Hysteretic Energy Dissipation Research Articles

Evaluation of Rotation Capacity and Bauschinger Effect Coefficient of I-Shaped Beams Considering Loading Protocol Influences

Recent catastrophic earthquake events have reinforced the necessity of evaluating the seismic performance of buildings. Notably, the buildings can go into the plastic phase during a striking earthquake disaster. Under this condition, the current design codes assume seismic response reduction by virtue of the energy dissipation capacity of the structural members. In the strong-column–weak-beam design, which involves I-shaped beams and boxed columns, the mechanism is defined as a standard design scheme to prevent the building from collapsing. Therefore, energy dissipation relies highly on the I-shaped beam performance. However, the I-shaped beam performance can differ depending on the loading history experienced, whereas this effect is untouched in the prevailing evaluation equation. Hence, this study first performs cyclic loading tests of 11 specimens using different loading protocols. The experimental results clarify the fluctuation in the structural performance of I-shaped beams depending on the applied loading hysteresis, proving the necessity of considering the stress history for proper assessment. Furthermore, the database of experimental results is constructed based on the previous experimental studies. Ultimately, the novel evaluation equation is proposed to reflect the influences of the loading protocol. This equation is demonstrated to effectively assess the member performance retrieved from the experiment of 65 specimens, comprising 11 specimens from this investigation and 54 specimens from the database. The width–thickness ratio, shear span-to-depth ratio, and loading protocols are utilized as the evaluation parameters. Moreover, the prediction equation of the Bauschinger effect coefficient is newly established to convert the energy dissipation capacity under monotonically applied force into hysteretic energy dissipation under the cyclic forces.

Hybrid bridge bent using stretch length anchors with post-tensioning and shear key alternatives

Precast concrete bridge bents are good candidates for accelerating bridge construction. In seismic regions, in addition to construction speed, there is a need to improve seismic performance of bridges. One promising solution is self-centering bridge bents that use post-tensioning and external energy-dissipation devices as a hybrid system. This paper presents cyclic load experiments of hybrid two-column bridge bents to assess their performance regarding self-centering and hysteretic energy dissipation. The cyclic experiments were conducted on 42% scaled bridge bents that used unbonded post-tensioning (PT) bars for self-centering and stretch length anchors (SLAs) as external energy dissipators. A total of six experiments are investigated: three with PT bars and SLAs and three with PT bars only. The variables included the number of PT bars in each column (two or four), the initial post-tensioning force in the columns, and the shear key details in the footings and cap beam. The PT bars remained elastic until 4.0% drift ratio but some variation was observed in the post-tensioning forces especially for columns with two PT bars. For post-tensioned bridge bents with or without SLAs, increasing the number of PT bars in each column from two to four enabled efficient self-centering by limiting the residual drift ratio to 0.5%. There was no damage to the concrete for bents with four PT bars and there was repairable concrete damage for bents with two PT bars. The hysteretic energy dissipated by bridge bents with SLAs in addition to PT bars was 1.8 to 3.2 times the hysteretic energy of bridge bents with only PT bars.

Experimental investigation on seismic behavior of damaged self-centering friction beam-column joints after repair

Self-centering beam-column joints are an effective strategy to improve the seismic resilience of frame structures. Extensive research has been conducted on the seismic performance of newly constructed self-centering joints, involving experiments, theoretical analyses, and simulations. Nevertheless, less attention has been paid to evaluating the seismic resilience of self-centering joints after repair. To address this gap, this paper presents a series of experiments to investigate the mechanical properties of damaged self-centering friction beam-column joints (SCFJ) after repair. Three SCFJs damaged by cyclic loading are repaired using epoxy injection, CFRP wrapping, and replacement concrete. The repaired joints are then subjected to cyclic loading under the same conditions as the original loading. A comprehensive analysis is conducted of the hysteretic curve, skeleton curve, energy dissipation, stiffness degradation, and residual displacement of both the original and repaired SCFJs. The results show that the repaired SCFJs maintain their commendable self-centering capacity. Specifically, the replacement concrete method is the most effective in restoring the initial seismic performance of the SCFJs. The epoxy injection method is the fastest repair method and successfully restore the SCFJ to approximately its original ultimate strength and approximately 85% of its energy dissipation and self-centering capacity. The CFRP wrapping method is able to largely restore the self-centering capacity of the SCFJ to its original level, but with a notable decrease in stiffness.

