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1
Umar, Muhammad, Syed Azmat Ali Shah, Khan Shahzada, Muhammad Tayyab Naqash e Wajid Ali. "Assessment of Seismic Capacity for Reinforced Concrete Frames with Perforated Unreinforced Brick Masonry Infill Wall". Civil Engineering Journal 6, n. 12 (1 dicembre 2020): 2397–415. http://dx.doi.org/10.28991/cej-2020-03091625.
Testo completoAbstract (sommario):
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
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Marinković, Marko, Santiago Calvinisti e Christoph Butenweg. "Numerical analysis of reinforced concrete frame buildings with decoupled infill walls". Gradjevinski materijali i konstrukcije 63, n. 4 (2020): 13–48. http://dx.doi.org/10.5937/grmk2004013m.
Testo completoAbstract (sommario):
Reinforced concrete (RC) buildings with masonry infill walls are widely used in many countries all over the world. Although infills are considered as non-structural elements, they significantly change dynamic characteristics of RC frame structures during earthquake excitation. Recently, significant effort was spent on studying decoupled infills, which are isolated from the surrounding frame usually by adding a gap between frame and infill. In this case, the frame deformation does not activate infill wall, thus infills are not influencing the behaviour of the frame. This paper presents the results of the investigation of the behaviour of RC frame buildings with the INODIS system that decouples masonry infills from the surrounding frame. Effect of masonry infill decoupling was investigated first on the one-bay one-storey frame. This was used as a base for parametric study on the frames with more bays and storeys, as well as on the building level. Change of stiffness and dynamic characteristics was analysed as well as response under earthquake loading. Comparison with the bare frame and traditionally infilled frame was performed. The results show that behaviour of the decoupled infilled frames is similar to the bare frame, whereas behaviour of frames with traditional infills is significantly different and demands complex numerical models. This means that if adequate decoupling is applied, design of infilled frame buildings can be significantly simplified.
3
Grubišić, Marin, Tanja Kalman Šipoš, Ante Grubišić e Benjamin Pervan. "Testing of Damaged Single-Bay Reinforced Concrete Frames Strengthened with Masonry Infill Walls". Buildings 13, n. 4 (13 aprile 2023): 1021. http://dx.doi.org/10.3390/buildings13041021.
Testo completoAbstract (sommario):
Despite achieving consensus and having current knowledge on the behaviour and contribution of masonry infill walls, there remain unresolved issues regarding their nonlinear behaviour as a method for strengthening existing reinforced concrete (RC) frames with effective modifications, primarily infills and the interconnection of infills and frames. The challenge for safely and economically designing frames with competent walls is to utilise the stiffening benefits while ensuring that the increased lateral forces and reduced drift capacity do not hinder performance. This study aims to investigate the potential of using masonry infill to strengthen previously slightly damaged RC frames. Experimental tests were conducted on previously slightly damaged RC frame specimens infilled with vertically hollowed-clay and solid-clay masonry units, connected to the frame elements using traditional methods (i.e., avoiding the use of modern composite materials). These strengthened infilled frame structures were subjected to constant vertical and cyclic lateral loading, which revealed improved stiffness, strength, and damping characteristics, enhancing their overall behaviour. As the main novelties, the study found that when damaged RC frames were strengthened with masonry infill walls, their performance resembled that of undamaged infilled RC frames. The strengthened infilled frame structures exhibited enhanced stiffness, strength, and hysteretic damping. The increase in stiffness was observed regardless of the type of masonry units and the strengthening technique employed. However, the improvements in strength and hysteretic damping were influenced by the specific masonry units, particularly their robustness, and the chosen reinforcement method.
4
Leite, João, Paulo B. Lourenço e Nuno Mendes. "Design Proposal for Masonry Infill Walls Subject to Seismic Actions". Applied Sciences 12, n. 1 (5 gennaio 2022): 503. http://dx.doi.org/10.3390/app12010503.
Testo completoAbstract (sommario):
Several factors influence the behaviour of masonry infilled frames, which have been the subject of previous research with moderate success. The new generation of European design standards imposes the need to prevent the brittle collapse of infills and makes the structural engineer accountable for this requirement, yet it fails to provide sufficient information for masonry infill design. The present study aimed to compare experimental results with the provisions of the standard for the computation of the demand and capacity of infilled frames. Three reinforced concrete buildings with different infill solutions were constructed at a 1:1.5 scale. The infill walls were tested until collapse, or severe damage, using the shake table of the National Laboratory for Civil Engineering, Portugal, and their response was measured using accelerometers attached to the walls. The European normative standard provides results close to the experimental ones as far as demand and capacity are concerned. Based on the experiments, two design proposals for infill walls are presented here, one for the definition of the natural frequency of the infills, and another for a reduction factor to account for the presence of openings in the out-of-plane capacity of infills.
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Hao, Wei Jie, e Xing Fu Hu. "Summary of Seismic Performance of the Frame Structure with Infill-Walls". Applied Mechanics and Materials 501-504 (gennaio 2014): 1600–1603. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1600.
Testo completoAbstract (sommario):
Frame structure with infill-walls has been widely used in China, Many domestic experts and scholars have done a great deal studies on the seismic behavior of infilled frames and theorizes that the infill-walls greatly influences the frame structure on seismic behavior. In this paper, summarized the seismic performance of infilled frames from three aspects: the arrangement and structure of infill walls and their connection with frame beam-column.
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Ferraioli, Massimiliano, e Angelo Lavino. "Irregularity Effects of Masonry Infills on Nonlinear Seismic Behaviour of RC Buildings". Mathematical Problems in Engineering 2020 (29 giugno 2020): 1–18. http://dx.doi.org/10.1155/2020/4086320.
Testo completoAbstract (sommario):
Despite extensive research studies, the seismic response of infilled reinforced concrete buildings remains an open problem due to both the complexity of the interaction between the infill and the frame and the large number of parameters involved. Thus, guidelines for both modelling and analysis are still lacking and the infill walls are normally treated as nonstructural components in seismic codes. However, it may be not conservative to neglect the influence of infills. In fact, the infill masonry walls may significantly affect the stiffness, strength, and energy dissipation capacity of RC buildings, even when they are regularly distributed. Recognizing this influence and its importance on the vulnerability of infilled frames, Eurocode 8 requires amplifying seismic action effects due to infills. In this paper, the effectiveness of the Eurocode 8 design provisions for infill irregularity in plan and/or elevation was investigated. To this aim, different in-plan layouts of infill walls were selected as marginal cases for which Eurocode 8 does not require amplification of the action effects due to the presence of infills, or the additional measures to counteract these effects are not mandatory. The seismic vulnerability of the infilled RC buildings was evaluated using nonlinear static and nonlinear dynamic analyses. Both cracking and crushing of masonry and stiffness and strength degradation were considered in the analysis. The effect of the layout of the masonry infills on the seismic response in terms of resistance and displacement was evaluated. Results show that in one of the case studies here examined, it is not conservative to neglect the influence of infill panels. In fact, structural failure due to torsion and soft-storey effects may occur even in cases where Eurocode 8 does not require the amplification of the action effects. Finally, the total shear demand on columns may be underestimated, even in cases where the code provisions for infills irregularity are not mandatory, and the additional shear demand in the columns induced by the masonry infill is very low.
7
Wang, Xiaomin, Yuhan Su, Jingchang Kong, Maosheng Gong e Chunhui Liu. "The Over-Strength Coefficient of Masonry-Infilled RC Frame Structures under Bidirectional Ground Motions". Buildings 12, n. 9 (23 agosto 2022): 1290. http://dx.doi.org/10.3390/buildings12091290.
