• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1655-1665
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• 2014

Dynamic displacements of structures shows general behavior of structures. Generally, It is used to estimate structure condition and trustworthy physical quantity directly. Especially, measuring vertical displacement which is affected by moving load is very important part to find or identify a problem of bridge in advance. However directly measuring vertical displacement of the bridge is difficult because of test conditions and restriction of measuring equipment. In this study, Artificial Neural Network (ANN) is used to suggest estimation method of bridge displacement to overcome constrain conditions, restriction and so on. Horizontal strain and vertical displacement which are measured by appling random moving load on the bridge are applied for learning and verification of ANN. Measured horizontal strain is used to learn ANN to estimate vertical displacement of the bridge. Numerical analysis is used to acquire learning data for axis strain and vertical displacement for applying ANN. Moving load scenario which is made by vehicle type and vehicle distance time using Pearson Type III distribution is applied to analysis modeling to reflect real traffic situation. Estimated vertical displacement in respect of horizontal strain according to learning result using ANN is compared with vertical displacement of experiment and it presents vertical displacement of experiment well.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.142-149
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• 1996

Pyramid type three roll bending machines are widely used in roll-bending process to produce singly curved plate. In forming singly curved plate, controlling the vertical displacement of the center roller is most important to acquire the shape required and automation system of the process. In this paper roller bending process is modeled as an elastic-plastic phenomenon and analyzed using beam theory and finite element method. In finite element analysis the workpiece is modeled by using beam elements and plane strain elements respectively. Through the analyses vertical center roller displacement is obtained to get constant curvature distribution along arc length. The relationship between center roller displacement and curvature in steady state as well as residual stress and strain along plate thickness direction are calculated through finite element analysis.

• Geotechnical Engineering
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• v.6 no.3
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• pp.53-64
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• 1990

Load tests for ten small-scale foundation models combined with geotextile and sand mat were conducted to study the effect of geotextile, sand mat, and foundation types on deformation of foundation soils. In addition, the experimental results were compared with those obtained from numerical analysis using a software program. The main conclusions were summarized as follows : 1. The restraint effect on GIT is more outstanding on the lateral displacement than on the vertical one. 2. The only use of SIM has better effect for the restraint of lateral displacement than vertical ogle. 3. The use of both SIM and GIT are required for the restraint of lateral and vertical displacement.

• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.321-327
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• 2014

In this paper, linear dynamic equations are derived from nonlinear dynamic equations of constrained multibody systems using the QR decomposition method. The derived linear equations are applied to a railway vehicle bogie. The vibration characteristics of the railway vehicle are investigated by calculating the natural mode and transfer function of the bogie frame in relation to rail-roughness input. The main modes of the bogie were found below 35Hz, and the local modes above 198Hz. The magnitude of the vertical transfer function varied with the forward velocity due to vertical and pitch modes, which were influenced by the forward velocity. The magnitude of the lateral transfer function was negligibly small, and the mode in the longitudinal direction was excited for longitudinal transfer function regardless of the forward velocity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2368-2373
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• 2012

In this research, finite element method was carried out to evaluate the defomation of pipe and surface displacement for backfill of underground ficility. Various conditions for analysis were employer, including two different pipes(PE and concrete pipe), two different excavation depth(60cm and 150cm) and width(1.5D and 2D), a regular sand backfill, and four different flowable backfills. The vertical deformation of 60 cm diameter for PE was measured three times more than that of 30 cm diameter. The measured deformations for regular backfill and four flowable backfills were 0.320mm, and 0.135mm to 0.155mm, respectively. It ratio was around 40%. In case of 30cm diameter of concrete pipe, the measured vertical defomation was around 0.004mm for all the backfill materials. In case of installation depth, the effect of flowable backfill for flexible pipe is better than for rigid pipe. There is little effect on the deformation of concrete pipe with regular sand backfill and flowable backfill.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.601-613
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• 2007

