Brick Masonry Infill Research Articles

Fragility analysis of masonry infill R.C. frame using incremental dynamic approach

The current study aims to investigate damage assessment of the RC frames with brick masonry infill (BMI). The effects of near-source ground motions (GMs) are considerably predominant in the seismic response of the structure as related to far-source ground motion due to their forward directivity plus long period. The near-source ground motion is characterized by enormous everlasting ground translation, strong peak ground acceleration (PGA), and a very low-frequency pulse. The Indian codes have not yet incorporated the influence of near-source GM into their design response spectra. Hence, IDA curves that represent ground motion uncertainty have been established for ten near-field ground motion records. Further, the fragility curves have been constructed to envisage progressive damage to the structure. The spectral acceleration-based fragility curves for the ten-story RC frames without BMI, with BMI, and with the open ground story are developed. It is proved that the BMI frame shows better performance during seismic motions. The probability of damage for the collapse prevention state is reduced for frames with BMI, and with open-ground story frames as compared to a frame without BMI.

INFLUENCE OF DIFFERENT INTERFACE MATERIALS AND OPENINGS IN INFILL OF REINFORCED CONCRETE INFILLED FRAMES

This study analytically investigates the behaviour of trapezoidal infilled frames (TIFs) with brick masonry infills having openings and various interface materials between the brick panel and reinforced concrete frame. Single-storey single-bay frame specimens are analysed under in-plane static loading. For this investigation, the optimum angle of the column inclination for the trapezoidal frame must be determined in terms of maximum lateral stiffness. The optimum angle must be further analysed and compared with rectangular bare and infilled frames, with various materials of the interface. This infilled frame is extended to analyse the openings in the infill further. To study the effects of openings in infilled panels, TIFs with different sizes and positions of window openings are analysed and compared with the rectangular frame. This study further analyses three different combinations of interfaces and determines the intermediate stiffness of the frame combination. The main focus of this investigation is to reduce the high rigidity of the TIF leading to high base shear. It is found that, the infilled frame is stiffer than the bare frame, and the cement mortar interface is stiffer than the lead–cork interface. This research uses ABAQUS software, a finite element analysis program, for expanding the observational analysis.

Out-of-Plane behavior of clay brick masonry infills contained within RC frames using 3D-Digital image correlation technique

The present study investigated the out-of-plane (OOP) behavior of traditional solid clay brick masonry-infilled reinforced concrete frames for different slenderness ratios, bonding patterns, and connection details to assess the development of arching mechanism, infill-frame interaction, and failure mechanisms. Full-field strain and crack width analysis, failure progression, and out-of-plane deformation characteristics were evaluated using a non-contact 3D-DIC (digital image correlation) technique. The experimental investigation ascertained that full-brick thick lower slenderness ratio (13.4) specimens observed higher capacity (3.7 times), deformation ability (>1.2 times), and energy dissipation characteristics (>3.5 times) compared to half-brick thick slender (28.8) specimens. The presence of tie bars enhanced the stability of the wall against out-of-plane failure. However, it did not significantly modify the load and deformation behavior in the peak and post-peak stages. The OOP deformation profiles, arching mechanism, and the distributed damage in infill in lower slenderness ratio specimens, which led to higher OOP lateral load resistance, were precisely captured using the 3D-DIC technique. The increase in width of the cracks (1.6–2.9 times) in Flemish bond (lower slenderness ratio) specimens compared to their running bond counterparts was accurately appraised using the DIC. Based on the experimental results, a unified out-of-plane lateral load–deflection idealized model was proposed. The appropriateness of the proposed model was further verified by comparing it with previously developed models and experimental studies. The research study revealed that the out-of-plane lateral load behavior of infilled frames was significantly modified due to strong and stiffer solid clay masonry, considering different structural bonding patterns and slenderness ratios. The 3D-DIC technique was found to be a resourceful tool for comprehending the deformation and damage characteristics of infilled frames, especially under out-of-plane lateral loads.

In-plane behavior of Chuan-Dou style wooden frames with infill under cyclic loading

Chuan-Dou style wooden frames (CDWFs) with different infill are used widely for residential buildings in Southwest China due to their cost-effectiveness and ease of construction. Four full-scale samples of CDWF were laboratory tested to study the contribution of different infills on its seismic behavior. They are two bare wooden frames, a frame with wooden panel infills and a frame with brick masonry infills. One bare wooden frame was subjected to monotonic load to determine the reference displacement for the in-plane Cyclic loading test in the other frame samples. The damage characteristics, ultimate lateral load carrying capacity, hysteretic behavior, stiffness degradation, strength degradation and energy dissipation were investigated. Test results indicated that the CDWF has exceptional ductility to lateral movement and good energy dissipation capacity. Both the wooden panel infill and brick masonry infill increase the lateral load resistance, lateral stiffness and energy dissipation of the CDWF system. The contribution of masonry infills to the improvement of lateral resistance capacity of wooden frames is much greater than that of wooden panel infills.