Testo completoAbstract (sommario):
The over-strength coefficient is one of the key factors for the seismic safety of a structure. For RC frames, the infill wall may improve the lateral bearing capacity, while the seismic demand increases as well, which leads to the unexpected seismic performance of an infilled RC frame in past earthquakes. Therefore, it is necessary to systematically study the over-strength effect of the infilled RC frames from the point of seismic capacity and demand. In this paper, 36 RC frame structures with/without infill walls are designed, and the corresponding finite element modelings, considering the in-plane and out-of-plane performance coupling effect of infill walls, are established to conduct incremental dynamic analyses (IDA). The seismic capacity values of over-strength coefficients are calculated, utilizing the IDA results under bidirectional ground motions. The effects of seismic precautionary intensity and number of stories on the over-strength coefficient of the RC frame with/without infill walls are discussed. The over-strength coefficient capacity value of the infilled frame is apparently higher than that of the bare frame, due to the contribution of infill walls. However, the seismic demand analysis of the over-strength coefficient shows that the capacity–demand ratio of masonry-infilled RC frame structures is greatly reduced, especially for the bottom soft-story infilled frame.
8
YUEN, Y. P., e J. S. KUANG. "MASONRY-INFILLED RC FRAMES SUBJECTED TO COMBINED IN-PLANE AND OUT-OF-PLANE LOADING". International Journal of Structural Stability and Dynamics 14, n. 02 (5 gennaio 2014): 1350066. http://dx.doi.org/10.1142/s0219455413500661.
Testo completoAbstract (sommario):
The structural responses of infilled frames subjected to combined in-plane and out-of-plane loadings are usually analyzed by separately applying in-plane and out-of-plane loads. The interaction effect of in-plane and out-of-plane loads on the structural behavior of the frames is ignored; thus errors in predicting the actual force-transfer mechanisms and modes of failure of the structures can be incurred. To solve the problem, this paper presents a discrete finite element modeling technique, which employs a damage-based cohesive crack representation of fracture behavior of masonry infills, followed by a study on the force-transfer mechanisms and failure modes of the anchored and unanchored infilled reinforced concrete (RC) frames subjected to interactive in-plane and out-of-plane loads. The analysis indicates that under out-of-plane loading the diagonal compressive thrust of masonry-infill walls, which is induced by in-plane lateral loading and acts on the walls, may reduce the in-plane load capacity of the RC frame by up to 50% and cause buckling of infill walls. On the other hand, the anchorage can effectively prevent the separation of infill walls from the bounding frame and provide stabilizing forces to the walls against buckling.
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Sattar, Siamak, e Abbie B. Liel. "Seismic Performance of Nonductile Reinforced Concrete Frames with Masonry Infill Walls—II: Collapse Assessment". Earthquake Spectra 32, n. 2 (maggio 2016): 819–42. http://dx.doi.org/10.1193/091514eqs141m.
Testo completoAbstract (sommario):
This paper quantifies the collapse performance of a set of masonry-infilled reinforced concrete (RC) frame buildings that are representative of 1920s-era construction in Los Angeles, California. These buildings have solid clay-brick infill walls and vary in height (2–8 stories), wall configuration (bare, partially, and fully infilled frames), and wall thickness (1–3 wythes). The buildings’ collapse behavior is assessed through dynamic analysis of nonlinear models. These models represent the walls by diagonal struts whose properties are developed from finite-element (FE) analyses, as described in the companion paper, and represent beam-columns with lumped-plasticity models. The results indicate that the presence of infill walls can increase the risk of collapse. The most collapse prone of the buildings considered are those with strong, heavy infill walls, which induce large force demands in the frame elements. The partially infilled frames, which have a soft and weak first story, also perform poorly.
10
Shendkar, Mangeshkumar R., Denise-Penelope N. Kontoni, Ercan Işık, Sasankasekhar Mandal, Pabitra Ranjan Maiti e Ehsan Harirchian. "Influence of Masonry Infill on Seismic Design Factors of Reinforced-Concrete Buildings". Shock and Vibration 2022 (27 febbraio 2022): 1–15. http://dx.doi.org/10.1155/2022/5521162.
Testo completoAbstract (sommario):
Infill walls are the most common separator panels in typical reinforced-concrete (RC) frame structures. It is crucial to investigate the influence of the infill walls on the earthquake behavior of RC frames. The load resistance of infill materials was often not taken into account in the designing phase, whereas the infill walls have significant contributions to the structural behavior under lateral and vertical loadings. A three-dimensional 4-story RC building is designed, and in order to make a realistic model, different infill walls configurations were taken into account with the openings in the infill. Four different models were created for structural analysis for infill wall effects, namely, full RC infilled frame (Model I), corner infill at ground story RC infilled frame (Model II), open ground story RC infilled frame (Model III), and bare RC frame (Model IV). Static adaptive pushover analysis has been performed for all structural models by using the SeismoStruct software. The double strut nonlinear cyclic model was used for modeling the infill walls. In this study, three different compressive strengths of infill walls are taken into consideration, and the effects on seismic design factors (namely, the response reduction factor, the ductility, the overstrength factor, and the deflection factor) are calculated. The obtained values of the response reduction factor (R) are compared with the given values in the BIS code. The results show that the R factors of all RC infilled frames are decreased when the compressive strength of the masonry infill reduces. However, the R values of bare frames are less than the corresponding values recommended in the BIS code. It is worth noting that the National Earthquake Hazards Reduction Program (NEHRP) provisions underestimate the deflection factors of the reinforced-concrete (RC) frames according to the evaluated deflection factors of the herein studied RC frames.
11
Guan, Min Sheng, Hong Biao Du, Wei Chen e Yu Hua Wu. "Seismic Performance of the Reinforced Concrete Frame Structures with Infilled Walls of Different Configuration". Applied Mechanics and Materials 580-583 (luglio 2014): 1458–62. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1458.
Testo completoAbstract (sommario):
Using the three-strut model, five types of frame structures, i.e., without infilled walls, with full infilled walls, without bottom-storey infilled walls, without middle-storey infilled walls and without top-storey infilled walls, were studied. The mode analysis and nonlinear time-history analysis were carried out on each model. In order to investigate the effects of infilled walls with different configurations on the seismic behavior of reinforced concrete frame structures, the structural periods, the ratio of Tt to T1 and the maximum interstorey drifts were analyzed. The results indicate that the infilled walls enhance the lateral stiffness of frames, and the configuration of infilled walls has little influence on the calculation of structural periods. It also shows that the weaker storey is formed due to the unreasonable layout of infilled walls, thus leading to the collapse of the whole structures under the seismic action.
12
Meng, Qing Li, Chun Yu Chu e Jun Chen. "The Study on Infilled Walls Effect in RC Frame Infilled Wall Structure". Applied Mechanics and Materials 353-356 (agosto 2013): 1783–90. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.1783.
Testo completoAbstract (sommario):
The seismic damage and even collapse of the infilled walls in RC frame infilled wall structure is the issue that needs thorough study, In this paper, firstly introduces the improved infilled wall model which can consider the interaction of in-plane and out-of-plane, and can judge the damage state of infilled walls, as well as the interaction between RC frame and infilled walls. Then, based on the finite element software OpenSees, under rare earthquake, performed the nonlinear numerical simulation of two finite element models-RC frame without infilled walls and RC frame with infilled walls, comparative analysis differences of both plastic hinge zone’s steel strain, drift and acceleration response, and in-depth study of the infilled walls effect in RC frame infilled wall structure and reason analysis.