It is reported that factors affecting the behavior of reinforced earth retaining walls built on soft ground are not only basic physical properties but also the increase of load by the reinforced earth retaining walls, consolidation period, pore water pressure, etc. This study analyzed the behavior of reinforced earth retaining walls and soft ground using SAGE CRISP, a ground analysis program. First, we examined the effect of the replacement method, which was to prevent the excessive displacement of reinforced earth retaining walls, in improving the behavior of the walls. Second, we compared and analyzed how the behavior of ground is affected by the vertical interval of stiffeners on the back of reinforced earth retaining walls after the application of the replacement method. Lastly, we proposed the optimal replacement width and depth in the application of the replacement method. The results of this study proved that the replacement method is considerably effective in improving the behavior of reinforced earth retaining walls. In addition, the vertical interval of stiffeners on the back of reinforced earth retaining walls appeared effective in improving the horizontal displacement of the top of retaining walls but not much effective in improving the vertical displacement of the back of retaining walls. In addition, improvement in horizontal-vertical displacement resulting from the increase in replacement width was not significant and this suggests that the increase of replacement width is not necessary. With regard to an adequate replacement depth, we proposed the ratio of replacement depth to the height of retaining walls(D/H) according to the ratio of the thickness of the soft layer to the height of retaining walls(H/T).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1889-1894
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• 2012

A small-scale chamber test laboratory for controlled low strength materials with bottom ash and recycled in-situ soil have been carried out. Laboratory test which was simulated during construction stage was conducted. The vertical deflection of 4.43mm to 6.6mm, and the horizontal deflection of 5.49mm to 15.9 mm were measured during backfilling. In case of loading, the vertical deflection of 2.41mm to 8.69mm, and the horizontal deflection of 1.66mm to 2.53mm were measured. Its residual deflections were 1.40mm to 5.93mm for vertical and 1.66mm to 2.53mm for lateral. The vertical and horizontal deflecto of controlled low strength materials were smaller than that of sand backfill. Also, it was same trend for the measured surface settlement.

• Journal of the Korea Concrete Institute
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• v.27 no.5
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• pp.551-558
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• 2015

Lateral displacement in the most complex-shaped tall buildings is caused by eccentric gravity loads which are induced by the difference in location between a center of mass and a center of stiffness. The lateral displacements obtained from analysis, using conventional procedures, are prone to overestimate the actual values because much of realignment efforts made during construction phase are ignored. In construction sequence analysis, the self-leveling of slab and the verticality of columns/walls could be considered at each construction stage. Moreover, the displacement compensation can be achieved by manual process such as re-centering - locating to global coordinates through surveying. Because the lateral displacement increases with the building height, it is necessary to set up adjustment plan through construction stage analysis in advance in order to result in displacements less than the allowable limits. Because analytical solution includes lots of assumptions, the pre-adjusting displacement should be reasonably controlled with considerations for the uncertainty due to these assumptions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1587-1592
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• 2010

The effects of specimen geometry and loading conditions on the stress distribution in a sandwich specimen under combined loads are investigated by elastic finite element analysis. A commercial software NASTRAN is used in plain-strain two-dimensional finite element analysis of sandwich specimens; the analysis was performed for three different specimen shape factors and four different combined displacement conditions. The results of computational analysis suggest that the effect of the combined displacement angle, which is defined as the ratio of the shear displacement to the normal displacement, on the size of the non-homogeneous stress distribution is observed only in the case of the shear stress and von Mises stress. Also as the combined displacement angle increases, the size of the nonhomogeneous stress distribution decreases in the case of the shear stress and increases in the case of the von Mises stress. In addition, as the specimen shape factor, which is defined as the ratio of the specimen length to the height, increases, the size of the non-homogeneous stress distribution under combined displacement conditions decreases significantly.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.5-13
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• 2003

The soil nailing is one of the useful support-system in urban excavation because of the presence of other structures in the vicinity Since the soil nailing system was introduced, model experiments and theoretical studies have been performed to investigate behavior of soil nailed wall. However, there are few data in the case of multi-layered soil strata just like Seoul Metropolitan area in Korea. The feed back analyses are carried out using the measured wall displacement data for soil nailing construction sites with multi-layered strata in order to analyze the distance and the coefficients of extension zone of ground behind soil nailed wall. As a result, the distance of extension zone increased with increasing of the final excavation depth and the ratio of the distance to the final excavation depth was shown to be about 94% of the final excavation depth. Also, the coefficients of extension zone increased with enlargement of soil layer thickness and converged into constant value of 1.05. On the other hand, the maximum vertical displacements by the feed back analysis and Caspe's method were shown to be approximately 80%, 150~280% of the maximum horizontal displacement respectively.