Hysteretic Performance Research Articles

Self-centering rocking steel frame with column mid-height uplift: Experimental and numerical investigation

This paper proposes a self-centering rocking steel frame with column mid-height uplift (SCRSF-CMU) that exhibits high post-yield stiffness and energy dissipation capacity. The hysteretic performance of the SCRSF-CMU was investigated through cyclic loading tests. A numerical model of the SCRSF-CMU was established and validated against experimental results. Subsequently, the seismic performance of the SCRSF-CMU was compared with that of the self-centering rocking steel frame with column base uplift (SCRSF-CBU) using nonlinear time history analysis. Finally, the seismic responses of the SCRSF-CMU and SCRSF-CBU under varying earthquake intensities were analyzed using the endurance time analysis. The results indicate that the designed SCRSF-CMU demonstrates excellent lateral force resistance, energy dissipation, and self-centering capabilities. The rocking effect and the restoring force of the post-tensioned steel strands effectively controlled the residual lateral displacement of the specimens. The multi-scale numerical model of the SCRSF-CMU accurately captured its hysteretic behavior and deformation patterns. Compared to the SCRSF-CBU, the SCRSF-CMU exhibited superior rocking deformation capacity, post-yield stiffness, and hysteretic energy dissipation. Under MCE excitation, both SCRSF-CMU and SCRSF-CBU showed uniform inter-story drift distribution with minimal residual deformation, creating a satisfactory condition for the post-earthquake repair work if necessary. The high post-yield stiffness of the SCRSF-CMU was more effective in reducing both maximum and residual displacements. Endurance time analysis revealed that SCRSF-CMU and SCRSF-CBU exhibited relatively uniform inter-story drift distribution under SLE, DBE, and MCE earthquakes. Under FE excitation, the inter-story drift ratio of both structures were nearly identical; however, under DBE and MCE excitations, the maximum roof drift ratio and inter-story drift ratio of the SCRSF-CBU were larger, indicating that the SCRSF-CBU had higher deformation demands than the SCRSF-CMU.

Seismic performance on PSPC beam - concrete encased CFST column frame with a built-in reduced beam section

The concrete-filled steel tubular (CFST) column is widely used to connect with a steel beam owing to the quick dry connection and acceptable seismic performance. Therefore, a partially steel-reinforced precast concrete (PSPC) beam with an embedded H-beam was developed to combine the merits of both the prefabrication in the precast concrete beam and the quick assembly in the steel beam. In this study, the developed beam was proposed to connect the concrete encased CFST column with a reduced beam section. A half-scaled frame substructure specimen with two floors and two bays was designed and tested under the cyclic loading to investigate the seismic performance. A series of seismic properties were analyzed, including the failure phenomena, hysteretic performance, stiffness degradation, and energy dissipation capacity. The dog-bone configuration was found to benefit the beam hinge failure mechanism and an acceptable deformation capacity (the ductility coefficient up to 2.77). The function of the H-beam contributed to stable energy absorption (the equivalent damping coefficient from 0.33 to 0.37). Finally, the proposed frame was compared with a reinforced concrete frame and a steel-reinforced concrete frame through numerical analysis. The partial steel-reinforced configuration had a positive influence on the bearing capacity, hysteretic performance, and safety storage. In addition, it could improve the cost-effectiveness with little decrease in the bearing capacity.

Development of a novel rotational metallic damper as a dissipative connector in rocking steel core systems: Cyclic behavior and seismic demand

Rocking systems with stiff rocking cores have been proposed as a promising solution for mitigating concentrations of story drift and enhancing structural seismic resilience. This study introduces a novel rotational metallic damper, termed the rotational steel rod damper (RSRD), developed for use in rocking steel core systems to improve energy dissipation capacity. The configuration, working mechanism, and application of the RSRD in rocking steel core systems are described. Three critical energy-dissipating elements, low-yield-point steel rods with different edge shapes, were isolated from the RSRD and tested to validate the efficacy of an optimal hourglass shape, defined through cubic equations, in enhancing low-cycle-fatigue performance. Two RSRD specimens were then tested and analyzed, focusing on failure modes, cyclic behavior, rotational strength, and energy dissipation. Both specimens demonstrated positive and stable hysteretic performance and energy dissipation capacity, with maximum equivalent viscous damping ratios of 0.51 and 0.53. Subsequently, structural models of seven steel frames were developed in OpenSees for case studies. Nonlinear response history analyses were performed under 20 ground motion records scaled to DBE and MCE levels. Dynamic behaviors, particularly the seismic demand on RSRDs, were examined. Numerical results confirmed the efficacy of the RSRD in mitigating inter-story drift. The location of the pivoting point of the rocking core significantly influenced the rotational demand on the RSRD. The proposed RSRD presents an innovative energy-dissipating alternative for the development of rocking steel core systems.

