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Prestressed concrete frames with infill walls (IW‐PC frames) are commonly used in civil engineering as a structural element. The possibility of structures undergoing progressive collapse is a cause for concern due to its severe consequences. This has become a significant topic in the academic community in recent years. However, research on the resistance of IW‐PC frame structures to progressive collapse is still insufficient. Therefore, this paper investigated the dynamic effects of progressive collapse on the IW‐PC frame, reinforced concrete frame with infill walls (IW‐RC), prestressed concrete frame (PC), and common reinforced concrete frame (RC). The study was conducted using the finite element software OpenSees. The study revealed that the vertical displacement during stabilization of the IW‐PC frame increased by 92.5% and 71.7% compared to the IW‐RC frame and decreased by 93.9% and 92.6% compared to the PC frame for middle column and side column failure, respectively. Additionally, the IW‐PC frame exhibited the highest dynamic load carrying capacity, which was 7.67 and 7.56 times higher than that of the RC frame, respectively. The mechanical properties of the frame were altered by the coupling effect of prestressed tendons and infill walls, making the IW‐PC frame more monolithic. [ABSTRACT FROM AUTHOR]

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This study was carried out to examine the seismic performance of Kancingan house walls and the behavior of their timber frames, brick infill, and anchor nails during cyclic loading tests. Kancingan House, a timber frame building with brick infill walls, is a cost-effective and efficient method of wall construction commonly used in houses in Merauke, Indonesia. The experimental method was used to determine the seismic performance of the walls built using buswood with a module width of 100 cm and a height of 130 cm through cyclic load testing. The result showed a maximum lateral load of 26.43 kN with a displacement of 19.08 mm under compression loading and 28.78 kN under tensile loading with 15.6 mm displacement. The initial stiffness was measured at 5.03 kN and 9.59 kN/mm for compressive and tensile loading, respectively. Furthermore, ultimate load and displacement of 21.14 kN and 23.02 kN were obtained at a displacement of 30.68 mm under compressive loading and 25.23 mm under tensile loading. The ductility values of 10.76 and 9.78 were obtained under compressive and tensile loading. In conclusion, the study found that each wall element supports the seismic performance of the structure. As opposed to the timber frame, the infill walls have not suffered much damage except a hair crack because of the presence of anchor nails that keep the infill wall from collapsing when it loses its bond with the timber frames. [ABSTRACT FROM AUTHOR]

To overcome negative effects of traditional masonry infilling walls (MIWs) on the seismic resilience of a self-centering prestressed concrete (SCPC) frame, a novel SCPC frame with sliding infill walls (SCPC-SIW frame) is proposed. This study compares the seismic performance of the SCPC-SIW frame and the SCPC frame with MIWs (SCPC-MIW frame) through quasi-static tests, fragility analysis, and risk assessment. To begin, quasi-static tests on single-story SCPC-SIW and SCPC-MIW frame specimens are performed to compare their failure characteristics, hysteresis response, energy dissipation, and self-centering ability. The numerical simulation methods for SCPC-SIW and SCPC-MIW frame specimens are then presented and validated. Subsequently, two four-story SCPC-SIW frames and two four-story SCPC-MIW frames are designed, and their dynamic response under MCE is preliminary analyzed. Finally, the fragility analysis and risk assessment of these multi-story SCPC-SIW and SCPC-MIW frames are conducted to determine the probability of their peak inter-story drift ratio (PIDR), residual inter-story drift ratio (RIDR), and peak floor acceleration (PFA) exceeding the specified limit states under any intensity earthquake and within 50 years. The results indicate that, except for cracks caused by fatigue damage appearing on the SIW at the end of loading, the SCPC-SIW frame specimen remains undamaged, whereas the SCPC-MIW frame specimen exhibits diagonal step cracks on the MIW. The hysteresis curve of the SCPC-SIW frame specimen exhibits an ideal and repeatable flag shape, whereas the stiffness and strength of the SCPC-MIW frame specimen degrade during the test. Besides, the probability of exceeding the 4% PIDR and exceeding 0.2% and 0.5% RIDRs within 50 years for the SCPC-SIW frame is significantly lower than that for the SCPC-MIW frame. The SCPC25-MIW frame has a higher probability of exceeding the 1 g PFA within 50 years than the SCPC25-MIW frame. In other cases, the SCPC-SIW frame has a lower probability of exceeding 1 g, 2 g, and 3 g PFA within 50 years than the SCPC-MIW frame. [ABSTRACT FROM AUTHOR]

In this paper, an innovative infill wall is proposed and examined experimentally and parametrically. The proposed wall has an innovative design and is constructed with lightweight concrete strengthened by waste glass. The proposed wall not only demonstrates robust performance against out-of-plane loading, but also exhibits exceptional behavior under elevated temperatures. Additionally, the necessary equations used to predict the wall's behavior are also presented. The results reveal that glass powders affect weight loss. During the initial temperature application, ranging up to 600 °C, specimens with 0% and 8% glass powder experienced maximum and minimum weight loss, respectively. At 200 °C, glass powder concentrations below 4% caused a reduction in compressive strength, f c ′ , while concentrations between 4% and 8% led to an increase in f c ′ . Consequently, the optimal glass powder volume was determined to be 6% for specimens under varying temperature conditions. The out-of-plane loading tests indicated that although the wall was exposed to heat up to 800 °C, the resistance did not decrease significantly. Given its role as a non-load-bearing wall without the application of gravity, this innovative structure is anticipated to perform admirably in fire scenarios during seismic events. [ABSTRACT FROM AUTHOR]