13
Xu, Qinghu, Xuezhi Zhen, Yu Zhang, Mengjun Han e Wenkang Zhang. "Numerical Simulation Study of Progressive Collapse of Reinforced Concrete Frames with Masonry Infill Walls under Blast Loading". Modelling and Simulation in Engineering 2022 (11 novembre 2022): 1–16. http://dx.doi.org/10.1155/2022/1781415.
Testo completoAbstract (sommario):
The influence of masonry infill walls on the progressive collapse performance of reinforced concrete (RC) frame structures was investigated in this paper, using a nonlinear dynamic analysis approach. Based on ANSYS/LS-DYNA finite element software, two finite element models of RC frame structures with and without masonry infilled walls were established. Then, the collapse modes of the two RC frame structure models were analyzed for different scaled distance blast loads, different locations of column damage, and different span numbers. The results show that with the increase of explosive amount, the collapse degree of the structure is more serious in the same time. Under the condition of destroying the outermost central column, the degree of progressive collapse of the RC frame model with infilled walls in the same time is lower than that of the RC frame model without infilled walls. The RC frame model with infilled walls is more resistant to collapse when the outermost side columns are damaged. With the increase of span number, the structure is more likely to be damaged and collapsed.
14
Shendkar, Mangeshkumar R., Denise-Penelope N. Kontoni, Sasankasekhar Mandal, Pabitra Ranjan Maiti e Omid Tavasoli. "Seismic Evaluation and Retrofit of Reinforced Concrete Buildings with Masonry Infills Based on Material Strain Limit Approach". Shock and Vibration 2021 (5 aprile 2021): 1–15. http://dx.doi.org/10.1155/2021/5536409.
Testo completoAbstract (sommario):
The seismic evaluation and retrofit of reinforced concrete (RC) structures considering masonry infills is the correct methodology because the infill walls are an essential part of RC structures and increase the stiffness and strength of structures in seismically active areas. A three-dimensional four-storey building with masonry infills has been analyzed with nonlinear static adaptive pushover analysis by using the SeismoStruct software. Two models have been considered in this study: the first model is a full RC-infilled frame and the second model is an open ground storey RC-infilled frame. The infill walls have been modeled as a double strut nonlinear cyclic model. In this study, the “material strain limit approach” is first time used for the seismic evaluation of RC buildings with masonry infills. This method is based on the threshold strain limit of concrete and steel to identify the actual damage scenarios of the structural members of RC structures. The two models of the four-storey RC building have been retrofitted with local and global strengthening techniques (RC-jacketing method and incorporation of infills) as per the requirements of the structure to evaluate their effect on the response reduction factor (R) because the R-factor is an important design tool that shows the level of inelasticity in a structure. A significant increase in the response reduction factor (R) and structural plan density (SPD) has been observed in the case of the open ground storey RC-infilled frame after the retrofit. Thus, this paper aims to present a most effective way for the seismic evaluation and retrofit of any reinforced concrete structure through the material strain limit approach.
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Sakr, Mohamed, Saher R. El-khoriby, Ayman A. Seleemah e Essam A. Darwish. "FE Modeling of CFRP-Retrofitted RC Frames with Masonry Infill Walls". Civil Engineering Journal 3, n. 4 (30 aprile 2017): 267–87. http://dx.doi.org/10.28991/cej-2017-00000090.
Testo completoAbstract (sommario):
A number of numerical and experimental studies have been reported in recent literature to investigate the effects of infill walls on the seismic response of RC infilled frames. Many experimental studies used CFRP sheets as an external bracing system for retrofitting the infilled RC frames. It has been found that the common mode of failure of such retrofitted frames is the debonding of the CFRP-concrete adhesive material. In the current study, the behaviour of CFRP retrofitted infilled RC frames was investigated with a finite element micro model. In that model, a four-node shell element was used for modeling the concrete, infill panel and CFRP sheets. The interaction between concrete frame and infill panel was modelled using contact surfaces to allow the occurrence of separation and prevent penetration. Nonlinearities of the concrete, infill panel, steel and CFRP sheets were considered. To allow the occurrence of debonding mode of failure, the adhesive layer was modelled using cohesive surface-to-surface interaction model, which assumes that the failure of cohesive bond is characterized by progressive degradation of the cohesive stiffness, which is driven by a damage process based on the fracture energy. The proposed model was verified using experimental results from the literature. Results indicated that the cohesive model could capture the debonding mode of failure which has been observed experimentally. The validated micro model was used to investigate the effects of the strip end area, the anchor location and partial bonding of the CFRP sheet to the infill panel surface on the behaviour of infilled frames. The results of parametric study showed that, to get the highest efficiency of the CFRP retrofitted infilled frame, bonding about 25% only of the diagonal length from each end is sufficient to get the same behaviour of the totally bonded sheet.
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Karodi, Rashi. "Comparative Study of Seismic Analysis of R.C.C. Framed Structure with Full Infilled walls, without Infilled walls and Partially Infilled walls". International Journal for Research in Applied Science and Engineering Technology 7, n. 2 (28 febbraio 2019): 646–49. http://dx.doi.org/10.22214/ijraset.2019.2089.
Testo completo
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Han, Sang Whan, e Chang Seok Lee. "Cyclic behavior of lightly reinforced concrete moment frames with partial- and full-height masonry walls". Earthquake Spectra 36, n. 2 (20 febbraio 2020): 599–628. http://dx.doi.org/10.1177/8755293019899960.
Testo completoAbstract (sommario):
Existing lightly reinforced concrete (RC) moment frames are vulnerable to earthquakes. The seismic behavior of these frames could be affected by the presence of masonry infill walls. The objective of this study was to investigate the seismic behavior of gravity-designed RC frames having partial- and full-height masonry infill walls. For this purpose, experimental and numerical studies were conducted. Three one-story and one-bay gravity-designed RC moment frames with and without partial- and full-height masonry infill walls were made and tested under cyclic lateral loads. Numerical models for RC moment frames and masonry walls were proposed based on test data. Nonlinear static and incremental dynamic analyses (IDAs) were conducted for three-story RC moment frames with and without partial- and full-height masonry infill walls using the numerical models. Both experimental and numerical studies demonstrated that the masonry-infilled RC frames had larger lateral strength and stiffness than bare RC frames, whereas their drift capacity was less than that of bare frames. The partial-height masonry-infilled RC model frame had the least collapse strength among the frames.
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Mondal, Goutam, e Sudhir K. Jain. "Lateral Stiffness of Masonry Infilled Reinforced Concrete (RC) Frames with Central Opening". Earthquake Spectra 24, n. 3 (agosto 2008): 701–23. http://dx.doi.org/10.1193/1.2942376.
Testo completoAbstract (sommario):
Window and door openings are inevitable parts of infill walls for functional reasons. Currently, publications like FEMA-273 and ATC-40 contain provisions for the calculation of stiffness of solid infilled frames mainly by modeling infill as a “diagonal strut.” However, such provisions are not provided for infilled frames with openings. The present study proposes a reduction factor for effective width of diagonal strut over that of the solid reinforced concrete (RC) infilled frame to calculate its initial lateral stiffness when a central window opening is present. The study is based on initial lateral stiffness which is taken at 10% of the lateral strength of the infilled frames.
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Ren, Wen Jie, Zhi Cheng Ma e Zhi Qiang Wang. "Research on Seismic Behavior of Infilled Frame Structure". Applied Mechanics and Materials 256-259 (dicembre 2012): 2148–51. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2148.
