• Structural Engineering and Mechanics
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• v.73 no.4
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• pp.381-395
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• 2020

Study on the inelastic response of bare and masonry infilled Reinforced Concrete (RC) frames repaired using Carbon Fibre Reinforced Polymers (CFRP) and Glass Fiber Reinforced Polymers (GFRP) subjected to quasi- static loading is presented in the work. The hysteresis behaviour, stiffness retention, energy dissipation and damage index are the parameters employed to analyze the efficacy of FRP strengthening of bare and brick in-filled RC frames. It is observed that there is a significant improvement in load carrying capacity of brick infilled frame over bare RC frame. Also FRP strengthened brick infilled frame performs much better than FRP repaired bare frame under quasi static loading. Repair and retrofitting of brick infilled RC frame shows an improved load carrying and damage tolerance capacity than control frame.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.439-444
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• 2003

The response of a 1:5 scale 3-story masonry-infilled RC frame which was designed only for gravity loads were simulated by using a nonlinear analysis program, RUAUMOKO 2D. The objective of this study is to understand behavior of masonry-infilled panel and to verify the correlation between the experimental and analytical responses of a masonry-infilled RC frame. It is concluded from this comparison that the strength, stiffness and local behavior of the structure can be predicted with some reliability using this macro-model.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.227-234
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• 2001

The responses of a 1:5 scale 3-story masonry-infilled RC frame which was designed only for gravity loads were simulated by using a nonlinear analysis program, DRAIN-2DX The objective of this study is to verify the correlation between the experimental and analytical responses of masonry-infilled RC frame. It is concluded from this comparison that the strength and stillness of the whole structure can be predicted with quite high reliability using compressive strut (compression link element, Type 09) while some local behavior cannot be described reasonably.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.313-320
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• 2003

The responses of a 1:5 scale 3-story masonry-infilled RC frame which was designed only for gravity loads were simulated by using a nonlinear analysis program, DRAIN-2DX. The objective of this study is to verify the correlation between the experimental and analytical responses of a masonry-infilled RC frame. It is concluded from this comparison that the strength and stiffness of the whole structure can be predicted with quite high reliability using compressive strut (compression link element, Type 09).

• Steel and Composite Structures
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• v.42 no.1
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• pp.123-137
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• 2022

The fundamental period (FP) is one of the most critical parameters for the seismic design of structures. In the reinforced concrete (RC) infilled frame, the infill walls significantly affect the FP because they change the stiffness and mass of the structure. Although several formulas have been proposed for estimating the FP of the RC infilled frame, they are often associated with high bias and variance. In this study, an efficient soft computing model, namely the group method of data handling (GMDH), is proposed to predict the FP of regular RC infilled frames. For this purpose, 4026 data sets are obtained from the open literature, and the quality of the database is examined and evaluated in detail. Based on the cleaning database, several GMDH models are constructed and the best prediction model, which considers the height of the building, the span length, the opening percentage, and the infill wall stiffness as the input variables for predicting the FP of regular RC infilled frames, is chosen. The performance of the proposed GMDH model is further underscored through comparison of its FP predictions with those of existing design codes and empirical models. The accuracy of the proposed GMDH model is proven to be superior to others. Finally, explicit formulas and a graphical user-friendly interface (GUI) tool are developed to apply the GMDH model for practical use. They can provide a rapid prediction and design for the FP of regular RC infilled frames.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.121-129
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• 2017

In this paper, the shake table test for the masonry infilled reinforced concrete frame with non-seismic details was carried out in order to evaluate its dynamic behaviour and damage under seismic condition. The tested specimens were the RC frame and the masonry infilled RC frame and the dynamic characteristics, such as a resonant period, acceleration response, displacement response and base shear force response, were compared between them. As a result of the shake table test, RC frame specimen had flexural cracks at the top and bottom of the column and shear cracks at the joints. In the case of masonry infilled RC frame, the damage of the frame was relatively minor but the sliding cracks and diagonal shear cracks on the masonry wall were severe at the final excitation. The resonant period of infilled RC frame specimen was shorter than that of the RC frame specimen because the masonry infill contributed to increase the stiffness. The maximum displacement response of the infilled RC frame specimen was decreased by about 20% than the RC frame specimen. It was analyzed that the masonry infill wall applied in this study contributed to increase the lateral strength of the RC frame with non - seismic detail by about 2.2 times and the stiffness by about 1.6 times.

