection performance compared to the conventional PHC pile-footing connection in terms of ductility ratio, stiffness degradation and energy dissipation capacity.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.569-574
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• 2007

The paper presents an application of the model to a practical problem of train-induced vibrations. The aim of this study is to vertify for performance of isolators which was developed in KRRI supported floating slab track. Laboratory tests on developed isolations show that the energy dissipation, under cyclic loading of constant amplitude, can be suitably represented by a combination of a viscous and a hysteretic damping. Also, other tests for structural performance are carried out, such as elastic material test, compression test and so on. The specimen, $400{\times}400{\times}300mm$, is placed between two stiff steel plates designed to uniformly distribute the compression stress on the surface.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.363-368
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• 2000

The Korean Bridge Design Standard Specifications adopted the seismic design requirements in 1992. However, The current seismic design requirements for bridges are based on the USA seismic codes for sever earthquake. This provides the basic factors that affects the performance of spiral reinforced concrete piers for seismic loading, and The specimen tests are performed based on load-displacement, effective stiffness and displacement ductility, etc. The quasi-static test was adopted in order to investigate seismic performance of the spiral reinforced concrete pier specimens which had different transverse steel amount, spacing and longitudinal steel ratio under different axial load levels. This study is concluded that seismic design for transverse reinforcement content of spiral reinforced concrete column has influenced on axial load and effective stiffness etc.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.943-948
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• 2003

The experimental study for oblong section was carried out by the column test in weak axis. The column specimens had 3 types of transverse steel configurations, such as interlocking spirals, interlocking circular hoop ties and rectangular ties. The oblong columns with interlocking spirals and with interlocking circular hoop ties showed better seismic performance than the rectangular columns with rectangular hoops and cross-ties. The objectives of this study were to provide experimental data on the behavior of interlocking spiral columns under cyclic loading, to compare the performance of columns with interlocking spirals to columns with various transverse steel configurations, to study the flexural detailing of interlocking spirals, interlocking circular hoops, and other transverse steel configurations as the transverse reinforcement, and to make recommendations for the design of bridge columns incorporating interlocking spirals, circular hoops as the transverse reinforcement.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.121-126
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• 2003

The objective of this research is to evaluate of seismic performance for reinforced concrete bridge piers with lap splices of longitudinal reinforcement steels using predicting of nonlinear hysteric behavior. For the purpose, enhanced analytical trilinear hystretic model has been proposed to simulate the force-displacement hysteretic curve of RC bridge piers under repeated reversal loads. The moment capacity and corresponding curvature in the plastic hinge have been determined, and the enhanced hysteretic behavior model by five different kinds of branches has been proposed for modeling the stiffness variation of RC section under cyclic loading. The strength and stiffness degradation index are introduced to compute the hysteretic curve for various confinement steel ratios, In addition, the modified curvature factor has been introduced to forecast of seismic performance of longitudinal steel lap spliced and retrofitted specimens. The results of this research will be useful to predict of seismic performance for longitudinal steel with lap spliced and its retrofitted specimens.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.739-748
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• 2004

A hybrid dust-collector combining a fabric filter with centrifugal force was developed to enhance the performance of the conventional fabric filter systems and its performances were evaluated to compare to that of the existing dust collector. The pressure drop rapidly increased with increasing the elapsed time and the face velocity in two filtration systems. But the increasing ratio of a hybrid dust-collector compare to the existing dust collector was lower. This results were confirmed from the performance such as cleaning interval, residual pressure drop and dust loading rate. The overall collection efficiency of the hybrid dust-collector was more than 99.6% and this showed a improvement of 0.6～2% than that of the existing dust collector. Especially, the fractional collection efficiency at the particle size of around 1${\mu}{\textrm}{m}$ is about 4% higher than that of the existing dust collector.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.188-195
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• 2000

This study was conducted to develop the mathematical model and the computer simulation program(TPPMWV) for predicting the tractive performance of off-road wheeled vehicles operated on various soil conditions. The model takes into account main design parameters of a wheeled vehicle, including the radius and width of front and rear tires, the weight of vehicle, wheelbase and driving type(4WD, 2WD). Soil characteristics, such as the peressure-sinkage and shearing characteristics and the response to repetitive loading, are also taken into consideration. The effectiveness of the developed model was verified by comparing the predicted drawbar pulls using TPPMWV with measured ones obtained by field tests for two different driving types of wheeled vehicle. As a results, the drawbar pulls predicted by the TPPMWV were well matched to the measured ones within the absolute errors of 5.25%(4WD) AND 9.42%(2WD)for two different driving types, respectively.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.1
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• pp.71-77
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• 2016

In this study, the seismic performance of connections between filled composite beam (CG beams) and forming angle composite (FAC) column was experimentally evaluated. First, the bending tests were conducted on two CG beams and the axial tests were conducted on two FAC columns. Then, based on these preliminary test results, the cyclic loading test were performed on two interior connections between CG beam and FAC column. The main difference of two specimens is the plate shape of the CG beam. The test results showed that both specimens achieved the maximum story drift capacity over 0.04 radian which is required for special moment frame.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.57-60
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• 2005

This study discusses spalling and fire enduring performance of high performance concrete (HPC) RC column subjected to loading under heating for 3 hours. According to the test, both the plain concrete and the concrete attached with fire enduring PC panel exceed allowable temperature after 60 minutes due to the exposure of steel bar and falling off of concrete resulting from severe spalling failure. It leads to buckling of main bar and at the same time, occurrence of collapse of plain HPC column member is observed after 2 hours and 1 hour 40 minutes's exposure to fire, respectively. On the other hand, HPC applying both PP fiber of 0.1$\%$ by mass of concrete and PP fiber+lateral confinement by metal lath maintains their original cross section, which is satisfied with the 3 hours fire endurance criteria, by discharging internal vapour pressure and enhanced lateral confinement force.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.207-210
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• 2005

The objective of this research is to evaluate of seismic performance for reinforced concrete bridge piers with lap splices of longitudinal reinforcement steels using predict of nonlinear hysteric behavior. For the purpose, analytical trilinear hysteretic model has been used to simulate the force displacement hysteretic curve of RC bridge piers under repeated reversal loads. The moment capacity and corresponding curvature in the plastic hinge have been determined, and the enhanced hysteretic behavior model by five different kinds of branches has been proposed for modeling the stiffness variation of RC section under cyclic loading. The strength and stiffness degradation index are introduced to compute the hysteretic curve vary confinement steel ratio. In addition, the modified curvature factor has been introduced to forecast of seismic performance of longitudinal steel lap spliced and retrofitted specimens.