Analysis of Brick Masonry Infill Frame with Opening Using ANN

Analysis of Brick Masonry Infill Frame with Opening Using ANN

Flexural Behavior of Cross-Connected Brick Masonry Infill Wall Panels Supported on Reinforced Concrete Beam Grids

Flexural Behavior of Cross-Connected Brick Masonry Infill Wall Panels Supported on Reinforced Concrete Beam Grids

Seismic performance evaluation and risk assessment of typical reinforced concrete frame buildings with masonry infill and conventional vertical extension in Nepal

Many reinforced concrete (RC) frame buildings in Nepal were significantly damaged by the 7.8 magnitude (Mw) earthquake in Nepal on April 25, 2015. To contribute to mitigate future earthquake disasters, the current study focuses on two specific characteristics of residential RC frame buildings in the capital city of Nepal, Kathmandu: the application of brick masonry infill to exterior and partition walls, and the conventional vertical extension of building stories different from the design. Although these factors are likely to significantly affect the seismic performance, their effects are frequently neglected in practical design and construction management in developing countries. Hence, the main objective of this research is to investigate and clarify the seismic performance of RC frame buildings considering the above factors through experimental and numerical investigations. The present paper (1) briefly introduces the characteristics of a typical residential RC frame building in Kathmandu, (2) illustrates the numerical modeling parametrically considering three different contributions of brick masonry infill walls and (3) investigates the seismic performance of the RC frame building considering the effects of the infill wall modeling and the vertical extension through numerical analyses. Consequently, it was found that the consideration of the in-plane stiffness and strength of the infill walls resulted in both positive and negative contributions to the seismic performance of low-rise (up to three stories) and medium-rise (more than three stories) buildings respectively, quantitatively clarifying significant effects of the presence of infill and the vertical extension. These findings contribute to provide realistic solutions to upgrade the seismic performance by utilizing or removing the brick masonry infill walls or by managing the building stories to mitigate future earthquake disasters on typical RC frame buildings not only in Nepal but also in other countries with similar backgrounds.

Formulation of Performance Levels and Relevant Limitations for Clay Brick Masonry Infills in Seismic Analysis of R/C Frame Structures

Observation of damage caused by recent earthquakes highlights, once again, that the presence of infills significantly affects the seismic response of reinforced concrete (R.C.) frame buildings. Therefore, in spite of the fact that infills are non-structural elements, and thus they are normally not considered in structural analyses, in many cases their contribution should not be neglected. Based on these observations, the study proposed in this paper consists in the evaluation of the seismic response of infills in time-history finite element analyses of R.C. frame structures by means of a two-element model, constituted by two diagonal nonlinear beams. A “concrete”-type hysteretic model predicts the in-plane state of infills, through a force-displacement backbone curve expressly generated, and scanned in terms of performance limits, to this aim. This model is demonstratively applied to a real case study, i.e. a R.C. frame building including various types of brick masonry perimeter infills and internal partitions, damaged by the 30 October 2016 Central Italy earthquake. The time-histories seismic analyses carried out on it allows checking the influence of infills on the response of the structure, as well the effectiveness of the proposed model in reproducing the observed real damage on the masonry panels.

In-plane Quasi-static Cyclic Load Tests on Reinforced Concrete Frame Panels with and without Brick Masonry Infill Walls

ABSTRACT In this paper, the influence of brick masonry infill walls on the seismic performance of reinforced concrete (RC) frames is investigated. The presence and the location of a door opening are considered as test variables. Four RC frames were tested: a control specimen (RC bare frame), an infilled RC frame, an infilled RC frame with door opening at the loading end, and an infilled RC frame with door opening in the center. The test specimens were full scale representatives of typical RC frames with brick masonry infill walls. The data from the testing was interpreted in terms of failure modes, hysteresis curves, energy dissipation characteristics, stiffness degradation, and performance levels as established by standards. It was observed that the infill walls improve the RC frame performance in term of strength and stiffness, whereas the addition of a door opening reduces this performance improvement. Shifting the door opening from the side to the center improved the RC frame performance in term of strength and stiffness.