Seismic Performance of Precast Concrete Bridge Piers with Built-In Steel Tube Connection Key

Investigating the seismic behavior of precast concrete bridge piers is crucial in the design process due to the complex stress distribution in the connecting components. To demonstrate the seismic behavior of precast concrete bridge piers with hybrid joint connections, three bridge piers were designed with a scaling ratio of 1:8 and then tested under low cyclic loading conditions. The tests involved varying shapes of steel tube connection keys as parameters. This study involved examining failure modes and crack development, as well as analyzing the hysteretic performance, deformation capacity, energy dissipation, and stiffness degradation of the specimens. Furthermore, a finite element model was developed using ABAQUS, and the validity of the modeling approach suggested in this study was confirmed through tests. The results indicate that the precast piers exhibit reduced concrete damage at the joints. The enhanced strength of the joints is attributed to the incorporation of steel tube connection keys. The circular steel tube connection key integrated into the precast bridge pier offers a superior bearing capacity, energy dissipation, and stiffness degradation compared to the cross-shaped steel tube connection key. The presence of the built-in circular steel tube connection key in the precast bridge pier suggests that it complies with the seismic structural measures and is consistent with the design principle of “strong joint and weak member”.

Seismic performance of high-rise shear wall with concealed truss under high axial force ratio

In this paper, the high-rise shear wall with a concealed truss was proposed for improving seismic performance. Reinforcing bar truss and steel truss were used in the proposed shear walls. The innovative composite shear wall incorporates two combinations, i.e., one involving two load-bearing systems, including a truss and shear wall, while the other combines steel and concrete as distinct materials. Five specimens with different structural forms were tested under cyclic loading tests. The resulting failure characteristics, hysteretic performance, strength, deformation, energy dissipation capacity, stiffness, and strain characteristics were studied. The influence of various structural forms on the seismic performance of shear walls under the high axial force ratio was also analyzed. The results showed stable hysteresis curves for the innovative shear walls. Also, it was found that the high-rise shear walls with concealed trusses effectively control crack propagation compared to conventional high-rise shear walls. The proposed walls exhibited a uniform and broader crack distribution. Concealed trusses in the high-rise shear walls enhanced the plastic energy dissipation zone at the base, improving the corresponding energy dissipation capacity. Using different types of trusses did not exhibit any significant difference in the resulting seismic performance. Finally, an evaluation method for the ultimate strength and stiffness of the shear walls with concealed trusses was proposed and validated.

Numerical Investigation on the Hysteretic Performance of Self-Centering Precast Steel–Concrete Hybrid Frame

To improve the construction performance and seismic resilience of precast reinforced-concrete frame structures, an innovative self-centering precast steel–concrete hybrid frame has been proposed and subjected to cyclic loading tests. In this paper, a comprehensive numerical analysis was conducted to further investigate the frame’s hysteretic behavior. Initially, a numerical model was developed using the finite element software OpenSees. Numerical analyses of two frame specimens were conducted, demonstrating good agreement between the numerical and experimental hysteretic characteristics, thus validating the model’s accuracy. Subsequently, based on the numerical simulations, a quantitative comparison of hysteretic performance between a novel frame and a traditional reinforced-concrete frame of the same scale was performed. While the proposed frame exhibited slightly lower initial stiffness and energy dissipation capacity than the traditional frame, it outperformed in terms of load-carrying capacity and self-centering ability. Finally, parametric analyses were carried out to assess the influence of various design parameters on the hysteretic performance, including friction force in the web frictions devices, initial post-tensioned force of the prefabricated steel–concrete hybrid beams, the steel arm length, and the column longitudinal reinforcement ratio. The results showed that increases in these four parameters improved the load-carrying capacity and initial stiffness of the proposed frame. Additionally, an increase in the friction force, steel arm length, or column longitudinal reinforcement ratio enhanced the frame’s energy dissipation capacity, while an increase in the initial post-tensioned force or a decrease in the friction force enhanced the frame’s self-centering capacity.

