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Nader K A Attari - One of the best experts on this subject based on the ideXlab platform.
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new formulation for predicting Diagonal Tension capacity of masonry brick walls strengthened with textile reinforced mortar trm
Materials and Structures, 2021Co-Authors: M Shabdin, M Zargaran, Nader K A AttariAbstract:In this paper, a new analytical model for evaluating the in-plane shear capacity of strengthened clay brick masonry walls using textile reinforced mortar is proposed. The accuracy of the proposed model is calibrated with the experimental data. The thickness of masonry wall, the thickness of reinforcement layer, the number of reinforcement layers on each sides of the specimen (fiber percentage), reinforcement configuration (strengthening on one side or both sides of the specimen), and the type of textile reinforcements (alkali resistant-glass textiles or carbon textiles) are the major parameters in the experimental investigations that are considered in the proposed model. The presented analytical model could show a reasonable agreement with the experimental results.
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experimental Diagonal Tension shear test of un reinforced masonry urm walls strengthened with textile reinforced mortar trm
Construction and Building Materials, 2018Co-Authors: M Shabdin, M Zargaran, Nader K A AttariAbstract:Abstract The presented study is part of ongoing experimental program on Un-Reinforced Masonry (URM) walls strengthened with Textile reinforced mortars (TRM). Ten walls were tested under Diagonal Tension (shear) test method in order to consider the effect of strengthening system on the behavior of brick walls. One plain wall was tested as reference. Two walls were overlaid with 15 and 25 mm thick of high strength mortar on one face without any textile sheet. Another seven walls were externally strengthened with 15 and 25 mm thick of AR-Glass Textile Reinforced Mortar (TRM) on one or both faces. Results confirmed the efficient possibility of shear strengthening of existing URM walls using TRM, especially for those strengthened on both faces. On the other hand, one face strengthened walls were sensitive to the applied load and can buckle or experience out-of-plane deformations. TRM extremely improved Diagonal load carrying capacity and deformation capacity, which caused the strengthened walls fail in a ductile manner. The governing failure mode was out-of-plane deformation for one face strengthened walls, and failure of both faces strengthened walls was controlled by initiation of substrate toe crushing in compression continued by Diagonal crashing. Results showed that for masonry walls strengthened on both faces, during pure in-plane Diagonal load, there is no need to mechanical connection between TRM and masonry substrate. However, out-of-plane failure is an important issue for masonry walls, especially for those strengthened on one face. Therefore, connectors must be designed for out-of-plane lateral force to ensure that masonry wall and TRM reinforcement layer work together properly.
Michel Bruneau - One of the best experts on this subject based on the ideXlab platform.
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Diagonal Tension field inclination angle in steel plate shear walls
Journal of Structural Engineering-asce, 2017Co-Authors: Fangbo Wang, Michel BruneauAbstract:AbstractResearch was conducted to investigate how the inclination angle of the Diagonal Tension field action varies in steel plate shear walls (SPSWs) and to determine what optimum constant angle b...
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capacity design of vertical boundary elements in steel plate shear walls
Scopus, 2008Co-Authors: Jeffrey W Berman, Michel BruneauAbstract:Design requirements now appear in the 2005 AISC Seismic Provisions for Structural Steel Buildings (AISC, 2005b), referred to herein as The Provisions, for steel plate shear walls (SPSWs) that are designed such that their web plates buckle in shear and develop Diagonal Tension fi eld action when resisting lateral loads. Energy dissipation and ductility during seismic events is principally achieved through yielding of the web plates along the Diagonal Tension fi eld. Consistent with capacity design principles, The Provisions require that the vertical and horizontal boundary elements (VBEs and HBEs) of SPSWs, as shown in Figure 1, be designed to remain essentially elastic with the exception of plastic hinging at the ends of horizontal boundary elements. The commentary of The Provisions provides some guidance on how to achieve this requirement. However, the methods described in the commentary, as shown in this paper, do not necessarily lead to VBEs that meet the requirement of essentially elastic behavior under the forces generated by fully yielded web plates. This paper reviews the current approaches provided in The Provisions commentary for determination of capacity design loads for the VBEs of SPSWs and also describes how the capacity design objective may be achieved using nonlinear static analysis. Then, a new procedure is proposed that uses a fundamental plastic collapse mechanism and linear beam analysis to approximate the design actions for VBEs of SPSWs for given web plates and horizontal boundary member sizes. The proposed procedure does not involve nonlinear analysis, making it practical for use in design. VBE design loads are estimated using both the current and proposed procedures for two example SPSW confi gurations. The resulting design loads are then compared with the VBE design loads as determined by nonlinear pushover analysis.
Yan Zhou - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation into the seismic behavior of squat reinforced concrete walls subjected to acid rain erosion
Journal of building engineering, 2021Co-Authors: Yan Zhou, Shansuo Zheng, Liuzhuo Chen, Li Long, Bin WangAbstract:Abstract Acid rain erosion will continuously deteriorate the physical and mechanical properties of materials and finally degrade the seismic performance of reinforced concrete (RC) structures. Nevertheless, the effect of acid deposition on squat RC walls, an important part of lateral force-resisting systems, has not been reported in existing research. Thus, in this paper, an artificial climate simulation method was used to accelerate the acidic attack process on four squat RC wall specimens with an aspect ratio of 1.0. Then quasi-static loading tests were conducted to observe their cyclic behavior under different acid rain spraying cycles (ARSCs). The results show that as ARSCs increase, the degree of degradation of concrete strength and the corrosion weight loss of steel bars have a rising trend, and the bearing capacity and deformation capacity of the squat RC walls deteriorate gradually. Simultaneously, the ratio of shear displacement to total lateral displacement increases, indicating a more noticeable shear failure characteristic with the addition of ARSCs. Moreover, the failure mode shifts from the mixed flexure and Diagonal compression mode to the Diagonal Tension mode with a significant decrease in ductility and energy-dissipation capacity. It is also found that the degradation rate of the shear strength of squat walls under acid rain erosion is larger than that of the flexural strength, which may lead to the transition of failure mode.
