Hysteretic Performance Research Articles

Study on influencing factors of hysteretic performance of cantilever fully-bolted prefabricated beam-column joint

In order to improve the construction efficiency and integrity of prefabricated RC frames, a cantilever fully-bolted prefabricated beam-column joint is proposed. Through the reciprocating loading test, the change rules of rotation characteristics, mechanical properties and stiffness degradation of this type of joint were obtained. The failure mode of the joint is found: the steel plate in the connection area undergoes a slight flexural deformation, the concrete on the outside of the connection area forms a plastic region of about 1/3 beam length, the concrete crack develops obliquely from horizontal cracking with the increase of stiffness, and the damage characteristic develops from bending damage to shear damage. The initial stiffness of the precast joint is about 1.5 times that of the cast-in-place joint, the yield load is increased by 31 %, the peak load by 52 % and the ductility coefficient by a maximum of 96 %, with significantly better mechanical properties than the cast-in-place joint. Parametric analysis was carried out based on the tests. When the flexural stiffness ratio of the cantilevered section to the reinforced concrete beam section is less than 0.5, it is a weak connection. Damage to the section cantilever section occurs, and the stiffness degrades significantly. It is recommended that the joint be designed for a strong connection, with a stiffness ratio of around 0.6. The cantilever section's length greatly influences the joint's stress transfer. It is recommended that the length be taken to be about 0.6 and no greater than 0.75 for the width of the precast reinforced concrete beam. The design process of a prefabricated RC frame is given on this basis. A research basis has been laid for the engineering application of this new type of connection.

Experimental and numerical study on hysteretic behaviour of corrugated steel plate shear walls under lateral loads

This paper presents experimental and numerical investigations of the hysteretic performance of the corrugated steel plate shear wall (CSPSW) subjected to lateral loads, and proposes an effective hysteretic model for the CSPSW with interactive buckling or yielding of the corrugated steel plate (CSP). First, a cyclic loading test for a CSPSW with interactive buckling was conducted. The CSPSW test specimen exhibited high strength, lateral stiffness, and good energy dissipation capacity. In accordance with the cyclic test, a numerical model was developed to simulate the hysteretic behaviour of the CSPSW. Subsequently, extensive parametric analyses were performed to investigate the effects of the concerned geometry parameters on the hysteretic performance of CSPSWs, such as the height–thickness ratio, aspect ratio, corrugation angle, horizontal subpanel width and surrounding frame stiffness. The available limits of the height–thickness ratio, aspect ratio and surrounding column stiffness for CSPSWs were suggested. Based on the experimental and numerical results of the hysteretic curves and theoretical derivations, a hysteretic model for a CSPSW with interactive buckling or yielding of the CSP was proposed and verified by tests and finite element models. The results showed that the proposed hysteretic theoretical model can reproduce the hysteretic performance of CSPSWs with reasonable accuracy.

Cyclic loading tests and numerical simulations of an assembled X-shaped flexural steel damper

This paper proposes an assembled X-shaped flexural steel damper. Welding is waived for the novel damper. As the kernel element of the damper, the X-shaped flexural steel plates have the advantages of ease of installation and replacement if necessary. In the analytical part, the effective height of the flexural steel plate was suggested, and then, the yield displacement, yield load and initial stiffness of the damper were derived. The proof-of-concept cyclic loading test was conducted using one reduced-scale specimen within a four-bar linkage experimental setup. The hysteretic performance indexes, including strength, stiffness and energy dissipation, were quantified. The high-fidelity finite element (FE) models were established by ABAQUS. The parametric study was further conducted based on the verified FE model. The considered parameters were the height and thickness of the steel plates. The testing results indicate that the proposed damper has plump hysteretic curve with good energy dissipation capacity and excellent ductility, although slight slip behavior can be found due to the gap caused by the assembling process. The results obtained from analytical method and numerical model are in good agreement with the experimental data. The results of parametric analysis show that the numerical results well agree with analytical predictions, indicating the numerical model can reflect the mechanical behavior of AXSFD. A benchmark frame building was selected to demonstrate the seismic control efficacy of the damper. The nonlinear time history analysis results indicate that the damper reduced both peak and residual interstory drift ratios for the protected structure.