Innovative systems for earthquake-resistant masonry infill walls: Characterization of materials and masonry assemblages

Masonry infill walls are the standard solution to build envelopes and partitions walls in reinforced concrete buildings in southern Europe. In Portugal, masonry infill walls appeared in the sixties, with the massive use of reinforced concrete frames for residential and commercial buildings. Since then and until our days the masonry infills walls (cavity walls) have not experienced significant changes, apart from some variations in thickness and introduction of thermal isolation between the masonry layers. The construction system remains based on cavity walls without any connection between layers and constructed with horizontal perforated bricks and poor mortars. Their vulnerability under seismic actions is recognized by the scientific community and proven whenever an earthquake occurs. Nevertheless, they continue to be used, because until now there was not much innovation in the development of attractive solutions to be implemented in new constructions, and particularly there are no clear design and detailing construction guidelines that can contribute to higher quality masonry infill walls with reduced seismic vulnerability.This paper aims to contribute for the advance on the innovation in brick masonry infills by presenting two proposals of new masonry infill walls systems to be enclosed by RC frames. An extensive experimental campaign is presented and results are discussed on mechanical properties of materials and masonry assemblages associated to the two innovative masonry infill wall systems. The data provided in this paper is important to understand further in-plane and out-of-plane experimental tests to be carried out on the masonry infill walls as well as further numerical simulations and analytical analysis of the masonry infill systems.

Effect of Lintel Beam on Seismic Response of Reinforced Concrete Buildings with Semi-Interlocked and Unreinforced Brick Masonry Infills

The primary focus of this study is to evaluate the nonlinear response of reinforced concrete (RC) frames with two types of brick infills viz., unreinforced brick masonry infill (URM) and semi-interlocked brick masonry infill (SIM) together with lintel beams, subjected to seismic loads. The seismic response is quantified in terms of response reduction factor and base shear. Infill walls are modeled using double strut nonlinear cyclic element. Nonlinear static adaptive pushover analysis is performed in the finite element program SeismoStruct. The response reduction factor (R) is computed from adaptive pushover analysis and performance for all models is obtained. The results showed that the average R factor of the RC framed structure with semi-interlocked masonry (SIM) is 1.31 times higher than the RC frame with unreinforced masonry (URM) infill. The R value of the bare frame with the lintel beam is found to be less than the corresponding value recommended in the Indian Standard Code. The results obtained in this study highlight that if the impacts of lintel beams and various brick infill scenarios are considered in the RC frames then the R values used for the design of RC frame buildings with infills would be underestimated (i.e., the evaluated R values are greater than the R values used for the design purpose).

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

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

SEISMIC EVALUATION AND RETROFIT ON AN EXISTING HOSPITAL BUILDING

The nonlinear pushover analysis was used to evaluate an existing 8-storey reinforced concrete framed hospital building under seismic force and presented in this manuscript. The ‘Guru Teg Bahadur Hospital' is one of the important hospitals at Delhi-India, it was selected for this research. The three-dimensional frame model was used to model the building with a fixed base. The beams and columns were modeled by using three-dimension line frame elements with the centre lines joined at nodes. Diagonal strut elements were used to model the brick masonry infills. The slabs were considered as rigid diaphragms. The plastic hinge rotation capacities as per Federal Emergency Management Agency 356 (FEMA 356) with Performance Levels were adopted in this study, considering the axial force-moment and shear force-moment interactions. The nonlinear pushover analysis of the selected building was done with infills and it was observed that the infills (due to their small number in the considered building) do not make any appreciable effect on the performance level, except their failure at an early stage. The Capacity Spectrum Method (CSM) and Displacement Coefficient Method (DCM) were used to estimate the performance point of the building. The values of various coefficients as per Federal Emergency Management Agency 440 (FEMA 440) were adopted. The DCM was observed to give slightly higher target displacements, as compared to CSM. It was observed in the nonlinear pushover analysis that the unreinforced masonry (URM) infills collapse before the performance point of the building for the Maximum Considered Earthquake (MCE). As the intervention inside the functioning hospital is extremely difficult, it was explored whether it is possible to safeguard the infills by stiffening the building by providing external buttresses. Two cases of retrofitting schemes with 1.2m wide and 3m wide buttresses in transverse direction were used and analysed. It was found that this is not a practicable approach, as the infills collapse even with 3m wide buttresses.

