Skeleton Curves Research Articles

Seismic behavior of novel resilient and corrosion-resistant composite columns using strain-hardening engineered cementitious composites and steel-FRP composite bars

This paper proposed a novel composite column with exceptional resilience and corrosion resistance achieved through the casting of engineered cementitious composites (ECCs) in the plastic hinge region and the utilization of steel-FRP composite bars (SFCBs). A total of six specimens were tested under constant axial load and cyclic lateral load to examine their seismic performance and reparability. The influence of the type of longitudinal reinforcement (steel bar, SFCB, and GFRP bar) and the matrix type (ECC and concrete) in the plastic hinge region was discussed. Test results indicated that configuring SFCB in the columns facilitated drift-hardening characteristics, which in turn enhanced resilience. The adoption of ECC in the plastic hinge region further reduced residual deformation of the composite columns while significantly improving both lateral strength and ductility. The maximum repairable limit of the specimens increases by a factor of 1.36, 1.86, and 2.5, respectively, as the FRP content increases from 0% to 31.3%, 56.4%, and 100%. The specimens reinforced with SFCBs can be quickly restored to their intended use without repair, before reaching a 2% drift ratio. The slip effect of SFCBs has a substantial impact on increasing the lateral displacement of test columns, and this effect tends to increase with an increase in FRP content. A fiber model was developed for predicting the skeleton curves, and its accuracy was validated through comparisons between the predicted and test results.

Experimental study on the seismic performance of concrete-filled steel tube columns with a multiple-chamber round-ended cross-section

Reinforced concrete bridge piers with round-ended sections are susceptible to bending, bending–shear, and shear failure after earthquakes in high-intensity areas, thus necessitating improved seismic performance. This study introduced a novel design for a concrete-filled steel tube (CFST) column, featuring a multi-chambered, round-ended cross-section. The use of longitudinal and transverse stiffeners divided the column section into distinct chambers, thereby enhancing the seismic performance of the columns. A total of 12 groups of static tests were performed to examine the effect of chamber layout, axial compression ratio, and aspect ratio on columns’ hysteresis behavior, and the hysteresis curves, skeleton curves, failure modes, stiffness degradation, ductility, and energy dissipation capacity were obtained. Results demonstrated the favorable seismic performance of composite columns. Additionally, an increase in chambers led to a full hysteresis curve, enhancing bearing and energy dissipation capacities. The displacement ductility coefficient (μ) ranged between 3.88 and 7.45, and the design parameters have minimal influence on the stiffness degradation of the composite beam. Based on the results, the long and short sides of the CFST columns with a large length–width ratio should be arranged to be relatively close in length.

Seismic performance of ternary composite geopolymer recycled concrete columns: Experimental study and modeling

In order to achieve seismic-resistant structures cast from green building materials, a new kind of column, ternary composite geopolymer concrete with recycled aggregates containing recycled fireclay brick aggregates (GRA-RFBAC) column, was proposed in this paper. The ternary binder material in GRA-RFBAC was produced by the combination of industrial by-products (ground granulated blast furnace slag (GGBS), recycled fireclay brick powder (RFBP), and fly ash (FA)) and alkali-activated solution. Cyclic loading tests of five reinforced GRA-RFBAC columns, each with a shear-to-span ratio of 3.07, were conducted to investigate the seismic performance. The influence of the recycled aggregate containing recycled fireclay brick aggregate (RA-RFBA) replacement ratio, stirrup spacing, and axial compression ratio on the seismic performance of GRA-RFBAC columns was discussed. The results indicated that all specimens showed similar flexural failure modes under cyclic loading. The first cracking of concrete occurred within the drift ratio range of 0.18%–0.41%, the failure drift ratio varied from 3.27% to 4.11%, and the peak load of the specimens ranged from 237.50 kN to 288.87 kN. Although increasing the RA-RFBA replacement ratio led to a decrease in both the bearing capacity and lateral stiffness of the columns, the GRA-RFBAC columns showed comparable or even better seismic performance than Portland cement concrete columns. Moreover, a prediction model for the skeleton curve of GRA-RFBAC columns was proposed and verified by comparing the prediction results with the test results.