Hysteretic performance of thin-walled Q690 high-strength steel H-section beam-columns bent about the weak-axis

High-strength steel has broad application prospects in steel structures as its weight to strength ratio is low, but the reduced ductility limits its application in seismic design. In order to evaluate the application potential of high-strength steel in light steel structures, four Q690 high-strength steel beam–columns with large width to thickness ratios were tested under cyclic loading about the weak axis. The failure mode, ultimate strength, hysteretic curve, stiffness degradation, ductility and energy dissipation capacity of the tested specimens are discussed. Subsequently, a finite element analysis model is established, and an extensive parametric study is carried out using the verified finite element model. The test results show that the failure mode is the local buckling of column base. The hysteretic behavior of the specimens is mainly affected by the axial load ratio and the flange width to thickness ratio. The results of the parametric study show that the extent of development of plasticity in the cross-section is related to the axial load ratio. The calculated ultimate strength of the beam–column shows that Eurocode 3 is conservative for the classification of the beam–column as having a Class 4 cross-section, members with Class 4 cross-sections should in fact be classified as having Class 3 cross-sections. Accordingly, a section classification for a high-strength steel beam–column subjected to weak axis bending is discussed.

Research on hysteretic performance of a semi-rigid energy dissipation connection for precast cladding panels

A novel semi-rigid energy dissipation connection (SEDC), capable of transitioning the precast cladding panel from a rigid connection to a flexible connection with the primary structure as the seismic action increases, is proposed in the present study. The combination of the bending part and friction part endows the connection with the ability to provide adjustable sliding force and sufficient energy dissipation for the precast cladding panel. The design methods of SEDC, including the elastic stiffness, the yield force, the yield displacement, and the bear capacity, are proposed, followed by a coordinated design method between the precast cladding panels and the primary structure based on SEDC. Fourteen SEDC specimens are designed and tested under monotonic and cyclic loading tests to investigate the semi-rigid workability of SEDC and to evaluate the influence of design parameters of the bending and friction parts. Two working processes, which are the static friction process and the sliding friction process, are clearly reflected by the monotonic test results. The cyclic test results indicate that the SEDC specimens demonstrate satisfactory plastic development with full hysteretic curves, stable load capacity, reliable deformation ability, and favorable energy dissipation ability. The U-shaped bending plates exhibited a track-like deformation pattern without any observed tears or cracks. The NAO friction pads demonstrated a fragmented damage pattern, while the Brass friction pads demonstrated a linear scratch damage pattern. SEDC specimens equipped with Brass friction pads exhibited better low-cycle fatigue performance, which can be attributed to the favorable wear resistance of the Brass material. In addition, finite models of SEDCs are established and validated based on Abaqus. The combined working mechanism of SEDC, including the contribution ratio of load capacity and dissipated energy from the bending part and the friction part, is clearly revealed. Furthermore, the influence of parameters including the thickness (t), width (B), straight section length (l), radius (R), and height (h) of the bending part, as well as the pre-tightening force (pc) and the friction coefficient (f) of the friction part, are also summarized based on both the experimental and numerical analyses. Further discussions, including the calculation of the seismic behavior factor and the measurements for accurate construction, are conducted.