Testo completoAbstract (sommario):
The infilled frame structure is a kind of structural system used widely in the industrial and civil building. Although the infill walls are no-load-bearing components, the walls are also subjected to some earthquake actions. During some domestic and foreign large earthquakes in recent years, the infill wall were destroyed seriously and the frame were destroyed lightly. The damage of the infill wall not only influences the application of the building, but also increases repair costs for restoring the building, seriously, even endangers the life safety. This paper analyzes the influence of the connection method between the infill wall and the frame on the seismic behaviors of the infilled frame structure. Finally, some new technologies to protect the infill wall and the frame from damage under earthquake are introduced.
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Zhou, Xiaojie, Xiaoyuan Kou, Quanmin Peng e Jintao Cui. "Influence of Infill Wall Configuration on Failure Modes of RC Frames". Shock and Vibration 2018 (25 giugno 2018): 1–14. http://dx.doi.org/10.1155/2018/6582817.
Testo completoAbstract (sommario):
An improper configuration of masonry infill walls in RC frame may lead to short column effect on the columns, which is harmful to the seismic behavior of the structure. In this study, a bare frame and two single-story, single-bay RC frames, partially infilled with masonry, were tested under cyclic loading. The failure mechanism and seismic performance of these partially infilled RC frames (with an infill height of 600 mm) with different types of connections were analysed. Based on the experiment, nonlinear finite element simulation and analysis were conducted to study the effects of the infill walls and connections. The results show that both mechanical performance and failure mode are affected by the infill height, the type of connection between the frame and the infill, and the ratio of shear bearing capacity of the frame column to that of the infill. For the masonry-infilled frame with rigid connection, the higher the infill wall is, the lower the shear bearing capacity ratio will be. Thus, the effect of the lateral constraint of the infill wall on the column increases, and the shear span ratio of the free segment of the column decreases, resulting in the short column effect. Based on the analysis results, a value of 2.0 is suggested for the critical shear bearing capacity ratio of the frame column to the infill wall. If the shear bearing capacity ratio is less than 2.0 and the shear span ratio of the column free segment is not more than 2.0, the short column effect will occur. For the infilled frame with flexible connection, both the lateral constraint from the wall to the column and the wall-frame interaction decrease; this reduces or prevents the short column effect. The conclusion can present guidance for the design and construction of masonry-infilled RC frame structure.
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Xu, Wen Xuan, Qi Bao, Zhan Li e Jun Yu Fan. "Numerical Analysis on the Behavior of Autoclaved Aerated Concrete Block Infilled Wall Subjected to Gas Explosion". Applied Mechanics and Materials 723 (gennaio 2015): 259–65. http://dx.doi.org/10.4028/www.scientific.net/amm.723.259.
Testo completoAbstract (sommario):
As a common threat to the public safety, gas explosion and its damage on structures have drawn more and more attention in the academic fields. In this paper, a series of numerical simulations are conducted to study the behavior of autoclaved aerated concrete block infilled walls under gas explosion loading. Firstly, considering the difference between the blocks and the mortar, a refined numerical model is established, and the constitutive model of Brittle Damage in LS-DYNA is hired to describe the material behaviours of both materials. Based on the laboratory material test data, the parameter of the material model are selected reasonably. Then, massive numerical calculation is carried out and the dynamic response of autoclaved aerated concrete block infilled walls is captured and discussed. At last, the anti-blast ability of block infilled walls is compared with that of clay infilled wall of the same thickness. It is found that the anti-blast ability of block infilled walls is weaker than the clay infilled walls for the difference of material density and boundary conditions.
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Gong, Xiao Ying, e Jun Wu Dai. "Nonlinear Seismic Analysis of Masonry Infilled RC Frame Structures". Applied Mechanics and Materials 117-119 (ottobre 2011): 288–94. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.288.
Testo completoAbstract (sommario):
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.
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Arumugam, Vijayakumar, Lakshmi Keshav, Aravindan Achuthan e Somashekar Dasappa. "Seismic Evaluation of Advanced Reinforced Concrete Structures". Advances in Materials Science and Engineering 2022 (16 maggio 2022): 1–8. http://dx.doi.org/10.1155/2022/4518848.
Testo completoAbstract (sommario):
Many reinforced concrete frame buildings were developed and constructed in Coimbatore zone III before 2002. In 2002, the seismic code IS 1893 was updated. As a result, structures constructed earlier in 2002 do not meet the codal criterion. The majority of structures through infilled walls were nondesigned with infills in consideration. This paper goals to appraise seismic exposure of an advanced reinforced present concrete building with infilled and without infilled frames. A pushover analysis was used to conduct this analysis. According to ATC40, the analysis shows the comportment levels of several building components for various stated concert objectives.
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Yakut, Ahmet, e Ismail Ozan Demirel. "Influence of Clay Tile Brick Infill Walls on Seismic Response of Buildings". Advanced Materials Research 747 (agosto 2013): 273–76. http://dx.doi.org/10.4028/www.scientific.net/amr.747.273.
Testo completoAbstract (sommario):
Majority of buildings in Turkey and in most developing countries are made with reinforced concrete frames infilled with clay tile brick walls. Despite this, influence of these walls is not accounted for in design. Past earthquake observations have shown that the infill walls have great influence on performance of buildings. In this paper, influence of the brick infill walls on strength and stiffness of RC buildings are presented through analytical results obtained for some typical buildings. Comparison of results showed that stiffness of the walls and their capacity is greatly influenced by the infill walls. The change in the strength and stiffness has been based on ratio of the wall area to the total floor area with providing expressions to determine these.
25
Hu, Peifang, Yong Liu, Jingfeng Wang, Wanqian Wang e Guangdong Pan. "Experimental Investigation and Numerical Analyses on Cyclic Behavior of the Prefabricated Concrete Frame Infilled with CFS-CLPM Composite Walls". Buildings 12, n. 11 (16 novembre 2022): 1991. http://dx.doi.org/10.3390/buildings12111991.
Testo completoAbstract (sommario):
A novel CFS composite wall filled with cement-based lightweight polymer material (CFS-CLPM composite wall) has been proposed and proven to have excellent architectural and mechanical performance. To promote its application in prefabricated concrete (PC) frame structures, two full-scale specimens were designed and tested under cyclic loading to investigate the failure mode, hysteretic response and energy dissipation of the PC frame infilled with the CFS-CLPM composite wall. The experimental results indicated that CFS-CLPM composite walls can significantly improve the lateral behavior of the PC frame in terms of load capacity, elastic stiffness and energy dissipation capacity, while slightly reducing its ductility because of the infill-frame interaction. Subsequently, finite element (FE) analyses for the PC frame infilled with CFS-CLPM composite walls were developed and verified against the experimental results. The force-transferring mechanisms between the PC frame and the CFS-CLPM composite walls were revealed by analyzing the stress distributions. The parametric analyses demonstrated that the influential parameters for lateral resistances of the PC frame structure infilled with CFS-CLPM composite walls were the strength of CLPM, the span-to-height ratio and the thickness of CFS-CLPM composite walls. Finally, a formula considering the mechanical contribution of the CFS-CLPM composite wall was proposed to predict the elastic lateral stiffness of the structures. The results of this study could provide a basis for the application of CFS-CLPM composite walls in PC frame structures.
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Candigliota, Elena, e Alain Le Maoult. "Rc Infilled Frame: Shaking Table Tests on a Full Scale Model". Key Engineering Materials 347 (settembre 2007): 285–90. http://dx.doi.org/10.4028/www.scientific.net/kem.347.285.
