Experimental Study on Lateral Strength Evaluation of Unreinforced Masonry-Infilled RC Frame

2016 ◽  
Vol 32 (3) ◽  
pp. 1725-1747 ◽  
Author(s):  
Kiwoong Jin ◽  
Ho Choi ◽  
Yoshiaki Nakano
Keyword(s):  
Compressive Strain ◽  
Concrete Block ◽  
Unreinforced Masonry ◽  
School Buildings ◽  
Rc Frame ◽  
Rc Frames ◽  
Equivalent Strut ◽  
Lateral Strength ◽  
Curvature Distribution ◽  
Typical School

In this study, RC frames with unreinforced masonry (URM) infill for typical school buildings in Korea are experimentally investigated to evaluate their seismic performance. For this purpose, one-bay, one-fourth scale specimens, with unreinforced concrete block (CB) infill having different boundary conditions due to beam rigidity, are tested under in-plane cyclic loading, using a distinctive measurement scheme consisting of three-axis strain gauges attached to all CB units. In this paper, the diagonal strut mechanism of CB infill including its main strut angle, average compressive strain, and equivalent strut width is discussed using principal compressive strains on CB units. The lateral strength carried by CB infill and RC frame from the overall response of the specimens is also explained, based on the compressive stress acting on the infill and the curvature distribution along RC members during the test.

scholarly journals Effects of Single and Multi Openings in Brick Infills on the Seismic Response of Infilled RC Frames

2018 ◽  
Vol 215 ◽  
pp. 01036
Author(s):  
Maidiawati ◽  
Jafril Tanjung ◽  
Hamdeni Medriosa ◽  
Yulia Hayati
Keyword(s):  
Seismic Response ◽  
Dissipated Energy ◽  
Rc Frame ◽  
Infilled Frames ◽  
Masonry Infill ◽  
Infilled Frame ◽  
Rc Frames ◽  
Central Opening ◽  
Lateral Strength ◽  
Infilled Rc Frames

Many researchers have performed a lot of studies of the seismic behavior reinforced concrete (RC) frame with masonry infill. They found that masonry infill affects the lateral strength, stiffness and ductility performance of the RC frame structures. However, when openings appeared in the panel infill for door and windows, the responses of the overall structure are entirely changed. The primary purpose of this study is to experimentally investigate the behavior of brick infilled RC frames possessing single opening and two openings. Four specimens of 1/4-scale single bay RC frames with brick infills were made that were one bare frame, one frame with full infill and two frames with infills having a central opening and two openings with the opening ratio of 25%. The specimens were tested under lateral reversed cyclic loads. Consequently, different responses of failure mechanism, lateral strength, stiffness and energy dissipated were observed among the specimens. The brick full infill failed in shear with propagation cracks in central part of the panel, but in the case of the infills with single and two openings, the cracks were dominated at the corners of the openings. The in-plane strength, stiffness and dissipated energy of infilled frames decreased when openings appeared in the panel. However, the seismic performance of brick infilled frame with the opening of 25% of panel area is better than those of bare frame. The brick infilled frames with a central opening and two openings are similar in lateral strength and dissipated energy. It seems that area and position of the openings control the seismic response to the overall infilled frame structure of the openings

scholarly journals Seismic performance of brick masonry infilled frame structures with bed joint reinforcements

2020 ◽  
Vol 156 ◽  
pp. 03004
Author(s):  
Maidiawati ◽  
Jafril Tanjung ◽  
Yulia Hayati ◽  
Agus ◽  
Satria Rangga
Keyword(s):  
Seismic Performance ◽  
Frame Structure ◽  
Frame Structures ◽  
Rc Frame ◽  
Infilled Frame ◽  
Rc Frames ◽  
Lateral Strength ◽  
Plane Direction ◽  
Infilled Rc Frames ◽  
Reversed Cyclic

This paper presents the evaluation of the seismic performance of brick infilled RC frame structures with bed joint reinforcements based on reversed cyclic lateral load tests. Three specimens of the structural model of 1/4 scale-down single-story single-bay brick infilled RC frame was prepared, which were brick infilled RC frames with and without bed joint reinforcements. Two specimens of brick infills with bed joint reinforcements were different in the spacing of bed joint rebars. The specimens were tested by applying a reversed cyclic lateral loading in-plane direction. During the tests, the crack propagation was observed at the peak and residual drifts of each loading cycle to recognize the failure mechanisms of the specimens. As the results, although the use of the bed joint reinforcements ineffective to increase the lateral strength of the overall infilled frame structure. The rebars in mortar bed joints role to sustain the lateral strength in plastic deformation, and provide the whole structure with high ductility. It seemed that the rebars in mortar bed joints confined the brick infills. Therefore, the infilled RC frames can survive in large deformation without failure of the infills in out of the plane direction.

