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The Top 20 Most-Cited Papers from 2022 to 2023
2020 Vol. 35, No. 12
Display Method:
2020, 35(12): 1-7.
doi: 10.13206/j.gjgS20091601
Abstract
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Abstract:
Self-centering structure is a new type of resumable structure, which can effectively control the residual deformation after earthquake and can be restored after a little maintenance. In recent years, self-centering structure has become a hot spot in the field of seismic engineering. At present, self-centering structure dissipates seismic energy mainly in two ways:plastic deformation of metal or friction damper. However, the above two modes usually have a large reduction resistance, which puts forward higher requirements on the reset members and adversely affects the self-centering performance of the joints. How to reduce the reduction resistance is an important problem that needs to be solved for such structure.
Based on the above problem, a new type of self-centering concrete-filled square steel tubular column-steel beam joint with slotted energy dissipation plates is proposed. The reduction resistance of the joints can be effectively reduced by setting slots on the energy dissipation plates. The joints is mainly composed of square concrete-filled steel tube column, steel beam, cantilever beam, slotted energy dissipation plates, cover plates, shear plates and strands, etc. In order to explore the failure mode, seismic performance, selfcentering performance and energy dissipation capacity of the joints, finite element software ABAQUS was used to simulate and analyze the self-centering square concrete-filled steel tubular column-steel beam joints. The moment-angular hysteretic curves, bearing capacity and characteristic moment, single-cycle hysteretic energy dissipation and residual deformation were obtained. Five joints were designed to compare the influences of the number of slots, the width and thickness of energy dissipation plates and the prestress of strands on seismic performance of the joints.
The results show that under seismic behavior, the hysteretic curves show "double flags" shape, and the joints have good bearing capacity, self-centering capacity and energy dissipation capacity. The main components are basically in elastic and the energy dissipation plates have obvious plastic deformation under 4. 00% displacement angle, indicating that the joints can control the damage locally and reduce the plastic damage on main components. The more slots of energy dissipation plates, the worse energy dissipation capacity and the better self-centering performance. However, it has no significant influence on the bearing capacity and characteristic moment of the joints. With the increase of width and thickness of energy dissipation plates, the energy dissipation capacity increases, the self-centering capacity decreases, and the bearing capacity increases. With the increase of prestress in strands, the initial stiffness, bearing capacity and decompression moment are increased, and the self-centering capacity is enhanced, but the energy dissipation capacity is less affected.
Self-centering structure is a new type of resumable structure, which can effectively control the residual deformation after earthquake and can be restored after a little maintenance. In recent years, self-centering structure has become a hot spot in the field of seismic engineering. At present, self-centering structure dissipates seismic energy mainly in two ways:plastic deformation of metal or friction damper. However, the above two modes usually have a large reduction resistance, which puts forward higher requirements on the reset members and adversely affects the self-centering performance of the joints. How to reduce the reduction resistance is an important problem that needs to be solved for such structure.
Based on the above problem, a new type of self-centering concrete-filled square steel tubular column-steel beam joint with slotted energy dissipation plates is proposed. The reduction resistance of the joints can be effectively reduced by setting slots on the energy dissipation plates. The joints is mainly composed of square concrete-filled steel tube column, steel beam, cantilever beam, slotted energy dissipation plates, cover plates, shear plates and strands, etc. In order to explore the failure mode, seismic performance, selfcentering performance and energy dissipation capacity of the joints, finite element software ABAQUS was used to simulate and analyze the self-centering square concrete-filled steel tubular column-steel beam joints. The moment-angular hysteretic curves, bearing capacity and characteristic moment, single-cycle hysteretic energy dissipation and residual deformation were obtained. Five joints were designed to compare the influences of the number of slots, the width and thickness of energy dissipation plates and the prestress of strands on seismic performance of the joints.
