• Journal of the Korea Concrete Institute
• /
• v.23 no.2
• /
• pp.177-184
• /
• 2011

This paper describes an analytical study on the design approach of PC system with continuous connections at member ends. In multi-ribbed moment resisting slab (MRS) system, double tee members are connected continuously over inverted tee beams with the continuous reinforcements placed within topping concrete. Thus, negative moments are concentrated within the narrow connection area. In order to propose a design method, experimental results of the companion study were examined using detailed nonlinear analysis. Then nonlinear static analysis was used to evaluate the partial continuity effect and the moment redistribution mechanism. Material and cross sectional properties were obtained from experimental results of the companion study. Plastic hinge properties for nonlinear static analysis were modeled with cracking moment, nominal moment, corresponding member deformations, etc. The analysis results showed that a large amount of negative moment of MRS slab can be reduced by applying partial continuity and moment redistribution in MRS joint.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.37 no.2
• /
• pp.68-74
• /
• 2000

The problem of electromagnetic coupling through a narrow slit in a parallel-plate waveguide(PPW) covered by a dielectric slab with a conducting strip on the slab is considered for the case that the TEM wave is incident in the PPW. Coupled integral equations for the tangential electric field in the slit and the induced current over the strip are derived and solved numerically by use of the method of moments. In order to show the effect of the conducting strip on the coupling, some numerical results for the reflected and transmitted powers in the guide, the coupled power through the slit, the equivalent slit admittance, and radiation pattern are presented. From the results, it is observed that the maximum available power coupled through the slit exterior to the PPW amounts upto 50% of the incident power in the PPW.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.209-212
• /
• 2008

Corrugated steel-concrete composite deck with I-beam welded is lighter and has higher load carrying capacity than RC slabs due to an I-beam embedded in the corrugated deck. The methods suggested from ACI and design standard of roadway bridge are used to evaluate effective moment inertia of RC structures. This paper presents evaluation and application of effective moment inertia for corrugated steel-concrete composite deck with I-beam welded by using the methods suggested from design standard of roadway bridge, ACI and CEB-FIP MC-90. In order to evaluate effective moment inertia, a series of flexural experiments were carried out. Five beams were built and the parameters considered in the experiments were studs, shape of the sections and connections of the beams. By using the aforementioned methods, effective moments of inertia was calculated and they were compared with the experimental results. As a result, The method suggested from CEB-FIP MC-90 yielded more satisfactory agreement than that from ACI. It was found that the beam has studs showed high load-carrying capacity and high effective moment of inertia.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.2
• /
• pp.703-709
• /
• 2013

Recently, the study on the commercialization technology of Rope Platform Screen Door (RPSD) is on the process. The study is specifically on RPSD, which the rope screen ascends to allow passage with securing safety of passenger and the condition of aboveground station. For this human-centered design of RPSD, it is important to present system technology. However, it is also necessary to scientifically measure and research the emotions, senses or minds of users in the future. Therefore, this study analyzed the human factors to be considered with designing the system on RPSD, which is installed in Nokdong Station on Gwangju Subway as a trial. Moreover, the emotional evaluation was done by analyzing the factors as how they are effected in general; it processed by checking whether it is safe, height of rope is stable, it has openness (pressure) or strong by examining the moments that a set of ropes blocks rail from platform, and when train is arrived.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.37 no.12
• /
• pp.15-21
• /
• 2000

In this study, the electromagnetic coupling through a narrow slit in the upper wall of a short-ended parallel-plate waveguide(PPW) covered by a dielectric slab with a nearby conducting strip on the slab Is considered for the case that the TEM wave is incident in the PPW. Coupled integral equations whose unknowns are the slit electric field and the induced electric current over the strip are derived and solved numerically by use of the method of moments. From results, it has been observed that most of the incident power can be coupled exterior to the guide by appropriately setting the strip width and position, though the slit is very narrow. In addition, the differences between the radiation phenomena, observed in the cases that the conducting strip and the upper Plate of the PPW form a cavity and that strip behaves like a parasitic element, are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.1
• /
• pp.411-417
• /
• 2013

The moment responses of electric pole foundations for a railroad were investigated using real-scale load tests. Large overturning moments were applied to two square rigid piles with a 1.1 m width and a 2.2 m embedded depth. Two different installation methods-with and without a form-were applied to evaluate the influence of the form work on the moment capacities of the foundations. The reduction of ground strength caused by the excavation without a form is more pronounce than the decrease of frictional strength due to the smooth concrete surface with a form. From the test results, it is found that the current design method which applies a proportional coefficient to consider the effect of a form work is not appropriate. When the normal and frictional stressed is considered separately, the effect of a form work can be estimated reasonably by reducing the friction angle between soil and foundation by 20%.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.4B
• /
• pp.319-328
• /
• 2009