• Earthquakes and Structures
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• v.12 no.6
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• pp.699-712
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• 2017

This study evaluates the effectiveness of a newly developed retrofitting scheme for masonry-infilled non-ductile RC frames experimentally and by numerical simulation. The technique focuses on modifying the load path and yield mechanism of the infilled frame to enhance the ductility. A vertical gap between the column and the infill panel was strategically introduced so that no shear force is directly transferred to the column. Steel brackets and small vertical steel members were then provided to transfer the interactive forces between the RC frame and the masonry panel. Wire meshes and high-strength mortar were provided in areas with high stress concentration and in the panel to further reduce damage. Cyclic load tests on a large-scale specimen of a single-bay, single-story, masonry-infilled RC frame were carried out. Based on those tests, the retrofitting scheme provided significant improvement, especially in terms of ductility enhancement. All retrofitted specimens clearly exhibited much better performances than those stipulated in building standards for masonry-infilled structures. A macro-scale computer model based on a diagonal-strut concept was also developed for predicting the global behavior of the retrofitted masonry-infilled frames. This proposed model was effectively used to evaluate the global responses of the test specimens with acceptable accuracy, especially in terms of strength, stiffness and damage condition.

• Journal of the Korean Society of Safety
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• v.32 no.1
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• pp.66-74
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• 2017

Masonry walls which are commonly used for partitions in low-rise reinforced concrete (RC) structures, can be easily exposed to high risks under strong earthquakes. Since the strength degradations cannot be protected under the ground motions, their applications cannot be recommended for building structures which are designed to possess high seismic performances. However, masonry-infilled walls are typically considered as non-structural elements in evaluating the seismic performance of building structures. In order to figure out this problem, this study performed experiments using two specimens-only RC frame and RC frame infilled with masonry walls- under static loading. Also, the study established analytical models representing fully infilled frames and bare frame, and compared their structural behavior with test results. In addition, analytical model representing partially infilled frames was established and analyzed. Test results indicated that strength and energy dissipating capacity were increased for IW-RN(fully infilled frames) compared to the NW(bare frame). The nonlinear static analysis of the three specimens was also conducted using the inelastic plastic hinge frame element and diagonal strut models, and the analytical results successfully simulated the nonlinear behaviour of the specimens in accordance with the test results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.116-124
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• 2011

RC frames with unreinforced masonry infiledl walls are common in worldwide. Since infilled walls are normally considered as non-structural elements, their presence is often ignored by engineers. In this study, to improve the seismic performance of masonry walls, hexagonal block was developed and the influence of masonry infilled wall on the seismic performance of reinforced concrete(RC) frames that were designed in accordance with current code provisions without the consideration of earthquake loadings are investigated. Two 1/2 scale, single story, single bay, frame specimens were tested. The parameters investigated included that the strength of infilled wallls with respect to that of the lateral load history. The experimental results indicate that infilled walls can significantly improve the lateral stiffness and strength of RC frames. The lateral loads developed by the infilled frame specimen is higher than that of the bare frame. It also indicates that infilled walls can be potentially used to improve the performance of existing nonductile frames. For this purpose. methods should be developed to avoid irreparable damage and catastrophic failure.

• Structural Engineering and Mechanics
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• v.74 no.6
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• pp.821-832
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• 2020

The fundamental period is an important parameter for seismic design and seismic risk assessment of building structures. In this paper, a simplified theoretical method to predict the fundamental period of masonry infilled reinforced concrete (RC) frame is developed based on the basic theory of engineering mechanics. The different configurations of the RC frame as well as masonry walls were taken into account in the developed method. The fundamental period of the infilled structure is calculated according to the integration of the lateral stiffness of the RC frame and masonry walls along the height. A correction coefficient is considered to control the error for the period estimation, and it is determined according to the multiple linear regression analysis. The corrected formula is verified by shaking table tests on two masonry infilled RC frame models, and the errors between the estimated and test period are 2.3% and 23.2%. Finally, a probability-based method is proposed for the corrected formula, and it allows the structural engineers to select an appropriate fundamental period with a certain safety redundancy. The proposed method can be quickly and flexibly used for prediction, and it can be hand-calculated and easily understood. Thus it would be a good choice in determining the fundamental period of RC frames infilled with masonry wall structures in engineering practice instead of the existing methods.