The results show that under seismic behavior, the hysteretic curves show "double flags" shape, and the joints have good bearing capacity, self-centering capacity and energy dissipation capacity. The main components are basically in elastic and the energy dissipation plates have obvious plastic deformation under 4. 00% displacement angle, indicating that the joints can control the damage locally and reduce the plastic damage on main components. The more slots of energy dissipation plates, the worse energy dissipation capacity and the better self-centering performance. However, it has no significant influence on the bearing capacity and characteristic moment of the joints. With the increase of width and thickness of energy dissipation plates, the energy dissipation capacity increases, the self-centering capacity decreases, and the bearing capacity increases. With the increase of prestress in strands, the initial stiffness, bearing capacity and decompression moment are increased, and the self-centering capacity is enhanced, but the energy dissipation capacity is less affected.
2020, 35(12): 16-21.
doi: 10.13206/j.gjgS20091801
Abstract:
A new shear metal damper with square tubes serving as out-of-plane stiffeners is proposed. The damper is mainly composed of a core plate, square tubes welded to the core plate, flange plates at two sides and connectors for installation. In this displacement-based metallic device, the input seismic energy is mainly dissipated through the shear deformation of the core plates. The core plates are made of a low-yield-point steel with a nominal yield stress of 225 MPa, called LYP225 steel. This material possesses relatively low yield strength, moderate hardening level and good ductility, hence is suitable for metal dampers.
The paper presents the results of quasi-static tests conducted for evaluating the cyclic elastoplastic response, ultra-low fatigue failure modes and energy dissipation behavior of shear dampers made of LYP225 steel. A total of three full-scale steel shear dampers were tested with the loading condition and flange shape as test variables. The essential mechanical characteristics and ultra-low fatigue behavior of the damper specimens under cyclic loadings were investigated, and the influence of the flange shape to the failure mode was analyzed.
The test results show that the shear damper made of LYP225 steel possesses good ductility (the ultimate shear angle of the specimens achieved 4. 7%), plump hysteretic response (no sign of buckling of components and no pinching of the hysteretic loops observed during the cyclic tests), favorable energy dissipation capacity (the equivalent damping ratio of the specimens stably maintained approximately 0. 5), and satisfying ultra-low cycle fatigue performance (the loads of the specimens under thirty cycles of design amplitude were stable with slight cracks developed). The cracks of the flanges developed at the welding regions limit the deformation capacity and energy dissipation capacity of the dampers. The " dog-bone" configuration for flanges can well delay the initiation of these undesirable cracks and improve the seismic performance of the dampers. The maximum overstrength factor of specimens reached as large as 1. 63, and this hardening phenomenon is beneficial for energy dissipation but need careful consideration for preventing the second damage to the main structural components.
A new shear metal damper with square tubes serving as out-of-plane stiffeners is proposed. The damper is mainly composed of a core plate, square tubes welded to the core plate, flange plates at two sides and connectors for installation. In this displacement-based metallic device, the input seismic energy is mainly dissipated through the shear deformation of the core plates. The core plates are made of a low-yield-point steel with a nominal yield stress of 225 MPa, called LYP225 steel. This material possesses relatively low yield strength, moderate hardening level and good ductility, hence is suitable for metal dampers.
The paper presents the results of quasi-static tests conducted for evaluating the cyclic elastoplastic response, ultra-low fatigue failure modes and energy dissipation behavior of shear dampers made of LYP225 steel. A total of three full-scale steel shear dampers were tested with the loading condition and flange shape as test variables. The essential mechanical characteristics and ultra-low fatigue behavior of the damper specimens under cyclic loadings were investigated, and the influence of the flange shape to the failure mode was analyzed.
The test results show that the shear damper made of LYP225 steel possesses good ductility (the ultimate shear angle of the specimens achieved 4. 7%), plump hysteretic response (no sign of buckling of components and no pinching of the hysteretic loops observed during the cyclic tests), favorable energy dissipation capacity (the equivalent damping ratio of the specimens stably maintained approximately 0. 5), and satisfying ultra-low cycle fatigue performance (the loads of the specimens under thirty cycles of design amplitude were stable with slight cracks developed). The cracks of the flanges developed at the welding regions limit the deformation capacity and energy dissipation capacity of the dampers. The " dog-bone" configuration for flanges can well delay the initiation of these undesirable cracks and improve the seismic performance of the dampers. The maximum overstrength factor of specimens reached as large as 1. 63, and this hardening phenomenon is beneficial for energy dissipation but need careful consideration for preventing the second damage to the main structural components.
