• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.151-160
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• 1999

It is recommended to have symmetric plan and elevation in structural design of hight-rise building structures to reduce torsional response of the structures. However it is not always allowed to do so due to architectural purposes. in many cases high-rise buildings are asymmetric. The purpose of this study is to predict the torsional behavior of high-rise building structures with asymmetric plan. Equivalent lateral stiffness and deformation shape factor are used for prediction of torsional response of high-rise buildings. Overall torsion of a structure is estimated by equivalent lateral stiffness and torsion of each floor is estimated by deformation factor in each 2-D lateral force resisting elements.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.138-144
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• 2000

The detent force caused by the interaction of magnets with the teeth of a armature core deteriorates the driving performance of a permanent magnet linear synchronous motor. In this paper, we analyze the fields and forces of a linear synchronous motor with segmented or skewed magnet arrangement according to lateral overhang length of permanent magnets. For the analysis, the 3-dimensional equivalent magnetic circuit network method is used. The detent force and the static thrust are analyzed according to the segmented or skewed angle and the overhang length of permanent magnets, and the optimal angles that the detent force is minimized are found out in each case. The analysis results are compared with the experimental ones and shown a reasonable agreement.

• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.35-41
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• 2008

In general, flat plate systems have been used as a gravity load resisting system (GLRS) in building. Thus, this system should be constructed with lateral force resisting system (LFRS) such as shear walls and brace frames. GLRS should retain the ability to undergo the lateral drift associated with the LFRS without loss of gravity load carrying capacity. And flat plate system can be designed LFRS as ordinary moment frame with the special details. Thus, flat plate system designed as GLRS or LFRS should be considered internal forces (e.g., unbalanced moments) and lateral deformation generated in vicinity of slab joints render the system more susceptible to punching shear. ACI 318 (2005) allows the direct design method, equivalent frame method under gravity loads and allows the finite-element models, effective beam width models, and equivalent frame models under lateral loads. These analysis methods can produce widely different result, and each has advantage and disadvantages. Thus, it is sometimes difficult for a designer to select an appropriate analysis method and interpret the results for design purposes. This study is to help designer selecting analysis method for flat plate system and to verify practicality of the modified equivalent frame method under lateral loads. This study compared internal force and drift obtained from frame methods with those obtained from finite element method under gravity and lateral loads. For this purposes, 7 story building is considered. Also, the accuracy of these models is verified by comparing analysis results using frame methods with published experimental results of NRC slab.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.419-426
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• 2005

This study is to propose a modified equivalent frame model for flat plate slabs under lateral loads. ACI 318 (2002) allows equivalent frame methods to conduct two-way slab system analysis subjected to gravity loads as well as lateral loads. Since the equivalent frame method in the ACI 318 (2002) has been developed base on the behavior of two-way system for gravity loads, and nay not predict the behavior of flat plate slabs under lateral loads with good precision. This study develops a modified equivalent frame model which can give more precise answer for flat plate slabs under lateral loads. This model reflects the actual force transfer mechanism among the components of flat plate slab system, which are slabs, columns and torsional members, more accurately under lateral loads than existing equivalent frame models. The accuracy of this model is verified by comparing the analysis results using the proposed model with the results of finite element analysis. The analysis results of other existing models are included in the comparison. For this purpose, 2 story building having 3 spans in both directions is considered. Analytical results show that the modified equivalent frame model produces comparable drift and slab internal moments with those obtained from finite element analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.4
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• pp.602-609
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• 2001

This paper is concerned with the orthotropic problem of diaphragm-type air springs which consist of rubber linings, nylon reinforced rubber composite and bead ring. The analysis is carried out with a finite element method developed to consider the orthotropic properties, geometric nonlinearity using four-node degenerated shell element with reduced integration. Physical stabilization scheme is used to control the zeroenergy mode of the element. The analysis includes an inflation analysis and a lateral analysis of an air spring for the deformed shape and the spring load with respect to the vertical and l ateral deflection. Numerical results demonstrate the variation of the outer diameter, the fold height, the vertical force and the lateral force with respect to the inflation pressure and the lateral deflection.

