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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.

This paper studies the impact of half-height infilled walls on the failure modes of frame columns through quasi-static tests of both frame models and half-height infilled wall frame models. Based on the experimental results, a seismic analysis model of reinforced concrete (RC) frame structures is established, and parametric studies are carried out to analyze the effects of masonry materials and masonry heights on the seismic performance of structures. The results show that the load-bearing capacity and stiffness of the structure are improved, while the ductility of the structure is reduced because of the existence of infilled walls. As the height of infilled walls increases, there is a notable decrease in the free height of frame columns. At a wall-to-column height ratio of 0.2, the masonry walls exert a negligible effect on the frame structure’s seismic performance. In contrast, at a ratio of 0.6, there is a transition in column failure modes from bending to shearing. When evaluated at consistent masonry heights, aerated concrete block-infilled walls demonstrate the least impact on the seismic performance of RC frame structures. Thus, in the absence of additional structural enhancements, the use of aerated concrete blocks is recommended to mitigate the negative implications of infilled walls on the seismic integrity of RC frames.

Infilled walls and frames typically employ closely spaced rigid connection, which, under seismic actions, can lead to adverse effects such as amplified seismic responses, overall torsion, and the formation of weak layers in the structure. Flexible connection isolating the infilled walls from the frames can effectively mitigate the adverse effects of rigid connections. In order to reduce the structural mass and seismic impacts, Autoclaved Aerated Concrete (AAC) masonry flexible connection infilled walls have been widely researched. However, most AAC masonry flexible connection infilled walls require complex process operations for AAC blocks, which is not conducive to practical applications in engineering. Therefore, an AAC flexible connection infilled wall with Basalt Fiber Grating (BFG) strips instead of steel bars, with simplified process operations, has been proposed. Existing finite element models for BFG strip-reinforced AAC masonry flexible connection infilled walls employ solid elements, which are difficult to apply to large-scale structural simulations; moreover, existing simplified models for flexible connection infilled walls cannot simulate out-of-plane loading. In this paper, based on homogenization methods, using simplified elements to simulate components, a simplified model for the BFG strip-reinforced AAC masonry flexible connection infilled frame is proposed. Utilizing this model, stress analyses under both in-plane and out-of-plane loading are conducted and compared with corresponding experimental results. The results indicate that the in-plane simplified model (ISM) fits well with the experimental results in terms of hysteresis curves, with similar relationships between stiffness degradation and strength attenuation. The displacement force curve of the out-of-plane simplified model (OSM) before reaching the peak load is in good agreement with the experimental results. The maximum plastic range of OSM is 5% smaller than the test results, and it can be considered that the plastic ranges of the two are comparable, manifesting the models’ capability to adequately manifest arching behavior. The simplified model enables simulation of out-of-plane loading and provides a new approach for modeling large-scale frame structures with flexible connection infilled wall.

Out-of-plane (OOP) damage is one of the main failure modes for infill walls in frames during earthquakes, which can result in significant economic losses, injuries, and fatalities, and is difficult to repair. This paper investigates the effect of in-plane(IP) damage on the out-of-plane performance of infill walls using recycled concrete blocks with the finite element software ABAQUS and t was used to model and analyse the infill walls with recycled concrete block frames, and the modelling method is verified by the test results. The out-of-plane performance of 20 infill walls with recycled concrete block specimens of different aspect ratios and block sizes was investigated under various inter-story drift damage conditions. The results indicate that in-plane damage has little effect on the out-of-plane bearing capacity when the inter-story drift is 0.15%, and the initial out-of-plane stiffness of the infill walls increases by 5.4%. However, when the in-plane inter-story drift reaches 0.5%, the out-of-plane bearing capacity decrease by more than 50%, and the initial stiffness and ductility also decrease significantly. The study found that the thickness-to-diagonal length ratio of the infill walls has a prominent effect on the out-of-plane strength reduction, and an empirical formula for the in-plane damage and the out-of-plane strength reduction coefficient was proposed and fitted to the data obtained from the finite element analysis with a root mean square error of 0.18.

User-defined plastic hinge properties obtained experimentally are used to examine the structural behavior of bare, infilled walled frames with and without anchor bars in reinforced concrete (RC) buildings. Experimentally obtained moment-curvature relationships of structural members (i.e., beams and columns) are used to determine the plastic hinge properties of each section. Three building frames are modeled and examined for time-history analysis using 20 ground-motion records. Seismic performance levels of three buildings are analyzed to determine the effects of anchor bars. Limit states at each performance level are defined, and the multi-record incremental dynamic analysis curves are obtained; 16%, 50%, and 84% fractal curves are obtained for each case. Cumulative distribution functions are constructed to summarize the varieties in the roof-drift ratios of three RC buildings with different frame types for design-based and maximum-considered earthquake hazards. It is found that, with an increased spectral acceleration of ground motions, the probability of exceeding the performance levels of infilled walled frames in reinforced buildings is reduced with the help of anchor bars. The increased stiffness of RC buildings with infilled wall frames exhibiting lower ductility is re-gained by the absorption energy of the anchor bars.

