• Journal of the Earthquake Engineering Society of Korea
• /
• v.8 no.4
• /
• pp.1-10
• /
• 2004

The purpose of this study is to investigate the flexural behavior of square concrete filled carbon tube (CFCT) columns subjected to constant axial load with the cyclic lateral load. Two parameters, wnding angle and thickness of tube, were chosen to evaluate the flexural capacity and behavior of rectangular CFCT columns. Selected two parameters were considered simultaneously in order to evaluate the flexural behavior of a rectangular CFCT columns more precisely. Flexural strength, deformation capacity, ductility and energy dissipation capacity of rectangular CFCT columns were evaluated by calculating the area of load-displacement envelope curves and load-dispalcement hysteresis curves obtained from experiment. Also, the ductile capacity obtained from experiment was compared to that of reinforced masonry wall for the comparison of existing structural element.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.6
• /
• pp.84-91
• /
• 2019

For the goal of the proposal for optimum position of offset outrigger system, a structural schematic design of 70 stories building was carried out, using the general structure analysis program of MIDAS-Gen. In this research, the primary factors of this analysis research were the shear wall stiffness, the frame stiffness, the outrigger stiffness, the stiffness of column linked in outrigger system, etc. To achieve the aim of this study, we analyzed and studied the lateral displacement in top level, the force distribution of outrigger, the existing model of optimal outrigger location, and so on. This paper proposed the optimal position of offset outrigger system. Furthermore it is considered that the study results can be useful in getting the structure engineering data for seeking the optimal position of offset outrigger in the tall building.

• Tunnel and Underground Space
• /
• v.24 no.5
• /
• pp.395-403
• /
• 2014

In this study, a steel pipe type rockbolt manufactured from special material was developed which has high strength and lightweight characteristics. Achievement of grout filling between rockbolt and hole wall was investigated through grout injection tests. Yield force of the developed rockbolt was also examined through tensile tests, which was compared with that of the deformed bar type rockbolt. In addition, the strength and elongation properties of the developed rockbolt were investigated through pull-out tests at three domestic sites showing different RMR classes. It is finally supposed that the developed rockbolt can be suitable for the permanent tunnel support because it has high strength and high durability rather than deformed bar type rockbolt.

• Journal of the Korea Concrete Institute
• /
• v.19 no.6
• /
• pp.685-692
• /
• 2007

When the shear force governs the response of an RC element, as in the case of a low-rise shear wall, the effect of shear on the element's response is thought to be responsible for the 'pinching effect' in the hysteretic loops. However, it was recently shown that this undesirable pinching effect can be eliminated in the hysteretic load-deformation curves of a shear-dominant element if the steel grid orientation is properly aligned in the direction of the applied principal stresses. In this paper, the presence and absence of the pinching mechanism in the hysteretic loops of the shear stress-strain curves of RC elements was explained rationally using a compatibility aided truss model. The analytical results indicate that the pinching effect of the RC elements is strongly related to the direction of the steel arrangement. The area of the energy dissertation does not increase proportionally to the difference between the direction of the principal compressive stress and the direction of the steel arrangement.

• Proceedings of the KSME Conference
• /
• 2001.06d
• /
• pp.97-103
• /
• 2001

The effects of the electrohydrodynamic (EHD) flow and turbulent diffusion on the collection efficiency of a model ESP composed of the plates with a cavity were studied through numerical computation. The electric field and ion space charge density were calculated by the Poisson equation of the electrical potential and the current continuity equation. The EHD flow field was solved by the continuity and momentum equations of the gas phase including the electrical body force induced by the movement of ions under the electric field. The RNG $k-{\varepsilon}$ model was used to analyze the turbulent flow. The particle concentration distribution was calculated from the convective diffusion equation of the particle phase. As the ion space charge increased, the particulate collection efficiency increased because the electrical potential increased over the entire domain in the ESP. The collection efficiency decreased and then increased, i.e. had a minimum value, as the EHD circulating flow became stronger when the electrical migration velocity of the charged particle was low. However, the collection efficiency decreased with the stronger EHD flow when the electrical migration of the particle was higher relatively. The collection efficiency of the model ESP increased as the turbulent diffusivity of the particle increased when the electrical migration velocity of the particle was low. However, the collection efficiency decreased for increasing the turbulent diffusivity when the electrical migration of the particle was higher relatively.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.11 no.4
• /
• pp.171-187
• /
• 1991

In the present study, an analytical solution method is proposed for the seismic design of cantilever sheet pile walls and anchored sheet pile walls used in harbor construction. Seepage pressures, together with a change in magnitudes of effective horizontal soil pressures, are included in the proposed solution method. Also, the Mononobe-Okabe analysis as well as the Westergaard and Matsuo-Ohara theory of hydrodynamic pressures is used in the proposed method. Further, the choice of values for safety factors is examined for the seismic design of anchored sheet pile walls, and the effects of various parameters(dredge line slope, differential in water levels, anchor position, and wall friction angle) on embedment depth, anchor force, and maximum bending moment are analyzed for anchored walls in dense sand deposits. In addition. the tables that could be used for preliminary seismic design of anchored walls in dense sands are presented. The proposed method deals with the sheet pile walls with free earth support.