2020, 35(12): 22-28.
doi: 10.13206/j.gjgS20082602
Abstract:
With the development of high-rise buildings, horizontal load has become a key factor in structural design. Steel plate shear walls (SPSWs) are widely utilized in practical engineering due to its superior lateral resistant performance. Researchers have carried out indepth research on the mechanical performance. SPSWs have advantages of high ultimate lateral resistance, but their disadvantages still exist:the hysteretic curve appears " pinching" under cyclic load, especially the huge noise produced by thin steel plate, which affect the human comfort of buildings. Corrugated steel plate has advantages of large out-plane stiffness and high ductility due to the existence of corrugation, "in-pate shear yielding" mechanism can be achieved. Compared with ordinary SPSWs, steel corrugated shear walls (SCSWs) still need further investigations. Analysis of lateral resistance of SCSWs under the combined action of lateral load and vertical load is lacking.
The finite element analysis(FEA) was used to analyze the lateral resistant mechanism of SCSWs, and the corresponding threshold flexural rigidity of columns was proposed, influence of vertical load on the performance of infill plates was studied, and design suggestions were given. Firstly, the finite element software ABAQUS was used to simulate the cyclic load test, and the results of test and simulation fitted well, which verified the validity and accuracy of FEA. Through the load-displacement curves of two typical cases, two different lateral resistant mechanisms were revealed. The fact that corrugated plate could resist lateral load through "in-plate shear yielding" or "diagonal tension-field" mechanism was revealed by comparing the bending moment distribution of two typical cases, and the lateral resistant mechanism was determined by the parameter of infill plates only. When SCSWs resist lateral load in "diagonal tension-field" mechanism, low residual resistance may occur due to the "diagonal tension-field" can not be fully developed with the existence of corrugation. Secondly, based on the requirements of the flexural rigidity of columns of unstiffened flat steel shear walls, the influence of the flexural rigidity of boundary columns on the performance of infill corrugated plates was analyzed. It was revealed that with the increase of normalized aspect ratio, the effect of flexural rigidity of boundary columns was more significant. The corrugated infill plate could be considered to resist lateral load with "in-plate shear yielding" mechanism when the normalized aspect ratio λn ≤ 0. 45. In this case, the requirements of the flexural rigidity of columns were small, the boundary columns with flexural rigidity EI ≥ 0. 5EI* were recommended. Infill plates with normalized aspect ratio λn ≤ 0. 45 were recommended to ensure sufficient residual resistance. Finally, the influence of vertical load on the performance of infill plate in the range of λn ≤ 0. 45 was analyzed. Observing the change of lateral resistance of infill plates when changing the axial pressure on columns, the fact that vertical load had little effect on the maximum resistance was revealed. But the residual resistance would drop due to the shear force of infill plates could not be fully developed when boundary columns had large vertical compression in residual state. With the increase of λn, the drop of residual resistance was more significant. This situation could be avoided by increasing the cross-sectional area of boundary columns.
With the development of high-rise buildings, horizontal load has become a key factor in structural design. Steel plate shear walls (SPSWs) are widely utilized in practical engineering due to its superior lateral resistant performance. Researchers have carried out indepth research on the mechanical performance. SPSWs have advantages of high ultimate lateral resistance, but their disadvantages still exist:the hysteretic curve appears " pinching" under cyclic load, especially the huge noise produced by thin steel plate, which affect the human comfort of buildings. Corrugated steel plate has advantages of large out-plane stiffness and high ductility due to the existence of corrugation, "in-pate shear yielding" mechanism can be achieved. Compared with ordinary SPSWs, steel corrugated shear walls (SCSWs) still need further investigations. Analysis of lateral resistance of SCSWs under the combined action of lateral load and vertical load is lacking.