This paper focuses on the seismic vulnerabilities of multi-storey buildings in hilly regions like Sikkim and Uttarakhand, where rapid construction is driven by population growth and tourism. The study particularly evaluates step-back buildings on hilly slopes, comparing their vulnerability to standard buildings on flat terrain. Using non-linear analysis to assess structural aspects like displacement and storey drift ratio, the research examines the performance of these buildings in both uphill and downhill orientations against typical three-storey and six-storey structures, respectively. The findings indicate that step-back buildings, especially those without infill walls, are more susceptible to seismic damage. For instance, on the uphill side, a step-back building shows a mean drift ratio 15.11% greater in the X direction and 4.57% greater in the Y direction compared to a three-storey regular building (3SR). This vulnerability is exacerbated when infill walls are absent, with mean drift ratios in step-back buildings being 74.75% and 33% higher in the X and Y directions, respectively. Moreover, at a seismic acceleration of 0.36 g, the mean displacement of a step-back building is 83% greater in the X direction and 51% greater in the Y direction than those with infill walls (SBIN), underscoring the significant role of infill walls in enhancing earthquake resilience. The study also highlights that short columns in step-back buildings are particularly prone to severe damage, especially just above the uppermost foundation level. While infill walls offer substantial mitigation of damage at the Design Basis Earthquake (DBE) level, at the Maximum Considered Earthquake (MCE) level, step-back buildings still endure severe damage compared to regular buildings with infill walls. Consequently, the research establishes that step-back buildings demonstrate greater vulnerability at DBE levels without infill walls and are more susceptible to damage than flat terrain buildings at MCE levels, emphasizing the need for careful design and reinforcement strategies in earthquake-prone hilly areas. [ABSTRACT FROM AUTHOR]

Construction industrialization addresses various challenges in the traditional construction industry, enabling building structures to conserve resources and enhance energy efficiency while reducing emissions. Precast shear walls involve the factory-based production of components, followed by transportation to a construction site for assembly. The method of connecting these components is crucial for precast concrete shear wall systems. Common connection methods include lap-spliced connections, post-tensioned connections, welded connections, bolted connections, and sleeve connections. However, challenges such as construction precision and technology proficiency have limited their application. In response, a novel precast concrete shear wall system utilizing angle steel connectors has been proposed. These angle steel connectors enhance the shear resistance of horizontal joints between precast concrete shear walls and the foundation, providing provisional support for specimen positioning and installation. Presently, the seismic performance of this innovative precast shear wall system under the combined actions of cyclic horizontal loads and axial pressure or tension has been extensively investigated. In practical engineering applications, precast concrete shear wall systems are often accompanied by infill walls. However, there is limited research on the seismic performance of precast concrete shear wall systems with infill walls. To address this gap, this study designed and fabricated two novel precast concrete shear walls with different infill wall constructions. One specimen featured an infill wall composed of a single wall panel, while the other had an infill wall consisting of two panels. Pseudo-static tests were conducted on both specimens under constant axial compression. Subsequently, the seismic performance and force mechanism of the two specimens were compared with the novel precast concrete shear walls without infill walls. The test results demonstrated that the specimen with two infill wall panels exhibited superior overall performance compared to the one with a single continuous infill wall panel. Furthermore, it was observed that, during the loading process, the edge columns of specimens with infill walls provided the majority of the increased load-bearing capacity, while the infill walls made a limited contribution to the overall load-bearing capacity of the structures. [ABSTRACT FROM AUTHOR]

Experimental and numerical studies were conducted to investigate interaction between reinforced‐concrete grid frame (CGF) and ceramsite foam concrete (CFC) infill. In the experiments, compressive tests were performed on the CGF and RC grid frame filled with the CFC which forms a composite wall, namely CGFW. To investigate the mechanical properties of the CGFW and the interactions between the CGF and CFC infill, the failure modes, integral stiffness, local strains, and load distribution coefficients of the composite wall were analyzed. The experimental results indicated that the CFC infill could uniformly transmit loads and significantly improve the bearing capacity and vertical stiffness of the CGFW while reducing the ductility of the composite wall. The load distribution coefficients of the CFC infill were stable at 0.51 ± 0.06 before peak load and damage evolutions in concrete columns were effectively alleviated due to obvious interactions between the CGF and CFC infill. To evaluate the interaction mechanisms of the two, numerical analysis was carried out by changing the sizes of central grid, opening rates, and reinforcement ratios of the composite walls. The finite element model with plastic damage constitutive of concrete was calibrated by comparing the experimental results. The numerical results indicated that the interaction between the CGF and CFC infill was insensitive to changes in grid sizes, and the interaction between the two was significantly different with the same reinforcement method of frame beams and columns. In addition, the CFC infill played an important role in the stability of CGF as the opening rate significantly affected the mechanical properties of the CGFW, and a stable path of load transfer was the key factor to ensure the interaction between the CGF and CFC infill. [ABSTRACT FROM AUTHOR]

Introduction: Autoclaved Aerated Concrete (AAC) is a lightweight and energy‐efficient material which makes it one of the most convenient materials to be used in infill walls. Accordingly, AAC walls are becoming more and more favored infill systems in earthquake‐prone regions. Although the infills are not considered primary components in seismic design, they are highly susceptible to be damaged under seismic actions in in‐plane (IP) and out‐of‐plane (OOP) directions. Objective: Past post‐earthquake site surveys indicated that the failure of infill walls may result in severe casualties, injuries, and economic losses. In addition, damage to infills may hinder the functionality of critical buildings, which are expected to be in service after earthquakes. The application of horizontal bed‐joint reinforcement between infill courses is one of the promising solutions to increase the seismic resilience of infill walls. Methodology: This paper presents the experimental performance investigation of AAC infill walls with flat‐truss bed‐joint reinforcement being subjected to lateral loading in IP and OOP directions. The specimens represent relatively thin infills with a thickness of 150 mm, which are generally used in indoor environments. To consider the seismic actions in the IP direction, two full‐scale infill wall specimens (one unreinforced reference and one with flat‐truss reinforcement) built in reinforced concrete frames were first tested under reversed cyclic IP displacement reversals and then tested under the cyclic OOP displacements. Conclusions: The results revealed that the use of flat‐truss reinforcement enhanced the OOP strength, ultimate displacement, and energy dissipation capacity of infill walls that have been subjected to cyclic IP displacements previously. [ABSTRACT FROM AUTHOR]