Effects of Prestressing Magnitude and Position on Seismic Performance of Unbonded Prestressed Concrete Beams

To study the effects of the jacking stress level, height and strength ratio of the prestress tendons (λ) on the seismic performance of unbonded prestressed concrete (UPC) beams, six UPC beams and one reinforced concrete (RC) beam were tested under cyclic loads. The hysteretic characteristics, skeleton curves, ductility properties, energy dissipation capacity, strain distribution of reinforcement and self-centering capability of the specimens were studied and discussed. Numerical parameter analysis was also carried out by using OpenSees. The results indicate that three failure modes of UPC beams under cyclic loading were observed, namely the tension-failure mode involving a broken rebar, the compression-failure mode involving concrete crushing and the balanced failure. By considering the influence of the prestress position and magnitude, the modified reinforcing index ω was proposed to determine the failure mode. The ω is suggested to be less than 0.3 to ensure sufficient ductility. The effective stress level is linearly and positively related to the stiffness from cracking to yield Kcr and the ultimate bearing capacity of the UPC beam under cyclic loading. The stiffness of the UPC beam is slightly larger than that of the RC beam before yielding, and significantly greater than that of the RC beam after yielding. Due to the large strength reserve after yielding, the integrated seismic performance of the UPC beam is similar to that of the RC beam. When the λ was unchanged, the increase in the relative height of the prestressed tendons αh is beneficial for the overall performance factor F, ductility and crack control. The stiffness degradation performance depends on the λ but is independent of the αh. The total energy dissipation of the non-tensioned UPC specimen was 59% higher than that of the RC beam. The cumulative total energy dissipation of the tensioned UPC specimen was only 13% lower than that of the RC beam with the same number of cycles, indicating that the UPC specimen had a considerable energy dissipation capacity.

Hysteretic behavior and moment-rotation model of self-centering beam-column connection with angle steel

The objective of this study is to develop a moment-rotation model (M-θ) to evaluate the hysteresis behavior of self-centering beam-column connection with replaceable angle steel. Based on the previous pseudo-static test results of 13 groups of 22 beam-column joint specimens, the hysteretic behavior of the joint and the prestress loss of the post-tensioned (PT) strand are further studied. According to the phased hysteretic characteristic of the beam-column joint and the connection characteristic of two interfaces, the M-θ model for beam-column connection is established, which is divided by four key points: opening point, yield point, peak point and ultimate point. The proposed M-θ model includes the bilinear moment-rotation (M-θs) model of the endplate-bolt interface based on the component method, and the trilinear moment-rotation (M-θr) model of the self-centering interface considering the prestress loss of PT strand and the phased mechanical behavior of each component. The accuracy of the proposed M-θ model is verified by the comparisons of theoretical calculation results and experimental skeleton curves, which provides a theoretical basis for the engineering design of this kind self-centering beam-column connection.

Seismic behavior of prefabricated frame with special‐shaped concrete‐filled steel tubular columns and H‐shaped steel beams

AbstractTo realize the prefabricated structure of special‐shaped concrete‐filled steel tubular (CFST) column frame and enhance the level of indoor room utilization, this paper proposed a novel prefabricated frame with special‐shaped CFST columns and H‐shape steel beams connection with side plate. To investigate seismic behavior of this prefabricated frame structure, a 2‐story and 2‐bay CFST frame specimen was fabricated and tested under reversed cyclic loading. The failure mode, hysteresis behavior, degradation of lateral stiffness and bearing capacity, ductility and energy dissipation were analyzed. Experiment results indicated that failure mode presented strong columns and weak beams. Hysteresis curve of frame showed fully shuttle‐shaped. The mean story drift angle was 1/36 at ultimate stage. Equivalent viscous damping coefficient was 0.038–0.464. The bearing capacity degradation was relatively gentle, but the overall stiffness degradation was more obvious. It suggested that the frame had proper seismic and energy dissipation property. After the test, the seismic property of test frame was further investigated through the numerical simulation approach. The failure mode and skeleton curve obtained from the simulation were nearly consistent with test results, indicating that numerical analysis results were precise and with high reference meaning.