The finite element analysis(FEA) was used to analyze the lateral resistant mechanism of SCSWs, and the corresponding threshold flexural rigidity of columns was proposed, influence of vertical load on the performance of infill plates was studied, and design suggestions were given. Firstly, the finite element software ABAQUS was used to simulate the cyclic load test, and the results of test and simulation fitted well, which verified the validity and accuracy of FEA. Through the load-displacement curves of two typical cases, two different lateral resistant mechanisms were revealed. The fact that corrugated plate could resist lateral load through "in-plate shear yielding" or "diagonal tension-field" mechanism was revealed by comparing the bending moment distribution of two typical cases, and the lateral resistant mechanism was determined by the parameter of infill plates only. When SCSWs resist lateral load in "diagonal tension-field" mechanism, low residual resistance may occur due to the "diagonal tension-field" can not be fully developed with the existence of corrugation. Secondly, based on the requirements of the flexural rigidity of columns of unstiffened flat steel shear walls, the influence of the flexural rigidity of boundary columns on the performance of infill corrugated plates was analyzed. It was revealed that with the increase of normalized aspect ratio, the effect of flexural rigidity of boundary columns was more significant. The corrugated infill plate could be considered to resist lateral load with "in-plate shear yielding" mechanism when the normalized aspect ratio λn ≤ 0. 45. In this case, the requirements of the flexural rigidity of columns were small, the boundary columns with flexural rigidity EI ≥ 0. 5EI* were recommended. Infill plates with normalized aspect ratio λn ≤ 0. 45 were recommended to ensure sufficient residual resistance. Finally, the influence of vertical load on the performance of infill plate in the range of λn ≤ 0. 45 was analyzed. Observing the change of lateral resistance of infill plates when changing the axial pressure on columns, the fact that vertical load had little effect on the maximum resistance was revealed. But the residual resistance would drop due to the shear force of infill plates could not be fully developed when boundary columns had large vertical compression in residual state. With the increase of λn, the drop of residual resistance was more significant. This situation could be avoided by increasing the cross-sectional area of boundary columns.
2020, 35(12): 29-35.
doi: 10.13206/j.gjgS20111501
Abstract:
Coupled steel plate shear wall is a new type of lateral resisting system by linking coupling beam between steel plate shear walls. The introduction of coupling beam changes the anti-overturning mechanism, thus affecting the column's stability and structural deformation. Therefore, the cross-section of the coupling beam was used as a variable to study the influence of the coupling action derived from coupling beam on the stability and deformation of the coupling steel plate shear wall.
A full-scale 6-story steel plate shear wall was taken as the prototype, changing the coupling beam section, then Abaqus was used to simulate the monotonic and cycle loading. The results show that, the coupling effect of coupling beam can reduce the compression of the outer column then lighten the structural instability. With the increase of section height of coupling beam, the structural shear capacity is gradually increased, but the increasing trend is smaller and the instability of the shear capacity is increased gradually. Before the drift ratio reaches 1/50, the structure is in normal use stage, while the shear capacity decreases significantly and the structure is in the risk of collapse after exceeding the drift ratio of 1/30. When ductility is used as criterion, the coupling ratio has an optimal interval, as it rises from 0. 6 to 1. 2, the structural ductility basically shows the phenomenon of rapid rise→ gentle rise→ slow decline→rapid decline. The coupling ratio of the gentle rise stage can attain the optimal interval.
Coupled steel plate shear wall is a new type of lateral resisting system by linking coupling beam between steel plate shear walls. The introduction of coupling beam changes the anti-overturning mechanism, thus affecting the column's stability and structural deformation. Therefore, the cross-section of the coupling beam was used as a variable to study the influence of the coupling action derived from coupling beam on the stability and deformation of the coupling steel plate shear wall.
A full-scale 6-story steel plate shear wall was taken as the prototype, changing the coupling beam section, then Abaqus was used to simulate the monotonic and cycle loading. The results show that, the coupling effect of coupling beam can reduce the compression of the outer column then lighten the structural instability. With the increase of section height of coupling beam, the structural shear capacity is gradually increased, but the increasing trend is smaller and the instability of the shear capacity is increased gradually. Before the drift ratio reaches 1/50, the structure is in normal use stage, while the shear capacity decreases significantly and the structure is in the risk of collapse after exceeding the drift ratio of 1/30. When ductility is used as criterion, the coupling ratio has an optimal interval, as it rises from 0. 6 to 1. 2, the structural ductility basically shows the phenomenon of rapid rise→ gentle rise→ slow decline→rapid decline. The coupling ratio of the gentle rise stage can attain the optimal interval.
