• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.562-566
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• 2006

Lightweight body can cause a low stiffness due to the decrease of panel thickness and reinforcing member. The other way, high stiffness body demands an increase of mass. Front pillar section area is decreased due to driver's visual field. Global vehicle stiffness is affected by stiffness distribution ratio between upper part and lower part at side body structure. This paper will describe a process used to evaluate the stiffness distribution ratio based on research of strain energy analysis of the tip rotation method. In addition, optimum design schemes are presented for high stiffness and lightweight body structure considering the investigated stiffness distribution ratio. In this way the designer will be aided by a defined design guide and a set of supporting tool to help him work towards a good design

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.10
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• pp.901-906
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• 2007

Lightweight body due to the decrease of panel thickness and reinforcing member might cause low stiffness. On the other hand, high stiffness body requires an increase of mass. Front pillar section area has been decreased for increasing the driver's visual field. Global vehicle stiffness is affected by stiffness distribution ratio between upper part and lower part at a side body structure. This paper describes a process used to evaluate the stiffness distribution ratio based on strain energy. In addition, optimum design schemes are presented for high stiffness and lightweight body structure considering the investigated stiffness distribution ratio.

• Journal of Korean Society of Steel Construction
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• v.13 no.2
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• pp.133-141
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• 2001

A tubular member holding an axially through-gusset connection is often used to transmit axial compression in a steel truss structures. The elastic buckling loads of the member is affected by the stiffness ratio($\beta$) and the length ratio(G) because of two elements with different properties. In current code, however, the strength is evaluated with an effective length factor k=0.9 without considering the above effect. Therefore this study analyzed a theoretical mechanism based on the elasticity theory and performed a finite element analysis to investigate the influence parameters on the elastic buckling strength of axially loaded member.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.363-370
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• 2004

This Paper presents the response force distribution factor(RDF) and its application to recalculation of member forces in case of partial changes of structures. Using RDF, the mutuality of response forces between members can be estimated. The reanalysis technique recalculates directly any displacement or member force under consideration in real time without a full reanalysis in spite of local changes in member stiffness or connectivity using RDF. It is expected that RDF and the reanalysis technique can be used to develop efficient analysis techniques for tall buildings.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.857-862
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• 2007

The purpose of this research is to compare the stiffness increment effects with the floor plan shapes by the stiffness increment factors. For this, we generated the standard floor plans with Box and T type shapes. Then applied the stiffness increment factors -outrigger, material strength, member section- to those floor plans, and generated several alternative analysis models that make the effects of the factors to the lateral displacement exposed. Finally, we analyzed the stiffness increment effects and compared with each other by the stiffness increment factors. As a result, we found that the increment effects have not influence to floor plan shapes, and orders of stiffness increment effects are outrigger, core wall and material strength. We expect that the results of this study could be effectively utilized in the schematic structural design of tall buildings.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.209-216
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• 2000

The purpose of this study is to investigate elasto-plastic behaviour and estimate ultimate resistance capacity of the residential-commercial building subjected to lateral force along the height of structure. Four types of residential-commercial building are chosen as analytical models and investigated by pushover analysis. Pushover analysis estimates initial elastic stiffness, post-yielding stiffness, and plastic hinges on each story of structures through three-dimensional nonlinear analysis program CANNY-99. Skeleton curve of bending stiffness model is bilinear, shear stiffness model is trilinear, and axial stiffness model is elastic. Skeleton curve of axial stiffness model has the axial compression and tension stiffness of reinforced concrete members. This study presents the change of inter story drift, story stiffness and hinge of story and member.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.525-532
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• 2014

In this study, practical design method of coupling beams is proposed. The member forces varies according to the location of the members and the members at 25%~40% of building height shows large member forces. The 100mm increase of wall thickness causes 3~4% variation of member forces and the 100MPa increase of concrete strength decrease approximately 3% of member forces. The required strength of coupling beams is twice the resistant strength and 80% reduction of coupling beam stiffness is necessary to fulfill the design criteria. The stiffness reduction of coupling beams is not necessary over the entire stories and the strength reduction range can be estimated considering design requirements.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.87-94
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• 2019

This study deals with the reliability analysis approach of the temporary structure that can consider the uncertainty in rotational stiffness at the joints of the members, for which the semi-rigid connections are modelled as rotational spring and its coefficient is treated as a random variable following uniform distribution. In addition, this study introduces a computational procedure of the effective length coefficient for more accurate buckling load according to connection conditions of the supporting members attached to the joint. From the results of this study, it can be seen that the failure probability of the joint-hinge model (Case 1) presented in the design standard is higher than that of the practical model (Case 5) considering the rotational stiffness at the joints. This implies that the design standard leads to a conservative design of the temporary structure. The results also confirmed that the failure probability of the vertical member, i.e., the most critical member, can be further reduced when the base connection is provided with a fixed end. The comparative results between FORM, SORM and MCS further demonstrated that FORM can have a high level of numerical efficiency while ensuring the accuracy of the solution, compared with SORM and MCS. Based on these results, the proposed approach can be used as an accurate and efficient reliability analysis method of the three dimensional temporary structure.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.385-400
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• 2017

This paper presents an experimental study on the behavior of axially-loaded steel RHS (rectangular hollow section) compression members that are partially reinforced along their lengths with welded steel plates. 28 slender column tests were carried out to investigate the effects of the slenderness ratio of the unreinforced member and the ratio of the reinforced length of the member to its entire length. In addition to the slender column tests, 14 stub-column tests were conducted to determine the basic mechanical properties of the test specimens under uniform compression. Test results show that both the compressive strength and stiffness of an RHS member can be increased significantly compared to its unreinforced counterpart even when only the central quarter of the member is reinforced. Based on the limited test data, it can be concluded that partial reinforcement is, in general, more effective in members with larger slenderness ratios. A simple design expression is also proposed to predict the compressive strength of RHS columns partially reinforced along their length with welded steel plates by modifying the provisions of AISC 360-10 to account for the partial reinforcement.

• Journal of Korean Association for Spatial Structures
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• v.13 no.1
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• pp.87-96
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• 2013

This study investigated characteristics of buckling load and effective buckling length by member rigidity of dome-typed space frame which was sensitive to initial conditions. A critical point and a buckling load were computed by analyzing the eigenvalues and determinants of the tangential stiffness matrix. The hexagonal pyramid model and star dome were selected for the case study in order to examine the nodal buckling and member buckling in accordance with member rigidity. From the numerical results, an effective buckling length factor of adopted models was bigger than that of Euler buckling for the case of fixed boundary. These numerical models indicated that the influence of nodal buckling was greater than that of member buckling as member rigidity was higher. Besides, there was a tendency that the bifurcation appeared on the equilibrium path before limit point in the member buckling model.