Experimental study on the seismic performance of two-storey UHPC modular building structure

Ultra-high performance concrete modular building is a new structural system in which the module units made by the factory with UHPC materials are transported to the site for assembly. To study the seismic performance of UHPC module building structures, a two-story full-scale module building structure made by UHPC is designed in this study. Lateral cyclic loading tests are performed to investigate the seismic performance of the module building structures. The bearing capacity, failure mode, stiffness degradation, hysteretic performance, residual deformation, and strain skeleton curve are analyzed. Results indicate that the specimen undergoes three stress stages: elasticity, yield, and ultimate under lateral cyclic loading. At ultimate load capacity, the maximum inter-story drift ratio reached 1/57, and the load-bearing capacity was approximately 1.20 times the yield strength. The average ductility factor of the specimens was 3.42. The cracks mainly appear at the bottom and top of the walls of the module unit, and initial cracks occur at the top of the wall of the upper module unit. The specimen exhibits excellent seismic performance, full hysteretic curves, good dissipation capacity and ductility. The four corners between module units are connected by grouting sleeves in a reliable way to transfer force, which can ensure the overall deformation requirements of the structure.

Experiment and restoring force model study of precast shear walls with new rabbet-unbonded horizontal connection

The 'rabbet-unbonded horizontal connection' (RUHC) is a new connection form of precast shear wall. This study conducted a low-cycle repeated loading test on three RUHC walls to investigate the hysteretic performance of the walls with the 'axial compression ratio' and 'unbonded level' as the main variables and the results showed that the above two parameters remarkably affected the seismic performance of RUHC walls. Based on the analysis of test skeleton and hysteresis curve characteristic, the influence of parameters such as axial compression ratio and unbonded level on the load and displacement during the loading process was analyzed. The theoretical values of yield, peak and limit points were calculated, and the skeleton curve model was proposed. Moreover, the unloading stiffness formula was proposed by the non-linear relation of dimensionless parameters and Matlab software fitting, and the hysteresis rule model was established. Finally, a three-fold-linear restoring force model of RUHC walls composed of the theoretical skeleton curve and hysteresis rule was established and verified. This model provides an effective prediction for the hysteresis characteristics and a theoretical basis for conducting elastic-plastic analysis of RUHC structures.

Finite element analysis of hysteretic characteristics of steel member under cyclic loading

Abstract In this paper, the square, H-shaped and C-shaped steel members with three cross-section forms are selected. Considering the cross-section form, slenderness ratio and constraints at both ends, the force-displacement curve and single-ring energy consumption of steel members under cyclic loading are simulated and analysed. The buckling performance and hysteresis characteristics of steel members with different properties are compared. The results show that the section form has the greatest influence on the energy dissipation level of the component. The hysteretic performance of H-shaped section member is the best, followed by C-shaped section member and square section member. The energy consumption level of the component is negatively correlated with the slenderness ratio, and the single-cycle energy consumption of the steel component decreases with the increase of the slenderness ratio. The constraint condition has the smallest influence on the energy consumption level of the component, and the energy consumption of the component under the end solid-solid constraint and solid-hinge constraint is similar.

Experimental study on the working mechanism and seismic performance of novel energy-dissipation boxes with different configurations

This paper presents a novel composite energy-dissipation beam-column joint that incorporates friction side plates (FSPs) and composite energy-dissipation boxes (EDBs). As replaceable components of this innovative joint, the composite EDBs significantly influence its overall seismic performance. To conduct a comprehensive study of the composite EDBs, eight specimens were fabricated, with parameters including filling material, construction gaps, and secondary loading. This investigation primarily examined the failure modes, hysteretic performance, strength degradation, stiffness degradation, and energy-dissipation capacity of the composite EDBs. The results indicated that increasing the construction gap can delay the buckling of dog-bone energy-dissipation plates (DB-EDPs), while secondary loading enhanced both the strength and stiffness of the specimens. Additionally, the filling material effectively restrained the out-of-plane buckling of the DB-EDPs, thereby improving the load-bearing capacity of the composite EDBs. The effectiveness of the filling materials was ranked as follows: wood > steel box > rubber. Finally, a theoretical load-bearing capacity formula for the specimens was derived, and the applicability was validated by comparing the experimental values with the theoretical predictions.