2020, 35(12): 36-42.
doi: 10.13206/j.gjgS20091501
Abstract:
Steel plate shear wall structure is a kind of anti-side force structural system that uses steel plates embedded in steel frames as the basic structural unit. Using connecting beams, two steel plate shear walls are connected to form a joint steel plate shear wall. The introduction of connecting beams can firstly make the steel plate wall structure more flexible and convenient, which is beneficial to increase the overall bending capacity and rigidity of the steel plate wall structure, and even form a steel core tube structure system with better lateral resistance. The second is to use steel coupling beams to dissipate energy and enhance the energy dissipation capacity of the structure.
In this paper, the hysteretic behavior of the jointed steel plate shear wall was studied. The existing experiments were simulated by ABAQUS finite element modeling software. The validity of the model was verified by comparing the results. First, by changing the height of the connecting beam and the thickness of the wall plate, 10 sets of steel plate shear wall models with different coupling ratio (CR) were obtained, and a single push analysis was performed to obtain the relationship between the CR and the axial force ratio of the column. The axial force of the frame side column and the inner column will approach as the CR increases. When the CR is less than 0. 6, the inner column of the right steel plate shear wall was stretched and the side column was compressed. When the CR is greater than 0. 6, the inner column and side column of the right side steel plate shear wall were compressed. Because the increase in CR is due to the enhanced coupling effect of the coupling beam on the structure, and the coupling beam can transmit axial force, the greater the CR, the stronger the coupling effect of the coupling beam, and the stronger its ability to transmit axial force. Therefore, the axial force of the side column can be shared, and the column 3 and the column 4 can be compressed at the same time. When the CR is small, the overturning moment is mainly resisted by the coupling formed by the side column axial force. As the CR increases, the inner column axial force increases correspondingly, which can resist overturning and protect the side column. In an ideal state, the side column and the inner column are destroyed at the same time. Then, in order to study the influence of the CR on the hysteretic performance of the joint steel plate shear wall, the CR was changed by changing the coupling beam section and the thickness of the wall panel, and six specimen models were obtained. The effect of the CR, coupling beam section size and wall thickness on the bearing capacity, ductility, stiffness degradation, energy dissipation capacity and failure mode of the joint steel plate shear wall structure was studied through pseudo-static analysis. The research shows that when the CR is between 0. 4~0. 6, the coupling beam and the wall panel can produce sufficient shear yield. The plastic hinge at the end of the column finally appeared, causing structural damage. Steel coupling beams can participate in the energy dissipation of the structure well, and the "steel plate shear wall-frame" anti-lateral force system has been improved to the "steel plate shear wall-steel coupling beam-frame" anti-side force system.
Steel plate shear wall structure is a kind of anti-side force structural system that uses steel plates embedded in steel frames as the basic structural unit. Using connecting beams, two steel plate shear walls are connected to form a joint steel plate shear wall. The introduction of connecting beams can firstly make the steel plate wall structure more flexible and convenient, which is beneficial to increase the overall bending capacity and rigidity of the steel plate wall structure, and even form a steel core tube structure system with better lateral resistance. The second is to use steel coupling beams to dissipate energy and enhance the energy dissipation capacity of the structure.