This study describes an experimental and numerical investigation on the seismic behaviour of masonry infilled hinged steel frames with openings. Experimental tests of six half-scaled, single-storey and single-bay specimens including one bare hinged steel frame, one solid infilled hinged steel frame, and four masonry infilled hinged steel frames with different opening sizes were carried out under lateral cyclic loading. The cracking patterns, failure modes, hysteretic behaviour, characteristic loads and displacements, stiffness degradation and equivalent viscous damping ratios of these specimens were compared. Furthermore, detailed three-dimensional finite element (FE) models of test specimens were developed in the commercially available FE code ABAQUS, and a series of nonlinear pushover analyses were performed. In particular, the lateral load–displacement relationships of test specimens were numerically simulated and validated against the experimental results. In addition, the mechanical behaviour of infilled walls under lateral loading was investigated.

A structure is subjected to progressive collapse when an element fails, resulting in failure of adjoining structural elements which, in their turn, cause further structural failure leading eventually to partial or total collapse. The failure of a primary vertical support might occur due to extreme loadings such as bomb explosion in a terrorist attack, gas explosion and huge impact of a car in the parking area. Different guidelines such as the General Services Administration (GSA 2003 ) and the Unified Facilities Criteria (UFC 2009 ) addressed the structural progressive collapse due to the sudden loss of a main vertical support. In the current study, a progressive collapse assessment according to the UFC guidelines is carried out for a typical ten-story reinforced concrete framed structure designed according to codes [(ACI 318-08) and (ASCE 7-10)] for minimum design loads for buildings and other structures. Fully nonlinear dynamic analysis for the structure was carried out using Applied Element Method (AEM). The investigated cases included the removal of a corner column, an edge column, an edge shear wall, internal columns and internal shear wall. The numerical analysis showed that simplification of the problem into 3D bare frames would lead to uneconomical design. It was found for the studied case that, the infilled masonry walls have a valuable contribution in mitigating progressive collapse of the reinforced concrete framed structures. Neglecting these walls would lead to uneconomical design.

Experiments were performed on four specimens of steel frames with infilled recycled aggregate concrete shear walls (SFIRACSWs), one specimen of infilled ordinary concrete wall, and one pure-steel frame were conducted under horizontal low cyclic loading. The influence of the composite forms of steel frames and RACSWs (namely, infilled cast-in-place and infilled prefabricated) on the failure modes, transfer mechanisms of lateral force, bearing capacity, and ductility of SFIRACSWs is discussed, and the concrete type and connecting stiffness of beam–column joints (BCJs) are also considered. Test results showed that infilled RACSWs can increase the bearing capacity and lateral stiffness of SFIRACSWs. The connecting stiffness of BCJs slightly influences the seismic behavior of SFIRACSWs. In the infilled cast-in-place RACSWs, the wall cracks mainly extended along the diagonal direction. The bearing capacity was 2.4 times higher than in the pure steel frame, the initial stiffness was 4.3 times higher, and the displacement ductility factors were 2.44–2.69 times higher. In the infilled prefabricated RACSWs, the wall cracks mainly extended along the connection between the embedded T-shape connectors and walls before finally connecting along the horizontal direction. Moreover, shear failure occurred in the specimens. The bearing capacity was 1.44 times higher than that of the pure steel frame, the initial stiffness was 2.8 times higher, and the displacement ductility factors were 3.32–3.40 times higher. The degradation coefficients of the bearing capacity were more than 0.85, indicating that the specimens demonstrated a high safety reserve.

In accordance with damages of infilled wall frame structures in Wenchuan earthquake, the current 2010 version of \"Seismic Design Code of Building\" is attached herewith increasing significance to infilled wall, which switches \"consider the impact of infilled wall on seismic performance of frame structure and avoid main structure destruction caused by setting infilled wall unreasonably \" from a general provision into a mandatory provision, however, a specific quantitative description on the impact of infilled wall on seismic performance of frame structure is still absent. The impact of infilled wall on seismic performance of frame structure is analyzed in the paper, and two suggestions pertain to design and research of infilled wall is proposed under current phase: on the one hand, \"conceptual design\" should be kept on highlighting in the seismic design of infilled wall frame structures; on the other hand, based on the concept of \"performance-based seismic design\", the idea that infilled wall should be treated distinctively is put forward.

Infilled wall is always regarded as a nonload bearing element, its energy-dissipation capacity and impact for the frame structure under earthquake have not been taken seriously. In this paper the function of infilled wall for frame structure was discussed, energy-dissipation capacity of different measures were analysed and compared from the point of passive control theory. This paper provides the reference for the further research of filler wall.