• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.45-52
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• 2018

The paper aimed to find out the lateral behavior of outrigger system in high-rise building considering floor diaphragm. To achieve this goal, a structural schematic design of 80 stories building was conducted by utilizing MIDAS-Gen. In this research, the key parameters of the structure analysis were the outrigger location in plan, the slab stiffness, the outrigger stiffness and the kind of diaphragm. For the purpose of this study, we analyzed and studied the lateral displacement in top floor, the story drift and the stress in slab. The research results indicated that the outrigger location in plan, the slab stiffness, the outrigger stiffness and the kind of diaphragm had an effect on lateral behavior in outrigger system of tall building. And the results of this analysis research can provided the assistance in getting the basic data of structure design for looking for the lateral behavior of outrigger system in the high-rise building.

• Explosives and Blasting
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• v.37 no.2
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• pp.14-21
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• 2019

Distinct element method is a powerful numerical tool for modelling the jointed rock masses. It is also a useful tool for modelling of later stage of blasting requiring large displacement. The distinct element method utilizes a rigid block idea in which the interacting force between distinct elements is calculated from contact displacement as elements penetrate slightly. The properties of joints defined as the boundaries of distinct elements are critical parameters to determine the block behavior, and affect the deformation and failure mode. However, regardless of real joint properties, joint stiffnesses have sometimes been selected without special concern just to prevent elements from penetrating too far into each other in some quasi-static problems. Depending on whether the main interest in the analysis is the prediction of the deformation with high precision, or the prediction of the block behaviour after failure, the input data such as joint stiffness may or may not have a significant effect on the results. The purpose of this study is to provide a sound understanding of the effect of the joint stiffness on the distinct element analysis results, and to help guide the selection of input data.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.21-28
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• 2024

In this paper, two prediction models based on deep neural network that could predict cross-sectional stiffness of a rotor blade were proposed. Herein, we employed structural and material information of cross-section. In the case of a prediction model that used material properties as the input of the network, it was designed to predict the cross-sectional stiffness by considering elastic modulus of each cross-sectional member. In the case of the prediction model that used structural information as a network input, it was designed to predict the cross-sectional stiffness by considering the location and thickness of cross-sectional members as network input. Both prediction models based on a deep neural network were realized using data obtained by cross-sectional analysis with KSAC2D (Konkuk section analysis code - two-dimensional).

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1033-1042
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• 2005

Until recently tensile stresses in concrete have not been considered, since it does not affect the ultimate strength of reinforced concrete flexural members significantly However, to verify the load-deflection relationship, the effect of tensile stresses between reinforcing bars and concrete, so-called tension stiffening effect must be taken into account. Main parameters of the tension stiffening behavior are known as concrete strength, and bond between concrete and reinforcing bars. In this study total twenty specimens subjected to bending were tested with different concrete strength, coverage, and de-bonding length of longitudinal bars. The effects of these parameters on the flexural rigidity, crack initiation and propagation were carefully checked and analyzed.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.107-116
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• 2011

Rigid soil containers (or rigid boxes) are often used for 1g shaking table tests. The rigid boxes, however, do not accurately simulate the amplification of ground acceleration and phase difference of seismic motion in the model ground due to the confinement of shear deformation and the reflection of seismic wave at the box walls. Laminar soil containers (or laminar shear boxes) can simulate the free field motion at convincingly superior accuracy than the rigid ones. In this study, the soft ground is modeled for both types of boxes and is subjected to seismic loading using a 1g shaking table. The comparison of the results using the two types of soil containers illustrates that, in case of the rigid box, the ground acceleration shows non uniform distribution and the phase synchronization of input motion. Whereas, the dynamic behavior of the laminar shear box shows good agreement with the free field behaviors such as the amplification of ground acceleration and the occurrence of phase difference.

• Journal of the Korean Society for Railway
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• v.18 no.2
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• pp.139-148
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• 2015

By increasing the vertical stiffness of the rail fastening system, the dynamic wheel load of the vehicle can be increased on the ballast track, though this increases the cost of track maintenance. On the other hand, the resistance acting on the wheel is decreased, which lowers the cost of the electric power to run the train. For this reason, the determination of the optimal fastener stiffness is important when attempting to minimize the economic costs associated with both track maintenance and energy to operate the train. In this study, a numerical method for evaluating the optimal vertical stiffness of the fasteners used on ballast track is presented on the basis of the process proposed by L$\acute{o}$pez-Pita et al. They used an approximation formula while calculating the dynamic wheel load. The evaluated fastener stiffness is mainly affected by the calculated dynamic wheel load. In this study, the dynamic wheel load is more precisely evaluated with an advanced vehicle-track interaction model. An appropriate range of the stiffness of the fastener applicable to the design of ballast track along domestic high-speed lines is proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.137-143
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• 2020

This study proposes an improvement plan for the evaluation of the bearing capacity and settlement of sewer pipe bases for the improvement of design methods for determining pipe breakage. Under the same conditions, the safety of crushed stone foundation was the lowest. Concrete VR pipe and prefabricated plastic foundations were found to be safe at most excavation depths. The bearing capacity of a rigid pipe foundation was determined by the shape of the foundation, soil conditions, and groundwater, irrespective of the type of foundation. As the depth of the excavation increases, the settlement tends to decrease immediately, and as the diameter of the pipe increases, the settlement tends to increase immediately at the same depth. It is thus reasonable to consider the bearing capacity and the instant settlement amount to solve the problems caused by the settlement of a rigid sewer pipe.

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

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.49-60
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• 2014

For simple and accurate analysis for behaviors of multi-span suspension bridges which are expected to be frequently constructed as strait-crossing bridges, the deflection theory as the peculiar theory of a suspension bridge can be applied. This paper performs a structural analysis for four-span suspension bridges using the deflection theory. Simply-supported beams with tension are used for girders and the deflections of the beams due to the vertical loads and moments at supports are calculated. The calculation is performed iteratively until the deflections satisfy the compatibility equations of cables. The results of the deflection theory analysis considering tower rigidity are compared with those of the finite element analysis for verification. Importance of the tower rigidity for four-span suspension bridges is confirmed using various compatibility equations of the cable due to variation of the constraint conditions between main cable and top of towers. In addition, the simple parametric analysis for variation of the center tower rigidity is performed.

• Composites Research
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• v.31 no.4
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• pp.161-170
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• 2018

Cylindrical composite lattice structures are manufactured by filament winding process. The fiber volume fraction non-uniformity and resin rich layers that can occur in the manufacturing process affect the stiffness and strength of the structure. Through the cross-section examination of the hoop and helical ribs, which are major elements of the composite lattice structure, we observed the fiber volume fraction non-uniformity and resin rich layers. Based on the results of the cross-section examination, the stiffness of the ribs was analyzed through the experimental and theoretical approaches. The results show that the fiber volume fraction non-uniformity and resin rich layers have an obvious influence on the rib stiffness of composite lattice structure.