Static analysis of the hysteretic performance of the central columns in subway station enhanced by engineered cementitious composite jacket under high variable axial force

Engineered cementitious composite (ECC), a cement-based composite material known for its high tensile strain and ductility, was utilized to enhance the seismic performance and operational safety of the central columns in vulnerable areas of subway stations. By establishing refined solid finite element models of ECC composite columns and ordinary concrete columns, and conducting dynamic time history analysis on the vertical axial force at the top of the column, a comparative analysis was performed using a static model to determine the difference in hysteretic performance between ECC composite columns and ordinary concrete columns. Furthermore, sensitivity analysis is conducted based on different structural parameters. The results demonstrate that ECC composite columns exhibit significant improvements in bearing capacity, ductility, and energy dissipation, while also reducing stiffness degradation compared to ordinary concrete columns under various vertical variable axial loading conditions. Increasing the diameter of longitudinal reinforcement and reducing the stirrup spacing can effectively enhance the bearing capacity and ductility of columns. Additionally, employing an ECC jacket can effectively improve the shear capacity of the columns. Furthermore, modifying the frequency, amplitude, and phase of the vertical axial force will significantly alter the stress distribution and damage failure of the columns.

Experimental and numerical investigation into hysteretic performance of orthogonal double corrugated steel plate shear wall

The orthogonal double corrugated steel plate shear wall (ODC-SPSW) is comprised of two identical corrugated plates that are arranged orthogonally and interconnected through high-strength bolts located at the valleys of the corrugations. Due to the strong axis of one corrugated plate coinciding with the weak axis of the other corrugated plate, the flexural rigidity of each plate can be significantly enhanced in its weak axis, thereby improving its shear resistance. The ODC-SPSW has itself boundary elements in two side and connected only with frame beams at its top and bottom, leading to conveniently moving within the frame. This paper presents experimental and numerical analyses of the shear resistance and the hysteretic performance of ODC-SPSW. Two experimental specimens subjected to cyclic loading were tested, and accordingly finite element (FE) simulations were conducted, both reaching an excellent agreement. Firstly, the test results of two ODC-SPSW specimens under cyclic loading are reported and analyzed. Second, FE models are established to simulate the hysteretic energy-dissipation performance of the test specimens. The numerical results from FE Model agree well with the test results, thus validating the FE models. Moreover, a parametric study was conducted using the validated FE model through changing various geometrical parameters, such as aspect ratio, bolt number and arrangement, corrugation depth, corrugated steel plate thickness, boundary element dimensions of the ODC-SPSWs. It is found that these parameters affect significantly the ultimate shear resistance and hysteretic energy-dissipation capacity of the ODC-SPSW. The numerical result obtained indicated the dimensions of the boundary elements have little effect on the shear resistance and hysteresis performance of the ODC-SPSWs. Finally, some design recommendations are concluded which can provide valuable references for the practical design of ODC-SPSWs.

Seismic behavior of prefabricated beam-column joint with π-shaped connector

An innovative beam-column π-shaped joint, which was suitable for the low-rise prefabricated lightweight steel composite structure, was proposed in this paper. Firstly, with consideration of the variables of the column type, bending stiffness ratio between the beam and π-shaped connector, π-limb length, perforated end plate thickness, and with or without web connecting plate, twelve π-shaped joint specimens were prepared and their seismic behavior was experimentally investigated in aspects of failure mode, hysteretic performances, ultimate moment, stiffness degradation, deformation capacity, energy dissipation capacity, and strain response. Then the numerical model of the π-shaped joint was established and validated with the test data, which facilitates the further investigation of the influence of the bending stiffness ratio, π-limb length, and perforated end plate thickness on the seismic performance of the π-shaped joint. The test results showed that the application of the CFST column could improve the ultimate moment, initial stiffness, and energy dissipation of the π-shaped joint compared to the SHS column. Meanwhile, the introduction of the web connecting plate could avoid the separation of beam and column, resulting in a significant improvement in the seismic performance of the π-shaped joint. The test and numerical results demonstrated that decreasing the bending stiffness ratio, increasing the π-limb length and perforated end plate thickness was beneficial to further improve the seismic behavior of the π-shaped joint, and their corresponding suggested values were also provided in the present study.