Brick infill walls are one of the most common types of nonstructural elements used for exterior enclosures as well as interior partitions in steel frame buildings. The recent earthquakes have shown that damage to masonry infill walls may cause danger for human lives and dramatically affects economic losses. The damage estimation of masonry infill walls and the effects within the corresponding consequences of the performance-based earthquake engineering need fragility functions. The procedure implemented in this study is based on incremental dynamic analyses of two models, i.e. with and without brick infill walls. The primary objective is to develop fragility curves that permit the estimation of damage in masonry infill walls. Comparative analyses were conducted among the models considering four damage levels. The increase in the height has reduced the probability of damage to infill walls, so there was slight damage in drifts less than 3%. Therefore, with increases in stiffness, the probability of damages to the infill walls will increase. The fragility curves obtained by HAZUS show that there is a negligible variation in the infill walls seismic fragility estimated by the number of bays.

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Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Our country is located on important fault lines. Investigation of structural behavior in terms of various parameters is important for earthquake safety of structures. In this study, the effect of infill wall on the behavior of steel structures, which is one of the frequently preferred structural system types, is investigated. In practice, infill walls are usually included in the analysis as vertical loads, but their effects on the structural behavior, especially under horizontal loading, are ignored because they are not included in the model. As it is known, investigating the effect of the inclusion or exclusion of infill walls in the numerical model on the behavior of structures is also important in terms of structural safety. The numerical models examined in the study were analyzed in three dimensions in SAP2000 program. Structural behavior under earthquake effect was investigated by the equivalent seismic load method and the structural performance was investigated by the incremental equivalent seismic load method. In the light of the results obtained from the analyses, it was observed that the period values increased and the peak displacements decreased when the infill walls were considered as pressure bars in the numerical model compared to the case where the infill walls were considered only as vertical load. On the other hand, in the same investigation, it was concluded that the base shear force increased, and the plastic hinge point was reached with less displacement when the infill wall was included in the model as a pressure bar. [ABSTRACT FROM AUTHOR]

The seismic response of infilled frames draws considerable interest in the earthquake engineering community for the last decades. Whilst the early studies were concerned with added lateral stiffness and strength, recent studies focused primarily on deformability and performance improvement. In this study, an experimental campaign was conducted to investigate the seismic performance of ductile reinforced concrete (RC) frames infilled with hollow clay bricks and autoclaved aerated concrete blocks. The effectiveness of different infill wall construction techniques, such as the use of isolation joints, mesh overlays, and horizontal sliding joints were evaluated by carrying out cyclic tests on seven half-scale RC frame specimens. Strength and stiffness degradation, energy dissipation and damage propagation of tested infill wall systems obtained by deducing bare frame (BF) response from the infilled frame (IF) were compared. Damage limit states in terms of story drift were proposed based on specific points located on the normalized experimental load-displacement backbone of infill walls. A detailed description of physical damage corresponding to each damage state was reported for visual quantification of the infill wall performance. [ABSTRACT FROM AUTHOR]

The interactions between reinforced concrete (RC) frames and infill walls play an important role in the seismic response of frames, particularly for low-rise frames. Infill walls can increase the overall lateral strength and stiffness of the frame owing to their high strength and stiffness. However, local wall-frame interactions can also lead to increased shear demand in the columns owing to the compressive diagonal strut force from the infill wall, which can result in failure or in serious situations, collapse. In this study, the effectiveness of a design strategy to consider the complex infill wall interaction was investigated. The approach was used to design example RC frames with infill walls in locations with different seismicity levels in Thailand. The performance of these frames was assessed using nonlinear static, and dynamic analyses. The performance of the frames and the failure modes were compared with those of frames designed without considering the infill wall or the local interactions. It was found that even though the overall responses of the buildings designed with and without consideration of the local interaction of the infill walls were similar in terms the overall lateral strength, the failure modes were different. The proposed method can eliminate the column shear failure from the building. Finally, the merits and limitations of this approach are discussed and summarized. [ABSTRACT FROM AUTHOR]

In this paper, an innovative infill wall is proposed and examined experimentally and parametrically. The proposed wall has an innovative design and is constructed with lightweight concrete strengthened by waste glass. The proposed wall not only demonstrates robust performance against out-of-plane loading, but also exhibits exceptional behavior under elevated temperatures. Additionally, the necessary equations used to predict the wall’s behavior are also presented. The results reveal that glass powders affect weight loss. During the initial temperature application, ranging up to 600 °C, specimens with 0% and 8% glass powder experienced maximum and minimum weight loss, respectively. At 200 °C, glass powder concentrations below 4% caused a reduction in compressive strength, fc′, while concentrations between 4% and 8% led to an increase in fc′. Consequently, the optimal glass powder volume was determined to be 6% for specimens under varying temperature conditions. The out-of-plane loading tests indicated that although the wall was exposed to heat up to 800 °C, the resistance did not decrease significantly. Given its role as a non-load-bearing wall without the application of gravity, this innovative structure is anticipated to perform admirably in fire scenarios during seismic events.

