• 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.

• Earthquakes and Structures
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• v.11 no.4
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• pp.609-627
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• 2016

Results of an experimental program are presented in this paper for the influence of vertical load on the in-plane behavior of masonry infilled steel frames. Five half-scaled single-story, single-bay steel frame specimens were tested under cyclic lateral loading. The specimens included four infilled frames and one bare frame. Two similar specimens as well as the bare frame had moment-resisting steel frames, while the remaining two specimens had pinned steel frames. For each frame type, one specimen was tested under simultaneous vertical and lateral loading, whereas the other was subjected only to lateral loading. The experimental results show that the vertical load changes the cracking patterns and failure modes of the infill panels. It improves dissipated hysteresis energy and equivalent viscous damping. Global responses of specimens, including stiffness and maximum strength, do no change by vertical loading considerably. Regarding the ductility, the presence of vertical load is ignorable in the specimen with moment-resisting frame. However, it increases the ductility of the infilled pinned frame specimen, leading to an enhancement in the m-factor by at least 2.5 times. In summary, it is concluded that the influence of the vertical load on the lateral response of infilled frames can be conservatively ignored.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.513-518
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• 1999

The objective of this experiment is to observe the elastic and inelastic behaviors of high-rise reinforced concrete frame with infilled masonry. To do this a building frame designed according to Korean seismic code and detailed in the Korean conventional manner was selected. An 1:12 scale plane masonry-infilled frame model was manufactured according to similitude law. Push-over test were performed under the roof displacement control. To simulate the earthquake effect, the lateral force distribution was maintained to be an inversed triangular by using whiffle tree. From the tests, story displacements, lateral story forces, local plastic rotations and the relations between inter-story drift versus story shear are obtained. Based on the test results, conclusions on the characteristics of the elastic and inelastic behaviors of a high-rise reinforced concrete frame with infilled masonry are drawn.

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.411-414
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• 1999

Five reinforced concrete rigid frame and masonry infilled wall and cut off type masonry infilled wall were constructed and tesed during vertical and cycle loads simultaneously. Experimental programs were accomplished to evaluate the structural performance of test spcimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility etc. Test variables are hoop reinforcement ratio and masonry infilled wall with on without. All the specimens were modelling in one-third scale size.

• Advances in concrete construction
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• v.5 no.3
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• pp.257-270
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• 2017

An experimental investigation was carried out to study the strength and behavior of reinforced cement concrete (RCC) frames with ferrocement and fiber reinforced concrete infill panel. Seven numbers of $1/4^{th}$ scaled down model of one bay-three storey frames were tested under reverse cyclic loading. Ferrocement infilled frames and fiber reinforced concrete infilled frames with varying volume fraction of reinforcement in infill panels viz; 0.20%, 0.30%, and 0.40% were tested and compared with the bare frame. The experimental results indicate that the strength, stiffness and energy dissipation capacity of infilled frames were considerably improved when compared with the bare frame. In the case of infilled frames with equal volume fraction of reinforcement in infill panels, the strength and stiffness of frames with fiber reinforced concrete infill panels were slightly higher than those with ferrocement infill panels. Increase in volume fraction of reinforcement in the infill panels exhibited only marginal improvement in the strength and behavior of the infilled frames.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.453-456
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• 2004

RC frames built prior to the advent of the philosophy of ductile concrete is one type of existing construction susceptible to damage. Strengthening and stiffening of such frames has been accomplished by infilled frames with cast-in-place, reinforced concrete walls. Placement of CIP shear walls within strategic bays of a structure appears to be a logical and economical method to strengthen a reinforced concrete frame and to stiffen a building in order to reduce architectural and mechanical damage. This study investigates the seismic performance of cast-in place infilled shear wall within existing frames. The object of this study is to clarify the seismic capacity and characteristics in the hysteretic behavior of bare frame, CIP infilled shear wall and CIP infilled wall reinforced diagonal bars.

• 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.