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.

scholarly journals Assessment of Seismic Capacity for Reinforced Concrete Frames with Perforated Unreinforced Brick Masonry Infill Wall

2020 ◽  
Vol 6 (12) ◽  
pp. 2397-2415
Author(s):  
Muhammad Umar ◽  
Syed Azmat Ali Shah ◽  
Khan Shahzada ◽  
Muhammad Tayyab Naqash ◽  
Wajid Ali
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Research Work ◽  
Rc Frame ◽  
Concrete Frames ◽  
Infill Wall ◽  
Reinforced Concrete Frames ◽  
Infill Walls ◽  
Rc Frames ◽  
Infilled Rc Frames

Infill walls increase the strength and stiffness of the reinforced concrete frames, but they usually are not considering in design. However, when the infills are considered in the design, the opening for doors/windows necessitates investigation as well. This research work aims to investigate the effect of perforations (openings) in the infill walls on the performance of infilled RC frames, in other words, this research investigates the number of infill walls in infilled RC frames. Based on the current construction practices in Pakistan, two full scales perforated infilled RC frames were constructed in the laboratory. One infilled RC frame has an eccentric door and window (specimen-1) while the other has only window at its centre (specimen-2). Both the specimens were tested against reverse cyclic loading (quasi-static test). From the experimental testing, it was found that infilled RC frame having less amount of opening in infill wall has more resistance to lateral loads, have more stiffness and dissipated higher energy as compared to infilled RC frame having a significant size of the opening in infill wall. Similarly, displacement ductility (µD) and Response modification factor (R) also depend on the quantity of opening in infill wall in infilled RC frame. Doi: 10.28991/cej-2020-03091625 Full Text: PDF

Progressive Collapse Analysis of Reinforced Concrete Frames with Unreinforced Masonry Infill Walls considering In-Plane/Out-of-Plane Interaction

2015 ◽  
Vol 31 (2) ◽  
pp. 921-943 ◽  
Author(s):  
Khalid M. Mosalam ◽  
Selim Günay
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Progressive Collapse ◽  
Unreinforced Masonry ◽  
Concrete Frames ◽  
Infill Wall ◽  
Infill Walls ◽  
Rc Frames ◽  
Out Of Plane ◽  
Plane Interaction

Reinforced concrete (RC) frames with unreinforced masonry (URM) infill walls are commonly used in seismic regions around the world. It is recognized that many buildings of this type perform poorly during earthquakes. Therefore, proper modeling of the infill walls and their effect on RC frames is essential to evaluate the seismic performance of such buildings and to select adequate retrofit methods. Using damage observations of RC buildings with URM infill walls from recent earthquakes, this paper presents a new approach to consider in-plane/out-of-plane interaction of URM infill walls in progressive collapse simulations. In addition, the infill wall effect to induce shear failure of columns is simulated with a nonlinear shear spring modeling approach. The research endeavor is accompanied by implementation of the developed modeling aspects in the publicly available open-source computational platform OpenSees for immediate access by structural engineers and researchers.

scholarly journals Advanced Composite Retrofit of RC Columns and Frames with Prior Damages—Pseudodynamic Finite Element Analyses and Design Approaches

Fibers ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 56
Author(s):  
Theodoros Rousakis ◽  
Evgenia Anagnostou ◽  
Theodora Fanaradelli
Keyword(s):  
Finite Element ◽  
Brick Wall ◽  
Rc Frame ◽  
Base Shear ◽  
Infill Wall ◽  
Rc Columns ◽  
Premature Failure ◽  
Displacement Ductility ◽  
Lap Splices ◽  
Rc Frames

This study develops three-dimensional (3D) finite element (FE) models of composite retrofits in deficient reinforced concrete (RC) columns and frames. The aim is to investigate critical cases of RC columns with inadequate lap splices of bars or corroded steel reinforcements and the beneficial effects of external FRP jacketing to avoid their premature failure and structural collapse. Similarly, the RC-frame FE models explore the effects of an innovative intervention that includes an orthoblock brick infill wall and an advanced seismic joint made of highly deformable polymer at the boundary interface with the RC frame. The experimental validation of the technique in RC frames is presented in earlier published papers by the authors (as well as for a four-column structure), revealing the potential to extend the contribution of the infills at high displacement ductility levels of the frames, while exhibiting limited infill damages. The analytical results of the advanced FE models of RC columns and frames compare well with the available experimental results. Therefore, this study’s research extends to critical cases of FE models of RC frames with inadequate lap splices or corroded steel reinforcements, without or with brick wall infills with seismic joints. The advanced pseudodynamic analyses reveal that for different reinforcement detailing of RC columns, the effects of inadequate lap-spliced bars may be more detrimental in isolated RC columns than in RC frames. It seems that in RC frames, additional critical regions without lap splices are engaged and redistribution of damage is observed. The detrimental effects of corroded steel bars are somewhat greater in bare RC frames than in isolated RC columns, as all reinforcements in the frame are considered corroded. Further, all critical cases of RC frames with prior damages at risk of collapse may receive the innovative composite retrofit and achieve higher base shear load than the original RC frame without corroded or lap-spliced bars, at comparable top displacement ductility. Finally, the FE analyses are utilized to propose modified design equations for the shear strength and chord rotation in cases of failure of columns with deficiencies or prior damages in RC structures.