It is a well-known fact that the absence of infill walls at the ground story, which is termed as “open ground story” may lead to a soft-story deficiency, especially in the case of non-ductile buildings. The previous severe earthquakes have shown that catastrophic destruction may occur in such a condition. Therefore, the seismic assessment of open ground story reinforced frames, where the effects of infill walls are incorporated, is of vital importance. However, the effects of infill walls are generally disregarded or considered indirectly in the seismic assessment procedures of the codes. This may mislead the actual condition of the open ground story buildings at different performance levels. This study aims to assess a non-ductile reinforced concrete frame with an open ground story regarding the collapse prevention performance level. The pushover and incremental dynamic analyses results are evaluated following the code limitations for collapse prevention. The results demonstrate the measure of misleading caused by the ignorance of infills at the upper stories while applying these code limitations. [ABSTRACT FROM AUTHOR]

A series of studies on self-centering frame structures initiated since the 1990s have thoroughly validated the effectiveness of this system in controlling the damage of structural components. However, these studies primarily focused on controlling the damage to structural components, with limited analyses on the response of non-structural infill walls in self-centering structures. This limitation has to some extent hindered the engineering application of self-centering structures. To investigate the seismic performance and damage evolution of autoclaved aerated concrete (AAC) block infill walls in a self-centering frame structure, and verify the effectiveness of separation method in mitigating the wall damage, a single-story single-span self-centering frame was established as the platform for conducting quasi-static tests. The digital image correlation (DIC) technique was employed to detect the damage development of the wall. The test results demonstrated that the fully infilled wall was subject to overall lateral compression from the adjacent columns and the damage concentrated at the contact regions. The self-centering frame with a fully infilled AAC block wall showed improved performance in terms of strength, stiffness and energy dissipation, whereas the wall damage was severe. Moreover, it was verified that the self-centering design helped to suppress the development of residual displacement caused by the damaged infill wall and achieve a repairable-level residual displacement response. The adoption of a separation layer between the infill wall and the structural members could effectively mitigate the damage to the infill wall and the separated infill wall barely affected the hysteresis performance of the structure. • Quasi-static tests on the self-centering frame-infill wall structure. • Application of DIC technique to clarify the damage evolution of infill wall. • Verification of the effectiveness of the separation layer in mitigating the wall damage. [ABSTRACT FROM AUTHOR]

This paper focuses on the seismic vulnerabilities of multi-storey buildings in hilly regions like Sikkim and Uttarakhand, where rapid construction is driven by population growth and tourism. The study particularly evaluates step-back buildings on hilly slopes, comparing their vulnerability to standard buildings on flat terrain. Using non-linear analysis to assess structural aspects like displacement and storey drift ratio, the research examines the performance of these buildings in both uphill and downhill orientations against typical three-storey and six-storey structures, respectively. The findings indicate that step-back buildings, especially those without infill walls, are more susceptible to seismic damage. For instance, on the uphill side, a step-back building shows a mean drift ratio 15.11% greater in the X direction and 4.57% greater in the Y direction compared to a three-storey regular building (3SR). This vulnerability is exacerbated when infill walls are absent, with mean drift ratios in step-back buildings being 74.75% and 33% higher in the X and Y directions, respectively. Moreover, at a seismic acceleration of 0.36 g, the mean displacement of a step-back building is 83% greater in the X direction and 51% greater in the Y direction than those with infill walls (SBIN), underscoring the significant role of infill walls in enhancing earthquake resilience. The study also highlights that short columns in step-back buildings are particularly prone to severe damage, especially just above the uppermost foundation level. While infill walls offer substantial mitigation of damage at the Design Basis Earthquake (DBE) level, at the Maximum Considered Earthquake (MCE) level, step-back buildings still endure severe damage compared to regular buildings with infill walls. Consequently, the research establishes that step-back buildings demonstrate greater vulnerability at DBE levels without infill walls and are more susceptible to damage than flat terrain buildings at MCE levels, emphasizing the need for careful design and reinforcement strategies in earthquake-prone hilly areas.

Lightweight masonry blocks (LMBs) are more environmentally favorable than solid clay bricks, and have gradually become the main material for the infill walls of modern buildings. It is of great importance for proposing a suitable hysterical model of LMBs infill walls to accurately predict the seismic responses of modern buildings. However, cyclic loading tests of LMB infill walls demonstrate that the existing formulas of equivalent strut models significantly overestimate the stiffness and underestimate the peak strength. To this end, the force-displacement curves of 24 cyclic loading tests of LMB infill walls sourced from existing literature are statistically analyzed. The modification coefficients of stiffness and peak strength are put forward, and other parameter values such as yield strength coefficient, unloading stiffness coefficient and pinching effect coefficient are also recommended. Then a full-scale cyclic loading test of an LMB infill wall is designed and conducted to verify the accuracy of the modified model. In addition, the applicability of the modified model is also verified by two infill wall tests from existing literature. The results indicate the modified model can accurately simulate the global hysteretic response of LMB infill walls, and the simulation accuracy of the peak strength is increased to more than 90%. This model provides a useful tool for the accurate evaluation of the seismic performance of modern buildings infilled with LMBs. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The bundled lipped channel–concrete (BLC-C) composite wall structure is a new structure with several advantages such as a high bearing capacity and good seismic performance. However, interface cracks between a BLC-C composite wall and the infill wall (non-structural wall) are a severe problem and need to be urgently resolved. Interface cracks affect not only the esthetics, but also the normal use of a building. The presence of interface cracks changes the perceptions of the owners of a structure, forcing them to question its safety and even take legal action against its developer. Therefore, in this study we aimed to investigate the initial cracking of the interface between a BLC-C composite wall and an infill wall. Unidirectional horizontal loading tests were conducted on two infill wall specimens constrained by BLC-C composite walls on both sides. The finite element analysis software ANSYS was used to simulate the loading process of the tests. The test results were compared to verify the accuracy of the finite element model. A finite element analysis was conducted to determine the effect of the horizontal displacement of the specimens when the interface initially cracked under different parameters such as the widths of the BLC-C composite wall, infill wall, and opening as well as the strength grade of the bricks and maximum normal contact stress. The results showed that a decrease in the width of the BLC-C composite wall or a rise in the width of the infill wall delayed the appearance of interface cracks. A large opening also delayed the occurrence of interface cracks. An enhancement in the strength grade of the bricks led to an earlier appearance of interface cracks. Interface cracks occurred later with an increase in the maximum normal contact stress between the BLC-C composite wall and the infill wall. [ABSTRACT FROM AUTHOR]