Fatigue Analysis of BRB Weld under Low Period and Large Deformation based on DIC Technology

This paper conducts an in-depth study on the fatigue performance of buckling-restrained braces (BRBs) under low-cycle large deformation conditions. As a device that utilizes the hysteretic energy dissipation of metal yielding, BRBs have been widely used in the design of new structures and the seismic strengthening of existing structures. Its remarkable advantages include stable performance, convenient fabrication, low cost, and excellent hysteretic performance. Applying DIC technology to the fatigue analysis of BRB welds under low-cycle large deformation can achieve full-field measurement of deformation and stress at the weld, providing strong technical support for in-depth study on the fatigue performance of BRB welds.

Full-scale experimental study on tribological performance of FPBs for highway bridges with various solid lubricants under fast loading

Friction pendulum bearings (FPBs) have proven to be effective for the seismic isolation of highway bridges. Previous studies often employed scaled model shaking table tests to investigate dynamic responses of the structures or quasi-static tests to assess the hysteretic performance of FPBs. However, it is noteworthy that the stress on the friction surface is reduced due to the size effect in scaled model in shaking table tests, while quasi-static tests of prototype bearings cannot simulate the sliding velocity experienced during seismic events, which is a sensitive parameter for the performance of FPBs with solid lubricant plates. Research on the performance of full-scale FPBs under fast frictional loading is very limited. This paper addresses this knowledge gap by studying the velocity demand for a highway bridge with FPBs and conducting fast sliding performance tests using full-scale FPBs. The results indicate that under a 0.2 g PGA earthquake, the velocity demand for FPBs can reach 0.5 m/s. Through testing full-scale FPBs at various loading speeds, it was found that solid lubricant plates by UHMWPE material exhibit poor thermal stability during wear tests, solid lubricant plates by PTFE material lack sufficient tangential tear strength under fast loading, and solid lubricant plates by PET material show good wear resistance but have a high breakaway force and levered maximum force during the running-in stage. Subsequently, this study developed ultra-high performance friction plate (UHPF) as the solid lubricant for FPBs, achieving ideal hysteretic performance under fast loading. The full-scale FPB specimens in this paper are the ones manufactured for the continuous beam bridges in the Shenzhen-Zhongshan Sea-crossing Link project in China. The dimensions of the bearing, axial load, and loading speed is much more stringent than those in previous FPB tests, providing results that are highly important for engineering applications.

Seismic Performance Analysis of the Internal Joint in the New Demountable Fabricated Concrete Frame with Prestressed Mortise–Tenon Connections

This paper proposed a novel demountable fabricated joint in frame, which is connected by the prestressed and mortise–tenon connection. The prefabricated components of the demountable structures are designed to be reused, and the joint presented in this paper will promote the sustainable application of prefabricated components in future. The damage process and damage pattern of the internal joints under the horizontal load were analyzed using the refined numerical analysis model based on ABAQUS 6.14. Parametric analyses were conducted simultaneously for five parameters: axial compression ratio, the area and effective initial stress of unbonded prestressed strands (UPSs), the local reinforcement ratio in the core zone of the demountable joint, and the friction coefficient between the interface of concrete. The results showed that the demountable joint exhibits excellent energy dissipation potential under horizontal loads, but the damage was concentrated in the core zone. The deformation of the joint mainly consisted of the self-deformation of the prefabricated components, including bending, bearing and shear, as well as the relative slip deformation between the prefabricated components. The axial compression ratio has a more significant effect on the hysteresis performance compared to the areas of the UPSs and the reinforcement ratio. The initial effective stress of the UPS and the friction coefficient have relatively minor influence on the hysteretic performance of the joint. Finally, this paper recommends the design parameter values (axial compression ratio should not exceed 0.4, area of unbonded prestressed reinforcement should be not lower than Asn=0.02 and not higher than Asn=0.1, the initial stress of the UPS takes the value of 0.75fpu) and outlines optimization measures.