Seismic Performance of U-Shaped Connection for Prefabricated Steel Plate Shear Wall

In this investigation, a U-shaped connection (U-C) was introduced for a prefabricated steel plate shear wall with beam-only connections. This design replaces a portion of shear bolts with tension bolts to enhance bolt efficiency and reduce the overall bolt count, and it is suitable for a prefabricated high-rise steel structure. Four 1/3 scale specimens were designed, and an array of performance aspects including failure modes, hysteretic behavior, skeleton curves, energy dissipation capacity, stiffness degradation, and key performance indicators were systematically investigated through a combination of quasi-static tests and finite element analyses. The results showed that the combination arrangement of tensile and shear bolts in U-C effectively reduced the usage of bolts used and reduced installation costs; under low cycle reciprocating loads, the ultimate bearing capacity and energy dissipation capacity of a beam-only-connected prefabricated steel plate shear wall with U-shaped connection (BPSW-U) had slightly decreased compared with the prefabricated steel plate shear wall with discontinuous cover-plate connection (DCPC). Nevertheless, the BPSW-U excelled in preserving the integrity of the frame beams, channeling structural plastic deformations primarily into the infilled steel plate. This design feature ensures that post-earthquake functionality recovery can be achieved by simply replacing the infilled steel plate.

Low-Cyclic Reversed Loading Tests on Full-Scale Precast Concrete Composite Wall Connected by Tooth Groove and Grouted Sleeve.

In this paper, a novel precast concrete composite wall connected by tooth groove and grouted sleeve was introduced, which is produced in factories by means of structure-insulation integrated prefabrication, and the prefabrication and assembly process were presented minutely. To verify the feasibility and reliability of this novel tooth groove and grouted sleeve connection method and explore the joint connection performance and the seismic performance of the precast concrete composite wall connected by tooth groove and grouted sleeve, low-cyclic reversed loading tests with an axial compressive ratio of 0.1 were performed on two full-scale precast concrete composite walls. Moreover, the failure mode, hysteretic curve, skeleton curve, stiffness degradation, displacement ductility, energy dissipation capacity, and reinforcement strain were comprehensively discussed. The research results showed that under the vertical axial load and low-cyclic reversed load, the distributed reinforcements in the wall panel only played a structural role, while the connecting reinforcements at horizontal joints can always effectively transfer stress without bond failure, and the tooth groove and grouted sleeve connection performance was reliable. In addition, the hysteretic curves of the precast concrete composite wall connected by tooth groove and grouted sleeve were full, showing good ductile deformation capacity and energy dissipation capacity. In general, the precast concrete composite wall connected by tooth groove and grouted sleeve not only possessed favorable seismic performance but also showed obvious advantages such as green energy saving, high assembly rate, and less on-site wet operation, which can be applied to practical engineering under reasonable design.

Energy dissipation evaluation of butterfly-shaped steel plate shear keys under different loading protocols

This paper proposes a novel energy dissipation shear key (ED shear key) for small-to-medium-span highway bridges using butterfly-shaped steel plates for enhanced energy dissipation capacity. Reversed cyclic loading tests were conducted on two series of specimens which had different designs of structural dimensions. Four distinctive loading protocols were adopted to allow an in-depth examination of the seismic hysteretic behavior and energy dissipation capacity of the ED shear keys. The test results reveal that the ED shear keys exhibited distinctive characteristics before and after buckling of steel plates. The recorded force-displacement curves of the ED shear keys were plump before buckling and typically became pinched after buckling. The loading protocol had a significant effect on the energy dissipation of the ED shear key specimens, with an over 90% increase in energy dissipation observed under the constant-amplitude loading protocol compared to the incremental-amplitude ones. It was found from the test results that the profile of the force-displacement skeleton curves was hardly affected by the loading protocols, as a result a trilinear skeleton model is developed to characterize the force-displacement relationship of the ED shear keys. Furthermore, by decomposing the force-displacement hysteresis curve into a skeleton part and a Bauschinger part, an evaluation model is established for predicting the energy dissipation capacity of the ED shear keys. Validation against the test results indicates that the evaluation model can provide a satisfactory accuracy for predicting the energy dissipation of the ED shear keys subjected to various loading protocols.

