• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.60-67
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• 2021

According to the 「Guidelines of Structural Design for Piloti Building」 of the Ministry of Land, Infrastructure and Transport (2018), the natural period of middle and low rise building of upper-walled lower frame type, such as the domestic multiplex house in piloti style, is suggested for safety to apply the existing code formula of the wall structure. However, the current code formula of the wall structure was provided based on actual measurement of high-rise wall-type structures that mainly exhibit bending behavior. So it is considered that it is not suitable for a piloti-type house with four stories or less, where the wall behaves in shear. See also Park et al. (2000) confirmed that the effect of the lower frame part is greater than that of the upper wall part in the natural period of complex structures with 10 or more floors through analytical studies. Therefore, in this study, in order to examine the effect of the lower frame on the natural period of the middle and low-rise piloti structure, the estimation of natural period by the finite element analysis, approximation formula and ccurrent code formula was performed for the target structures with the shear and flexural stiffness of the upper wall and the shear stiffness of the lower frame as variables. As result, it was found that the change in the shear stiffness of the lower frame had a greater effect on the natural period of the whole building than the change in the bending or shear stiffness of the upper wall.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2255-2262
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• 2015

Recent study about near-surface is proposed to overcome non-economic of underground railway and to reduce people's complaints of ground elevated railway. In this report, precast modular structure system replacing temporary facilities is applied to ensure the construction ability and economic feasibility. To verify the performance of connection joint between permanent structural wall and upper slab, loading test is carried out. As a result of the test, wall replacing temporary structure to slab connection is possible to transfer bending moment. By 30% increase of bending resistant performance for connection joint using coupler, coupler connection joint is more advantageous to resist bending moment compared to channel connection.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.51-61
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• 1999

When a structure is built on the ground under consolidation, the instant corresponding contact pressure which the upper structure exerts on the ground is established. But, as the consolidation of the ground proceeds, the contact pressure is changed because of the flexural rigidity of the upper structure. This varied contact pressure exerts influence on the consolidation behavior of the ground. And, this varied consolidation behavior exerts on the contact pressure in retum. This kind of interaction between the upper struture and the olwer ground under consolidation contimues till all the consolidation process in finished. So this problem cannot be defined as a linear problem. In this paper an approximation method which can analyse this non-linear interaction problem is proposed by the FEM.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.73-83
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• 2001

The mass and stiffness of upper wall-lower frame system(mixed building structures) change sharply at transfer floor due to different structural system in upper and lower part. These mixed building structures generally show the stiffness, weight or geometric vertical irregularities. The purpose of this study is to investigate the response characteristics of these structures by push-over analysis and nonlinear time history analysis. For four types of analysed models, only the variation of upper wall stories was considered. The conclusions of this study are following; (1) In the push-over analysis, yielding hinges in beams and columns of lower frame occurred at the base shear of similar magnitude in all models. But as the number of stories of upper wall increases, yielding hinges at ends of coupling beams were observed in the small magnitude of base shear. (2) In the nonlinear time history analysis, yielding of lower frame occurred at beams with as small ground acceleration as 55gal, and in upper walls yielding was concentrated on coupling beams and shear walls near the transfer floor. (3) As the number of stories of upper walls decreases, the story stiffness of the lower frames decreased relatively and the occurrence of soft stories in the lower frame was observed.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.3 s.3
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• pp.103-110
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• 2001

The objective of this study is to investigate the behavior of superstructure considering several factors such as change of pile rigidity, soil characteristics, and the constraint condition of support. The results of this study are as follows: 1. Pile-rigidity computed by the rotating deformed plane method is continuously varied up to approximately 5D(D=diameter of pile) below the ground level. This result is consistent with the previous study$^{(12)}$, in which the pile deformation occurs at approximately $3{\sim}6$ times of pile diameter from the ground level. 2. For bridge structure-pile system, analytical results of internal forces and deformations show different values for modified pile rigidity and unchanged pile rigidity. 3. Detaild analysis considering modified pile rigidity is required for the long-span bridge design with structure pile system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.556-563
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• 2005

This paper proposed a new substructural identification method to estimate the bending stiffness of a bridge deck, a fundamental structural health index of a super-structure. The proposed method can estimate the bending stiffness without considering actual supporting conditions by using substructural identification method while most of conventional methods need reasonable assumptions on supporting conditions which are hard to be assessed in a real bridge in operation. The mathematical formulation is derived and the results of laboratory tests are summarized. It was verified that the proposed method gives consistent estimation results regardless of actual supporting conditions.

• Computational Structural Engineering
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• v.10 no.4
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• pp.327-336
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• 1997

When a structure is built on the consolidation ground, the instant elastic deflection occures according to the characteristics of the ground and the load on it. And the corresponding contact pressure is established. But, as time passes, the secondary consolidating deflection is added to the instant elastic deflection, the upper structure, due to its flexural rigidity, resist to the additional curvature. So the variation of the contact pressure occurs. And this new contact pressure exerts influence on the consolidation form again. The new consolidation form exerts influence on the contact pressure in return. This kind of interaction continues till all the consolidation of the ground is finished. So the consolidation problem can not be definded as the linear problem. This paper intends to scheme an approximate iteration method to analyse this non-linear interaction problem between the upper structure and the lower consolidation ground which supports the former.

• Journal of Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.93-102
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• 2005

Manufacturing conventional column base plate requires much manpower and time. In this research, a new method for constructing column base plate is introduced to improve on conventional methods through the use ofcast steel that is available for adjusting base plate thickness and enlarging base plate stiffness. The main purposes include reducing welding work, enlarging base plate stiffness, and clarifying the stress flow. Also, construction convenience and improvement in quality can be expected. For developing this cast steel base plate, test specimens of conventional and cast steel base plates are made and tested to analyze strength and stiffness. Also, the efficiency for long-term use is checked by fatigue tests. From these comparative tests, cast steel base plates have the same strength and stiffness as conventional base plates.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.161-169
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• 2011

Two-way slabs reinforced with high-performance steels, which have several practical advantages of a reduction of congestion in heavily reinforced members, savings in the cost of labor and repair, the higher corrosion resistance, and a reduction of construction time, were constructed and tested. The influences of the flexural reinforcement ratio, concentrating the reinforcement in the immediate column region, and using steel fiber-reinforced concrete (SFRC) in the slab on the punching shear resistance and post-cracking stiffness were investigated, and compared with the punching shear test results of the slabs reinforced with conventional steels and GFRP bars. In addition, the strain distribution of flexural reinforcements and crack control were investigated, and the effective width calculating method for the average flexural reinforcement ratio was estimated. The use of high-performance steel reinforcement increased the punching shear strength of slabs, and decreased the amount of flexural reinforcements. The concentrating the top mat of flexural reinforcement increased the post-cracking stiffness, and showed better strain distribution and crack control. In addition, the use of SFRC showed beneficial effects on the punching shear strength and crack control. It was suggest that the effective width should be changed to larger than 2 times the slab thickness from the column faces.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.501-510
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• 2002

The middle diaphragm of box girder is to prevent the deformation of the cross section of box girder, to distribute load produced at upper flange onto the both sides of web. But if inner space of box girder is barred by the middle diaphragm, it is impossible to use in inner space of box girder and it is felt constraint on maintenance-management. The effect of middle diaphragm of box girder is intended to be expressed by the stiffness of diaphragm in comparing the diaphragm with opening of box girder with diaphragm without opening of box girder through the experiment.