This study quantified the data by applying the EDA techniques considering the data structure, and the results were then used for the frequency analysis. Although traditional methods based on the method of moments provide very sensitive statistics to the extreme values, the EDA techniques have an advantage of providing very stable statistics with their small variation. For the application of the EDA techniques to the frequency analysis, it is necessary to normalization transform and inverse-transform to conserve the skewness of the raw data. That is, it is necessary to transform the raw data to make the data follow the normal distribution, to estimate the statistics by applying the EDA techniques, and then finally to inverse-transform the statistics of transformed data. These statistics decided are then applied for the frequency analysis with a given probability density function. This study analyzed the annual maxima one hour rainfall data at Seoul and Pohang stations. As a result, it was found that more stable rainfall quantiles, which were also less sensitive to extreme values, could be estimated by applying the EDA techniques. This methodology may be effectively used for the frequency analysis of rainfall at stations with especially high annual variations of rainfall due to climate change, etc.

• Korean Journal of Applied Biomechanics
• /
• v.33 no.4
• /
• pp.164-174
• /
• 2023

Objective: The aim of this study was to quantitatively analyze the impact characteristics of the lower extremity on strike pattern during running. Method: 19 young subjects (age: 26.53 ± 5.24 yrs., height: 174.89 ± 4.75 cm, weight: 70.97 ± 5.97 kg) participated in this study. All subjects performed treadmill running with fore-foot strike (FFS), mid-foot strike (MFS), and rear-foot strike (RFS) to analyze the impact characteristics in the lower extremity. Impact variables were analyzed including vertical ground reaction force, lower extremity joint moments, impact acceleration, and impact shock. Accelerometers for measuring impact acceleration and impact shock were attached to the heel, distal tibia, proximal tibia, and 50% point of the femur. Results: The peak vertical force and loading rate in passive portion were significantly higher in MFS and FFS compared to FFS. The peak plantarflexion moment at the ankle joint was significantly higher in the FFS compared to the MFS and RFS, while the peak extension moment at the knee joint was significantly higher in the RFS compared to the MFS and FFS. The resultant impact acceleration was significantly higher in FFS and MFS than in RFS at the foot and distal tibia, and MFS was significantly higher than FFS at the proximal tibia. In impact shock, FFS and MFS were significantly higher than RFS at the foot, distal tibia, and proximal tibia. Conclusion: Running with 3 strike patterns (FFS, MFS, and RFS) show different impact characteristics which may lead to an increased risk of running-related injuries (RRI). However, through the results of this study, it is possible to understand the characteristics of impact on strike patterns, and to explore preventive measures for injuries. To reduce the incidence of RRI, it is crucial to first identify one's strike pattern and then seek appropriate alternatives (such as reducing impact force and strengthening relevant muscles) on that strike pattern.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.16 no.2
• /
• pp.115-124
• /
• 2003

In this paper, the effects of vehicle loads on flat slab system are investigated on the basis of the previous studies for beam-gilder parking structural system. The influence surfaces of flat slab for a typical design section are constructed lot the purpose of obtaining maximum member forces under vehicle loads. In addition, the equivalent vehicle load factors for flat slab parking structures are suggested using artificial neural network. The network responses we compared with the results obtained by numerical analyses to verify the validation of Levenberg-Marquardt algorithm adopted as training method in this Paper. Many parameter studies for the flat slab structural system show dominant vehicle load effects at the center positive moments in both column and middle strips, like the beam-girder parking structural system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.2
• /
• pp.257-267
• /
• 2001

This paper presents a design for a single-layer feeder waveguide array using $\pi$-junctions with the inductive wall. The feed structure consists of a single waveguide placed on the same layer as radiating waveguide and is characterized by the unit divider, called a $\pi$-junction. This $\pi$-junction with an inductive wall splits part of the power into two branchs waveguide through one coupling window, and can excite densely arrayed waveguide at equal phase and amplitude. The power dividing characteristics of the cascade of $\pi$ -junctions are analyzed by Galerkin's method of moments. The numerical results show reasonable agreement with the experimental results. From the optimum simulation results based on the feeder waveguide using $\pi$-junction, we obtained the scattering matrices of the feeder divided power at 3.95 GHz.