Experimental Study on Seismic Performance of Prefabricated Columns Connected Using a Novel Dry Sleeve

Prefabricated structures are widely used because of their advantages of energy savings, environmental protection, standardization, and universality. However, due to the complex structure of the joints, it is easy to make the joint installation difficult and the prefabricated column connection unreliable, and further lead to the poor seismic performance of the structure. Therefore, a new type of dry sleeve joint with double screw sleeve without support is proposed, and the seismic performance and influencing factors of the new dry-sleeve-joint prefabricated column are studied. This study encompasses seven reinforced concrete columns characterized by cross-sectional dimensions of 600 mm × 600 mm. Among these, five specimens feature a novel dry sleeve connection, while the remaining two specimens were entirely cast-in-place. Low-cycle reversed loading experiments were conducted on all specimens to analyze and compare the damage patterns, hysteresis curves, skeleton curves, displacement ductility, energy dissipation capacity, and ultimate bearing capacity between precast and cast-in-place columns. Several parameters, including fabrication method, axial compression ratio, longitudinal reinforcement diameter, and hoop spacing, were examined. The findings demonstrated that the calculated-to-tested ratio of the ultimate bearing capacity for the prefabricated specimens was determined to be 0.62, indicating a high level of safety. The displacement ductility coefficient for each specimen ranged from 2.43 to 3.31, while the ultimate drift ratio was within the range of 1/41 to 1/33, satisfying the specified requirements for seismic performance. However, the hysteresis curve of the prefabricated specimens exhibited a pinching effect, which may be related to the existence of a weak layer on the joint surface of the post-cast section. In general, the shape of the new dry sleeve is maintained in the test, the connection form can effectively transfer the force, and the longitudinal bars can be strained and yield when the prefabricated column reaches the peak load. The new type of dry sleeve connection can be used for longitudinal reinforcement connection of reinforced concrete columns with seismic design.

Experimental study on the seismic behavior of an innovative stepped beam-column joint

Achieving favorable seismic performance in joints while maintaining flush alignment on the upper and lower surfaces of the beam flanges remains a current challenge. To address this issue, this paper introduces an innovative stepped beam-column joint. To study the seismic performance of the joint, four beam-column joint specimens with different configurations were tested under cyclic loading. The plastic development process, failure modes, hysteresis loops, skeleton curves, stiffness degradation, ductility, load-bearing capacity, and energy dissipation capacity of the joint specimens were carefully investigated. All joint specimens exhibited superior seismic performance and load-bearing capacity. Moreover, variations in plate configurations led to discrepancies in the final failure modes among different joint specimens. Finally, finite element models were established and verified for each joint specimen, and analyses of the tensile forces on outer bolts were conducted. Through the experimental and numerical analysis results, it was concluded that the proposed innovative stepped joint could exhibit excellent seismic performance, and could be recommended for practical application in engineering.