Many areas of Indonesia are located near earthquake faults, resulting in the recurrence of earthquake phenomena in various regions of Indonesia. This research is an experimental study on the behavior of prefabricated foam concrete as wall infill material under lateral cyclic loading. This study analyzed the relationship between load and displacement in prefabricated foam concrete as an infill wall. The test object consisted of 2 wall models: reinforced concrete frames (DB 1) and prefabricated foam concrete infill wall (DB 2). Lateral cyclic loading with displacement control method is carried out to evaluate the structural behavior of the wall regarding ASTM E2126-02a. The test results showed that the strength value of the DB 2 specimen resulted in a 29.61% increase of strength than the DB 1 specimen. Furthermore, the relative stiffness degradation on both specimens is not too significant in both the loaded and unloaded state, so there may be no pinching effect. It’s more likely to lead to a more stable condition with higher energy dissipation capability without decreasing the strength of the specimen when compared to the DB 1 specimen. Therefore, foam concrete precast panel can be utilized as an alternative infill material for walls on a reinforced concrete frame structure to be replaced with clay bricks, hebel, batako, etc [ABSTRACT FROM AUTHOR]

The infill wall has a significant influence on the progressive collapse resistance of the precast concrete (PC) frame, and there is no corresponding design method at present. In order to obtain a reliable calculation method for progressive collapse, a numerical and analytical analysis of progressive collapse resistance of PC frames with infill walls was conducted. According to the 3∶1 scale test of PC frames with and without infill walls after removing middle column, and considering the displacement of middle column under the asymmetric distribution of infill walls, a mechanical model based on equivalent strut was established by introducing asymmetry coefficient. Based on the finite element (FE), numerical models of the sub frames with the asymmetric infill walls were established, and displacement-load curves of the middle column were obtained, based on which, the analytical solutions were compared with the test results of bare, double, and single infill wall PC frames, and the results were found in good agreement. A comparison of the calculation results with the recommended values in current codes indicates that the displacement of PC frames under the peak load of catenary is increased when considering the infill wall. The recommended value of the displacement, whose middle column is 0.2 times of the span, is suitable for the bare PC frames, but conservative for the PC frames with infill walls. The results provide a basis for the calculation of the progressive collapse resistance of PC frames with infill walls.

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

The results of an experimental study of four infilled frames with brick masonry walls subject to reversal cyclic lateral load are presented. The variables studied were the height to length aspect ratio of the wall and the use of joint reinforcement. The investigation was motivated by the fact that the Mexican code establishes the same specifications about the use of joint reinforcement for infill walls as for confined walls, because there is not enough experimental evidence on joint reinforced infill walls. To investigate the possible interaction of the study variables in the seismic performance of the walls, two pairs of specimens, scaled 1:2, with different aspect ratios (H/L = 0.75, 0.41) were tested. The specimens in each pair were identical except that one of them included steel bars into the bed-joints as reinforcement leading to amount   p h f y h = 0.6   MPa . The infill walls with H/L = 0.41 were included from a previous study. The behavior of the specimens was defined in terms of lateral strength, ductility, displacement capacity, deformation of the joint reinforcement and crack pattern. The results indicate that joint reinforcement increases the strength of the system; however, the increase was more pronounced in longer walls. Ductility was reduced with horizontal reinforcement and this behavior was more important for longer walls. As occurred in confined walls, the joint reinforcement generates a more distributed cracking and reduces the width of the cracks. The experiments are described and this and other results are discussed in detail. [ABSTRACT FROM AUTHOR]

This article examined steel frames with shear beam-column connections to determine the effectiveness of different masonry infill walls under progressive collapse. This research concentrated on the shear connection, which is the most common type of steel beam-column connection in steel buildings. Furthermore, this work experimentally evaluated one-third-scale steel-framed configurations with a single shear beam-column connection and another infilled steel frame wall configuration from the literature to verify the validity of 3D finite element models developed using the program ABAQUS. Finite element models were then used to investigate 16 different kinds of steel frames with infill masonry as well as the influence of multiple frames and the number of stories. In addition, the effects of a fully infilled frame and those of a bare frame and an infilled frame with openings were compared in flexural and catenary action phases. Results revealed that the steel building's structural strength and energy dissipation against progressive collapse are significantly improved by infill walls. [ABSTRACT FROM AUTHOR]

The Behavior of eccentrically braced frame (EBF) in terms of stiffness and ductility is between moment resisting frame and concentrically braced frame. EBF should be designed in such a way that yielding is only concentrated in the link beam at the non-linear stage. Field survey after the Sarpol-e Zahab earthquake shows that despite several defects in structural design and construction of EBFs, they have remained stable. In this study, one of the damaged buildings in the Sarpol-e Zahab earthquake, in the form of a three-story four-bay frame was modeled in Etabs and its seismic behavior in two cases; with and without infill walls was studied. The results of the analyses show that the presence of diagonal struts of infill walls reduces the axial force of the braces, the shear force, and the bending moment of the link beams. Infill walls also reduce lateral displacement and period of EBF, and they increase the lateral stiffness. Therefore, in the condition that there are several defects in the design and construction of link beams and braces, connecting the infill walls to the structure has a positive achievement. In this condition, if there were not infill walls, there would be a possibility of structural collapse.

