• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.529-536
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• 1999

The objective of the research stated herein is to observe th elastic and inelastic behaviors and ultimate capacity of 1 : 5 scale 3-story reinforced concrete frame. Pushover tests were performed to 1:5 scale 3-story reinforced concrete frames without and with infilled masonry. To simulate the earthquake effect, the lateral force distribution was maintained to be an inverted triangle by using the whiffle tree. From the results of tests, the relations between the total lateral load and the roof drift, the distribution of column shears, the relation between story shear and story drift, and the angular rotations at the critical portions of structures were obtained. The effects of infilled masonry are investigated with regards to the stiffness, strength, and ductility of structures. Final collapse modes of structures with and without infilled masonry are compared.

• Journal of the Korea Concrete Institute
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• v.12 no.1
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• pp.101-112
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• 2000

In many structures, the masonry infill panels have been used for architectural reasons and their influence on the structure is often ignored by engineers. However, it has been recognized that the presence of masonry infills may debates. Recently, the pushover analysis technique is used for the prediction of the inelastic behaviors of structures in the seismic evaluation of existing buildings. However, the reliability of this analysis method has not been fully checked with the test results, particularly in the case of masonry-infilled frames. The objective of this study is to verify the correlation between the experimental and analytical reponses of a high-rise masonry-infilled reinforced concrete frame using DRAIN-2DX program and the test results performed previously. It is concluded from this comparison that the strength and stiffness of members can be predicted with quite high reliability while the ductility capacity of members can not be described reasonably.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.514-517
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• 2006

Nonseismic designed RC frame have a possibility of shear failure because of deficiencies of reinforcing details. To model the shear failure in numerical analysis, shear strength degradation models which include Moehle's and ATC 40 are compared and applied to push-over analysis. For numerical analysis, three storied building frame is selected and designed according to Korean Concrete Design Code(2003). From the numerical analysis, it is pointed out that there may be great difference in lateral drift capacity if a different shear strength model is used. And the capacity can be severely underestimated if the restraining model of plastic rotation of ATC 40 is used, compared to the use of shear spring for shear degradation.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.461-462
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• 2009

Since the modal pushover analysis (MPA) is introduced by A.K.Chopra in 2002, it has been the leading procedure for the seismic evalution of structures. However it has scarcely used on bridge structures dueing to its inherent limitation. In this paper, MPA is applied on cable-stayed bridges to check its applicability on such structures.

• Computers and Concrete
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• v.14 no.3
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• pp.279-297
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• 2014

This paper investigates the effects of confinement reinforcement and concrete strength on nonlinear behaviour of reinforced concrete buildings (RC). For numerical application, an eleven-storey and four bays reinforced concrete frame building is selected. Nonlinear incremental static (pushover) analyses of the building are performed according to various concrete strengths and whether appropriate confinement reinforcement, which defined in Turkish seismic code, exists or not at structural elements. In nonlinear analysis, distributed plastic hinge model is used. As a result of analyses, capacity curves of the frame building and moment-rotation curves at lower end sections of ground floor columns are determined. These results are compared with each other according to concrete strength and whether appropriate confinement reinforcement exists or not, respectively. According to results, it is seen that confinement reinforcement is important factor for increasing of building capacity and decreasing of rotations at structural elements.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.733-740
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• 2006

Inverted V (or chevron) braced steel frames have been seen as being highly prone to soft story response once the compression brace buckles under earthquake loading. To salvage chevron braced frames. the concept of the zipper column was proposed many years ago such that the zipper column can redistribute the inelastic demand over the height of the building. However. rational design method for the zipper column has not been established yet. In this paper, a new dynamic design method for the zipper column was proposed by combining the refined physical braced model and modal pushover analysis. Inelastic dynamic analysis conducted on 6 story building model showed that the proposed method was more superior to the existing static design method and was very effective in improving seismic performance of chevron braced steel frames.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.153-160
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• 2005

A new nonlinear static analysis method, Effective Modal Pushover Analysis (EMPA) which can evaluate earthquake responses such as story drift and plastic rotation of plastic hinges addressing higher mode effects was developed. Unlike existing nonlinear static procedure based on properties of fundamental vibration mode, the EMPA performs nonlinear static analysis using multiple effective modes constructed by direct combination of natural vibration modes. Therefore higher mode effects can be efficiently considered. In the present study, procedures of the EPMA evaluating inelastic earthquake responese were established and the results were verified by nonlinear time history analysis. The EMPA can be applied to seismic evaluation of high-rise buildings and irregular buildings where higher mode effects become conspicuous.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.23-30
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• 2005

The capacity spectrum method(CSM) can be used for the evaluation of inelastic maximum response of structures and has been recently used in the seismic design using the incorporation of pushover analysis and response spectrum method. To efficiently evaluate seismic performance of multi-degree-of freedom(MDOF) bridge structures, it is important that the equivalent response of MDOF bridge structures should be calculated. To calculate the equivalent response of MDOF system, equivalent responses are obtained by using Song method, Fajfar method and Calvi method. Also, those responses are applied to CSM method and seismic performance of bridge according to the ESDOF method are compared and evaluated straightforwardly.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.327-341
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• 2016

This study addresses the effect of pre-stressed cables on a pre-stressed mega-braced steel frame through employing static analysis and pushover analysis. The performances of a pre-stressed mega-braced steel frame and a pure steel frame without mega-braces are compared in terms of base shear, ductility, and failure mode. The influence of the cable parameters is also analyzed. Numerical results show that cable braces can effectively improve the lateral stiffness of a pure frame. However, it reduces structural ductility and degenerates structural pre-failure lateral stiffness greatly. Furthermore, it is found that 20% fluctuation in the cable pretension has little effect on structural ultimate bearing capacity and lateral stiffness. As comparison, 20% fluctuation in the cable diameter has much greater impact.

• Earthquakes and Structures
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• v.8 no.1
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• pp.133-152
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• 2015

This paper investigates the soil effect on seismic behaviour of reinforced concrete (RC) buildings by using the spread plastic hinge model which includes material and geometric nonlinearity of the structural members. Therefore, typical reinforced concrete frame buildings are selected and nonlinear dynamic time history analyses and pushover analyses are performed. Three earthquake acceleration records are selected for nonlinear dynamic time history analyses. These records are adjusted to be compatible with the design spectrum defined in Turkish Seismic Code. Interstory drifts and damages of selected buildings are compared according to local soil classes. Also, capacity curves of these buildings are compared with maximum responses obtained from nonlinear dynamic time history analyses. The results show that, soil class influences the seismic behaviour of reinforced concrete buildings, significantly.