Design, simulation and energy dissipation evaluating of a new lead shear damper

This study presents a novel design for a lead shear damper (LSD) that features lead blocks encased in laminated steel and rubber plates, intersected by X-shaped steel sticks. It combines the excellent energy dissipation and fatigue resistance of lead with the uniform yielding capabilities of X-shaped steel sticks along their height. Cyclic loading testing and fatigue tests are conducted in order to determine the mechanical properties of the LSD. The test results reveal that the LSD has a variable yielding force, and exhibits stiffness hardening when the damper's deformation direction deviates from the origin. However, when the deformation direction returns to the origin, there is no stiffness hardening observed, and the resistant force remains constant. Furthermore, this LSD can work effectively despite the failure of energy dissipation parts, which improves hysteretic energy dissipation under large deformation. In order to replicate the hysteretic behaviour, a uniaxial constitutive model is formulated and its parameters are determined by the utilization of the differential evolution approach, based on test data. The observed strong concurrence between the experimental and simulated hysteresis curves serves as compelling evidence for the efficacy of the differential evolution method. Meanwhile, a three-story building from the third-generation benchmark problem is employed as the testbed structure to examine the energy dissipation capacity of the developed dampers. Nonlinear seismic analysis on the benchmark model equipped with the proposed dampers is also conducted, and the results are compared to those fitted with conventional dampers, such as mild dampers and friction dampers. The findings of this study indicate that the performance of the LSD in reducing structural displacements is superior to that of mild dampers and friction dampers.

Seismic protection provided by a new diamond-shaped bracing system with a horizontally layered friction damper

We present a new diamond-shaped bracing system with a horizontally layered friction damper (HLFD) that remedies the drawbacks of existing vibration control systems and is applicable to existing reinforced concrete (R/C) buildings. We investigated the material properties and energy dissipation of the HLFD. Pseudo-dynamic testing was performed on two-story full-size frame specimens based on an existing R/C building lacking seismic protection. We studied the hysteretic characteristics, energy dissipation, and ability to control the seismic response. The hysteretic characteristics were subjected to non-linear dynamic analysis, and the results were compared to those of the pseudo-dynamic test. Next, the effects of the new system on an existing R/C building lacking seismic protection were evaluated in terms of the non-linear dynamics. We derived the seismic response force, displacement characteristics, energy dissipation, and damper forces and displacements before and after seismic strengthening. Without protection, the building exhibited shear collapse at an earthquake ground acceleration of 200 cm/s2. However, damage was minimal when the new protective system was installed. At a maximum earthquake acceleration of 300 cm/s2, seismic damage remained low.

Cyclic behavior of a shape-optimized dumbbell-type combined slit damper with phased yielding characteristic