Bu çalışmada, kat içinde farklı oran ve düzende yerleştirilen dolgu duvarların betonarme binaların sismik davranışlarına olan etkileri araştırılmıştır. Türkiye Bina Deprem Yönetmeliği (TBDY-2018)'ne uygun olarak tasarımı gerçekleştirilen binaların performansları zaman tanım alanında doğrusal olmayan analiz yöntemiyle tespit edilmiştir. Analizler için 11 adet deprem kaydı, yakın ve uzak fay etkileri, depremlerin büyüklüğü, zemin cinsi ve Ülkemizin faylanma mekanizması gibi parametreler dikkate alınarak seçilmiştir. Seçilen ivme kayıtları, basit ölçeklendirme yöntemi kullanılarak TBDY-2018'de verilen yatay elastik tasarım spektrumuyla uyumlu olacak şekilde ölçeklendirilmiştir. Analizlerde 5 farklı oranda dolgu duvar dikkate alınmıştır. Bu dolgu duvarlar diyagonal (eşdeğer) basınç çubuğu olarak analizlerde dikkate alınmıştır. Binanın sonlu eleman modelinde SAP2000, kesit analizlerinde ise RESPONSE2000 programı kullanılmıştır. Analizler sonucunda, her bir dolgu duvar oranı için binalardan elde edilen mod şekilleri, titreşim periyot değerleri, göreli kat ötelemesi oranları ve bina performans seviyeleri karşılaştırmalı olarak sunulmuştur.

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, nonlinear time‐history analyses are performed to assess the floor response spectra of bare and infilled reinforced concrete framed buildings with different number of stories and designed according to Eurocode provisions for different intensity levels of the seismic action. Infill walls are modeled by neglecting and by accounting for the effects of their out‐of‐plane response and of the in‐plane/out‐of‐plane interaction. To this aim, a recent out‐of‐plane response model is updated and improved. The results of the numerical analyses are compared in order to assess, first, the different floor spectra obtained for bare and infilled buildings and, second, the effect of the in‐plane/out‐of‐plane interaction on the results obtained for infilled buildings. The main parameters influencing the shape and the amplitude of floor response spectra are investigated, namely higher vibration modes, structural nonlinearity, and damping of the secondary element. This is also performed with the support of the discussion and application of current code and literature formulations. Based on the results of the numerical analyses, a simplified code‐oriented formulation for the assessment of floor response spectra in bare and infilled reinforced concrete framed structures is proposed. The proposed formulation may be a useful tool for the seismic assessment and safety check of acceleration‐sensitive nonstructural components. [ABSTRACT FROM AUTHOR]

The existing seismic provisions across the world account the non-linear response of a structure in a linear elastic design implicitly using a constant behavior factor, or response reduction factor (R). However, this factor (R) does not address the effects of changes in structural configurations, which eventually alters the dynamic behavior of the structure. Hence, the adequacy of prescribing a constant factor to account for the variable dynamic characteristics of structural systems always appears contentious. Further, seismic analysis of RC buildings usually ignores the interaction of the infill wall with the structural frame leading to inappropriate evaluation of dynamic characteristics of the structure. Hence, in the present research, it is attempted to investigate the sufficiency of the code-based 'R' factor in assessment of seismic behavior using non-linear static analysis (NLS) and non-linear dynamic analysis (NLD) for the structural models considered. Moreover, the results obtained, clearly envisages the influence of structural configuration changes and interaction of the infill wall with the RC MRF on dynamic characteristics in terms of ductility and over strength values. It can be clearly observed that, the code specified constant 'R' for a particular structural type appears erroneous, emphasizing the need for its adequate estimation. This should involve consideration of the dynamic characteristics of the structure resulting in a realistic assessment of seismic demand, thereby contributing to a safe, functional and economical design configuration. [ABSTRACT FROM AUTHOR]

Infill walls are a primary source of structural loss under service level and design basis earthquakes, so developing high-performance infill wall is an effective strategy to reduce seismic loss. While several high-performance infill walls have been proposed, most studies only reveal the damage characteristics of infill walls at the component level. However, the interaction between infill walls and structures can alter the seismic response of structures and consequently affect the loss of infill walls under earthquakes. Therefore, it is necessary to investigate the seismic responses and loss of high-performance infill wall at the structural level. In this paper, the working mechanism and damage characteristics of the slotted infill wall (SIW) are firstly introduced and verified through cyclic loading test. Then, an in-plane hysteresis model of SIW is developed, and the calculation method of key parameters is proposed. Finally, a numerical analysis model of a 10-story frame with slotted infill wall (SIW-F) is developed to study the seismic response and seismic losses. The results indicate that SIW-F's displacement response is larger than that of the frame with ordinary infill wall (OIW-F) on most floors. However, the floor acceleration response is less. The seismic loss of SIW-F is less than that of OIW-F, particularly under design basis earthquakes. The repair cost ratio of infill wall decreases from 19% to 8%, the total repair cost of the SIW-F decreases by 41%, and the total repair time also reduces by 25%. • The working mechanism and damage characteristics of the SIW is Introduced and verified. • A general in-plane hysteresis model of SIW is proposed, and calculation methods of key parameters are suggested. • The seismic responses of 10-story frames with SIW and OIW are comparatively evaluated. • The seismic loss including repair cost and time of 10-story frames with SIW and OIW are discussed. [ABSTRACT FROM AUTHOR]