Hysteretic performance of high-strength steel square hollow section T joints considering fracture behavior

The performance of high-strength steel (HSS) welding joints is crucial for tubular structure design. This paper investigates the hysteretic performance of HSS square hollow section (SHS) T joints considering fracture behaviors. The hysteresis and tensile tests of the HSS SHS T joints and a comparative analysis of failure modes and bearing capacity are conducted. Parameter analysis is conducted based on the validated FE model considering fracture and elastoplastic constitutive relationship with a wide range of parameters covered, including the cross-sectional width ratio and the wall thickness ratio between brace and chord, and the width-thickness ratio of the chord, and the seam weld size of the joint connection. The results show that fracture behavior can affect the failure mode and bearing capacity of the joints, and it cannot be ignored in the hysteresis analysis process. The energy consumption capacity and the ductility coefficients increase when β increases from 0.2 to 1.0, τ increases from 0.3 to 1.0 and 2 γ decreases from 40 to 20. Meanwhile, joints’ failure modes and residual strength vary with the above parameters. It is necessary to use the damage fracture constitutive model of steel in numerical simulation.

Comparative analysis of the seismic performance of ECC jacket reinforced columns with different cross-sectional forms subject to different load modes

Based on the high tensile strength and tensile strain of (engineered cementitious composites) ECC, it is applied to the weak link central columns of subway stations to enhance their seismic resilience. In this study, the effects of the column's cross-sectional shape, ECC jacket form, and the vertical gravity load and vertical dynamic load during seismic action on the hysteretic performance of the column were thoroughly analyzed. A constrained constitutive model for cementitious materials, a reinforced hysteresis constitute model, and a calculated damage factor for concrete were adopted to establish a three-dimensional refined column model with an experimentally verified error of less than 10 %. After that, the damage distribution and damage degree of the columns, as well as the changes in hysteretic performance such as hysteretic curve, skeleton curve, energy dissipation, and stiffness degradation were analyzed by the static model analysis. The results showed that the columns had higher damage levels under high frequency and high amplitude of dynamic axial compression ratio in the vertical direction compared to the constant high axial compression ratio, and the ECC jacket could effectively reduce the damage levels of the columns, but the use of the in-built ECC (IB-ECC) jacket was better than the out-sourced ECC (OS-ECC) jacket. In addition, the IB-ECC jacket did not significantly improve the peak bearing capacity of the columns, but significantly improved the ultimate bearing capacity and displacement ductility of the columns, while the OS-ECC jacket significantly improved the peak bearing capacity of the columns. The ECC jacket was also effective in slowing down the stiffness degradation of the columns. This study significantly contributes to the design strategies for enhancing the resilience of columns in subway stations.

Coupled vibration of low-medium-speed maglev vehicle-guideway system on isolated bridge with lead rubber bearings

This paper investigates the dynamic response of low-medium-speed (LMS) maglev vehicle moving on the isolated bridge with lead rubber bearings (LRBs). In the vehicle-guideway bridge model, the vehicle is simulated as a 50-degree-of-freedom model consisting of a car-body and ten bogie modules. The guideway bridge with LRB is established by the finite element method, and the guideway is interacted with the vehicle by the actively controlled electromagnetic forces. The LRB is simulated by the nonlinear spring element for reflecting the hysteretic performance, and a fast nonlinear analysis (FNA) method is proposed to achieve the potential nonlinear behavior of LRB under vehicle load. Then, the dynamic response of maglev vehicle running on the isolated bridge with LRB is investigated and compared to that on the non-isolated bridge. The effect of vehicle speed and LRB isolation degree on the coupled system responses is studied. Furthermore, the driving quality of vehicle on LRB bridge is discussed, and the applicability of LRB to maglev line bridge is thoroughly evaluated. The results show that the installation of LRB exhibits relatively insignificant influence on the vertical response of vehicle-guideway system, while could enlarge the lateral response. The lateral response of coupled system is much more vulnerable to the isolation degree, and it is recommended that the isolation degree of LRB should not exceed 2.50 to guarantee the driving comfort and running safety.