This paper proposed a shape-optimized dumbbell-type combined slit damper (SDCSD) that enables phased yielding. In SDCSD, the shape-optimized dumbbell-type energy dissipation element contributes to the elimination of stress concentration, while the phased yielding characteristic reduce the adverse effect of damage accumulation. The calculation method of mechanical properties of dumbbell-type energy dissipation element (EDE) and the working mechanism of SDCSD are introduced. Two different configurations of SDCSD were designed, including double dumbbell-type combined slit damper (DDCD) and stiffened dumbbell-type combined slit damper (SDCD). Quasi-static test on five specimens were carried out to discuss the effect of shape optimization, phased yielding mechanism and the mechanical properties of SDCSD. Additionally, numerical simulations were performed to further investigate the factors affecting the mechanical properties of the SDCD. The factors include the shape parameters (α and β), the thickness of the stiffening ribs (γ), the yield load ratio (Ry) and the height-to-thickness ratio (Rh). Based on the results of numerical simulation, the modified formula for calculating the mechanical properties of SDCD were presented. The results indicate that the dumbbell-type EDE obtains a more uniform stress distribution and higher material utilization. The stiffened dumbbell-type plate outperforms the conventional dumbbell-type plate in terms of hysteretic stability and energy dissipation. Both DDCD and SDCD could achieve the expected phased yielding, and DDCD provides superior loading and energy dissipation capacity. Moreover, the dumbbell-type EDE provides excellent energy dissipation when α is taken as 0.1 or 0.2 and β is taken as 0.3–0.5 or 0.5–0.6. The out-of-plane deformation of the dumbbell-type EDE is minimized when γ is taken as 0.5. It is recommended that the Ry and Rh of SDCD should be taken as 0.5 and 30–44, respectively. Besides, the modified formula reduces the maximum calculation error of mechanical properties from 49.99% to 23.53% and is considered to be applicable to the design of SDCD.

Cyclic performance of precast segmented bridge pier with inner column socket connection: A parametric study

To enhance the lateral bearing capacity and resilience of precast segmented bridge piers (PSBPs), a novel inner column (IC) socket connection at the bottom of the pier was proposed. The performance of the joint of the precast column and footing block determines the lateral bearing capacity of the pier and the bridge. Therefore, the joint adopts high-performance concrete (HPC) and engineered cementation composite (ECC) ICs. The cyclic performance of IC socket connection under pseudo-static tests with constant vertical loading was investigated. Numerical models against four bridge pier-tested specimens cited in the references were developed utilizing the OpenSees platform and ABAQUS software to verify modeling accuracy. Accordingly, three piers, two PSBPs with varying IC materials, and one standard PSBP without an IC were studied to confirm the effectiveness of IC in the PSBP system. Then, parametric analyses of their impact on PSBPs with IC were conducted, examining variables of the height ratio, cross-section area, concrete strength, reinforcement ratio, and reinforcement yield strength ratios of the IC in addition to vertical loading ratio and post-tension tendon area. The findings indicate that existing the IC improves PSBP performance in terms of hysteretic behavior, ductility, energy dissipation, and stiffness while ensuring self-centering behavior is within the acceptable range. Furthermore, a well-designed IC can effectively regulate the lateral resistance capacity and resilience performance of PSBPs. For PSBP construction, the IC socket connection utilizing modern materials is an effective connector and versatile for future bridge structure applications.

Numerical investigations on constitutive model parameters of HRB400 and HTRB600 steel bars based on tensile and fatigue tests

Abstract In recent years, HRB400 and HTRB600 steel bars have become the mainstream standard reinforcing steel used in concrete structures in China. However, significant controversy still exists regarding the selection of material constitutive models and the determination of model parameters for buckling, fatigue, hysteresis, and other material characteristics. In this article, an automated process of multi-parameter calculation of the constitutive model for reinforcing steel – simulation accuracy evaluation of the constitutive model – selection of the constitutive model of reinforcing steel is established based on the hybrid programming method using MATLAB and OpenSees software. First, tensile and low-cycle fatigue tests were carried out on HRB400 and HTRB600 steel bars. Second, based on the constitutive model in OpenSees software and the skeleton curve and characteristics such as yielding, fatigue, and hysteresis, the constitutive model parameters of HRB400 and HTRB600 steel bars are determined using indirect and direct fitting methods. Finally, the five similarity parameters of the simulated normalized cumulative hysteretic energy dissipation coefficient are compared with the test results. The results indicate that the simulation accuracy of the Reinforcing Steel model exceeds 72%, which is higher than other four models, making it the best choice for reinforcing steel in numerical simulation.

