Energy Dissipation Braces Research Articles

Assembled self-centering brace with replaceable friction damper for seismic resilience: Development and mechanical behavior research

A novel seismic resilient brace, integrating a replaceable friction damper mechanism with an assembled self-centering device of combination disc springs, has been developed and investigated through experimental research. This brace can be named as the Assembled Pre-pressed Disc-springs Self-centering Replaceable Energy Dissipation (APD-SRED) brace. The working principles, structural configurations, fabrication process and mechanical behaviors of this bracing system were discussed and analyzed firstly in detail. Subsequently, five brace specimens were designed incorporating different axial pre-compression forces within a combination disc springs system and varying friction forces in the damper device. Test results exhibit a stable and repeatable flag-shaped hysteretic responses with satisfactory energy dissipation, which can be implemented under the low cyclic reversed loading. Additionally, it can be noted that the excellent seismic resilience performance can be obtained by maintaining a relative balance between self-centering and energy dissipation characteristics. The stiffness and strength of this brace can withstand cyclical loading without degradation, making superiorities against sequential design earthquakes without the replacement or repair, and facilitating replacement of the friction energy dissipation components to meet different demands. Moreover, the proposed calculation model can be validated accurately predicting the mechanical behavior of the APD-SRED brace by considering friction effects in disc-springs. This validation was achieved through comparisons with experimental results, and several crucial design factors influencing the brace's behavior were analyzed and discussed for practical application in a parametric design. Finally, drawing upon a combination of experimental and analytical studies, this study ultimately presented practical design recommendations.

Development and experimental evaluation of cam-grip type compression-free energy dissipative braces

Recent efforts have focused on developing novel energy dissipation braces that allow only tensile yielding to overcome certain limitations of conventional braces and buckling-restrained braces (BRBs). Such limitations include insufficient information regarding the damaged state of braces in a post-earthquake scenario and the challenges associated with replacing heavy restraints to prevent steel cores from buckling. Generally, the available techniques adopt a saw-tooth mechanism that grips the core and only mobilizes the tensile forces in the brace. However, the discrete nature of saw-tooth systems may result in a slippage at the onset of the tensile loading cycle, thereby reducing the efficiency of the energy dissipation mechanism. This study introduces a novel Direction-based Force Control Mechanism (DFCM) utilizing a cam-type grip that ensures continuous gripping under reversed-cyclic loading. Using this mechanism, a new type of so-called compression-free energy dissipative braces (CEDBs) are developed and tested under reversed-cyclic loading. For this purpose, six CEDB specimens were fabricated and installed in a steel frame sub-assemblage. The frame-brace system was then subjected to quasi-static lateral drifts with increasing amplitudes to test the efficiency of the proposed device. The experimental results demonstrate that the proposed bracing system only mobilizes the tension forces with significantly low slippage with about 1 % drift (Δ ≈ 2 mm). The system also exhibits a stable energy dissipation mechanism and reliable hysteretic properties under multiple cycles of large inelastic deformations. Furthermore, the damaged steel cores can be conveniently observed and replaced after a severe shaking event, while the same DFCM can be repeatedly used. Therefore, the proposed bracing system emerges as a cost-effective option for enhancing the lateral performance of structures subjected to dynamic loadings and strong ground motions. Besides, an idealized hysteretic model for this system was developed and validated; two examples of specimens were conducted as uniaxial elements with the proposed bilinear hysteretic; based on experimental results, it is shown that the proposed bilinear hysteretic model can capture important mechanical properties and energy dissipation of the specimens with reasonable accuracy of both CEDB specimens which the average difference between experiment results and Idealized CEDBs in yield force is about 10.87 %, the ultimate force is about 1.90 %, and the corresponding cumulative energy dissipation is about 6.98 %.

Pseudo-dynamic tests of steel frame with disc spring self-centering energy dissipation braces under doublet earthquake and mainshock-aftershock sequence

To provide valuable insights into the seismic performance and self-centering behavior of self-centering braced systems, a 1/2-scale 3-story 1-bay steel frame equipped with disc spring self-centering energy dissipation braces (DS-SCBs) was designed, fabricated, and subjected to pseudo-dynamic testing. This testing encompassed various earthquake hazard levels, a doublet earthquake, and a mainshock-aftershock sequence. The experimental findings revealed the stable hysteretic response of the DS-SCB, with no observed degradation in stiffness or activation forces. Additionally, the test frame exhibited outstanding seismic performance, sustaining only confined damage under very rare earthquakes. Due to the presence of the DS-SCBs, the test frame performed commendable self-centering behavior, characterized by minimal residual deformations. Peak story drifts and floor accelerations under two earthquakes of the same hazard level were regarded as equivalent. Furthermore, the subsequent aftershocks exhibited no discernible impact on the seismic performance of the test frame. Floor acceleration spikes were observed at locations where the brace stiffness underwent changes or where adjacent stories moved in opposite directions. The steel frame equipped with DS-SCBs proved to be an attractive, low-damage alternative to conventional steel systems for the development of resilient urban areas.