In this paper, the hysteretic behavior of the jointed steel plate shear wall was studied. The existing experiments were simulated by ABAQUS finite element modeling software. The validity of the model was verified by comparing the results. First, by changing the height of the connecting beam and the thickness of the wall plate, 10 sets of steel plate shear wall models with different coupling ratio (CR) were obtained, and a single push analysis was performed to obtain the relationship between the CR and the axial force ratio of the column. The axial force of the frame side column and the inner column will approach as the CR increases. When the CR is less than 0. 6, the inner column of the right steel plate shear wall was stretched and the side column was compressed. When the CR is greater than 0. 6, the inner column and side column of the right side steel plate shear wall were compressed. Because the increase in CR is due to the enhanced coupling effect of the coupling beam on the structure, and the coupling beam can transmit axial force, the greater the CR, the stronger the coupling effect of the coupling beam, and the stronger its ability to transmit axial force. Therefore, the axial force of the side column can be shared, and the column 3 and the column 4 can be compressed at the same time. When the CR is small, the overturning moment is mainly resisted by the coupling formed by the side column axial force. As the CR increases, the inner column axial force increases correspondingly, which can resist overturning and protect the side column. In an ideal state, the side column and the inner column are destroyed at the same time. Then, in order to study the influence of the CR on the hysteretic performance of the joint steel plate shear wall, the CR was changed by changing the coupling beam section and the thickness of the wall panel, and six specimen models were obtained. The effect of the CR, coupling beam section size and wall thickness on the bearing capacity, ductility, stiffness degradation, energy dissipation capacity and failure mode of the joint steel plate shear wall structure was studied through pseudo-static analysis. The research shows that when the CR is between 0. 4~0. 6, the coupling beam and the wall panel can produce sufficient shear yield. The plastic hinge at the end of the column finally appeared, causing structural damage. Steel coupling beams can participate in the energy dissipation of the structure well, and the "steel plate shear wall-frame" anti-lateral force system has been improved to the "steel plate shear wall-steel coupling beam-frame" anti-side force system.
2020, 35(12): 43-49.
doi: 10.13206/j.gjgS20120701
Abstract:
A new modular composite shear wall with double steel plates and infill concrete is proposed for increasing lateral resistance of steel frame. The shear wall module is connected to the upper and lower beams by bolting. The wall modules are prefabricated in the factory, and the whole wall is fully bolted on the construction site. Therefore, the new type of composite shear wall is convenient and quick to construct, convenient for assembly and disassembly, and it can be removed at the end of the building life, and it is green and environmentally friendly. In thi paper, the lateral performance of the modular composite shear wall with double steel plates and infill concrete was analyzed numerically.
First, the experimental results on concrete filled steel box shear wall were referred to establish the ABAQUS finite element model for predictions, which shows the reliability of the established ABAQUS model. Then the 23 finite element models of the modular composite shear wall with double steel plates and infill concrete were established, and the number of wall modules, concrete compressive strength, steel yield strength, axial compression ratio and steel plate thickness were investigated to discuss the influence on the lateral resistance, the lateral stiffness and the ductility.
The wall can be divided into 1 to 4 modules. With the increase in the number of divided wall modules, the yield load and peak load of the wall decrease, and the overall capacity of the wall gradually decreases; the ultimate displacement of the wall gradually increases, the ductility coefficient became larger and the deformation capacity increased. For concrete compressive strength is taken as from 30 MPa to 80 MPa. As the strength of concrete increased, the lateral stiffness of the wall increased slightly, and the ultimate displacement basically showed a decreasing trend. The ductility coefficient of the wall gradually decreased. The deformability of the wall gradually decreased, but the reduction was not large. For the yield strength of steel plates is compared from 235 MPa to 500 MPa. As the yield strength of the steel plate increased, the yield load and peak load of the wall gradually increased, and the resistance increased; the yield displacement and ultimate displacement of the wall gradually increased, the ductility coefficient of the wall gradually increased, and the deformation capacity increased. For the axial compression ratio, the variation range was from 0. 1 to 0. 6, with an increase of 0. 1 for each level. When the axial compression was relatively small, increasing the axial compression ratio can increase the yield load and peak load of the composite shear wall. The steel plate thickness is analyzed from 2 mm to 6 mm. With the increase of the thickness of the steel plate, the yield load and peak load of the wall gradually increased, the resistance increased, the initial lateral stiffness of the wall gradually increased, the ductility coefficient gradually increased, and the deformation capacity increased.
From the analysis, it can be found that increasing concrete strength, steel plate yield strength, and steel plate thickness can improve wall resistance, and increasing steel plate yield strength and steel plate thickness will increase its ductility. The lateral stiffness of the modular composite shear wall with double steel plates and infill concrete under horizontal load is contributed by the concrete part and the steel plate. Increasing the thickness of the steel plate can improve its lateral stiffness. The more the number of the wall is divided into modules, the lower the initial stiffness and the lower the overall resistance. It is suggested that the number of divided modules should not exceed 3 under the conditions of meeting the construction environment.