Experimental study of the static and hysteretic performance of grouted steel beam-column inter-connections for modular integrated construction

Modular Integrated Construction (MiC) has gained prominence as a construction method, and the integrity of its structural connections plays a critical role in ensuring the overall stability and safety of buildings. This paper presents an experimental investigation into the static and hysteretic performance of grouted steel beam-column inter-connections designed for MiC. The study examines eight full-scale specimens subjected to both monotonic and cyclic loading conditions, with a focus on failure characteristics, deformation behavior, loading-displacement curves, loading-strain curves, skeleton curves of hysteretic loops, stiffness degradation, and energy dissipation. Key findings of the study include the observation of weld cracking between beam flanges and columns in all specimens, highlighting the necessity of welding quality control to prevent such issues. Grouted connections exhibited superior integrity, with no gap opening or misalignment between upper and lower columns. Additionally, it was found that grouting could enhance the stiffness of certain connections. Removal of diagonal stiffeners significantly decreased peak bearing capacity, emphasizing their importance. The composite action brought about by bolts connecting ceiling and floor beams also proved influential. According to Eurocode 3, all grouted specimens fall under the classification of semi-rigid connections, with a distinction made for partial and full-strength connections. This research contributes valuable insights into the static behavior and hysteretic performance of grouted steel beam-column inter-connections for MiC, providing essential knowledge for the structural design and safety of buildings utilizing this innovative construction method.

Effects of external loads-induced inclination damage on the seismic performance of traditional straight M-T joints

Under the earthquakes, wind, and other external loads, ancient timber structures have experienced various degrees of damages, in which the inclination damage of mortise and tenon (M-T) joints, induced by the external loads, has an adverse effect on the safety of the whole structure. To study the effect of various degrees of inclination damage on the seismic behavior of straight M-T joints, we fabricated four 1/3.2-scaled ancient straight M-T joint specimens, one without inclination and three with different degrees of inclination, and subjected them to the cyclic loading tests. The inclination of the joint was simulated artificially, i.e., pushing the intact joint to the predetermined inclination rotation and holding the loads, then unloading when the part of tenon entered a nonrecoverable plastic state. The failure modes, initial elastic stiffness, moment-resisting capacity, strength and stiffness degradation laws as well as energy dissipation and deformation capacities of the joints were investigated. The results showed that the plastic deformation of the tenon and mortise edge, tenon pull-out, and longitudinal splitting of the tenon were exhibited in the inclined joint specimens. Compared to the intact joint, the plastic deformation of the tenon and tenon pull-out for the inclined M-T joints were more apparent during the positive loading. The hysteretic curve of each joint exhibited an anti- "Z" shaped, and the greater the inclination degree, the more apparent the negative initial slipping and pinching effect. With an increase in the damage degree, the initial stiffness, ultimate moment-resisting capacity, and hysteretic energy dissipation behavior of the inclined M-T joint gradually degraded. When the damage degree was 3.89%, the positive yielding moment, peak moment, and initial stiffness of the inclined M-T joint degraded to 52.41%, 86.09%, and 67.19% of that of the intact joint. Based on the hysteretic characteristics and test results of the inclined M-T joints, the degradation formulas of the key parameters of seismic behavior for the inclined M-T joints were established, and an improved degraded hysteretic model, which can reflect the hysteretic behaviors of inclined M-T joint, was proposed. Good agreements between the model predictions and the test results were observed.