Earthquake Disaster Mitigation through Retrofitting of Unreinforced Concrete Block Masonry Buildings

2011 ◽  
Vol 255-260 ◽  
pp. 2627-2631
Author(s):  
Muhammad Shoaib ◽  
Amjad Naseer ◽  
Khan Shahzada ◽  
Akhtar Naeem Khan ◽  
M. Ashraf
Keyword(s):  
Experimental Study ◽  
Concrete Block ◽  
Unreinforced Masonry ◽  
Experimental Results ◽  
Disaster Mitigation ◽  
Masonry Buildings ◽  
Future Scenario ◽  
Scenario Earthquakes ◽  
Before And After ◽  
Lateral Strength

This paper presents an experimental study on the improvement of unreinforced block masonry buildings against earthquake disasters. Unreinforced concrete block masonry piers have been tested for lateral strength before and after retrofitting. Welded mesh and injection of cement grout techniques have been used for piers retrofitting. The analysis of experimental results demonstrates that proper retrofitting can decrease the risk to concrete block masonry buildings in future scenario earthquakes. Retrofitting increases not only the overall strength of unreinforced masonry piers but also the ductility.

A Novel Technique of Seismic Strengthening of Nonductile RC Frame using Steel Caging and Aluminum Shear Yielding Damper

2009 ◽  
Vol 25 (2) ◽  
pp. 415-437 ◽  
Author(s):  
Dipti R. Sahoo ◽  
Durgesh C. Rai
Keyword(s):  
Energy Dissipation ◽  
Lateral Load ◽  
Rc Frame ◽  
Test Protocol ◽  
Shear Yielding ◽  
Reduction In Force ◽  
Rc Frames ◽  
Lateral Strength ◽  
Lateral Displacements ◽  
Strength And Stiffness

A novel strengthening scheme for seismically-weak RC frames is proposed which utilizes external steel caging to improve flexural/shear strength of columns and aluminum shear-yielding damper ( Al-SYD) to further enhance lateral strength, stiffness and overall energy dissipation capacity of the frame. This paper describes the effectiveness of this scheme as evidenced in an experimental study on a reduced scale (1:2.5) single-story, single-bay, gravity-only designed reinforced concrete (RC) frame. The strengthened frame was simultaneously subjected to gravity loads and reversed cyclic lateral displacements as per ACI-374 loading protocol. An innovative connection scheme was designed to transfer a portion of frame lateral load to the energy dissipation device ( Al-SYD). Besides the significant increase in lateral strength and stiffness of the strengthened frame, RC frame members did not suffer any major damage during the entire test protocol. This indicates significant reduction in force demand on existing RC members because of enhanced energy dissipation through hysteretic shear yielding of aluminum panels. Moreover, the simple connection scheme proposed in this study proved very efficient in transferring the frame lateral load to strengthening elements.

Seismic performance of RC frames strengthened by RC infill walls

2021 ◽  
pp. 136943322199772
Author(s):  
Shao-Ge Cheng ◽  
Yi-Xiu Zhu ◽  
Wei-Ping Zhang
Keyword(s):  
Masonry Walls ◽  
Rc Frame ◽  
Seismic Line ◽  
Shake Table Tests ◽  
Infill Walls ◽  
Displacement Ductility ◽  
Rc Frames ◽  
Story Drift ◽  
Comparison Of The Results ◽  
Bending Failure

This study presents the shake-table tests of a 1/5-scaled RC frame retrofitted with RC infill walls. The intensity of input ground motions increased gradually to comprehensively evaluate the structural seismic behavior. We performed a comparison of the results from the RC frame with masonry walls and that with RC walls. The results showed that the presence of RC infills effectively improved the lateral structural stiffness and loading capacity of the frames and reduced their damage and story drift. RC walls acted as the first seismic line of defense, and their failure was dominated by bending failure and concentrated on the low stories. The displacement ductility of the structure decreased with increasing stiffness of the introducing infills.

scholarly journals Numerical Modeling of Masonry-infilled RC Frame

2019 ◽  
Vol 13 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Christiana A. Filippou ◽  
Nicholas C. Kyriakides ◽  
Christis Z. Chrysostomou
Keyword(s):  
Cyclic Loading ◽  
Numerical Model ◽  
Constitutive Models ◽  
Control Analysis ◽  
Rc Frame ◽  
Initial Stiffness ◽  
Element Analysis ◽  
Rc Frames ◽  
Rc Frame Structures ◽  
Infilled Rc Frames