Development and application of out-of-plane deformable X-shaped brace for energy dissipation and thermal stress mitigation: An experimental and numerical study

Exoskeleton systems are increasingly employed in both new and existing buildings to enhance seismic performance. Addressing the critical challenges of energy dissipation and thermal stress mitigation in these systems, an out-of-plane deformable X-shaped energy dissipation brace (OPD-XEDB), integrating an out-of-plane X-shaped brace with a shear-type metallic damper, was proposed in this study. A seismic design methodology for OPD-XEDB was firstly developed, ensuring effective energy dissipation of the damper before any potential brace buckling. Following this methodology, two specimens, exhibiting distinct failure modes of damper shear fracture and brace buckling, were designed and subjected to quasi-static loadings to explore their energy dissipation mechanisms. Upon these experimental results, a numerical model incorporating buckling and pinching behaviors was proposed and calibrated, effectively capturing the hysteretic responses of the specimens. This model was then employed in a comprehensive numerical analysis, validating the effectiveness of design methodology and determining the optimal specifications for the OPD-XEDB in a prototype building. Ultimately, thermal analysis and nonlinear time history analysis were conducted on the prototype building. The thermal analysis proved the effectiveness of the OPD-XEDB's out-of-plane configuration in mitigating thermal stress by out-of-plane deformation, significantly mitigating thermal stress in braces and interconnected moment frames by 96.59–96.66 %. The time history analysis revealed that the dampers in OPD-XEDBs dissipated 11.6–23.2 % of total seismic energy, effectively preventing substantial buckling in the X-shaped braces. This energy dissipation mechanism led to a remarkable 79.7 % reduction in steel consumption for post-earthquake retrofitting, thereby significantly enhancing the seismic resilience of the primary structure.

Seismic life-cycle cost evaluation of steel-braced frames: Comparing conventional BRBF with emerging SCVDF and HBF systems

In the past two decades, various self-centering bracing systems have been developed to enhance structural seismic resilience. However, compared to conventional bracing systems, their high initial cost and lower efficiency in controlling peak floor accelerations have reduced their economic benefits and limited their application in engineering projects. Accordingly, the self-centering viscous energy-dissipative brace (SCVDB) and the hybrid bracing system (HB), the synergistic combination of the SCVDB and buckling-restrained brace (BRB), have emerged as innovative approaches with exceptional capabilities in passive control over peak floor acceleration demand. Despite their promise, a comprehensive understanding of the life-cycle economic benefits of structures equipped with these bracing systems remains limited. This study aims to comprehensively highlight the life-cycle economic benefits associated with self-centering viscous energy-dissipative braced frames (SCVDFs) and hybrid braced frames (HBFs) compared to traditional buckling-restrained braced frames (BRBFs) across various structural heights using the improved HAZUS assessment methodology. Focusing on 4-, 8-, and 12-story buildings designed with BRBFs, SCVDFs, and HBFs, each maintaining identical peak inter-story drift ratios, the research conducts dynamic analyses combined with Monte Carlo simulations. Critical parameters such as residual inter-story drift (RID) limits defined for demolition, initial construction costs of the SCVDBs, and discount rates are considered. The analyses reveal that the expected annual earthquake-induced loss (EAL) for mid- and high-rise structures is more sensitive to RID limits than those of low-rise structures. The SCVDFs and HBFs exhibit lower EAL than BRBFs, even without considering the demolition situation. The RID limit, initial construction cost of SCVDBs, and discount rates significantly influence the relative economic benefits of SCVDFs and HBFs compared to BRBFs. In most scenarios, HBFs demonstrate superior economic benefits over SCVDFs. The HBF effectively utilizes the synergistic effects of SCVDBs and BRBs, substantially lowering initial construction costs and achieving favorable economic benefits across various structural heights within the considered parameter range.

Experimental study on hysteretic behavior of energy dissipation braces with bending plates and perforated shear plates

The shear plates had been adopted in the energy dissipation braces, but the ductility of energy dissipation braces with shear plates was poor. In this paper, a new-type bending plate-strip coupling energy dissipation brace (BSEB) with bending plates and perforated shear plates was proposed, and the strips included non-uniform strips, stiffening non-uniform strips, and T-shaped strips. The hysteretic behavior of five BSEBs was investigated through a quasi-static test. The experimental parameters included boundary condition, arrangement of perforated shear plates, and material. The experimental results indicated that the initial stiffness of BSEBs with pinned connection was significantly lower than that with bolted connection; The influence of arrangement of perforated shear plates on seismic performance of BSEBs could be little; The BSEB with perforated shear plates fabricated by stainless steel had higher initial stiffness and ultimate bearing capacity, and lower energy dissipation capacity and ductility; The fracture occurred in stiffening non-uniform strips, T-shaped strips, non-uniform strips, and bending plates in turn, and plastic strain occurred in stiffening non-uniform strips, non-uniform strips, T-shaped strips, and bending plates in turn. Finally, a few formulas for predicting the yield bearing capacity of a BSEB were developed and verified.