Experimental and numerical investigation of the seismic performance of concrete-filled steel tubular composite columns with UHPC plates

To study the seismic performance of concrete-filled steel tubular composite columns with UHPC plates. The pseudo-static tests were carried out on five specimens with the longitudinal distance of the column limbs and thickness of the UHPC plates as test parameters. Subsequently, a nonlinear finite element model of such composite columns was established based on OpenSees, and the calculation method of lateral bearing capacity of the specimen under compression-bending load was proposed. The results showed that the longitudinal distance of the column limbs significantly influenced the lateral bearing capacity as well as the initial stiffness of the specimens. The longitudinal distance of column limbs was increased from 250 mm to 650 mm, and the lateral bearing capacity as well as the initial stiffness of the specimens were increased by 246.0 % and 488.5 %, respectively. The thickness of the UHPC plate was increased from 50 mm to 100 mm, the lateral bearing capacity of the specimen was increased by 32.2 %, while the cumulative hysteretic energy consumption was reduced by 45.05 %. Keeping the same axial pressure ratio, the initial stresses in the column limb steel tubes of the concrete-filled steel tubular composite columns with UHPC plates specimens were higher compared to those of the concrete-filled steel tubular composite columns with ordinary reinforced concrete plates specimens, resulting in poorer ductility. The established nonlinear numerical model accurately captured the hysteretic performance of the specimen. Moreover, the proposed lateral bearing capacity calculation method has high accuracy and can predict the lateral bearing capacity of such structures well.

Seismic performance of GFRP-rubberized concrete-steel hybrid solid columns

The application of structured rubberized concrete offers an effective solution for recycling rubber tires. This paper proposes a novel GFRP-rubberized concrete-steel hybrid solid columns (GRSRC), which combines rubberized concrete with circular FRP-concrete-steel double-skin tubular columns (DSTCs). Quasi-static tests were carried out on 7 GRSRC specimens to investigate the influence of rubber contents, steel tube diameters, and axial load ratios on their seismic performance. The test results indicate that the GRSRC has excellent ductility, lateral displacement capacity, and energy dissipation capacity. The GRSRC exhibits slow strength degradation at large lateral displacements due to the double-tube confinement effect. Using rubberized concrete with a rubber content of 20% as a replacement for ordinary concrete has little impact on the seismic performance of the specimens. When the rubber content reaches 40%, the seismic performance decreases significantly. Furthermore, its lateral load-bearing capacity, energy dissipation capacity, and deformation capacity are also reduced with the decreasing diameter of the steel tube, resulting in brittle damage. Increasing the axial load ratio enhances the stiffness, lateral load-bearing capacity, and energy dissipation capacity but may reduce ductility, deformation capacity, and hysteretic performance. Finally, a simplified model of GRSRC restoring force is established and validated, providing a theoretical basis for practical engineering applications.

Experimental and numerical studies on open-close gap damper for self-centering prefabricated coupled shear wall

An open-close gap damper (OCGD) for self-centering prefabricated coupled shear walls was proposed, which could adapt to large deformations near the joints and help the structure achieve both self-centering and energy dissipation capacity. Static tests and numerical simulations were used to obtain the hysteretic curve of the damper, which verified its energy dissipation capacity. Through simulation, it was found that the proposed damper greatly improved the energy dissipation capacity of the structure without reducing its original self-centering ability. Finally, the relationship between the hysteretic performance and design parameters of the proposed damper was obtained through theoretical analysis, which provided a reliable basis for the design of open-close gap damper.

Seismic Behavior of Concrete Columns Reinforced with Weakly Bonded Ultra-High Strength Rebars and Confined by Steel Tubes.