Background: The behavior of masonry-infilled Reinforced Concrete (RC) frame structures during an earthquake, has attracted the attention of structural engineers since the 1950s. Experimental and numerical studies have been carried out to investigate the behavior of masonry-infilled RC frame under in-plane loading. Objective: This paper presents a numerical model of the behavior existing masonry-infilled RC frame that was studied experimentally at the University of Patra. The objective of the present study is to identify suitable numerical constitutive models for each component of the structural system in order to create a numerical tool to model the masonry infilled RC frames in-plane behavior by accounting the frame-infill separation. Methods: A 2D masonry-infilled RC frame was developed in DIANA Finite Element Analysis (FEA) software and an eigenvalue and nonlinear structural cyclic analyses were performed. It is a 2:3 scale three-story structure with non-seismic design and detailing, subjected to in-plane cyclic loading through displacement control analysis. Results: There is a good agreement between the numerical model and experimental results through a nonlinear cyclic analysis. It was found that the numerical model has the capability to predict the initial stiffness, the ultimate stiffness, the maximum shear-force capacity, cracking- patterns and the possible failure mode of masonry-infilled RC frame. Conclusion: Therefore, this model is a reliable model of the behavior of masonry-infilled RC frame under cyclic loading including the frame-infill separation (gap opening).

Cyclic Performance of Two-Story Ductile RC Frames With Infill Walls

2005 ◽  
Author(s):  
Yung-Hsin Yeh ◽  
Wen-I Liao
Keyword(s):  
Model Building ◽  
General Purpose ◽  
Rc Frame ◽  
Building Structures ◽  
Base Shear ◽  
Concrete Frames ◽  
Infill Wall ◽  
Infill Walls ◽  
Rc Frames ◽  
Short Beam

This paper presents the results of the experimental and analytical investigations conducted on four 0.8 scale 2-story one bay ductile reinforced concrete frames with infill nonstructural walls subjected to cyclically increasing loads. The material properties and the member sizes of beams and columns in the four RC frame specimens are identical, but with different types of infill nonstructural wall. These four frames are the pure frame, frame with short column, frame with short beam and frame with wing walls. The four RC frame specimens were designed and constructed according to the general prototype building structures in Taiwan. Test results indicate that the ductility behavior of the frames with infill wall is similar to those of the pure frame. The ultimate base shear strength of the frames with infill walls is higher than those of the pure frame. Analytical results show that the proposed simplified multi-linear beam-column element implemented in a general purpose structural analysis program can accurately simulate the cyclic responses of the RC frame specimen incorporating the elastic flexural stiffness computations suggested by the model building codes.

Retrofitting Non-Ductile RC Frames for Seismic Resistance Using Post-Installed Shear Walls

2019 ◽  
Author(s):  
Chien-Kuo Chiu ◽  
Fu-Pei Hsiao ◽  
Wen-I Liao ◽  
Samuel Jonathan Quacoo ◽  
Chin-En Ho ◽  
...  
Keyword(s):  
Brittle Failure ◽  
Load Transfer ◽  
Shear Walls ◽  
Frame Structures ◽  
Seismic Capacity ◽  
Rc Structures ◽  
Structural Health ◽  
Rc Frames ◽  
Lateral Strength ◽  
Rc Frame Structures

Abstract Reinforced Concrete (RC) frame structures that were designed and built according to older standards can be damaged during destructive earthquakes as a result of insufficient lateral strength and/or deformation capacity. Such structures must be retrofitted to satisfy the current requirements and to survive future earthquakes. Owing to its high lateral strength and stiffness capacity of an RC wall, the post-installation of an RC wall in a non-ductile frame for retrofit is a widely used retrofitting technique. However, for frame structures with low-strength concrete, the typically used connected construction method on the interface between existing and new concrete may be not able to provide effective force transfer, and may cause unexpected brittle failure in the retrofitted structure. Such unexpected brittle failure may reduce the seismic capacity of the structure and threaten its safety. Therefore, in this experimental investigation, two retrofitting methods that use a post-installed RC wall are proposed to improve the load transfer mechanism on the interface. The first involves a wall with diagonal rebar and boundary spirals, and the second involves a wall with an additional inner frame. A typical traditional retrofitting specimen was constructed and tested for comparison. Reversed cyclic loading is used to test the seismic capacity of the specimens. Finally, post-embedded piezoceramic-based sensors were used to monitor the structural health and detect damage in one of specimens during the test. The experimental results demonstrate the effectiveness of the piezoceramic-based approach to structural health monitoring and the ability of the method to detect damage in shear governed RC structures under seismic loading.

scholarly journals Influence of exterior infill walls on the performance of RC frames under tsunami loads: Case study of school buildings in Sri Lanka

2021 ◽  
Vol 234 ◽  
pp. 111920
Author(s):  
Marta Del Zoppo ◽  
Kushan Wijesundara ◽  
Tiziana Rossetto ◽  
Priyan Dias ◽  
Marco Baiguera ◽  
...  
Keyword(s):  
Sri Lanka ◽  
School Buildings ◽  
Infill Walls ◽  
Rc Frames
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