Experimental Study on Seismic Performance of Composite Shear Wall with Horizontal Connection and Frame

Prefabricated concrete shear-wall structures are a primary form of prefabricated concrete construction. In this paper, the seismic performance of precast shear walls with frames is studied by experimental methods. The failure characteristics, hysteretic performance, energy dissipation capacity, stiffness degradation, and ductility of the shear wall are mainly analyzed. The results indicate that incorporating various frames into concrete shear walls can significantly enhance the traditional single seismic defense line. The maximum differences between the positive and negative initial stiffnesses of the framed shear wall are 32.6% and 29.7%, respectively. The maximum differences between the positive and negative ductility coefficients compared to the ordinary reinforced concrete shear wall are 15.7% and 20.7%, respectively. The maximum difference in equivalent viscous damping compared to the ordinary reinforced concrete shear wall is 26.5%.

Seismic performance of bolted middle joint for modular steel structure

A novel bolted connection for prefabricated modular structures is proposed. Five full-scale joint specimens were tested under cyclic loads, and finite element analysis was conducted to investigate the joint performance. The influences of the bolt diameter, the column flange thickness, the connecting plate thickness, and the connection forms between beam flanges of the upper and the lower box modules were analyzed, and the joint rotational stiffness was evaluated. According to the results, the bolted beam flanges can significantly improve the hysteretic performance, yield resistance, ultimate resistance and energy dissipation capacity of the joint. A thin connecting plate can effectively prevent the yielding of the ceiling beam web. The joint can be classified as a full-strength according to the Eurocode. Simplified formulas for the yield and ultimate resistances were proposed and evaluated to be accurate and practical for performance predictions and design of the proposed joint.

Experimental investigation on lateral resistance capacity enhancement effect of a self-centering shape factor in self-centering pier systems

In self-centering (SC) pier systems, a rocking interface is typically employed at the bottom of a pier to achieve a gap-opening mechanism. However, compared with the full-section bending state of the bottom section of a ductile pier (DP), the local compressive state of the rocking interface in the SC pier inevitably leads to a significant reduction in the lateral resistance capacity. Although a prestressing tendon (PT) force can improve the lateral resistance capacity, it also induces local damage. Moreover, its enhancement effect is limited, particularly in the case of a column with a high axial compression ratio. Therefore, this study proposes an innovative measure to significantly improve the hysteretic performance of an SC pier without inducing additional damage, which is to raise the location of the rocking interface. First, the SC shape factor ξSC is innovatively defined to quantify the above-mentioned measure, and its working mechanism is investigated in detail in this study. Second, a high-lateral-resistance SC pier system (HLRSCP), which applies the concept of ξSC, is proposed and introduced for its advantages. Third, hysteretic tests of the DP and HLRSCP with high axial compression ratios are performed and analyzed. Finally, the enhancement effect of ξSC on the lateral resistance capacity is parametrically examined using a finite element model, and the feasible region of ξSC is inferred and presented. The results validate the effectiveness and feasibility of the concept of the SC shape factor in improving the hysteretic performance of the SC pier system.

Seismic performance of various types of cold-formed steel composite shear walls with CFRP-toughened screw connections

The cracking of screw connections at the corners of wallboards is a typical failure mode for cold-formed steel (CFS) shear walls, resulting in premature performance degradation of CFS structures. A toughening method with carbon fiber reinforced polymer (CFRP) sheets at screw connection locations is proposed for strengthening the CFS shear walls. Totally 6 full-scale CFS shear walls with or without CFRP-toughened connections were tested, and the parameters of the lamination scheme, wallboard type and screw distance were investigated. A numerical model is developed for simulating the seismic behaviour of the tested specimens, and a theoretical model for predicting their shear strength is proposed. Results showed that the shear strength and lateral stiffness of the CFS walls with CFRP-toughened screw connections increased by more than 30 %, and the continuous lamination scheme provided greater strength. The fastener-based numerical model could effectively be used for predicting the hysteretic performance of toughened CFS shear walls well; both the pinch behaviour and ultimate strength are predicted well, and it can be used as an effective tool for the seismic design of toughened CFS shear walls with a theoretical model.