A new modular composite shear wall with double steel plates and infill concrete is proposed for increasing lateral resistance of steel frame. The shear wall module is connected to the upper and lower beams by bolting. The wall modules are prefabricated in the factory, and the whole wall is fully bolted on the construction site. Therefore, the new type of composite shear wall is convenient and quick to construct, convenient for assembly and disassembly, and it can be removed at the end of the building life, and it is green and environmentally friendly. In thi paper, the lateral performance of the modular composite shear wall with double steel plates and infill concrete was analyzed numerically.
First, the experimental results on concrete filled steel box shear wall were referred to establish the ABAQUS finite element model for predictions, which shows the reliability of the established ABAQUS model. Then the 23 finite element models of the modular composite shear wall with double steel plates and infill concrete were established, and the number of wall modules, concrete compressive strength, steel yield strength, axial compression ratio and steel plate thickness were investigated to discuss the influence on the lateral resistance, the lateral stiffness and the ductility.
The wall can be divided into 1 to 4 modules. With the increase in the number of divided wall modules, the yield load and peak load of the wall decrease, and the overall capacity of the wall gradually decreases; the ultimate displacement of the wall gradually increases, the ductility coefficient became larger and the deformation capacity increased. For concrete compressive strength is taken as from 30 MPa to 80 MPa. As the strength of concrete increased, the lateral stiffness of the wall increased slightly, and the ultimate displacement basically showed a decreasing trend. The ductility coefficient of the wall gradually decreased. The deformability of the wall gradually decreased, but the reduction was not large. For the yield strength of steel plates is compared from 235 MPa to 500 MPa. As the yield strength of the steel plate increased, the yield load and peak load of the wall gradually increased, and the resistance increased; the yield displacement and ultimate displacement of the wall gradually increased, the ductility coefficient of the wall gradually increased, and the deformation capacity increased. For the axial compression ratio, the variation range was from 0. 1 to 0. 6, with an increase of 0. 1 for each level. When the axial compression was relatively small, increasing the axial compression ratio can increase the yield load and peak load of the composite shear wall. The steel plate thickness is analyzed from 2 mm to 6 mm. With the increase of the thickness of the steel plate, the yield load and peak load of the wall gradually increased, the resistance increased, the initial lateral stiffness of the wall gradually increased, the ductility coefficient gradually increased, and the deformation capacity increased.
From the analysis, it can be found that increasing concrete strength, steel plate yield strength, and steel plate thickness can improve wall resistance, and increasing steel plate yield strength and steel plate thickness will increase its ductility. The lateral stiffness of the modular composite shear wall with double steel plates and infill concrete under horizontal load is contributed by the concrete part and the steel plate. Increasing the thickness of the steel plate can improve its lateral stiffness. The more the number of the wall is divided into modules, the lower the initial stiffness and the lower the overall resistance. It is suggested that the number of divided modules should not exceed 3 under the conditions of meeting the construction environment.
2020, 35(12): 50-57.
doi: 10.13206/j.gjgS20112702
Abstract:
Stainless steel and aluminum alloy were classified as the non-linear metallic materials due to the absence of obvious yielding point and yielding plateau. When the member cross-sectional stress level increases beyond the proportional limit strength that is usually lower than the nominal yield strength, there exists gradually decreased tangent modulus but remarkable strain hardening capacity, which has significant impact on the local plate buckling and overall column buckling resistances. The commonly adopted effective cross-section approach has been introduced into the calculation methods for predicting the column resistances that account for the local-overall interaction effect, while this may result in complicated computation process for irregular cross-sections and neglect the restraint conditions between adjacent constitutive plates.
The available experimental results on local-overall interactive buckling of axial compression members made of stainless steel and aluminum alloy were summarized, including welded stainless steel I-sections and box sections, and extruded aluminum alloy I-sections and box sections. The elaborated numerical models that were developed by means of the general finite element (FE) software package ABAQUS incorporated the representation of material non-linearity of stainless steel and aluminum alloy, the initial local and global geometric imperfections and the welding residual stresses. The numerically simulated buckling resistances and failure modes were compared with the test results, and thus the accuracy of the developed numerical models were verified. By using the validated FE models, a large number of axial compression members subjected to interactive buckling were generated, and the obtained numerical results were used to carry out parametric studies. The influences of the normalized nominal yield strength, the strain hardening exponent, the initial local and global geometric imperfections and the welding residual stresses on the column buckling resistance were explored.