An efficient nonlinear hybrid model of energy dissipation piers utilizing fiber beam and self-developed hysteretic spring elements

Energy dissipation piers comprised of concrete filled steel tubular (CFST) columns and steel shear links can exhibit good seismic performance by reasonable collaborative optimization design of columns and links. Considering the time and economic costs of experiments and fine element analysis (FEA), an efficient and accurate numerical model is critical to investigate the hysteretic behavior of energy dissipation piers under earthquake action. Therefore, a hysteretic constitutive law for steel shear links is first proposed including the theoretical shear force-deformation skeleton curve and the unloading and reloading rules during hysteretic loading. Next, a hysteretic spring model is developed for efficiently simulating the hysteretic mechanical behavior of steel shear links, which is validated to have good accuracy with comparison to fine FEA and experimental results. Then, a simplified hybrid model consisting of the self-developed spring model and fiber beam model and two multi-scale FEA models with different levels of refinement are established for nonlinear analysis of energy dissipation piers, respectively. The comparison of numerical and test results confirms that the innovative fiber beam-spring hybrid model can accurately describe the hysteretic performance of energy dissipation piers, especially the detailed mechanical behavior of steel shear links and column feet, which provides an efficient numerical tool for analysing the collaborative working mechanism of energy dissipation piers and similar energy dissipation structures.

Experimental and numerical study on the seismic behavior of RC frame with energy dissipation self-centering hinge joints

Conventional reinforced concrete joints dissipate seismic energy through the deformation of plastic hinges, resulting in excessive residual deformation and difficult-to-repair damage. This paper proposes a new beam-column joint type: an Energy Dissipating Self-Centering Hinge Joint (EDSCHJ) with a high-stiffness spring and replaceable dampers fixed at the joint zone. The high stiffness spring provides restoring forces, and the replaceable dampers are utilized to dissipate seismic energy. A quasi-static test was conducted to investigate the seismic performance of the EDSCHJ. Three types of self-centering hinge joints with different dampers are designed and tested, and the hysteretic response, skeleton curve, stiffness degradation curve, and equivalent viscous damping coefficient of the EDSCHJ were obtained. The test results show that the specimens are undamaged at a story drift of 5%, the EDSCHJ without damper exhibits excellent self-centering capability with only a small residual deformation, the hysteresis curve of the EDSCHJ with dampers exhibits a full hysteresis loop with good energy dissipation capacity, the high-stiffness spring has remained elastic without strength degradation, and the lateral stiffness derived from the skeleton curve aligns closely with theoretical calculations. Finally, the finite element model of EDSCHJ is established and validated by comparing the test and numerical results. The structural parametric analysis reveals that as the relative lateral stiffness increases, the dynamic responses of the structure with EDSCHJ exhibits a increasing trend in displacement and an decreasing trend in acceleration and base shear. Additionally, the simulation results indicate an optimum relative stiffness ratio ranging from approximately 0.09 to 0.61.

Experimental and numerical study on seismic performance of prefabricated new fly ash foam concrete structure

In view of the current situation of solid waste resource utilization and the introduction of exterior wall insulation limit policy, this paper proposes a new type of assembled fly ash foam concrete structure for rural areas. After that, a 1:3 scaled specimen model was designed for the proposed static test with three actuators loaded synchronously, and the seismic performance of each floor of the structure was investigated by hysteresis curves, skeleton curves, ductility coefficients, equivalent damping ratios, and stiffness degradation curves, and compared with that of ordinary concrete structures. Finally, ABAQUS was used to establish the structural model with different porosity, and the effects of different porosity on the seismic performance of the structure were determined by comparing the results of tests and finite elements. The results show that the peak load of the assembled new fly ash foam concrete structure model is 84.9 kN, the ultimate displacement is 49.5 mm, the equivalent damping ratio is increased by 24.0 %, and the ductility coefficient is 2.15 compared with that of the ordinary concrete structure, with the increase of the pore rate, the damage location is mainly concentrated from the surface of the specimen to the corners of the doors and windows. The pore rate of 0.101 can simultaneously meet the requirements of structural lighting, economy, and load-bearing capacity. The proposal of an assembled new fly ash foam concrete structure enriches the structural form and lays the foundation for the design and application of this structure in the future.

