• Steel and Composite Structures
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• v.46 no.5
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• pp.591-609
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• 2023

In some buildings, the lateral structural response of steel framed buildings depends on the shear walls and it is very important to study the behavior of these elements under near-field seismic loads. The link beam in the opening of the shear wall between two wall plates is investigated numerically in terms of behavior and effects on frames. Based on the length of the beam and its bending and shear behavior, three types of models are constructed and analyzed, and the behavior of the frames is also compared. The results show that by reducing the length of the link beam, the base shear forces reduce about 20%. The changes in the length of the link beam have different effects on the degree of coupling. Increasing the length of the link beam increases the base shear about 15%. Also, it has both, a positive and a negative effect on the degree of coupling. The increasing strength of the coupling steel shear wall is linearly related to the yield stress of the beam materials, length, and flexural stiffness of the beam. The use of a shorter link beam will increase the additional strength and consequently improving the behavior of the coupling steel shear wall by reducing the stresses in this element. The link beam with large moment of inertia will also increase about 25% the additional strength and as a result the coefficient of behavior of the shear wall.

• Earthquakes and Structures
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• v.27 no.1
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• pp.57-67
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• 2024

To assess the seismic performance of Plate-Shell Integrated Concrete Liquid-Storage Structure (PSICLSS), a scaled test model was constructed. This model incorporated a hybrid isolation system, which combined shape memory alloy (SMA), lead-cored rubber isolation bearing (LRB) and sliding isolation bearing (SB). By conducting shaking table test, the dynamic responses of both non-isolated and hybrid-isolated PSICLSS were analyzed. The results show that the hybrid isolation system can effectively reduce the acceleration and displacement responses of the structure. However, it also results in an increase in local hydrodynamic pressure and liquid sloshing height. Under extreme earthquake action, the displacement of isolation layer is small. When vertical ground motion is taken into account, the shock absorption rate of horizontal acceleration decreases. The peak hydrodynamic pressure increases significantly, and the peak hydrodynamic pressure position also changes. The maximum displacement of isolation layer increases, the residual displacement decreases.

• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.31-39
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• 2014

The helical pile is a manufactured steel pile consisting of one or more helix-shaped bearing plates affixed to a central shaft. This pile is installed by rotating the shaft into the ground to support structural loads. The advantages of helical piles are no need for boring or grout process, and ability to install with relatively light devices. The bearing capacity of the helical pile is exerted by integrating the bearing capacity of each helix plate attached to the steel shaft. In this paper, to estimate the bearing capacity of moderate-size helical piles, 6 types of helical piles were constructed with different shaft diameter, plate configuration and the penetration depth. A series of field loading tests was performed to evaluate the effect of helical pile configuration on the bearing capacity of helical pile, constructed in two different shaft diameters (i.e. 73 mm and 114 mm). In the same way, the diameter of bearing plate was also changed from 400mm to 250mm with one or three plates. As well, the penetration depth was varied from 3m to 6m to analyze the relation between the penetration depth and the bearing capacity. As a result, not only the increase of the shaft diameter, but also the number or diameter of helix bearing plates enhances the bearing capacity. Especially the configuration of the helix plate is more critical than the shaft diameter.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.131-136
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• 2008

We performed a non-destructive geophysical survey such as an elastic wave survey, electric specific resistance survey, plate loading test, etc. in order to grasp the structure and status of the ground around the pillar gate and to provide the directions and design data for preservation and maintenance during reconstruction. The result of electric specific resistance survey shows 50-1300 ohm-m range of general electric specific resistance distribution. Besides, the positions around 1m south of stone pillars, between stone pillar No.3 and 4, and 1m north of stone pillar No.2 and 3 show abnormality of relatively lower electric specific resistance than their surroundings. The abnormality of low electric specific resistance appearing between stone pillar No.3 and 4 shows consistency with the abnormal section appearing from the result of elastic wave reflection survey. The result of a plate loading test shows that allowable bearing force is over $10.70tf/m^2$, and the settlement amount at this time was calculated as 19.635mm. The design load during reconstruction of pillar gates was calculated as $16.37t/m^2$ by applying assumption values, which is far more than the allowable bearing force, so it is judged that a measure to strengthen the foundation ground is necessary.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1259-1268
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• 2004

To organize training in limited training area for an actuai combat, realistic training simulation plugged in by various battle conditions is essential. In this paper, we propose a virtual target overlay technique which does not use a virtual image, but Projects a virtual target on ground-based CCD image by appointed scenario for a realistic training simulation. In the proposed method, we create a realistic 3D model (for an instructor) by using high resolution Geographic Tag Image File Format(GeoTIFF) satellite image and Digital Terrain Elevation Data (DTED), and extract the road area from a given CCD image (for both an instructor and a trainee). Satellite images and ground-based sensor images have many differences in observation position, resolution, and scale, thus yielding many difficulties in feature-based matching. Hence, we propose a moving synchronization technique that projects the target on the sensor image according to the marked moving path on 3D satellite image by applying Thin-Plate Spline(TPS) interpolation function, which is an image warping function, on the two given sets of corresponding control point pair. To show the experimental result of the proposed method, we employed two Pentium4 1.8MHz personal computer systems equipped with 512MBs of RAM, and the satellite and sensor images of Daejoen area are also been utilized. The experimental result revealed the effective-ness of proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1409-1415
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• 2021