scholarly journals Examination of Anchorage of Mesh Wire on Seismic Response of Infilled Walls in RC Frames

2021 ◽  
Author(s):  
Ali Al-Maliki ◽  
◽  
Mohammed Sahib Mohammed ◽  
Maha Al-Soudani ◽  
Haifaa Nasser Husein ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Lateral Displacement ◽  
Lateral Load ◽  
Structural Behavior ◽  
Concrete Frames ◽  
Infill Wall ◽  
Infill Walls ◽  
Positive Effects ◽  
Rc Frames ◽  
Different Diameters

The infill walls may lose their positive effects during the first stages of earthquakes, either by leaving their plane or through breakage. That is why it is common to strengthen these walls before design earthquakes or to repair and strengthen them after suffering slight or moderate damage due to the occurrence of an earthquake. In this study, the effect of adding and strengthening these walls on the structural behavior of reinforced concrete structures was investigated. For this purpose, the infill walls were strengthened with a single mesh of reinforcement and covered with plaster. Five one-story, single bay and ½ scaled reinforced concrete frames were cast, one was built without infill, the second with a bare infill wall, and the other three with strengthened infill walls with anchorage of different diameters. All these specimens were tested under cyclic loading type reverse. The tests resulted in important relationships and curves, including the lateral load-lateral displacement, envelope curve-lateral load and lateral displacement, as well as stiffness- lateral displacement and others. Through these results, the effect of adding infill walls and the strengthening procedure of these walls on the structural behavior of the structures was discussed.

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 Shaking Table Test of a RC Frame with EPSC Latticed Concrete Infill Wall

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Baizan Tang ◽  
Xiaojun Li ◽  
Su Chen ◽  
Lihong Xiong
Keyword(s):  
Shaking Table Test ◽  
Comprehensive Evaluation ◽  
Shaking Table ◽  
Wall Material ◽  
Rc Frame ◽  
Seismic Responses ◽  
Concrete Wall ◽  
Infill Wall ◽  
Infill Walls ◽  
Rc Shear Wall

The expansive polystyrene granule cement (EPSC) latticed concrete wall is a new type of energy-saving wall material with load-bearing, insulation, fireproof, and environmental protection characteristics. A series of shaking table tests were performed to investigate the seismic behavior of a full-scale reinforced concrete (RC) frame with EPSC latticed concrete infill wall, and data obtained from the shaking table test were analyzed. The experimental results indicate that the designed RC frame with EPSC latticed concrete infill wall has satisfactory seismic performance subjected to earthquakes, and the seismic responses of the model structure are more sensitive to input motions with more high frequency components and long duration. The EPSC latticed concrete infill wall provided high lateral stiffness so that the walls can be equivalent to a RC shear wall. The horizontal and vertical rebar, arranged in the concrete lattice beam and column, could effectively restrain the latticed concrete infill wall and RC frame. To achieve a more comprehensive evaluation on the performance of the RC frame with latticed concrete infill walls, further research on its seismic responses is expected by comparing with conventional infill walls and nonlinear analytical method.

Effects of Modeling Staircases on Seismic Responses of Concrete Frames

2017 ◽  
Vol 23 ◽  
pp. 72-87 ◽  
Author(s):  
Majid Ghaderi Garakani ◽  
Saeed Mahjoubi ◽  
Shervin Maleki
Keyword(s):  
Frame Structures ◽  
Second Step ◽  
Seismic Loads ◽  
Rc Frame ◽  
Concrete Frames ◽  
Strong Earthquakes ◽  
Shell Elements ◽  
Rc Frames ◽  
Rc Frame Structures ◽  
Bracing System

Staircases in reinforced concrete (RC) frame structures have suffered severe damages in past earthquakes, despite being regarded as the main means of egress during emergencies. To make sure that staircases perform as safe passages in strong earthquakes, the performance of RC stair structures should be scrutinized under major earthquakes. In this research at first, staircases were simulated as shell elements in RC frames and analyzed under gravity loads in order to find the maximum forces and moments. In the second step, the influence of staircases on the structural behavior of RC frame structures under seismic loads was studied. The results showed that stairs act as a K-type bracing system. Furthermore, a parametric study was carried out and relations for calculating force and moment in stairs slabs that had been determined under gravity loads, were modified. In addition, affected areas of structure interacting with the stairs in an earthquake were distinguished.