The usage of weakly bonded ultra-high strength (WBUHS) rebars has emerged as a promising approach to enhance the resilience of concrete components due to their remarkable mechanical properties. To promote the application of WBUHS rebars, this paper presented an investigation on the seismic behavior of circular concrete columns reinforced with squarely arranged WBUHS rebars and externally confined by bolted steel tubes. Eight columns, including two reinforced with normal strength (NS) rebars and six reinforced with WBUHS rebars, were fabricated and tested under reversed cyclic lateral loading. Experimental results showed that the columns reinforced with WBUHS rebars exhibited remarkable drift-hardening capacity up to the drift of at least 5% as well as significantly reduced residual deformation even when subjected to relatively high axial compression with an axial load ratio of 0.33 in comparison to the traditional ductile columns reinforced with NS rebars. Notably, the precast columns reinforced with WBUHS rebars, with an embedment length of 20 times their diameter, behaved nearly identically in terms of resilience as cast-in-place columns. Additionally, a numerical analysis was performed to assess the hysteretic performance, and the analytical results, with consideration for the slippage of WBUHS rebars, were capable of capturing the hysteretic performance of test columns.

Seismic performance of novel low-damage stair system: Precast reinforced concrete stair isolated with a sliding joint

This research presents a solution that can solve the negative diagonal support effect of the traditional precast reinforced concrete stair with rigid connection (TS) and adverse stress centralization on the fragile reinforced concrete (RC) flight. This innovative low-damage stair system utilizes a sliding joint at the bottom of the precast RC stair (SS). Experimental and numerical investigations were implemented on specimens TS and SS to systematically evaluate the seismic responses of the presented low-damage stair system. Experiment results confirm that specimen SS could effectively eliminate the detrimental diagonal support effect of conventional stair systems and the unexpected overlarge stress concentration of the RC components. Therefore, the RC flight and landing beam of the proposed low-damage stair systems remained undamaged at the inter-story drift ratio up to the final level of 4.00%. Taking advantage of the sliding joint, specimen SS behaves with excellent hysteretic performance and energy dissipation capacity. Furthermore, parametric analysis results reveal that the concrete strength remarkably affects the seismic responses of the innovative stairs, while the impact of the friction factor of the sliding joint on the seismic performance is asymmetric during positive and negative loadings.

Quasi-static tests and seismic fragility analysis of RC bridge piers with high-strength steel bars and high-strength/ultra-high performance concrete

The use of high-strength steel bars (HSSB), high-strength concrete (HSC) and ultra-high performance concrete (UHPC) in bridge piers can obviously improve bearing capacity and save material consumption. However, the use of high strength materials may detrimentally affect the seismic performance of reinforced concrete (RC) piers. This paper tries to study the seismic performance of RC piers with HSSB and HSC/UHPC by quasi-static tests and seismic fragility analysis. Three RC piers, solid pier with normal strength steel bars (NSB) and normal strength concrete (NSC), solid pier with HSSB and HSC, and hollow pier with HSSB and UHPC, were designed and tested under quasi-static loading. The failure mode, hysteretic performance, stiffness degradation and residual displacement of three specimens were compared and analyzed. A fiber-based beam-column finite element model (FEM) was developed to simulate the nonlinear response of RC piers with HSSB and HSC/UHPC. On this basis, the seismic fragility analysis was performed to study the effects of high-strength materials on the seismic performance of RC piers. Research results show that, compared with NSC piers, HSC piers reinforced with a small amount of HSSB still exhibited slightly larger lateral bearing capacity but lower deformability due to the higher brittleness of HSC. The UHPC hollow pier presented obviously larger deformation capacity, and more slow decline speed of lateral stiffness than NSC and HSC solid piers. Meanwhile, the matching use of UHPC and HSSB in hollow pier can improve the elastic deformation, and then reduce residual displacement of RC piers. The proposed fiber-based finite element model (FEM) can simulate the nonlinear response of RC piers with different high-strength materials with reasonable accuracy. Fragility results demonstrate that, HSC pier presents lower seismic fragility than NSC pier at different damage states except for collapse due to lower ductility of HSC pier. The UHPC hollow pier with HSSB has lower seismic fragility than NSC and HSC solid piers at the same seismic intensity. Overall, the hollow pier with HSSB and UHPC can maintain good seismic performance while greatly saving material consumption.