Seismic performance analysis of steel frame installed with prefabricated external walls and new connection type

In order to solve the problems existing in prefabricated structure installed with non-structural elements, this paper proposes a new structure type, which is the steel frame installed with prefabricated external wall. Besides, a new connection method is also proposed and designed for this innovative structure type. Based on a specific engineering project, the full-scale pseudo-static cyclic loading test of the steel frame installed with prefabricated external wall (reinforced concrete) is conducted for analyzing the seismic performance of this structural system, which examines the ability of prefabricated external wall to adapt to the deformation of the main structure, the working performance of connection, the damage pattern of the whole structure and the influence of prefabricated wall on the load bearing capacity and stiffness of the main structure. The corresponding numerical simulation by ABAQUS is employed for further investigating the performance of prefabricated external wall and newly proposed connection methods. On the basis of verification about the accuracy of numerical model, the FEA (finite element analysis) models of the detail connection joints with different parameters are established, and the damage distribution, hysteresis curve, skeleton curve and stress distribution are analyzed and compared to explore the influence of the pre-tension force of bolts and thickness of steel plates on the seismic performance of the connections.

Mechanical Properties and Influence Factors of Ordinary Shear Links

The current specification requires the same limiting values of inelastic rotation and the overstrength factor for shear links with a length ratio less than 1.6. However, recent studies have shown that the mechanical properties of ordinary shear links with a length ratio ranging from 1.0 to 1.6 are obviously different from those of very short shear links with a length ratio less than 1.0. Additionally, shear links made of different steel materials have differences in mechanical properties. Based on Q345 steel, three ordinary shear links with a length ratio of 1.36 were designed to intensively explore the influence of stiffener configurations and spacing on mechanical properties. Under cyclic loading tests, the failure modes, hysteresis curves, skeleton curves, secant stiffness curves and energy dissipation capacities of shear link specimens were recorded. The results show that the overstrength factor and inelastic rotation of specimens SL-1 and SL-2, which had different stiffener configurations, reached 1.59 and 0.10, while those of specimen SL-3, which had wider stiffener spacing, reached 1.48 and 0.07, which showed that varying the stiffener configuration has no obvious effect, while relaxing stiffener spacing can result in severe buckling of the web. Additionally, its bearing capacity, inelastic rotation, secant stiffness and energy dissipation capacity reduced. Hence, the stiffener spacing should satisfy the requirements of the specification and not be too wide. Based on ABAQUS software, finite element models of ordinary shear links proved to be accurately consistent with test specimens in terms of mechanical properties. On this basis, 114 numerical models of ordinary shear links with different length ratios, stiffener spacings, flange-to-web area ratios, flange strengths, web depth-to-thickness ratios and stiffener thicknesses were designed to study the influence on the overstrength factor.

Identification of wheel track in the wheat field

Agriculture machinery navigating along permanent traffic lanes in the farmland may avoid causing extensive soil compaction. However, the permanent traffic lanes are frequently covered up or eliminated by following tillage practices. It is necessary to identify the wheel tracks designed as permanent traffic lanes in order to ensure the agriculture machinery travels along the designated wheel tracks when cultivating the field. This study proposed an identification method of wheel tracks based on the morphological characteristics of wheel tracks and the environmental conditions around the wheel tracks in the wheat fields. The proposed method first utilized the maximum interclass variance to identify the contours of the main part of the wheel track and the shadow regions around the wheel track’s edges. The main part of the wheel tracks was then separated from interference pixels by moving the centerline of the main part of the wheel track, which was derived by skeleton algorithm and curve fitting, towards the right or left edge of the wheel track at a specific distance. In a morphological opening operation, specific linear and circular structural elements were used to segment the shadow regions along the edge of the wheel track. The remaining wheel track was finally recognized by computing the complement of the region identified. After achieving the segmentation of wheel tracks, many reference points near the outside of the wheel track edge in the original image were chosen as fiducial points for evaluating the differences between the actual value and the recognized wheel track edge. The evaluation was based on computing the root mean squared error (RMSE) and the mean absolute error (MAE) of coordinates of reference points and recognized wheel track edge. The results showed that the largest RMSE and MAE were 24.01 pixels (0.0045 m) and 17.32 pixels (0.0032 m), respectively. The low values of RMSE and MAE reveal that the accuracy of the algorithm developed in this study is high, and using this algorithm may segment the wheel track in the wheat field accurately.