scholarly journals Seismic Analysis of a Residential Building Considering Different Types of Opening Arrangement in the Infill Wall

2021 ◽  
Vol 9 (10) ◽  
pp. 649-656
Author(s):  
Kapil Shankar Soni
Keyword(s):  
Failure Modes ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Residential Building ◽  
Base Shear ◽  
Seismic Behaviour ◽  
Infill Wall ◽  
Infill Walls ◽  
Time Period ◽  
Natural Time

Abstract: Infill walls are inevitable components of any structure to create dispassion between interior space and external condition. In general, there are some prevalent openings inside the infill walls because of practical needs, architectural observations or aesthetic inspections. In current design practice, strength and inflexibility contribution of infill walls aren't thought of. However, the presence of infill walls may impact the seismic reaction of structures exposed to earthquake loads and cause a conduct which is not the same as that estimated for a bare frame. Additionally, partial openings inside infill walls are significant parameter prompting the seismic behaviour of infilled frames in this manner retreating lateral stiffness and strength. In this study is proposed to compare various models of buildings considering the openings (10% of surface area) at different locations in the infill walls for the seismic behaviour. A G+13 residential building is considered in Zone III with soil type II and analysis is carried out by Response Spectrum Method. Various parameters are considered such as Natural Time period, Base shear, Storey displacement, Storey drift and Storey stiffness were studied. The comparative study could simplify designers and code developers in selecting and recommending appropriate analytical models for estimating strength, stiffness, failure modes and other properties of infill frames with openings. Keywords: Residential Building, Openings Infill Wall, ETAB Software, Natural Time Period, Base Shear, Storey Shear, Storey Displacement, Storey Drift, Storey Stiffness.

Nonlinear Seismic Analysis of Masonry Infilled RC Frame Structures

2011 ◽  
Vol 117-119 ◽  
pp. 288-294
Author(s):  
Xiao Ying Gong ◽  
Jun Wu Dai
Keyword(s):  
Seismic Design ◽  
Frame Structures ◽  
Lateral Stiffness ◽  
Rc Frame ◽  
Stiffness Ratio ◽  
Infill Wall ◽  
Infill Walls ◽  
Floor Slab ◽  
Rc Frame Structures ◽  
Lateral Stiffness Ratio

Many RC frame structures were severely damaged or collapsed in some layer. The phenomenon was significantly different from the expected failure mode in seismic design code. This paper comprehensively sums up the earthquake characteristics of masonry infilled RC frame structures. Based on an investigation of a masonry infilled RC frame structure damaged in the earthquake area, conduct the research on frail-layer caused by infill walls uneven decorated. On the hypothesis of keeping the main load-bearing component invariant, two models were considered, i. e. frame with floor slab, and frame with both floor slab and infill wall. Furthermore, divide them into groups of the bottom, the middle and the top frail-layer to discuss by changing the arrange of infill wall. Time history analyses using three-dimensional sophisticated finite element method were conducted. The major findings are: 1)infill walls may significantly alter the failure mechanism of the RC frames. 2)controlling the initial interlayers lateral stiffness ratio in a reasonable range is an effective method to avoid frail-layer damage. These findings suggest that the effects of infill wall should be considered in seismic design, keep the initial interlayers lateral stiffness ratio less than the paper suggested, and the structural elasto-plastic analysis model should take slabs and infill walls into account.

A Beam-and-Column Based Macro Model for Masonry Infill Walls in RC Frames under Cyclic Loading

2011 ◽  
Vol 255-260 ◽  
pp. 193-197
Author(s):  
Jia Chao Zhang ◽  
Lei Ming Zhang ◽  
Xi La Liu
Keyword(s):  
Structural Response ◽  
Seismic Action ◽  
Rc Frame ◽  
Wall Panel ◽  
Infill Walls ◽  
Masonry Infill ◽  
Macro Model ◽  
Masonry Infill Walls ◽  
Rc Frames ◽  
Proposed Model

Reinforced concrete (RC) frame with masonry infill walls is a very common structural system in low and medium rise buildings. The infill walls are usually considered as non-structural components in the design or assessment of buildings. However, many damages in earthquakes have shown that the infill walls can significantly change the structural response to seismic action. Consequently the evaluation of the seismic performance of RC frame with masonry infill walls becomes very important, and also turns to be a major challenge for structure engineers. In this paper a beam-and-column (BAC) macro model for walls is proposed to simulate the masonry infill walls in RC frames. In this model, the masonry panel is replaced by an equivalent rigid frame which is made up of some beam-and-column members. The geometric parameters of each member can be determined simply by equivalent stiffness combined with the original dimensions of wall panel. The physical characteristics are described directly by material properties of wall panel under investigation. To validate the rationality of proposed model, a masonry-infilled RC frame under cyclic reversed loading is analyzed by the proposed model. The results, including crack pattern, load versus displacement relation are then compared with the experiment response. Good agreements are found.

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