Testo completoAbstract (sommario):
Tests on shaking table have been carried out on a 3D full scale infilled r.c. frame specimen (55 tons). These tests have been performed by the EMSI Laboratory of C.E.A. Saclay (France) together with a research team of the Universities of Chieti-Pescara (Italy), Roma Tre (Italy) and Patras (Greece). These tests are included in Ecoleader European research program. Many characterization tests of infill components (mortar and bricks) have been performed in the SCAM Laboratory of the University of Chieti-Pescara while tests on masonry walls were made in the laboratory of University of Rome 3. The structure represents the first floor of a two floors frame structure previously tested. The mockup is a full-scale one storey rc infilled frame with four columns, 3 meters high, with about 4 meters side square floor and infilled with double bricks wall. The main aim is to get information about the behavior of real structures. The instrumentation with about one hundred channels was set up to measure the rc frame response and the different behavior of the double walls during the tests. First, monodirectional and bidirectional tests at low seismic intensity (0.10 g and 0.15 g PGA levels) have been performed on the bare frame in order to characterize its structural characteristics and to check the design provisions. Then, the bare frame has been infilled and other tests have carried out at increasing seismic intensity in order to define its serviceability and ultimate limit states. Monodirectional and bidirectional tests up to 0.45 g PGA level were carried out. The last sequence included a monodirectional test on the infilled frame with only two walls. The high seismic input (0.55 g PGA level) was parallel to the direction of the walls. In this paper, research program and some main test results are presented.
27
Kawan, Chandra Kiran. "Effect of stiffeners in lateral stiffness of masonry infill reinforced concrete (RC) frames". Journal of Science and Engineering 3 (1 dicembre 2015): 7–20. http://dx.doi.org/10.3126/jsce.v3i0.22383.
Testo completoAbstract (sommario):
Infilled frames are reinforced concrete frames with masonry infill. The provision of masonry walls as infill increases the lateral stiffness of frame. Unreinforced masonry infill effects the strength and stiffness of frame but being ignored for a long time. The main objective of this paper is to study the individual and combined effect of infill masonry wall, stiffeners and wooden frame in the lateral stiffness of infill reinforced concrete frame with central opening, with and without gap element consideration. From the analysis using SAP software, it is observed that with increase in openings, stiffness decreases but introducing stiffeners and wooden frame increases the lateral stiffness. Embedding the gap element as the boundary condition reduces the stiffness of the infilled frame. Numerical investigations are carried out by finite element modeling for analyzing the behavior of infilled frame. The single equivalent diagonal strut width was determined by obtaining the same lateral stiffness from finite element model, and also strut reduction factor for different conditions with central openings are proposed.
28
Mosalam, Khalid M. "1996 EERI Student Paper Award Modeling of the Nonlinear Seismic Behavior of Gravity Load Designed Frames". Earthquake Spectra 12, n. 3 (agosto 1996): 479–92. http://dx.doi.org/10.1193/1.1585894.
Testo completoAbstract (sommario):
Evaluating and, if necessary, retrofitting seismically loaded Gravity Load Designed (GLD) infilled frames requires accurate analytical models. This paper gives an overview of experimental and analytical investigations conducted on GLD steel frames infilled with unreinforced concrete block masonry walls. The presented analytical models can reasonably predict the seismic response of such structures. The experimental study adopts both quasi-static and pseudo-dynamic methods. Detailed finite element models and a more practical compression-only strut model for the infills are the analytical tools considered in the present study.
29
Arslan, Mehmet Emin, Ahmet Durmuş e Metin Hüsem. "Cyclic behavior of GFRP strengthened infilled RC frames with low and normal strength concrete". Science and Engineering of Composite Materials 26, n. 1 (28 gennaio 2019): 30–42. http://dx.doi.org/10.1515/secm-2017-0060.
Testo completoAbstract (sommario):
AbstractThis paper presents the experimental behavior of plane, non-strengthened and glass fiber reinforced polymer (GFRP) strengthened infilled reinforced concrete (RC) frames with low strength concrete (LSC) and normal strength concrete (NSC) under lateral reversed cyclic loading. For this purpose, eight full-scale, one-bay, one-storey plane and infilled (brick and aerated concrete blocks which are commonly used in RC construction) RC frames with LSC and NSC were produced and in-plane lateral loading tests were carried out. Test results indicate that infill walls considerably change the behavior of frames by increasing rigidity and load carrying capacity. By contrast, GFRP fabric used for strengthening of infilled RC frames improves ductility, load carrying and energy dissipation capacity of infilled frames with LSC and NSC as well. After all the test results were evaluated together, a GFRP strengthened brick infilled frame demonstrated the best performance under cyclic lateral loading.
30
ALVA, G. M. S., J. KAMINSKI Jr, G. MOHAMAD e L. R. SILVA. "Serviceability limit state related to excessive lateral deformations to account for infill walls in the structural model". Revista IBRACON de Estruturas e Materiais 8, n. 3 (giugno 2015): 390–426. http://dx.doi.org/10.1590/s1983-41952015000300008.
Testo completoAbstract (sommario):
Brazilian Codes NBR 6118 and NBR 15575 provide practical values for interstory drift limits applied to conventional modeling in order to prevent negative effects in masonry infill walls caused by excessive lateral deformability, however these codes do not account for infill walls in the structural model. The inclusion of infill walls in the proposed model allows for a quantitative evaluation of structural stresses in these walls and an assessment of cracking in these elements (sliding shear diagonal tension and diagonal compression cracking). This paper presents the results of simulations of single-story one-bay infilled R/C frames. The main objective is to show how to check the serviceability limit states under lateral loads when the infill walls are included in the modeling. The results of numerical simulations allowed for an evaluation of stresses and the probable cracking pattern in infill walls. The results also allowed an identification of some advantages and limitations of the NBR 6118 practical procedure based on interstory drift limits.
31
Jia, Yigang, Guangyu Wu, Yaxi Zhong, WenGuo Ren, Cheng Yu e Bao Wan. "Nonlinear Simulation Analysis on Loaded-Bearing Performance of Multistory Infilled R.C. Frame Structure with Openings Under Horizontal Force". Journal of Computational and Theoretical Nanoscience 14, n. 1 (1 gennaio 2017): 497–504. http://dx.doi.org/10.1166/jctn.2017.6351.
Testo completoAbstract (sommario):
The influence of infill walls on the mechanical property of RC frame structures is distinct, the rational lateral stiffness of infilled frame structures and the design method of filler wall which are considered in resistance urgently need to be discussed. A group of single-span single-story infilled frame models (three) are nonlinear simulation analyzed by using ANSYS program, and verify the results of ANSYS by comparing with their experimental results. Then, establish a group of single-span three-stories infilled frame models (seven) with different opening sizes and different opening locations to simulate and analyze the lateral performance of multistory infilled frame structure with openings. And the following conclusions are drawn: the frame beam is in the unfavorable condition of “short beam sheared” with the existence of the openings in up and down stories; the lower the location of story is, the bigger the lateral stiffness of infilled frame is, and the quicker the degradation speed of stiffness is and so on.
32
Saengyuan, Saharat, e Panon Latcharote. "Investigation of Seismic Performance for Low-Rise RC Buildings with Different Patterns of Infill Walls". Buildings 12, n. 9 (1 settembre 2022): 1351. http://dx.doi.org/10.3390/buildings12091351.