Study on the oblique seismic behavior of reinforced concrete L-shaped columns strengthened with carbon fiber reinforced polymer slabs

The oblique seismic performance of reinforced concrete L-shaped columns is an important factor that affecting the safety of structures. However, there is limited research on the oblique seismic performance of reinforced concrete L-shaped columns strengthened with carbon fiber reinforced polymer (CFRP) slabs mounted at the column bottom. In order to address the theoretical gap and meet the practical requirements, finite element analyses were conducted on L-shaped reinforced concrete columns. These analyses considered various parameters, including loading angle, strengthened method, volume stirrup ratio and axial compression ratio. The seismic performance indexes of L-shaped columns such as failure state, hysteretic curve, skeleton curve, carrying capacity, and ductility are investigated. The analyses results show that the failure mode of L-shaped column is bending failure, and the seismic performance of strengthened L-shaped column is better than that of unstrengthened L-shaped column. The CFRP slabs mounted at the column bottom could increase the peak carrying capacity and decrease the ductility coefficient of specimen. Therefore it is suggested to employ the method of strengthening column bottom by CFRP slabs in practical engineering application. Moreover, the peak carrying capacity of specimens under different loading angles is similar. With a higher loading angle, the positive peak carrying capacity of specimen increases, while the negative peak carrying capacity decreases. Finally, this study presents a novel method for determining the compression-bending carrying capacity of reinforced concrete L-shaped column, where the influence of torsion action is taken into account. This method offers valuable insights for the engineering design.

Study on the shear resistance of CFS walls with built-up side columns

This study experimentally and numerically investigated the shear resistance of cold-formed steel (CFS) walls with built-up side columns. Horizontal monotonic and reversed cyclic loading tests were performed on four full-scale CFS walls. The influence of aspect ratio on the shear resistance of the walls was investigated in terms of load-displacement curves, skeleton curves, energy dissipation, stiffness degradation, and cyclic bearing capacity degradation. The shear capacity, stiffness, and energy dissipation capacity of CFS walls with built-up side columns (CFSWs) were effectively improved with decreasing aspect ratio. In addition, finite element models of the wall specimens were established using ABAQUS and validated against the test results. A parametric study with twelve finite element models was also conducted to examine further the effect of essential parameters, including the aspect ratio, stiffeners, and thickness, on the lateral behavior of CFSWs.

Numerical Analysis Study on Seismic Performance of Semi-Rigid Steel Frame Infilled with Prefabricated Composite Wall Panels

The semi-rigid connected steel frame has good displacement ductility and energy dissipation capacity, and the interaction between the traditional steel frame and the filled wall is the critical factor affecting its seismic performance. In this paper, for the semi-rigid steel frame, the composite wall panel and the frame are separated by foam concrete mortar, and the effective connection is achieved by the tensioned steel bar. The premature brittle failure of composite wall panels can be prevented using friction energy dissipation between wall panels. By using ABAQUS simulation method, a semi-rigid steel frame composite wall is established. The failure mode, hysteresis curve and skeleton curve of simulation and test are compared and analyzed, and the reliability of the model is proved. The finite element model with the different number of wall panels is established to analyze its influence on the seismic performance of the structure. The results show that the frame structure realizes the effective connection between the composite wall panel and the concrete-filled steel tube frame, which jointly resists the earthquake action and reduces the damage of the earthquake action to the filled wall. With the increase in the number of composite wall panels, the ultimate load decreases gradually. The initial stiffness of the four layers of wall panels is more significant and decreases rapidly. When the wall panel has three or four layers, the energy dissipation capacity of the specimen is the strongest. The two are relatively close, stable at 24.48, and the increase is 5.15% compared with the second layer of the wall panel, and the increase is 12.72% compared with the third layer of the wall panel.