• The failure models and collapse mechanisms of self-centering PC frames were analyzed. • Effects of different design parameters on failure modes were evaluated. • Reasonable optimization measures were suggested to reduce the concrete damage. • Collapse mechanism of self-centering PC frames were compared with RC frames. • Calculation model was proposed to predict the progressive collapse resistance. In this study, the refined finite element (FE) models for the collapse resistance of self-centering precast concrete (PC) frames with and without infill walls were established. Based on the validated FE models, the effects of different design parameters on the failure modes at the beam ends as well as the collapse resistance of the structures were evaluated. Correspondingly, the reasonable optimization measures were suggested to reduce the concrete damage at the beam ends. The results indicated that the insufficient stirrup spacing may cause the concrete failed prematurely along the edge of the steel jackets due to stress concentration. Decreasing the thickness of steel angles could reduce the failure area of concrete at the beam ends, but also caused a significant reduction in the initial stiffness and vertical resistance of the structures. The thickness of steel jackets mainly influenced the size of failure area at the beam ends. The position of horizontal bolts and longitudinal bolts had effects on the failure modes of concrete at the beam ends as well as the collapse resistance of the structures, while the latter was particularly evident. Compared to the cast-in-place reinforced concrete (RC) frames with the same size and reinforcement ratio, the damage extent at crucial locations of the optimized self-centering PC frame structures was lower, while exhibiting similar collapse resistance. A calculation model considering the resistance contribution of structural and non-structural infill wall members was proposed to predict the vertical resistance of self-centering PC frame structures in the compressive arch action (CAA) stage. The accuracy of the calculation model was verified by comparing 23 FE models with different design parameters. [ABSTRACT FROM AUTHOR]

Betonarme yapı sistemlerinde dolgu duvarlar yaygın bir şekilde kullanılmaktadır. Dolgu duvarların yapıya sadece olumlu etkisinin olacağı ve bu etkiyi rezerv tutma düşüncesiyle, genellikle konvansiyonel analiz programlarında dolgu duvarlar salt düşey yük olarak çerçeveye etki ettirilmektedir. Oysaki yaşanan depremler sonrası yapılan araştırmalar, dolgu duvarların betonarme çerçeveye olumlu/olumsuz etkilerinin olduğunu göstermektedir. Dolgu duvar etkisinin modele yansıtılmaması, tasarımcıların yaptığı analizlerde çeşitli yapısal düzensizlikleri de görememesine neden olabilmektedir. Bu çalışmada, mevcut bir yapı seçilmiş ve öncelikle dolgu duvarlar salt düşey yük (DY) olarak ideCAD yapı analiz programında modellenmiş daha sonra dolgu duvarlar DY ve hem düşey yük hem de eşdeğer basınç çubuğu (DY+EBÇ) olarak Sap2000 yapı analiz programında oluşturulmuştur. Sap2000’deki DY+EBÇ modeli DY modeli ile mukayese edildiğinde; yapı performansının arttığı, burulma ve yumuşak kat gibi düzensizlik değerlerinin değiştiği görülmüştür.

This study investigates the effect of infill walls on the risk of progressive collapse in reinforced concrete (RC) frames. Previous studies are suggestive of the effect of infill walls on improving the structural strength and rigidity against seismic failures. However, there are few studies on the effect of infill walls under vertical forces induced by progressive collapse. It is anticipated that infill walls would also contribute to the structural strength and rigidity during a progressive collapse. The results of this study can help better our understanding of the performance of concrete frames with infill walls during the progressive collapse. To this end, a three-dimensional model was developed for the nonlinear finite element analysis of an RC frame with infill walls under progressive collapse conditions. Experimental results have been used for calibrating the numerical model. The effect of the infill wall, infill wall arrangement, openings in the infill wall, and the opening size, location, and shape were investigated. According to the results, infill wall significantly increased structural strength and rigidity against progressive collapse. Moreover, studied alternatives may help better understanding of the performance of infilled RC frames during progressive collapse. [ABSTRACT FROM AUTHOR]

The bundled lipped channel–concrete (BLC-C) composite wall structure is a new structure with several advantages such as a high bearing capacity and good seismic performance. However, interface cracks between a BLC-C composite wall and the infill wall (non-structural wall) are a severe problem and need to be urgently resolved. Interface cracks affect not only the esthetics, but also the normal use of a building. The presence of interface cracks changes the perceptions of the owners of a structure, forcing them to question its safety and even take legal action against its developer. Therefore, in this study we aimed to investigate the initial cracking of the interface between a BLC-C composite wall and an infill wall. Unidirectional horizontal loading tests were conducted on two infill wall specimens constrained by BLC-C composite walls on both sides. The finite element analysis software ANSYS was used to simulate the loading process of the tests. The test results were compared to verify the accuracy of the finite element model. A finite element analysis was conducted to determine the effect of the horizontal displacement of the specimens when the interface initially cracked under different parameters such as the widths of the BLC-C composite wall, infill wall, and opening as well as the strength grade of the bricks and maximum normal contact stress. The results showed that a decrease in the width of the BLC-C composite wall or a rise in the width of the infill wall delayed the appearance of interface cracks. A large opening also delayed the occurrence of interface cracks. An enhancement in the strength grade of the bricks led to an earlier appearance of interface cracks. Interface cracks occurred later with an increase in the maximum normal contact stress between the BLC-C composite wall and the infill wall.

