• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.398-405
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• 2001

Upper wall-lower frame(complex building) can be divided into three partition, namely, upper wall, lower frame, and transfer system which link two partitions. The purpose of this study is to investigate the elasto-plastic response characteristics of structures with variation in the stories of lower frame of complex buildings. The conclusions of this study was following; 1) In the push-over analysis for vertically irregular building, the distribution of lateral forces is judged which consider the effects of higher mode. 2) In proportion as the stories of lower frame increase inter-story displacement of lower frame increased, but that of upper wall decreased. 3) The appearance of yielding hinge with variations in the lower stories of complex buildings differed in lower frame of each model, but was almost the same in upper wall.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.170-177
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• 1999

The natural period calculation equations specified in the current building code are empirical formulas that depend on height and material type of the structure. Building with the upper wall and lower frame type is a unique structure which composed of two different structural system This type of structure needs either the deep transfer girder or the thick transfer plate that brings the sudden change of stiffness and mass. Therefore the natural period equations recommended by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamci analysis is compared with that of various codes. Ad approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended. by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamic analysis is compared with that of various codes, And approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended.

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.529-534
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• 2000

Hybrid building structure, which comprise both the residential and commercial spaces in a building, are composed of upper shear-walls and lower frames. In these hybrid structures, the structural analysis and design of transfer systems which link upper-wall and lower-frame are crucial. The available structural design methods for the transfer girder are performed by taking a prototype structure, and the details of transfer girder based on these design methods are presented and compared with regard to the dimensions and amount of reinforcements.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.443-450
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• 2001

The Mixed building structures can be divided into three partition, namely, upper wall, lower frame, and transfer system which link two partitions. The purpose of this study is to investigate the nonlinear response characteristics of structures, as the stories of lower frame of mixed building structures changes. The recorded earthquake ground motions of EI Centro 1940 NS is adopted, and the maximum ground accelerations are adjusted to 55ga1, 110ga1, 220ga1, 330ga1. The conclusions of this study are the following. 1) The responses of model that the story of lower frame is one were different from those of other models. 2) The process of ductility hinge occurrence of member was ends of coupling beam of upper wall and ends of beam of lower frame in 55ga1, bases of shear wall on pit floor in 110ga1, and bases of column of 1F in 220ga1.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.209-216
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• 2003

The purpose of this study is to investigate the response characteristics of pushover analysis of upper wall-lower frame system with X and Y-directions' lateral load Pushover analysis estimates initial elastic stiffness, post-yielding stiffness, and plastic hinges on each story of structures through three-dimensional nonlinear analysis program. The conclusions of this study are as follows; (1) As a result of pushover analysis, the magnitude of nonlinear response and distribution of yield hinge in lower structure are similar with both X and Y directions, but not in upper structure because of different relative stiffness. (2) The maximum drift ratio of roof is larger for X-direction than for Y-direction with respect to magnitude of shear wall areas in upper structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.851-856
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• 2000

When subjected to the strong earthquake ground motion, upper-wall lower-frame structures have high possibility of the weak-story failure in the lower frame part. Sufficient strength, energy dissipation capacity and ductility should be provided at the joint between the deep beam and the lower column. In this study, a typical structure was selected for a prototype and four 1:2.5 scaled models, representing the subassemblage including the exterior column and the deep beam, were constructed. The transverse reinforcement was designed according to ACI procedure¹ and the procedure proposed by Sheikh². The inelastic behavior of the subassemblages subjected to the cyclic lateral displacement were evaluated through investigation of the ultimate strength, ductility, load-deformation characteristics. From the test of 4 specimens, it is concluded that the specimens designed according to Sheikh's procedure revealed higher ductility than that by ACI procedure.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.1
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• pp.55-62
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• 2002

The upper wall-lower frame structures(mixed building structures) are usually composed of shear wall structure in the upper part of structure which is used as residential space and frame structure in the lower part of structure which is used as commercial space centering around the transfer system in the lower part of structure. These structures are characteristics of stiffness irregularity, mass irregularity, and vertical geometric irregularity. The purpose of this study is to investigate the nonlinear response characteristics and the seismic capacity of mixed building structures when the number of stories in the lower frame is varied. The conclusions of this study are following. 1) As the result of push-over analysis of structure such as roof drift(i.e. roof displacement/structural height) and base shear coefficient, when the stories of lower frame system are increased, base shear coefficient is decreased, but roof drift is increased. 2) According to an increase in stories of the lower fame, story drift and ductility ratio of upper wall system are decreased and behavior of upper wall system is closed to elastic. 3) When the stories of lower frame system are increased, the excessive story drift is concentrated on the lower frame system.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.223-228
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• 1999

The state of the current design practice in designing the so-called hybrid structures with the upper shear-wall and lower frame systems are reviewed through the investigation of the 43 design examples. In particular, the trend in the design of the transfer system between upper wall and lower frame systems are analyzed with respect to the depth, the length and the number of spans of transfer deep girders and the number of upper stories. Finally the most critical portions in this conventional transfer system, which should be studied in depth in the future, are pointed out to improve the current design and analysis practice.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.446-451
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• 2000

In case of strong earthquake, upper-sheat wall lowe-frame structures show the weak-story failure at lower part. Where we should guarantee sufficient strength, energy dissipation capacity and ductility. In this study, a typical structure was selected for a prototype and four 1:2.5 scaled models, representing the subassemblages including the interior column and the deep beam, were constructed. Experimental parameters include transverse reinforcement ratio and axial force. The non- linear behavior of the subassemblages subjected to the cyclic lateral displac-ement were evaluated through investigation of the ultimate strength, ductility, load-deformation characteristics. From the results of the tests on 4 specimens, it is concluded that the strength increased as the axial force increased and the ductility increased as the transverse reinforcement ratio increased.