• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.211-220
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• 2013

The nailed joints in wood construction are commonly designed to resist and carry the lateral load but also subject to withdrawal force like uplift load due to the wind. This research was conducted to evaluate the performance of nailed joint composed of dimension lumber and sheathing materials through the nail withdrawal and unsymmetric double shear joint test, and then compared to current design values. The withdrawal strength was greatly dependant on wood specific gravity, and the withdrawal strength of I-joist with OSB showed higher value in spite of low specific gravity. The maximum withdrawal loads were greater than that of derived current design values about 5 times. The lateral resistance of Japanese larch/OSB nailed joints was higher than that of SPF/OSB nailed joint, and derived allowable lateral strength of nailed joints in this study exceeded the current design values. The failure mode of nailed joints was primarily due to the nail bending and this tendency was notable in SPF/OSB nailed joint.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.805-816
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• 2010

For earthquake simulation test it is essential to make sure the similitude in behaviors between the full scale prototype and the reduced scale model. This paper presents the test results obtained through the cyclic lateral-force test, on two-story RC wall subassemblages. A lower 2-story portion of the prototype structure was selected as subassemblages. The global behavior such as the strength and ductility, and the local behavior such as flexural, shear and uplift deformation were measured. The test results of the 3 : 5 scale specimens representing the prototype were compared with those of 1 : 7 scale models. Two types of subassemblages were used: One with lintel beams and one without lintel beams. The comparison shows that 1 : 7 scale model simulated in general successfully the global and local behaviors of the prototype.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.27-35
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• 2010

The structures built under the groundwater level are affected by the buoyancy force, which is hydrostatic pressure in the up direction. Recently, buoyancy-resistant anchor method has been applied in many cases of the construction of the important structure of large size, which is built under the groundwater level so that it takes high uplift pressure. Even if the construction cost of the method is very high, it surely increases the safety rate. However, the diagnosis of the performance of the buoyancy-resistant permanent anchor and the investigation of resistance mechanism are still insufficient. Especially, the long-term behavior of the anchor has not been studied well due to the difficulty in observation procedure. The contribution of this paper is the establishment of reasonable design methodology. We have measured anchor axial forces for 10 years after the construction, by using an automated measurement and a manual measurement by establishing a load cell in anchor head. Through the data collected from the measurements, we analyze the construction-step behavior of the anchor according to the self-weight variation of the building and the long-term behavior (i.e. movement within 10 years after the construction) of the anchor according to the passage of time.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.217-225
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• 2013

In this study, by considering the rail fastening support distance and the distance between the bridge and the abutment, the behavior of concrete track installed on a railway bridge end deck and the bridge end rotation were analyzed. In order to analyze the track-bridge interaction, bridge and abutment specimens with concrete track structures were designed and used in laboratory testing. At a constant fastening support distance, an increase in the bridge end rotation caused an increase in the displacement of the rail. Therefore, the displacement of the rail directly affects the rail and clip stress. Further, it is inferred that the results of multiple regression analysis obtained using measured data such as angle of bridge end rotation and fastening support distance can be used to predict the track-bridge interaction forces acting on concrete track installed on railway bridge deck ends.

• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.41-54
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• 2021

In this study, probabilistic steady seepage behavior of soil foundation beneath water retaining structures according to the location of cutoffs was studied. A Monte Carlo Simulation based on the random finite element method that considers the uncertainty and spatial variability of soil permeability was performed to evaluate the probabilistic seepage behavior. Fragility curves were developed by calculating the failure probability conditional on the occurrence of a given water level from the probability distribution obtained from Monte Carlo simulations. The fragility curve was prepared for the flow quantities such as flow rate through foundation soil, uplift force on the base of structure, and exit gradient in downstream to examine the reliability of the water retaining structure and the foundation soil. From the fragility curves, the effect of the location of cutoff wall on the reliability of water retaining structure and foundation soil according to the rise in water level was studied.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.73-79
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• 2018

In the west coast, south coast, and river basin, the use of geotextile mats has been increasing to improve the soft ground for making industrial facilities space and farmland. As an initial step to improve the vast and soft ground, the geotextile mats are laid and bonded to increase the bearing capacity of the wide ground for supporting construction equipment. Seam strength of geotextile mats exert a force only about 50% of the tensile strength of the fabric, which causes problems such as uplift and sinking in the soft ground. In this study, various types of geosynthetic matting techniques were investigated and the tensile strength of each method was compared and analyzed. Numerical analysis shows that stress increment in the ground due to the overburden load decreases when the seam strength of the geosynthetics mats is increased. When the seam strength was increased to 60, 70 and 80%, the bearing capacity of ground by geotextile mat was increased.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.48-61
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• 2012