• Structural Engineering and Mechanics
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• v.31 no.4
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• pp.423-437
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• 2009

In order to perform a step-by-step force-displacement response analysis or dynamic time-history analysis of large buildings with masonry infilled R/C frames, a continuous force-deformation model based on an equivalent strut approach is proposed for masonry infill panels containing openings. The model, which is applicable for degrading elements, can be implemented to replicate a wide range of monotonic force-displacement behaviour, resulting from different design and geometry, by varying the control parameters of the model. The control parameters of the proposed continuous model are determined using experimental data. The experimental program includes fifteen 1/3-scale, single-story, single-bay reinforced concrete frame specimens subjected to lateral cyclic loading. The parameters investigated include the shape, the size, the location of the opening and the infill compressive strength. The actual properties of the infill and henceforth the characteristics needed for the diagonal strut model are based on the assessment of its lateral resistance by the subtraction of the response of the bare frame from the response of the infilled frame.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.688-693
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• 2001

It is almost impossible to have a straight web for processing in the continuous process systems. The cambered web usually causes the strip walking and damage during process. It is necessary to identify the lateral dynamics of the cambered web for the precise control of lateral behavior. In this paper, a dynamic model of the lateral behavior for a cambered web is developed by introducing the concept of steering angle equivalent to moment caused by the camber. This model can be extended to include terms associated with moment, induced by roller's tilting, web slippage, and shear force, etc. Using this model, a new feed-forward controller is proposed to enable the on-line camber estimation, which is difficult to be measured directly, and the prediction of lateral deflection caused by camber. Computer simulation study shows that the proposed controller successfully eliminates the effect of camber and has better control performance than that of the existing PID controller.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.32-35
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• 1996

This paper analyzes characteristics of PMLSM using 3 dimensional equivalent magnetic circuit network method (3-D EMC). PMLSM of which the effective electric-airgap is not only very large, but also the width is finite width lateral edges has much leakage flux. Therefore, 2-D analysis method cannot consider it so carefully that 3-D analysis method must required. 3-D EMC which will be used for analysis of PMLSM performs modeling of it including solt and teeth structure, uses the magnetic motive force of stator winding and permanent magnet as source. and calculates magnetic flux density and force considering nonlinear characteristics of materials. we verified analysis validity by comparing simulation results with expermental results.

• Journal of Korean Association for Spatial Structures
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• v.20 no.1
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• pp.87-94
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• 2020

A corrugated steel plate wall (CSPW) system is advantageous to secure the strength and stiffness required for lateral force resistance because of its high out-of-plane stability. It can also stably dissipate large amounts of energy even after peak strength. In this paper, a preliminary study has been carried out to use the CSPW system in the seismic retrofit of existing reinforced concrete (RC) moment frame buildings. The seismic performance for an example building was evaluated, and then a step-by-step retrofit design procedure for the CSPW was proposed. An equivalent analytical model of the CSPW was also introduced for a practical analysis of the retrofitted building, and the strengthening effect was finally evaluated based on the results of nonlinear analysis.

• Steel and Composite Structures
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• v.20 no.1
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• pp.57-70
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• 2016

The predominant type of buckling that I-steel concrete composite beams experience in the negative moment area is distortional buckling. The key factors that affect distortional buckling are the torsional and lateral restraints by the bottom flange. This study thoroughly investigates the equivalent lateral and torsional restraint stiffnesses of the bottom flange of an I-steel concrete composite beam under negative moments. The results show a coupling effect between the applied forces and the lateral and torsional restraint stiffnesses of the bottom flange. A formula is proposed to calculate the critical buckling stress of the I-steel concrete composite beams under negative moments by considering the lateral and torsional restraint stiffnesses of the bottom flange. The proposed method is shown to better predict the critical bending moment of the I-steel composite beams. This article introduces an improved method to calculate the elastic foundation beams, which takes into account the lateral and torsional restraint stiffnesses of the bottom flange and considers the coupling effect between them. The results show a close match in results from the calculation method proposed in this paper and the ANSYS finite element method, which validates the proposed calculation method. The proposed calculation method provides a theoretical basis for further research on distortional buckling and the ultimate resistance of I-steel concrete composite beams under a variable axial force.