Based on the summarized test results and obtained numerical data points, design expressions of the direct strength method (DSM) in the current North American Specification for the Design of Cold-Formed Steel Structural Members (AISI S100-16) were evaluated, and it was revealed that the existing expressions provided inaccurate and unsafe predictions for the interactive buckling resistance of axial compression members made of non-linear metallic materials. Newly modified calculation formulae of the direct strength method (DSM) for predicting the interactive buckling resistances were therefore proposed by regression analysis for various materials and cross-section types. By referring to the reliability index in the Chinese Unified Standard for Reliability Design of Building Structures (GB 50068- 2018) and the resistance partial factors provided in the Chinese Code for Design of Aluminum Structures (GB 50429-2007) and the Chinese Technical Specification for Stainless Steel Structures (CECS 410:2015), the reliability analysis of the newly proposed expressions were conducted under a total of four different load combinations and twelve load cases, and it was shown that the computed reliability index values were all higher than the target value of 3. 2. It can therefore be concluded that the proposed DSM expressions satisfy the reliability requirements set in the Chinese standards, and their applicability to predict the interactive buckling resistances of axial compression members made of non-linear metallic materials has also been demonstrated.
Stainless steel and aluminum alloy were classified as the non-linear metallic materials due to the absence of obvious yielding point and yielding plateau. When the member cross-sectional stress level increases beyond the proportional limit strength that is usually lower than the nominal yield strength, there exists gradually decreased tangent modulus but remarkable strain hardening capacity, which has significant impact on the local plate buckling and overall column buckling resistances. The commonly adopted effective cross-section approach has been introduced into the calculation methods for predicting the column resistances that account for the local-overall interaction effect, while this may result in complicated computation process for irregular cross-sections and neglect the restraint conditions between adjacent constitutive plates.
The available experimental results on local-overall interactive buckling of axial compression members made of stainless steel and aluminum alloy were summarized, including welded stainless steel I-sections and box sections, and extruded aluminum alloy I-sections and box sections. The elaborated numerical models that were developed by means of the general finite element (FE) software package ABAQUS incorporated the representation of material non-linearity of stainless steel and aluminum alloy, the initial local and global geometric imperfections and the welding residual stresses. The numerically simulated buckling resistances and failure modes were compared with the test results, and thus the accuracy of the developed numerical models were verified. By using the validated FE models, a large number of axial compression members subjected to interactive buckling were generated, and the obtained numerical results were used to carry out parametric studies. The influences of the normalized nominal yield strength, the strain hardening exponent, the initial local and global geometric imperfections and the welding residual stresses on the column buckling resistance were explored.
Based on the summarized test results and obtained numerical data points, design expressions of the direct strength method (DSM) in the current North American Specification for the Design of Cold-Formed Steel Structural Members (AISI S100-16) were evaluated, and it was revealed that the existing expressions provided inaccurate and unsafe predictions for the interactive buckling resistance of axial compression members made of non-linear metallic materials. Newly modified calculation formulae of the direct strength method (DSM) for predicting the interactive buckling resistances were therefore proposed by regression analysis for various materials and cross-section types. By referring to the reliability index in the Chinese Unified Standard for Reliability Design of Building Structures (GB 50068- 2018) and the resistance partial factors provided in the Chinese Code for Design of Aluminum Structures (GB 50429-2007) and the Chinese Technical Specification for Stainless Steel Structures (CECS 410:2015), the reliability analysis of the newly proposed expressions were conducted under a total of four different load combinations and twelve load cases, and it was shown that the computed reliability index values were all higher than the target value of 3. 2. It can therefore be concluded that the proposed DSM expressions satisfy the reliability requirements set in the Chinese standards, and their applicability to predict the interactive buckling resistances of axial compression members made of non-linear metallic materials has also been demonstrated.