• Korean Journal of Food Science and Technology
• /
• v.20 no.6
• /
• pp.742-748
• /
• 1988

The macro-and microstructure of Chinese cabbage used for Korean Kimchi preparation were examined and the texture characteristics of raw cabbage leaf and salted or blanched leaves were evaluated by cutting test. The length and thickness of leaf stalk increased with the order of pyllotaxis, but the thinning effect of outermost leaves was observed. The microstructure of cut-profile of stalk showed densely compacted vascular systems aligned in the center of stalk and the outer space was filled with large parenchima cells. Due to this structure, characteristic cutting curves were obtained by cutting test, composing three peaks of cutting for inner surface skin, center vascular system and outer surface skin. Salting and blanching increased the cutting force mainly due to the increase of Gutted cell wall number caused by the structure collapse.

• Journal of the Korean Society of Safety
• /
• v.21 no.3 s.75
• /
• pp.73-80
• /
• 2006

Generally beam design depends on the yielding and maximum strength of each member varying with its section shape. Web plate of H-shape beam has not been substituted with glass plate, because it is known that its strength and heat properties are different and it is limited to substitute the existing steel web with glass element. Ceiling height of each room should be decreased with more than 60-80cm due to the beam. Differently from this condition, glass web beam has a good point to see through it and sunshine can be penetrate into the other size especially when it is installed as of outside wall. And also, it can be safer due to controlling room inside easier, if the strength is applicate. This study is to show some applicability after finding out the properties using the test. The test members with a size of $1,600{\times}200{\times}300{\times}9mm$ being SS41 rolled steel having THK 9mm flange while having 8,10mm and reinforced glass 12mm thickness is bonded with epoxy bond under the condition of temperature $28^{\circ}C$, humidity 50%, bonding power 24Mpa. It is show reinforced glass has 5 times of fracture stress more than the common glass but $50{\sim}150%$ difference between these 2 kinds of glass was shown. Reinforce glass did not support the original upper flange after fracture but the common glass did the upper flange after unloading. Generally reinforced glass is stronger than the common one but the common glass having a part of crack on it, compared with reinforced glass having the overall fracture could be more useful in case of needing ductility.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.10
• /
• pp.895-900
• /
• 2013

A two-dimensional Stokes flow past a circular cylinder in a channel is analyzed. The circular cylinder is located at the center of the channel, and a plane Poiseuille flow exists upstream and downstream far from the circular cylinder. The Stokes approximation is used, and the flow is investigated analytically by using the eigenfunction expansion and the least square methods. From the analysis, the stream function and pressure distribution are obtained, and the pressure and shear stress distributions on the circular cylinder and channel wall are calculated. The additional pressure drop induced by the circular cylinder and the force exerted on it are calculated as functions of the length of the radius of the circular cylinder. For a typical length of the radius of the circular cylinder, the streamline pattern and pressure distribution are shown.

• Journal of Biosystems Engineering
• /
• v.16 no.2
• /
• pp.133-141
• /
• 1991

This study was undertaken to investigate the structural and configurational characteristics of the tailings return-unit in the commercially available head-feed combines and to study the aero-dynamical behavior of the tailings in the units. The mathematical model of the motion of tailings in the thrower casing was developed and the simulated trajectories for different type of units was analyzed to compare with the measured ones. The air-stream velocity profile in various locations along the tailings returning duct was measured to find the effect of configurational characteristics and blade tip speed. The results of the study are summerized as follows. 1. The ejecting angle, which is the angle between the direction of the particle velocity ejecting from the blade and the horizontal axis, was found to be about $66^{\circ}$ in both the simulation and experiment. The angle was much greater than the setting angle of actual duct of the combines studied, which were $48{\sim}56^{\circ}$. By comparison of these results, it was suggested to change duct setting angle so as to reduce the frictional force, between the duct wall and tailings, by reducing the difference between the ejecting and setting angles. 2. The velocity of the air stream in the duct was in general higher in the upper bound of the duct compared to the lower and decreased as the stream went toward the end of duct. The comparison of the tailings units among the combines studied showed a superior performance with the tapered duct having small diameter in the outlet and with greater number of thrower blade.