Testo completoAbstract (sommario):
Evaluating the structural performance of low-rise RC buildings with infill walls is an essential issue in Thailand, as most infill walls were not designed for lateral load resistance. The purpose of this study was to predict the structural behavior and illustrate the effects of infill walls. Residential, commercial, and educational buildings were selected as representative buildings with different patterns of infill walls. Based on the results, infill walls contributed to considerable strength and stiffness. Most of the infill walls that affected the low-rise buildings were at the ground floor level. The behavior of the buildings that had a contribution of infill walls was found to be brittle until the infill walls collapsed, and then the buildings became ductile. Some patterns in which infill walls were placed improperly led to a torsional effect, resulting in columns in the affected areas reaching failure criteria more than those without this effect. Considering the NLRHA procedure, only infill walls on the ground floor contributed to the building being subjected to a ground motion. The fully infilled frame tended to reach the infill crack before the other patterns. For the UMRHA procedure, only the first vibration mode was adequate to predict seismic responses, such as roof displacement and top-story drift.
33
Asteris, Panagiotis G., Athanasios K. Tsaris, Liborio Cavaleri, Constantinos C. Repapis, Angeliki Papalou, Fabio Di Trapani e Dimitrios F. Karypidis. "Prediction of the Fundamental Period of Infilled RC Frame Structures Using Artificial Neural Networks". Computational Intelligence and Neuroscience 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/5104907.
Testo completoAbstract (sommario):
The fundamental period is one of the most critical parameters for the seismic design of structures. There are several literature approaches for its estimation which often conflict with each other, making their use questionable. Furthermore, the majority of these approaches do not take into account the presence of infill walls into the structure despite the fact that infill walls increase the stiffness and mass of structure leading to significant changes in the fundamental period. In the present paper, artificial neural networks (ANNs) are used to predict the fundamental period of infilled reinforced concrete (RC) structures. For the training and the validation of the ANN, a large data set is used based on a detailed investigation of the parameters that affect the fundamental period of RC structures. The comparison of the predicted values with analytical ones indicates the potential of using ANNs for the prediction of the fundamental period of infilled RC frame structures taking into account the crucial parameters that influence its value.
34
Furtado, André, e Maria Teresa de Risi. "Recent Findings and Open Issues concerning the Seismic Behaviour of Masonry Infill Walls in RC Buildings". Advances in Civil Engineering 2020 (13 marzo 2020): 1–20. http://dx.doi.org/10.1155/2020/9261716.
Testo completoAbstract (sommario):
The extension of the damages observed after the last major earthquakes shows that the seismic risk mitigation of infilled reinforced concrete structures is a paramount topic in seismic prone regions. In the assessment of existing structures and the design of new ones, the infill walls are considered as nonstructural elements by most of the seismic codes and, generally, comprehensive provisions for practitioners are missing. However, nowadays, it is well recognized by the community the importance of the infills in the seismic behaviour of the reinforced concrete structures. Accurate modelling strategies and appropriate seismic assessment methodologies are crucial to understand the behaviour of existing buildings and to develop efficient and appropriate mitigation measures to prevent high level of damages, casualties, and economic losses. The development of effective strengthening solutions to improve the infill seismic behaviour and proper analytical formulations that could help design engineers are still open issues, among others, on this topic. The main aim of this paper is to provide a state-of-the-art review concerning the typologies of damages observed in the last earthquakes where the causes and possible solutions are discussed. After that, a review of in-plane and out-of-plane testing campaigns from the literature on infilled reinforced concrete frames are presented as well as their relevant findings. The most common strengthening solutions to improve the seismic behaviour are presented, and some examples are discussed. Finally, a brief summary of the modelling strategies available in the literature is presented.
35
Hadad, Hadad S., Ibrahim M. Metwally e Sameh El-Betar. "Cyclic Behavior of Braced Concrete Frames: Experimental Investigation and Numerical Simulation". Building Research Journal 61, n. 2 (1 marzo 2015): 101–14. http://dx.doi.org/10.2478/brj-2014-0008.
Testo completoAbstract (sommario):
Abstract RC shear walls have been widely used as the main lateral-load resisting system in medium and high-rise buildings because of their inherent large lateral stiffness and load resistance. But, in general, the energy dissipating capacity of RC shear walls is not very good and it has been found that using the bracing system gives good results. The main purpose of this paper is to study the effect of different types of bracing on the lateral load capacity of the frame. Also, the research contains a comparison between the braced and infilled frames to decide on the best system. The research scheme consists of four frames; the bare frame, two frames the first of which was braced with concrete, the second was braced with steel bracing and the fourth frame was infilled with solid cement bricks. All the specimens were tested under cyclic loading. The results gave some important conclusions; braced and infilled bare frames increased the lateral strength of the bare frame depending on the type of bracing and infill. Also, the different types of bracing and the infill increased the initial stiffness of the bare frame by a reasonable value. The energy dissipation for the braced and infilled frames is always higher than that for the bare frame up to failure. Also, numerical modeling was carried out with the nonlinear software platform (IDARC). The numerical results obtained with the calibrated nonlinear model are presented and compared with the experimental results. Good agreement was achieved between the numerical simulation and the test results.
36
Meng, Qing Li, Jun Chen e Chun Yu Chu. "The Passive Control Seismic Strengthen about RC Frame Infilled Wall Structure". Applied Mechanics and Materials 405-408 (settembre 2013): 1056–62. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1056.
Testo completoAbstract (sommario):
In this paper, a four-storey reinforced concrete frame infilled wall structure does not meet the seismic perform target, based on the seismic behavior target of both frame and infilled wall, to carry out the study on the passive control seismic strengthen of RC infilled wall structure with attached dampers. First, two kinds of passive control strengthen schemes were put forward. Scheme 1: Dampers were installed in the in-plane direction parallel with all 1-storey infilled walls; Scheme 2: Dampers were installed in the in-plane direction parallel with all 1-storey and 2-storey infilled walls. Then to establish the two types of passive control seismic strengthen model in OpenSees, carry out the rare earthquake nonlinear time-history analysis under El Centro, Parkfield and San Fenando ground motions. Finally, in accordance with the seismic performance target quantization index of RC Frame infilled wall structure used as hospital, i.e. considering storey drift ratio limit and infilled wall damage, judge the scheme 2 can meets the seismic performance target.
37
Abdelaziz, Mohamed Magdi, Mohamed Sayed Gomma e Hany El-Ghazaly. "Seismic evaluation of reinforced concrete structures infilled with masonry infill walls". Asian Journal of Civil Engineering 20, n. 7 (18 giugno 2019): 961–81. http://dx.doi.org/10.1007/s42107-019-00158-6.
Testo completo
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Zine, Ali, Abdelkrim Kadid e Abdallah Zatar. "Effect of Masonry Infill Panels on the Seismic Response of Reinforced Concrete Frame Structures". Civil Engineering Journal 7, n. 11 (1 novembre 2021): 1853–67. http://dx.doi.org/10.28991/cej-2021-03091764.