Lumped Plasticity Model and Hysteretic Performance of Ultra-High-Performance Concrete Rocking Pier.

Rocking piers using ultra-high-performance concrete (UHPC) have high damage-control capacity and self-centering characteristics that can limit the post-earthquake recovery time of bridges. To study the hysteretic behavior of UHPC rocking piers, a lumped plasticity model is proposed that comprises two parallel rotational springs and which can accurately calculate their force-displacement hysteretic behavior. Three states of the rocking piers, decompression, yield, and large deformation, are considered in this study. The model is verified based on existing experimental results, and the hysteretic characteristics of the UHPC rocking piers, such as strength, stiffness, and energy dissipation, are further analyzed. The research results show that the lumped plasticity analysis model proposed in this study can predict the force-displacement hysteretic behavior of the rocking piers accurately. Moreover, the hysteretic performance of the UHPC rocking piers is better than that of rocking piers using normal-strength concrete. An increase in the energy dissipation reinforcement ratio, pre-stressed tendon ratio, and initial pre-stress improves the lateral stiffness and strength of the UHPC rocking piers. However, the increase in the pre-stressed tendon ratio and initial pre-stress reduces their energy-dissipation capacity.

Hysteretic performance of circular high-strength concrete-filled double skin steel tubular columns: Experiment

In marine structures, utilizing high-strength materials in concrete-filled double skin steel tubular (CFDST) members can provide an optimized solution upon the tendency of light self-weight and high performance. The cyclic load in the marine environment usually determines the safety margin for whole offshore structures. Therefore, this paper experimentally investigated the hysteretic performance of circular high-strength concrete-filled double skin steel tubular (HCFDST) columns with out-of-code diameter-to-thickness ratios. The typical failure mode appeared with the infill material crushing, steel fracture and local buckling of outer tubes. Subsequently, the detailed analysis of hysteretic curves, skeleton curves and ductility, energy dissipation, stiffness degradation, and lateral force reduction was conducted to reflect the influences of hollow ratios, axial compression ratios, and infill types, e.g., increasing the hollow ratio from 0.54 to 0.68 and 0.82, respectively reduced the bearing capacity by 6.25% and 11.20%, and the ductility coefficient had an apparent decrease of 19.27% and 26.61%. The out-of-code HCFDST columns with reasonable design could behave with favorable hysteretic performance. A theoretical model considering the tensile strength effect of engineered cementitious composite (ECC) was finally established and verified to predict the moment-resisting capacity of HCFDST columns using ECC. The reported research on HCFDST columns can provide significant references to marine structure applications.

Experimental, mathematical model, and simulation of a dual-system self-centering energy dissipative brace equipped with SMA and variable friction device

The application of shape memory alloy (SMA) in seismic-resistant devices has received extensive attention due to its unique superelastic and shape memory effect. The poor energy dissipative capacity, insufficient reliability, and small bearing capacity are the main challenges that hinder the application of the developed SMA braces and dampers. The new system of self-centering energy dissipative (SCED) brace was proposed, fabricated, and tested, and the numerical model was defined and verified. The dates manifest that the load-displacement curve of the new dual-system SCED brace displays a typical flag shape. The new dual-system SCED brace exhibits the desirable energy dissipative ability and self-centering capacity and the theoretical and FE model established in this research can preferably express the hysteretic performance. The FE parametric analysis shows that the SMA screw preload has a small effect on the hysteretic curve of the new system brace, but it plays a decisive role in the shape of the hysteretic curve under small deformation. Furthermore, the bearing capacity and stiffness of the dual-system SCED brace can be adjusted by designing key parameters. The research shows that the new dual-system SCED device compensates for the shortcomings of the existing SMA braces and dampers, and it is a very promising and recommended self-centering energy dissipative device to use the wedge block system as the main energy dissipative system and SMA system as the main self-centering system.