M Shabdin - One of the best experts on this subject based on the ideXlab platform.
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new formulation for predicting Diagonal Tension capacity of masonry brick walls strengthened with textile reinforced mortar trm
Materials and Structures, 2021Co-Authors: M Shabdin, M Zargaran, Nader K A AttariAbstract:In this paper, a new analytical model for evaluating the in-plane shear capacity of strengthened clay brick masonry walls using textile reinforced mortar is proposed. The accuracy of the proposed model is calibrated with the experimental data. The thickness of masonry wall, the thickness of reinforcement layer, the number of reinforcement layers on each sides of the specimen (fiber percentage), reinforcement configuration (strengthening on one side or both sides of the specimen), and the type of textile reinforcements (alkali resistant-glass textiles or carbon textiles) are the major parameters in the experimental investigations that are considered in the proposed model. The presented analytical model could show a reasonable agreement with the experimental results.
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experimental Diagonal Tension shear test of un reinforced masonry urm walls strengthened with textile reinforced mortar trm
Construction and Building Materials, 2018Co-Authors: M Shabdin, M Zargaran, Nader K A AttariAbstract:Abstract The presented study is part of ongoing experimental program on Un-Reinforced Masonry (URM) walls strengthened with Textile reinforced mortars (TRM). Ten walls were tested under Diagonal Tension (shear) test method in order to consider the effect of strengthening system on the behavior of brick walls. One plain wall was tested as reference. Two walls were overlaid with 15 and 25 mm thick of high strength mortar on one face without any textile sheet. Another seven walls were externally strengthened with 15 and 25 mm thick of AR-Glass Textile Reinforced Mortar (TRM) on one or both faces. Results confirmed the efficient possibility of shear strengthening of existing URM walls using TRM, especially for those strengthened on both faces. On the other hand, one face strengthened walls were sensitive to the applied load and can buckle or experience out-of-plane deformations. TRM extremely improved Diagonal load carrying capacity and deformation capacity, which caused the strengthened walls fail in a ductile manner. The governing failure mode was out-of-plane deformation for one face strengthened walls, and failure of both faces strengthened walls was controlled by initiation of substrate toe crushing in compression continued by Diagonal crashing. Results showed that for masonry walls strengthened on both faces, during pure in-plane Diagonal load, there is no need to mechanical connection between TRM and masonry substrate. However, out-of-plane failure is an important issue for masonry walls, especially for those strengthened on one face. Therefore, connectors must be designed for out-of-plane lateral force to ensure that masonry wall and TRM reinforcement layer work together properly.
Mohamed Elgaaly - One of the best experts on this subject based on the ideXlab platform.
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hazard mitigation and strengthening of unreinforced masonry walls using composites
Composite Structures, 2006Co-Authors: Wael W Eldakhakhni, Ahmad A Hamid, Zeyad H R Hakam, Mohamed ElgaalyAbstract:An experimental investigation was conducted to study the behavior of unreinforced masonry (URM) walls retrofitted with composite laminates. The first testing phase included testing 24 URM assemblages under different stress conditions present in masonry walls. Tests included prisms loaded in compression normal and parallel to bed joints, Diagonal Tension specimens, and specimens loaded under joint shear. In the second testing phase, five masonry-infilled steel frames were tested with and without retrofit. The composite laminates increased the stiffness and strength and enhanced the post-peak behavior by stabilizing the masonry walls and preventing their out-of-plane spalling. Tests reported in this paper demonstrate the efficiency of composite laminates in improving the deformation capacity of URM, containing the hazardous URM damage, preventing catastrophic failure and maintaining the wall integrity even after significant structural damage.
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experimental study of thin steel plate shear walls under cyclic load
Journal of Structural Engineering-asce, 1993Co-Authors: Vincent Caccese, Mohamed Elgaaly, Ruobo ChenAbstract:The results of an investigation into the seismic behavior of unstiffened thin steel–plate shear walls is presented. Little work has been done in the past to investigate the behavior of unstiffened thin steel–plate shear walls in resisting lateral forces due to earthquakes or wind. Described is the cyclic testing of six, 1:4 scale specimens that include a moment-resisting frame, three specimens with varying plate thickness and moment-resisting beam-to-column connections, and two specimens with shear beam-to-column connections. Dissimilarities in behavior modes are found when the specimens of different plate thickness are compared to each other. The specimens with thinner plates exhibit an inelastic behavior that is controlled primarily by yielding of the thin plate, and the nonlinear system behavior is predominantly due to the stretching of the plate and the formation of a Diagonal Tension field. The specimens with thicker plates show an inelastic behavior that is primarily governed by the columns, and the capacity of the specimen with the thickest plate is limited by the instability of the column.