A simple and safe brick masonry infill construction for high seismic-prone area

West Sumatera Province has been known as one of the high seismic-prone areas in Indonesia. In this area, peoples commonly use the brick masonry as infill in the Reinforced Concrete (RC) frame structures. Field investigation after the earthquake informed that there were many bricks masonry infill collapsed caused by the earthquake motion. In this study, a simple and safe brick masonry infill construction in the RC frame structure is proposed for applying in the high seismic-prone area such as West Sumatera. The proposed construction method was defined based on the experimental works of the three 1/4 reduced-scale singe-bay and single-story RC frame specimens. The specimens include one specimen of RC frame infilled with brick masonry, one specimen of RC frame infilled with strengthened brick masonry by using chicken wire mesh, and one specimen of RC frame infilled with brick masonry infill and anchored to the columns with plain steel rebars. The wire mesh was sewn on both sides of the diagonal area of the brick masonry infill. All the specimens have subjected to lateral static reversed loading. The structural test results have shown that the strengthening using the chicken wire mesh increase the lateral strength of the RC frame about 22.%, while the use of the plain rebars anchor decreases the lateral strength about 1.8% and both methods can delay the failure of the brick masonry infill.

A SIMPLE METHOD FOR STRENGTHENING THE BRICK MASONRY INFILLED IN THE REINFORCED CONCRETE FRAME STRUCTURE

The collapse of the brick masonry infill in the Reinforced Concrete (RC) structures has been known as one of the causes of the many casualties during the earthquake. This clay brick masonry has been commonly used as partitions in the RC frame structures in earthquake-prone areas such as West Sumatera, Indonesia. Strengthening the brick masonry infill is expected to be able to increase the performance of the brick masonry against the earthquake motions, which also may improve the seismic performance of RC structures. In this study, four of 1/4 reduced-scale singe-bay and single-story RC frame specimens were prepared and tested under lateral static reversed cyclic loading. The specimens include one specimen of RC frame infilled with brick masonry and three specimens of RC frames infilled with strengthened brick masonry. Strengthening of the brick masonry infill has used three types of wire mesh, namely plastic wire mesh, steel wire mesh, and chicken wire mesh. The wire mesh was tacked on both sides of the diagonal area of the brick masonry infill. The wire mesh was then fastened to columns and beams of the RC frame by using chemical epoxy adhesive. The purpose of this experimental study is to define an effective, inexpensive, and easy to apply the strengthening of the brick masonry infill such that it may be applied by the local labors in West Sumatera, Indonesia. The structural test results have shown that all the strengthening methods increase the lateral strength of the RC frame and can delay the failure of the brick masonry infill. Even though the strengthening by using the steel wire mesh produced a higher increase in stiffness of the specimen compares to others, however strengthening by using chicken wire mesh performed the most effective strengthening method. The presence of the chicken wire mesh maintains the ductility of brick masonry infill and the RC frame as well.

Cyclic behavior of the R/C frames with reinforced masonry infills

This study focuses on the experimental works to define the behavior of the reinforced concrete (R/C) frame model with the strengthening of the brick masonry infill by using the embedded reinforcement bars subjected to lateral reversed cyclic loads. A previous study by applying the lateral monotonic static loads showed that the embedded reinforcement bars increased the lateral capacity of the R/C frame and also delayed the failure of the brick masonry infill and R/C frame structure as well. However, in order to define its seismic capacity, a lateral reversed cyclic loading is required. The experimental works in this study were conducted by preparing and testing the 1/4 scaled-down R/C frame specimens represented the first story of the middle multi-story commonly constructed in the earthquake-prone area such as West Sumatera, Indonesia. The R/C frame specimens were two R/C frames with brick masonry infills where one of them strengthened by the embedded reinforced bars. All specimens were tested for applying the lateral reversed cyclic loads. The applied lateral load, the lateral displacement, the progressive cracks, and the failure mode of the specimens were observed and recorded during experimental works. As it was expected, the presence of the embedded reinforced bars in the brick masonry infills increases the seismic capacity and stiffness of the R/C specimens and also delayed the failure of the specimens. The experimental results in this study imply the simple strengthening method for the brick masonry infills.

Behaviour of Reinforced Concrete Frames with Central Opening Masonry Infill under Lateral Reversed Cyclic Loading.