Hysteretic performance of prestressed concrete beams with AFRP tendons under cyclic loading

AbstractThis paper aims to evaluate the hysteretic performance of prestressed concrete beams with aramid fiber‐reinforced polymer (AFRP) tendons. Eight beams were constructed and tested under cyclic loading, with test variables covering the type of prestressing tendons (AFRP and steel), the ratio of internal tendons to external tendons (3:0 and 1:2) and the bond condition of internal tendons (fully bonded, partially bonded, and unbonded). Results showed that the failure of all the beams was dominated by concrete crushing and nonprestressed rebars rupturing at pure bending sections. AFRP prestressed beams exhibited commensurate bearing capacity, displacement ductility, energy dissipation and residual deformation with steel prestressed beams. The combination of internal and external tendons, and using unbonded or partially bonded tendons could improve the ductility of AFRP prestressed beams. Additionally, the finite element (FE) models of AFRP prestressed beams were developed using ABAQUS based on the coupling method under the local coordinate system. The simulated results closely matched the experimental results in terms of the failure mode and load–displacement curve. Parametric predictions, including the unbonded length of AFRP tendon, partial prestressing ratio, jacking stress and concrete strength were presented to extend the experimental works.

Experimental study of novel wrapped CFRP-strengthened CFS-to-sheathing screw connections

Cracking damage of the sheathing wallboards in screw connections is the typical failure mode of cold formed steel (CFS) structures under seismic effects, which limits the shear capacity and weakens the hysteretic performance of CFS structures. To improve the shear performance of CFS-sheathing screw connections, a novel screw connection with carbon fiber reinforced polymer (CFRP) reinforcement is proposed in this paper. Cyclic tests were conducted on a total of 26 sets of screw connections with different configurations and wall sheathings, and the effects on the failure modes and shear performance of the connections with and without CFRP reinforcement were investigated. The strengthening effects of the sheathing material, panel thickness and end distance on the shear properties of the connections were discussed. The results indicated that (1) except for specimens with 15 mm end distance, CFRP reinforcement can effectively avoid brittle cracking failure of the connections, and the failure mode tended to ductile failure of the bearing and pull-through damage. (2) in addition to the stiffness, the shear strength, deformation capacity, ductility and energy dissipation capacity of CFRP-strengthened connections are significantly enhanced. The effect of CFRP on the shear performance improvement of connections sheathed with gypsum board (GWB) and magnesium glass board (MgO) is greater than that of oriented strand board (OSB), and the strengthening effect is not significantly influenced by the board thickness. A toughness evaluation method for CFRP-strengthened connections was proposed, and the design formulae for the shear strength of the CFRP-strengthened screw connections were recommended based on the load resistance factor design (LRFD) method and allowable strength design (ASD) method.

Research on seismic performance of ITRAC-filled double steel plate composite shear wall

The iron tailings and recycled aggregate concrete(ITRAC)-filled double steel plate composite shear wall (ITRAC-CSW) is a new lateral force-resistant member that applies an optimized cross-sectional form. The ITRAC is recycled concrete produced from 100% solid waste aggregates. Three full-scale ITRAC-CSW specimens were fabricated to investigate the effects of axial compression ratio and shear span ratio on seismic performance by conducting the tests subjected to quasi-static load. The failure mode and the hysteretic performance of the specimens are analyzed. The ITRAC-CSW exhibits good bearing capacity, stiffness, and energy dissipation capacity. This indicates that ITRAC has the potential to replace concrete applications. The numerical simulations and parametric analyses were carried out through the finite element model to reveal the failure mechanism and parameter effects of specimens. Finally, the calculation method for the bearing capacity of ITRAC-CSW was proposed based on the confined strength of the ITRAC. The ratio of the calculated bearing capacity to the test results is between 0.901 and 1.097 and the calculation accuracy is within 10%. This calculation method can be a reference for the performance design of ITRAC-CSW.