Testo completoAbstract (sommario):
The present work concerns the numerical investigation of reinforced concrete frame buildings containing masonry infill panel under seismic loading that are widely used even in high seismicity areas. In seismic zones, these frames with masonry infill panels are generally considered as higher earthquake risk buildings. As a result there is a growing need to evaluate their level of seismic performance. The numerical modelling of infilled frames structures is a complex task, as they exhibit highly nonlinear inelastic behaviour, due to the interaction of the masonry infill panel and the surrounding frame. The available modelling approaches for masonry infill can be grouped into two principal types; Micro models and Macro models. A two dimensional model of the structure is used to carry out non-linear static analysis. Beams and columns are modelled as non-linear with lumped plasticity where the hinges are concentrated at both ends of the beams and the columns. This study is based on structures with design and detailing characteristics typical of Algerian construction model. In this regard, a non-linear pushover analysis has been conducted on three considered structures, of two, four and eight stories. Each structure is analysed as a bare frame and with two different infill configurations (totally infilled, and partially infilled). The main results that can be obtained from a pushover analysis are the capacity curves and the distribution of plastic hinges in structures. The addition of infill walls results in an increase in both the rigidity and strength of the structures. The results indicate that the presence of non-structural masonry infills can significantly modify the seismic response of reinforced concrete "frames". The initial rigidity and strength of the fully filled frame are considerably improved and the patterns of the hinges are influenced by structural elements type depending on the dynamic characteristics of the structures. Doi: 10.28991/cej-2021-03091764 Full Text: PDF
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Balik, Fatih Suleyman, Hasan Husnu Korkmaz, Mehmet Kamanli, Fatih Bahadir, Serra Zerrin Korkmaz e Alptug Unal. "An Experimental Study on Reinforced Concrete Infilled Frames with Openings". Advanced Materials Research 747 (agosto 2013): 429–32. http://dx.doi.org/10.4028/www.scientific.net/amr.747.429.
Testo completoAbstract (sommario):
In the last decade, seven major earthquakes caused significant casualties and extensive structural failures. Thousands of RC buildings were severely damaged or collapsed in Turkey due to various deficiencies. This has initiated experimental studies on strengthening methods and intensive researches regarding the rehabilitation of reinforced concrete structures by introducing reinforced concrete infill walls were carried out. Strengthening of reinforced concrete frames by cast-in-place reinforced concrete infills is commonly used in practice. Many structures were also repaired using this technique after the recent earthquakes. In this experimental research, six, one-bay/two-story, 1/3-scaled non-ductile, undamaged reinforced concrete (RC) frames were constructed and tested to investigate the behavior of frames strengthened by introducing infills with or without openings. The test specimens were subjected to reversed cyclic quasi-static lateral loading. The specimens were constructed with the most commonly observed deficiencies in residential RC buildings in Turkey. The first specimen was the reference bare specimen and contained no strengthening. The other specimens were infilled with RC panels with openings having different ratios and configurations. Strength, stiffness and storey drifts of the test specimens were measured and compared. Test results indicated that infilled RC frames displayed significantly higher lateral strength and stiffness than the non-ductile bare frame considerably.
40
Xi, Kailin, e Boquan Liu. "Seismic Performance and Finite Element Analysis of Reinforced Concrete Frames Considering a Masonry-Infilled Wall". Advances in Materials Science and Engineering 2022 (10 ottobre 2022): 1–16. http://dx.doi.org/10.1155/2022/6832624.
Testo completoAbstract (sommario):
This study investigated the seismic performance of a 1/3 scale, three-story, and three-span RC frame subjected to static cyclic lateral loading. The failure process and mode were analyzed using the digital image correlation (DIC) method. Based on the test, finite element (FE) models were developed and verified. Using the proposed FE models, the parametric study was performed to investigate the influence of the opening rate, the position of infill walls, and the block strength on the seismic performance of the frame. Test results indicated that FE simulation results are correspondent to the testing results. The infilled wall increased the horizontal bearing capacity of the structure and the energy dissipation capacity. The opening masonry-infilled wall reduced the energy consumption capacity and the initial stiffness of the structure. Removing the infill walls on the first floor would change the failure mode of the frame. Improving the block strength could improve the bearing capacity of frames but has little effect on the energy dissipation capacity of the frame.
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Furtado, André, Hugo Rodrigues e António Arêde. "Effect of the Openings on the Seismic Response of an Infilled Reinforced Concrete Structure". Buildings 12, n. 11 (18 novembre 2022): 2020. http://dx.doi.org/10.3390/buildings12112020.
Testo completoAbstract (sommario):
The seismic behavior of the infill masonry infill walls has a significant impact on the global response of reinforced concrete frame structures. One factor influencing its behavior is the existence of openings in the walls, such as doors and windows, which are crucial for the infill seismic performance. Although the numerical simulation of the seismic behavior of RC buildings with infill walls has evolved significantly in recent years in terms of micro- and macro-modelling, most of the existing studies are only related to infill walls without openings. Based on this motivation, four main objectives were defined for this research work: (i) present a simplified modeling approach and its calibration to simulate the seismic behavior of infill walls with central openings such as windows; (ii) evaluate the impact of the openings on the global seismic response of an RC building; (iii) study the impact of the irregular distribution of the infill walls (vertical and in-plane) on the global seismic response of an RC building; and (iv) study the impact of the central openings ratio (i.e., relative percentage between opening and infill wall area) on the global seismic response of an RC building structure. A four-story infilled RC building was used as a case study to perform parametric analyses investigating the impact of the masonry infill walls’ irregular distribution (vertical and in-plan) and their openings ratio. The results are discussed in terms of natural frequencies and vibration modes, initial lateral stiffness, and maximum lateral resistance. This study found that the openings caused a reduction in the natural frequencies of about 20% compared with the full infill (without openings). The openings did not modify the vibration modes. In addition, the openings reduced the initial stiffness by about 20% compared with the model without openings. The maximum strength increased about 50% with the infill walls, but this was reduced by the openings by 20%.
42
Sarhosis, V., K. D. Tsavdaridis e I. Giannopoulos. "Discrete Element Modelling of Masonry Infilled Steel Frames with Multiple Window Openings Subjected to Lateral Load Variations". Open Construction and Building Technology Journal 8, n. 1 (11 luglio 2014): 93–103. http://dx.doi.org/10.2174/1874836801408010093.
Testo completoAbstract (sommario):
Steel framed structures are routinely infilled with masonry or concrete walls. The infill offers in-plane shear resistance that adds to the one from the steel frame. However, the stiffness effect on the entire frame’s response is usually neglected. In recent years, researchers have recognised the lack of in-depth understanding on infilled steel frames; hence specialised computational tools have been developed to provide an easy way of assessing these interactive structural systems and aid practising engineers in evaluating the overall behaviour. A computational model to study the behaviour of masonry infilled steel frames for the non-standard case of variable potential positions of openings and their interaction, when subjected to in-plane monotonic loading, is herein developed. Using the Discrete Element Method (DEM) and the software UDEC, the masonry wall is modelled as an assemblage of distinct deformable blocks while the mortar joints as zero thickness interfaces. The numerical model validated against full scale experimental tests found in the literature and a good agreement obtained. In addition, a series of parametric studies were performed to draw the significance of the size and location of the openings on the lateral load capacity, as well as the stiffness and failure mechanisms of the infilled steel frames.From the results analyses, it was found that the inclusion of multiple openings significantly reduces the strength and stiffness of the system. In particular, placing an opening close to the point of application of the lateral load will result to further reduction of masonry infill’s stiffness.
43
Rashidi, Maria, Pejman Sharafi, Mohammad Alembagheri, Ali Bigdeli e Bijan Samali. "Operational Modal Analysis, Testing and Modelling of Prefabricated Steel Modules with Different LSF Composite Walls". Materials 13, n. 24 (20 dicembre 2020): 5816. http://dx.doi.org/10.3390/ma13245816.