This paper will describe the seismic behaviour of masonry infilled RC frame with a central opening structure under reversed cyclic lateral loading. To achieve the purpose of this study, four 1/4-scale single story and single bay RC frame specimens were tested, i.e. one bare frame, one clay brick masonry infilled RC frame without opening and two clay brick masonry infills with a central opening in infills. The ratios of opening size to panel area were 25% and 40%. Through reversed cyclic lateral loading tests, the seismic performance of RC frames with a central opening brick masonry infills was investigated. As the results, significant distinctions of failure mechanism, lateral strength, stiffness, and ductility were observed between these specimens. In the case of infills with a central opening, the cracks sprouted and developed at the corners of the opening. Although the presence of the opening in infill reduces the lateral strength and stiffness overall structure, the brick infilled frames with a central opening of 25% and 40% of panel area show better seismic performance as compared to the bare frame.

The Behaviours of the Brick-Masonry Infilled RC Frame Structure under Reversed Cyclic Lateral Loading

The experimental study for investigating the seismic responses of the Reinforced Concrete (RC) frame specimens is presented in this paper. Regarding this experimental, two one-bay and scaled-down specimens have been prepared and tested, i.e., RC bare frame and RC frame with brick masonry infill. The masonry infilled RC frame specimen was the RC frame which was infilled by the extracted brick masonry wall from the survive RC building in Padang city due to September 2007 Sumatra earthquake. These both of specimens, obviously, represent the typical low-rise RC building in West Sumatra, Indonesia. These specimens were tested to the constant vertical load, and lateral static reversed cyclic loading in the structural testing facilities. The lateral loading was applied incrementally and controlled by the drift angle of the specimens. The drift angle is the ratio between the lateral displacement of the top of the column and the column height of the specimen. The applied incremental lateral load and displacements at several points on the specimens were measured and recorded during the testing. The observation of the major cracks and its propagation were also conducted to identify the failure mechanism of the RC frame specimens. Comparison of the testing results for both of the specimens suggests that the masonry brick infill contributed to significantly increase the dissipating energy capacity, lateral strength, and stiffness of overall RC frames. On the other hand, unfortunately, the ductility performance of the brick masonry infilled RC frame specimen was decreasing. The presence of brick masonry infill in the RC frame seems to control the failure mechanism of the RC frame, reduces the deformation capacity of the boundary column, and alters the lateral and axial deformations of boundary columns.

In situ repair technique of infill masonry walls in steel frames damaged after an earthquake

The present paper first reviews the scientific information about masonry buildings in terms of the structural performance of different masonry walls, usual pre-earthquake retrofitting methods, and post-earthquake repair methods. From this, it is found that limited information is available on applicable repair methods for damaged masonry walls after the occurrence of an earthquake event. There is an essential need from the perspective of disaster management strategies to provide urgent aid to casualties of moderate seismic events well before preparing damage assessment data and a comprehensive retrofitting program for the earthquake-affected area. For this reason, three experiments were designed to investigate the effect of brick masonry infill on a simple steel frame and the success rate of a new method of repairing damaged infill. In the proposed repair method, cracks in the damaged masonry infill are stitched by crimped wire meshes in the shape of Band-Aids and cementitious plaster is used to coat the attached wire meshes. The crimped wire meshes must be fastened to the infill with hooked driven nails and must be attached perpendicular to diagonal crack paths and the four corners and centre of the infill. This method is presented for efficient and simple in situ repair interventions to provide temporary residency for casualties. Usage of plasters including accelerated cement or application of accelerated curing methods can reduce the time of repair construction and prepare the proposed method for urgent aids against aftershocks. No inappropriate structural effects of the steel frame-infill interaction were observed during these tests. Furthermore, the results indicated that the repair method not only restored the lost strength of the damaged infill but also recovered the stiffness and ductility of the reference specimen based on the experimental evidence. Following the experiments, a practical design methodology for the required crimped wire mesh specification based on the length of the infill diagonal cracks was recommended.

Probabilistic seismic performance assessment of brick masonry infill reinforced concrete building

The present study aims at investigation of seismic performance of brick masonry infill (BMI) reinforced concrete building through probabilistic approach. An existing seven storey reinforced concrete building situated in Indian seismic zone IV, which represents the typical properties of medium-rise non-ductile residential apartment buildings in India has been considered. Nonlinear seismic behavior of building with and without BMI is studied to evaluate seismic performance. Probabilistic seismic demand model (PSDM), fragility curves and damage probability matrix has been developed. Analytical fragility curves using incremental dynamic analysis have been developed. Sixteen natural ground motion records from PEER strong motion database are used to study the ground motion variability. Incremental dynamic analysis is performed and the maximum interstory drift is obtained as a response parameter for all simulations. The PSDM parameters are calculated using regression analysis for numerical models. The variation in the PSDM parameters is studied. Discrete probability matrices are developed for different damage stages. Finally, the effects of brick masonry infill on seismic performance are discussed.