This paper presents a mechanical model developed for the simulation of the monotonic behaviour of Steel frames with Reinforced Concrete infill Walls (SRCW). In particular, it deals with a specific typology of SRCW, obtained from the classical one through the interposition of dissipative elements in the columns and by stiffening and shaping the steel frame's corners in a way to prevent the brittle failure of the concrete in compression. This system has demonstrated in past researches to be able to overcome the typical problems of SRCWs and to assure, through a capacity design approach, a global ductile behavior. The selection of the main components to be included in the model is carried out on the base of the analysis of the available experimental tests and of the results of accurate 3D Finite Element model analyses. The behaviour of each component is represented though consolidated models present in the current state-of-the-art and, where necessary, calibrated using the results of the experimental and numerical analyses. The capacity of the proposed mechanical model in representing the global behaviour of the SRCWs is finally demonstrated comparing the results in terms of force–displacement curves with the ones obtained through the refined 3D Finite Element models. [ABSTRACT FROM AUTHOR]

The results of an experimental study of four infilled frames with brick masonry walls subject to reversal cyclic lateral load are presented. The variables studied were the height to length aspect ratio of the wall and the use of joint reinforcement. The investigation was motivated by the fact that the Mexican code establishes the same specifications about the use of joint reinforcement for infill walls as for confined walls, because there is not enough experimental evidence on joint reinforced infill walls. To investigate the possible interaction of the study variables in the seismic performance of the walls, two pairs of specimens, scaled 1:2, with different aspect ratios (H/L = 0.75, 0.41) were tested. The specimens in each pair were identical except that one of them included steel bars into the bed-joints as reinforcement leading to amount phfyh=0.6 MPa. The infill walls with H/L = 0.41 were included from a previous study. The behavior of the specimens was defined in terms of lateral strength, ductility, displacement capacity, deformation of the joint reinforcement and crack pattern. The results indicate that joint reinforcement increases the strength of the system; however, the increase was more pronounced in longer walls. Ductility was reduced with horizontal reinforcement and this behavior was more important for longer walls. As occurred in confined walls, the joint reinforcement generates a more distributed cracking and reduces the width of the cracks. The experiments are described and this and other results are discussed in detail.

Summary: This paper presents an innovative capacity‐based design procedure that aims to achieve the ideal seismic performance for the composite partially restrained (PR) steel frame‐reinforced concrete (RC) infill wall with concealed vertical slits (PSRCW‐CVS). The proposed method adopts the direct capacity design principles and preselected preferred plastic mechanism such that the RC infill wall undergoes ductile failure prior to the other steel components in the event of a rare‐level earthquake (i.e., earthquake with a 2% probability of exceedance in 50 years). Based on the ultimate resisting capacity of RC infill walls, the free‐body diagrams and simplified design formulae for the surrounding steel components, including the vertical boundary element (VBE), horizontal boundary element (HBE), PR connection, and shear connectors, were proposed. To demonstrate the reasonability of the capacity‐based design procedure, a five‐story PSRCW‐CVS structure was designed according to the proposed design method, followed by a series of nonlinear time history analyses. The overall seismic response of this example was evaluated in terms of story displacement, interstory drift ratio, residual story displacement, and residual interstory drift ratio. The proposed method yielded a more uniform interstory drift ratio distribution along the height of the five‐story PSRCW‐CVS structure. Structural damage was controlled by achieving the preselected preferred plastic mechanism. [ABSTRACT FROM AUTHOR]

Summary: In order to investigate the seismic performance of steel‐reinforced recycled concrete (SRRC) frame with infill wall, low cyclic loading tests on four frames with infill wall and one frame without infill wall were conducted. The failure modes, hysteresis loops, skeleton curves, bearing capacity, ductility, stiffness degradation, and energy dissipation capacity of specimens were analyzed. The seismic performance of SRRC frames with and without infill wall was compared. The influence of the aspect ratio of infill wall, the axial compression ratio of column, and the distance of horizontal reinforcements of infill wall were investigated. Test results show that compared to the SRRC frame without infill wall, the SRRC frame with infill wall had higher bearing capacity and initial stiffness, but faster stiffness degradation and worse energy dissipation capacity. With the increase of aspect ratio of infill wall and axial compression ratio of column, the bearing capacity and initial stiffness of SRRC frame with infill wall increased, whereas the ductility decreased. With the decrease of distance of horizontal reinforcements of infill wall, the initial stiffness and energy dissipation capacity of SRRC frame with infill wall increased. After the infill wall fails under earthquake, the remaining SRRC frame has good seismic performance. [ABSTRACT FROM AUTHOR]

Copyright of Acta Technica Napocensis: Civil Engineering & Architecture is the property of Universitatea Tehnica din Cluj-Napoca, Facultatea de Constructii and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to reasonably predict the seismic demand of composite partially-restrained steel frame-reinforced concrete (RC) infill walls with concealed vertical slits (PSRCW-CVS) subjected to the near-fault earthquake records with strong velocity-pulse effect, an innovative performance-based plastic design (PBPD) approach is developed in current study. The maximum effective cyclic energy (MECE), which can reflect this phenomenon that the structural dissipated input energy from near-fault pulse earthquake record commonly focuses on the largest yield excursion, is introduced and adopted as a new design indicator (ΔEh,max). The design base shear is determined according to the instantaneous energy balance concept and pre-selected desirable yield mechanism, which considers that the MECE demand obtained from MECE spectrum at target ductility ratio is equivalent to the instant energy supply from structural components. Additionally, the MECE calculating formula of each component of PSRCW-CVS structure is also provided. Four PSRCW-CVS illustrations (5-storey and 10-storey) with different target ductility ratio were designed according to the proposed PBPD methodology, and their seismic behaviors corresponding to the rare earthquake level were assessed through nonlinear time-history analysis method using the selected near-fault earthquake records with velocity-pulse effect. The analytical results show that four PSRCW-CVS structures can achieve the intended seismic behavior in terms of MECE, inter-story drift ratio, and residual inter-story drift ratio. The PSRCW-CVS structure exhibits the ideal progressively developed plastic mechanism. The reliability and reasonability of this PBPD method combined with MECE spectrum are verified, and it can be easily extended to other dual lateral load resisting systems. [ABSTRACT FROM AUTHOR]