Seismic behavior of reduced beam section joints considering concrete floor effect

SummaryThis study investigates the seismic impact of concrete floors on reduced beam section beam‐to‐column joints through four quasi‐static cyclic tests. We examine mechanical properties, failure modes, and processes against specific criteria. Additionally, we analyze hysteretic response, energy dissipation, stiffness, capacity, and stress–strain mechanisms. Moreover, the ABAQUS platform was used to reproduce the specimen nonlinear finite element model to compare and analyze the test results. The results showed that the specimens exhibit excellent energy dissipation capacity and ductility (with a coefficient of 5.00); the column‐bar connection characteristics affect the maximum capacity and plastic hinge behavior in the reduced beam area. The reduced section of beam's upper flange could not improve the overall seismic performance of the joint. The observed failure sequence is as follows: concrete floor cracking, beam flange yielding, reinforcement fracture, lower flange yielding in the reduced beam area, and overall joint failure. This sequence confirms that the joint fulfills the design criteria of a “strong column‐weak beam” by achieving the target of plastic hinge outward movement.

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.

Structural overall damage index based on structural strain energy

In order to accurately evaluate the overall damage degree of a structure after an earthquake and provide guidance for structural reinforcement and repair, it is crucial to develop a reasonable damage model that can effectively describe the structural overall damage. This has been a focal point of research in the field of seismic engineering. Structural strain energy (SSE) is a parameter that can sensitively reflect the damage condition of the entire structure. Therefore, based on SSE and considering the coupling effect of the first transcendental failure and cumulative hysteretic energy dissipation, a structural overall damage index is derived through theoretical analysis. This index aims to capture the extent of damage based on SSE. To validate the credibility of the proposed damage index, a 60-story truss frame-core tube structure model with outrigger (TCO), measuring 237.60 m in height, is selected as an example. Six representative damage indices are chosen for comparison purposes. The nonlinear dynamic characteristics of the entire structure are analyzed using incremental dynamic analysis (IDA). Additionally, the seven damage indices, including the code-specified values, are compared to verify the credibility and applicability of the proposed structural overall damage index.

Rate-independent hysteretic energy dissipation in collagen fibrils.

Nanoindentation cycles measured with an atomic force microscope on hydrated collagen fibrils exhibit a rate-independent hysteresis with return point memory. This previously unknown energy dissipation mechanism describes in unified form elastoplastic indentation, capillary adhesion, and surface leveling at indentation velocities smaller than 1 μm s-1, where viscous friction is negligible. A generic hysteresis model, based on force-distance data measured during one large approach-retract cycle, predicts the force (output) and the dissipated energy for arbitrary indentation trajectories (input). While both quantities are rate independent, they do depend nonlinearly on indentation history and on indentation amplitude.

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.

Cyclic behavior of self-centering RCFST column to beam joints with prefabricated connectors

This paper presents the cyclic behavior of reinforced concrete-filled steel tube (RCFST) column to beam joint with prefabricated connectors. The cyclic performance of four specimens was investigated to focus on the hysteretic behavior, reinforcement tension, residual deformation, and strain distribution of joints. The equivalent viscous damping coefficients (ξeq) corresponding to the four specimens range from 0.049 to 0.087 at the yield point. And the final residual drift ratio of the specimens ranged from 3.6% to 12.9%. The tested column-beam joint specimens had good hysteretic behavior, energy dissipation, and self-centering ability. The PT steel bars without hollow channel or weakened treatment enhanced the self-centering ability and workability of joints. The finite element models were developed to verify the main mechanical properties of the self-centering RCFST column to beam joint. The average of KE/ KFEA, Mc,y/ My,FEA and Mc,p/ Mp,FEA were 0.89, 0.98, and 1.03, respectively. The FEA models could predict mechanical properties of the joints with high accuracy.