Testo completoAbstract (sommario):
The modal properties of modular structures, such as their natural frequencies, damping ratios and mode shapes, are different than those of conventional structures, mainly due to different structural systems being used for assembling prefabricated modular units onsite. To study the dynamic characteristics of modular systems and define a dynamic model, both the modal properties of the individual units and their connections need to be considered. This study is focused on the former aspect. A full-scale prefabricated volumetric steel module was experimentally tested using operational modal analysis technique under pure ambient vibrations and randomly generated artificial hammer impacts. It was tested in different situations: [a] bare (frame only) condition, and [b] infilled condition with different configurations of gypsum and cement-boards light-steel framed composite walls. The coupled module-wall system was instrumented with sensitive accelerometers, and its pure and free vibration responses were synchronously recorded through a data acquisition system. The main dynamic characteristics of the module were extracted using output-only algorithms, and the effects of the presence of infill wall panels and their material are discussed. Then, the module’s numerical micromodel for bare and infilled states is generated and calibrated against experimental results. Finally, an equivalent linear strut macro-model is proposed based on the calibrated data. The contribution of this study is assessing the effects of different infill wall materials on the dynamic characteristics of modular steel units, and proposing simple models for macro-analysis of infilled module assemblies.
44
Bahreini, Vahid, Tariq Mahdi e MohammadMahdi Najafizadeh. "Numerical Study on the In-Plane and Out-of-Plane Resistance of Brick Masonry Infill Panels in Steel Frames". Shock and Vibration 2017 (2017): 1–16. http://dx.doi.org/10.1155/2017/8494657.
Testo completoAbstract (sommario):
Masonry infill walls are one of the main forms of interior partitions and exterior walls in many parts of the world. Nevertheless, serious damage and loss of stability of many masonry infill walls had been reported during recent earthquakes. To improve their performance, the interaction between these infill walls and the bounding frames needs to be properly investigated. Such interaction can dramatically increase the stiffness of the frame in the in-plane direction. To avoid the negative aspects of inappropriate interactions between the frame and infill wall, some kind of isolation needs to be introduced. In this paper, three different configurations have been evaluated by using the general finite element software, ABAQUS. Nonlinear pushover and time history analyses have been conducted for each of the three configurations. Results showed that isolation of the infill from the frame has a significant effect on the in-plane response of infilled frames. Furthermore, adequate out-of-plane stability of the infill wall has been achieved. The results show that masonry infill walls that have full contact at the top of the wall but isolated from columns have shown acceptable performance.
45
Moniuddin, Md Khaja, G. Vasanthalakshmi, K. Chethan e R. Ramesh Babu. "Dynamic Characteristics of a Model and Prototype for 3D-RC Structure". Slovak Journal of Civil Engineering 24, n. 2 (1 giugno 2016): 23–30. http://dx.doi.org/10.1515/sjce-2016-0009.
Testo completoAbstract (sommario):
Abstract Infill walls provide durable and economical partitions that have relatively excellent thermal and sound insulation with high fire resistance. Monolithic infilled walls are provided within RC structures without being analyzed as a combination of concrete and brick elements, although in reality they act as a single unit during earthquakes. The performance of such structures during earthquakes has proved to be superior in comparison to bare frames in terms of stiffness, strength and energy dissipation. To know the dynamic characteristics of monolithic infill wall panels and masonry infill, modal, response spectrum and time history analyses have been carried out on a model and prototype of a 3D RC structure for a comparative study.
46
Jin, Huan. "Comparative Study on the Effects of Infill Walls on Reinforced Concrete Frame Structures". Applied Mechanics and Materials 730 (gennaio 2015): 81–84. http://dx.doi.org/10.4028/www.scientific.net/amm.730.81.
Testo completoAbstract (sommario):
Based on the quasi-static test of single-layer, two-bay RC frame model, using DIANA finite element program, a finite element Macro-model of masonry-infilled frame structure was established, and nonlinear finite element analysis of frame structures filled with different masonry materials was conducted. As a result of the existence of infill walls, the failure modes of frame structure have been changed, and which is easy to cause shear failure at the top of frame columns. If masonry materials of infill walls are different, the effects of infill panels on frame structures will be different. Comparative analysis shows that the influence of clay bricks is the largest, followed by autoclaved bricks’ influence, while aerated concrete blocks’ influence is the smallest. Therefore, to avoid the associated failure mechanism caused by infill walls, lightweight masonry materials are suggested to be used in actual engineering.
47
Timurağaoğlu, Mehmet Ömer, Adem Doğangün e Ramazan Livaoğlu. "Comparison and assessment of material models for simulation of infilled RC frames under lateral loads". Journal of the Croatian Association of Civil Engineers 71, n. 1 (8 gennaio 2019): 49–56. http://dx.doi.org/10.14256/jce.2307.2017.
Testo completoAbstract (sommario):
In the present study, the behaviour of infilled RC frames under earthquake loading is investigated numerically, and the influence of three different concrete material models on the in-plane behaviour of infilled RC frames is evaluated using the finite element analysis (FEA). For this reason, the efficiency of infilled walls is examined on full scale models. Finite element analysis results show that mathematical model of concrete may change behaviour of infilled RC frames. The post-peak behaviour is especially influenced.
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Khalilzadeh Vahidi, Ebrahim, e Reza Moradi. "Numerical Study of the Force Transfer Mechanism and Seismic Behavior of Masonry Infilled RC Frames with Windows Opening". Civil Engineering Journal 5, n. 1 (27 gennaio 2019): 61. http://dx.doi.org/10.28991/cej-2019-03091225.
Testo completoAbstract (sommario):
Masonry infilled walls are widely used in reinforced concrete (RC) frams worldwide. However, infilled RC frame building failure is a common mode in destructive earthquakes. Further researcher is needed to bring insightful understandings into the behaviors of these structures. Therefore, this study investigates seismic parameters, ultimate tensile damage, and force transfer mechanisms in a reinforced concrete structure under in-plan load. For this purpose, the definitions and the relevant literature were reviewed. Then, an analytical software supporting an infill model was selected and described altogether with a particular modeling approach. Calibrating software results with those presented by Abdulhafez et al. (2014), the researchers designed a series of planer one-story one-bay reinforced concrete frames upon ACI 318M-14 Building Code. The seismic behavior of infilled frames were also studied using finite element method. Force transfer mechanisms in infilled frame with opening, which is one of the important items, was investigated in this study. Comparing the analysis outcomes with the bar frame, it was indicated that the ultimate load, stiffness, and toughness of the full in-filled frame were increased while the ductility was decreased. It was also revealed that the presence of opening in infilled frame decreased the ultimate load, stiffness and toughness corresponding full infilled frame. In addition, the increasing of opening size increased the reduction of the ultimate load, stiffness and toughness.
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Zhang, Jia Chao, Lei Ming Zhang e Xi La Liu. "A Beam-and-Column Based Macro Model for Masonry Infill Walls in RC Frames under Cyclic Loading". Advanced Materials Research 255-260 (maggio 2011): 193–97. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.193.
Testo completoAbstract (sommario):
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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Zhao, Xin, Mai Wu, Dan Dan Kong e Shun Wei Chen. "Study on Finite Element Model of Infilled Walls of Steel Frames". Advanced Materials Research 250-253 (maggio 2011): 2424–27. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2424.
Testo completoAbstract (sommario):
Autoclaved lightweight concrete (ALC) block infills are used widely for steel residential building system in China; the authors of this paper brought forward a kind of macro finite element (FE) model of ALC block infills of steel frames on the basis of experimental study. Furthermore the hysteresis model of the strut element of infill was established. At last the validity of the strut element was verified by comparison theory analysis results with experiment ones. The analysis method and theory of this paper can be applied to other kind of infills after being revised properly.