The Gysel divider has the advantage of easily setting the resistor in the circuit. If the line impedance in the Gysel divider is set differently, the input signal can be distributed to the two output ports at various distribution ratios. This paper proposes the Gysel divider that can change the power distribution to 1:3 or 3:1 by changing the line impedance. The impedance change of the line can be implemented by placing a floating copper plate on the bottom of the microstrip-line. When the floating copper plate and the ground plane are connected, the line operates as the microstrip-line, and when the floating copper plate and the ground plane are disconnected, the line operates as the coplanar-line. The proposed Gysel divider was fabricated at the center frequency of 1.5GHz. The fabricated 3:1 Gysel divider has a stable value S₁₁ of below -17dB, S₂₁/S₃₁ of 4.8±0.2dB, S₂₁(to high output port) of -1.39±0.12dB and S₃₁(to low output port) of -6.15±0.08dB over 1.3~1.7GHz.

• Journal of the Korean Geotechnical Society
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• v.38 no.10
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• pp.31-40
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• 2022

This study compares elastic moduli calculated using two stiffness testing methods with different strain ranges to evaluate the stress-settlement characteristics of foundation support layers. Elastic moduli were calculated by the soil stiffness gauge (SSG) in the micro-strain range and the plate load test (PLT) in the medium strain range. To apply the elastic moduli obtained by the two testing methods with different strain ranges to the design and construction of foundation soils, the correlation between each measurement value should be identified in advance. As a result of the comparative analysis of the elastic moduli calculated using the two methods in weathered soil and rock, which are representative support layers in Korea, the calculated elastic moduli differed depending on the types of soil and stress conditions. For various soil types, the static elastic modulus obtained by the PLT was reduced by 56% because of the difference in the strain level of the test compared with the dynamic elastic modulus obtained by the SSG. Therefore, the results show that it is necessary to apply corrections to the stress distribution, stress level, and dynamic effect according to the ground stiffness to effectively use the SSG instead of the PLT.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.53-66
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• 2007

A series of model tests were performed to investigate the soil arching effect in embankments supported by piles with geosynthetics. In the model tests, model piles with isolated cap were inserted through the holes in a steel plate, which could be operated up and down. Then geosynthetics was laid on the pile caps below sand fills. The settlement of soft ground was simulated by lowering the plate. As the plate was lowered, the soil arching was mobilized in the embankments. The deformation of both the sand fills and geosynthetics were captured by camera. Also the loads acting on pile cap and the tensile strain of geosynthetics were monitored by data logging system. Model tests showed that the embankment loads transferred on pile cap by soil arching Increased rapidly with settlement of the soft ground. In case of the absence of geosynthetics, the loads acting on pile caps dropped to residual value after peak value, whereas loads on pile caps gradually increased until constant value in case of geosynthetic-reinforced. This illustrated that reinforcing with the geosynthetics has a good effect to restrain the settlement of embankments. Also, the deformation shape of geosynthetics between pile caps was circular. The embankment loads transferred on pile caps can be estimated by considering both soil arching and tensile strain of geosynthetics in embankments supported by piles with geosynthetics.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.75-82
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• 2007

The purpose of this study was to analyze and compare the effect of gait time on the gait patterns in elderly female OA and non-OA patients. The intensity of the subjects joint pain was surveyed by using WOMAC. Twelve subjects participated in this study. Measurements were taken for every the 10 minutes for 30 minutes after walking by a force plate. The following variables were recorded; double stance support time, Fx, Fy, Fx_time, Fz and so on. From the investigation of these variables the following was observed and concluded. The Fz values for the OA group was 1.01BW at the start and after 30 minutes was 1.04BW on the other hand the non-OA group's Fz1 was 1.08BW and 1.10BW. There was no significant difference calculated between the two groups and at the start and end of the experiment about all the variables. Therefore, it is concluded that there was no negative effect caused by walking for the 30 minutes and that it was an effective way of strengthen both respiratory and muscle function.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.259-274
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• 2005

The purpose of this study was to compare the kinematic and kinetic parameters of lower extremity joints between novice and experienced sports aerobic dancers during two heights of depth jumps. Four male dancers were participated in this study and they performed 40cm and 60cm height depth jump three times, respectively. Four ProReflex MCU cameras (100frame/sec) and a Kistler force plate (1000Hz) were used for data collection. The results indicated that the duration of contact phase of experienced group was shorter than that of novice group regardless of jump height. For minimum angle of hip, knee, and ankle joints, the novice group had tendency to decrease the angle but the experienced group had increased the joint angle with jump height. There was no difference of total ground reaction force between the groups but the reaction force had tendency to increase with jump height. Thus, this study implied that repetition of jump and landing may induce joint related injury and further study such as. EMG analysis of lower extremity can be needed to verify the relationship between injury and ground reaction force.