Mechanical properties and constitutive models of butt-welds in Q345GJ thick steel plates

GJ steel is a high-performance steel manufactured in China, and its thick plates are widely used in building structures. The first companion study examined the material properties of the thick GJ steel plates (t ≥ 60 mm). This study focuses on the mechanical properties of butt welds in thick GJ steel plates (t ≥ 60 mm). Monotonic and cyclic tests were conducted on butt-weld specimens made of 60-mm and 100-mm thick Q345GJ steel plates in the longitudinal and transverse directions. In addition, the layered specimens obtained from five different thickness locations were tested. Based on the cyclic test results, the Chaboche constitutive parameters were calibrated and verified via the finite element analysis (FEA). Moreover, the differences in the static and cyclic mechanical properties of the base metal and butt welds were analysed. Compared with the base metal, the static tensile strength and hysteretic energy dissipation under the same cyclic loading protocol were better in the weld specimens; however, their ductility was significantly lower. Furthermore, the distribution of the mechanical properties along the thickness direction was more uniform in the weld specimens. Moreover, the weld specimens had higher yield surface reduction ratios. However, their initial and final yield surface sizes were larger than those of the base metals.

Experimental Study on Energy Dissipation Performance of SPA Shear Plate Metal Damper Based on Jacket Platform

Aiming at the problem of excessive vertical vibration caused by seismic primary waves in jacket structures located in seismic zones in China, a new type of shear plate metal damper with upper and lower elliptical openings (SPA) is proposed in this paper. The seismic model test is carried out to compare the shear plate metal damper with three traditional opening forms, central elliptical opening, single row opening, and double row opening, and the hysteretic curve, skeleton curve, and cyclic hysteretic energy dissipation capacity are analyzed. The results show that the energy dissipation performance of the new shear plate metal damper with upper and lower elliptical openings proposed in this paper is better than that of the other three types of dampers.

Seismic behavior of the brick masonry rural building strengthened with polypropylene grid cement mortar coating: Shaking table tests

Brick masonry structures are widely applied around the world, especially in Chinese rural areas, but their seismic performance is not satisfactory due to high brittleness of material and poor integrity of structure. Accordingly, a low-cost and highly efficient strengthening method for brick masonry structure is needed. This paper presents the shaking table tests for a 1/2-scale single-story brick masonry rural building strengthened with polypropylene grid cement mortar coating. The damage states of the test model under earthquake motions with different intensity were observed. The dynamic characteristics including natural frequency and damping ratio were discussed. The seismic response, such as acceleration, displacement, torsion angle, base shear and hysteretic energy dissipation, were analyzed. The results show that the weak areas of the test model were the corners of windows and door, the intersections between longitudinal wall and transverse wall and the top of longitudinal walls. With the input PGA of 1.0 g, the natural frequencies of the test model in the X and Y directions decreased to 93.1 % and 88.2 % of the initial values, respectively, the damping ratio in the X and Y directions increased to 2.56 and 1.61 times the initial values, respectively, and the maximum story drift and horizontal torsion angle were 1/122 and 0.0037 rad, respectively. The comparison between actual earthquake damage and test results showed that the use of polypropylene grid cement mortar coating to strengthen brick masonry rural building could result in good seismic behaviors.

Mechanical characteristics of a novel variable friction hybrid self-centering damper

A novel variable friction hybrid self-centering damper (VFHSCD) with significant self-centering and hysteretic energy-dissipating performance is proposed for resilient structures. This VFHSCD is composed of a novel variable friction self-centering device and an auxiliary restoring system, which is desired to alleviate the conflicting problem in designing the self-centering and friction energy dissipation performance of the existing variable friction self-centering dampers. The force-displacement relationship of VFHSCD is studied by theoretical and experimental methods first, and the self-centering and hysteretic energy-dissipating performances of the damper are then analyzed. The results show that the theoretical model of the force-displacement relationship of the damper agrees well with experimental results and presents typical flag-shaped self-centering characteristics and strong hysteretic energy dissipation performance. By using this theoretical force-displacement relationship, the effects of friction coefficient and inclination angle of the friction slopes, and the stiffness ratio and the pre-pressure ratio of the auxiliary restoring device to the transverse compression spring on the self-centering and damping performance of the VFHSCD are investigated. The results show that the VFHSCD can be optimally designed to obtain significant energy-dissipating capacity without the cost of weakening significantly its self-centering capacity.