It is of great importance to assure the running safety, ride comfort and serviceability in designing the floating slab track for mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction. The results of this study demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the dynamic response such as wheel-rail interaction force, rail bending stress and rail uplift force. Hence, it is efficient to decrease the spacing of springs or to increase the spring constants at the transition to obtain the running safety and serviceability. On the other hand, the vehicle body acceleration as a measure of ride comfort is little affected by the discontinuity of the stiffness at the transition, but by the system tuning frequency; thus, to obtain the ride comfort, it is of great significance to select the appropriate system tuning frequency. In addition, the effects of damping ratio, spacing of springs and train speed on the dynamic behavior of the system have been discussed.

• Journal of the Korean GEO-environmental Society
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• v.14 no.10
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• pp.11-16
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• 2013

Success or failure of the bi-directional pile load test for drilled shaft depends on point selection for loading cells, that is balanced location both uplift force and downward force. Methods to evaluate the ultimate unit side resistance in rockmass layer in both domestic and foreign are based on the uniaxial compression strength of rock core, which can hardly be obtained in domestic rockmass layers which are weathered rockmass layer and soft rockmass layer with very low RQD. Therefore, this study suggested the relation charts between the revised SPT N values and developed unit side resistance of each different layers, which were obtained from bi-directional pile load tests in various domestic sites. To evaluate the appropriateness of the relation charts, the developed unit side resistances from the relation charts were used to select the loading cell position and compared with the measured unit side resistances from field pile load test. Results showed that the developed side resistance from relation charts and the measured side resistance of weathered soil layer and weathered rock layer were very close. Average developed side resistance($1,325kN/m^2$), which are average of upper soft rock layer of loading device($1,151kN/m^2$) and lower($1,500kN/m^2$), was similar with the estimated value ($1,250kN/m^2$).

• Geotechnical Engineering
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• v.7 no.3
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• pp.51-64
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• 1991

The reliable estimation of pile bearing capacity is essential for the improvement of the re- liability and the cost-effectiveness of the design. There have been numerous pile bearing capacity prediction methods proposed up to now, however, execpt for the estimation made from the result of the pile loading test, not one method is appropriate for the reliable prediction. Due to the considerable time and expenses required to carry out the pile loading test, the test has seldom been utilized. The development of Simple Pile Loading Test(SPLT) which utilizes the pile skin friction as the required reaction force to cause the pile tip settlement, provides a solution to perform more pile loading tests and consequently a more economical pile design is possible. The separate measurement of skin friction and tip resistance during the course of performing SPLT provides a better understanding of the pile behavior than the result of the conventional pile loading test where only the total resistance is measured. On the other hand, there are some points to be clarified in order to apply the test results of SPLT to practical problem. They are the direction of the applied load to mobilize the skin friction and the use of reduced sized sliding core. In this research, both the SPLT and the conventional pile loading test on 406mm diameter steel pipe pile have been performed. From the result, it would be safe to use the measured SPLT skin friction value directly in the design, since the value is somewhat lower than the value measured in the conventional test. It is further assumed that the tip resistance value of the reduced sized sliding core should properly be analysed by taking the incluonce of scale effect into consideration.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.61-68
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• 2012

Most widely methods for reinforcement of soil utilized in Korea are anchor method, soil nail method and micro pile method. These methods are classified by the intended use of the structure to be constructed, but the reinforcement of the ground is accomplished contains in common the process of grouting work after inserting the reinforcements. Domestically, gravity grouting has been used mostly so far, but there has always been the risk of insufficient restoration of the loose ground area from the drill holes because the grouting is conducted only by gravity. On the other hand, pressure reinjection grouting may enhance the grouting quality by solving the problem of the existing grouting method considerably since it additionally reinjects grouting through pre-installed tube a certain time after the first grouting. Accordingly, this study evaluated the pullout characteristics by the grouting methods by performing model test on decomposed granite soil, and investigated the support increasing characteristics of reinforcements depending on the curing time, reinjection pressure, and uplift force variation of the pressure reinjection grouting. The result of this research shows that the pressure reinjection grouting demonstrated 1.1~1.3 times of performance of the gravity grouting, and suggests some analysis on optimal water content, reinjection pressure and curing time of the pressure reinjection grouting.