Seismic performance assessment of RC bridge piers with variable hysteresis performance dampers

A novel variable hysteresis performance damper (VHD)—multi-stage slip friction damper is developed and applied to implement multi-level seismic resistance of structures. Different from the conventional slip friction dampers, which feature only a single type of slip friction surface, this innovative damper incorporates two types: a flat slip surface and a wedge slip surface. The quasi-static cyclic loading tests of the VHD were carried out to investigate its variable hysteresis performance. The test results revealed that the developed damper presented excellent adaptive performance, and its hysteresis behavior changed from a complete rectangle with efficient energy dissipation to a flag-shaped curve with exceptional self-centering capacity as deformation increases. Subsequently, the developed VHD with unique adaptive performance was applied in RC bridge piers (BP) to improve the seismic performance. Nonlinear time history and fragility analysis methods were employed to assess the seismic performance of the RC bridge piers with VHDs (BP-VHD) in deterministic and probabilistic manners, considering maximum and residual deformations as performance indicators. For comparison, seismic responses of RC bridge piers with traditional buckling restrained braces (BRBs) and self-centering energy dissipation braces (SCEBs) were also presented. The analysis and comparison results demonstrate that the developed VHD is as effective as BRB in reducing maximum deformation at small PGAs, meanwhile, it can effectively reduce the residual deformation of the structure to allowable values when the PGA is large. Furthermore, the failure probability of BP-VHDs is lower compared to piers with BRBs and SCEBs, particularly concerning maximum and residual drift ratios as performance indicators. The application of the VHD can effectively achieve the goal of multi-level seismic resistance for RC bridge piers.

Shaking-Table Test and Finite Element Simulation of a Novel Friction Energy-Dissipating Braced Frame

To enhance the effect of seismic mitigation in medium-sized buildings, this study introduced a novel friction damper within a braced frame, forming a friction energy-dissipating braced frame (FDBF). The seismic reduction mechanism of the FDBF was examined, and its performance was evaluated through shaking-table tests and finite element simulations. The hysteresis performance of the novel damper was assessed through low-cycle repeated loading tests, which yielded predominantly rectangular and full hysteresis curves, exemplifying robust energy dissipation capacity. The shaking-table tests of the FDBF indicated significant modifications in the dynamic characteristics of the original frame structure, which notably reduced the natural vibration period and enhanced the damping. Additionally, the FDBF remarkably reduced both acceleration and displacement responses during seismic excitation. Optimizing the orientation of the energy dissipation brace significantly improved seismic reduction efficiency. A dynamic time history analysis, employing finite element software, was conducted on the FDBF equipped with a friction energy dissipation brace at each level. Comparative analysis with both the moment-resistant frame and ordinary braced frame revealed that the FDBF substantially lowered the peak acceleration at the apex of the structure, achieving a reduction rate of 40–50%. Under both design and rare earthquake conditions, the FDBF demonstrated superior seismic mitigation capabilities, especially under rare earthquakes. Future studies should investigate various structural types with energy dissipation braces at different levels to identify the most efficient layout for the novel friction energy dissipation brace, thereby guiding relevant engineering practices.

Experimental Study on 3D RC Frame Structures with VE Energy Dissipation Braces Using STM32-Matlab-OpenSees Hybrid Test Platform

This study aims to reveal the control mechanism of viscoelastic (VE) energy dissipation braces with strong mechanical nonlinear characteristics on the seismic response of reinforced concrete (RC) frame structures. Firstly, a new STM32-Matlab-OpenSees joint hybrid test platform is developed by introducing OpenSees, which is convenient for structural modeling and fast for structural calculation. The overall architecture and operation of the hybrid test platform are comprehensively analyzed. Then, a series of simulated seismic hybrid tests on three-dimensional (3D) RC frame structures with VE energy dissipation braces under different seismic waves are successfully carried out. Lastly, the hybrid test results of this structure system at different working conditions are compared and analyzed comprehensively. The research results show that the developed platform breaks the boundary limitation that OpenSees relies on the framework software OpenFresco and can only be connected to specific control systems in the hybrid test. Thus, it greatly expands the application scope of flexible configuration controller and actuator categories for the hybrid test platform, and it also provides a good reference value for the establishment and implementation of similar hybrid test platforms. Under the action of various seismic waves, VE energy dissipation braces has good universality for the shock absorption of RC frame structures. The damping control effect and energy dissipation efficiency of VE energy dissipation braces are significantly different under various seismic waves. In the design of RC frame structures with VE energy dispersion braces, it is very necessary to conduct the seismic analysis of the structures under multiple ground motions with wide frequency domain. The additional position of VE energy dissipation braces should be an important analysis indicators in the optimization design of the structures.

Seismic design and performance evaluation of hybrid braced frames having buckling-restrained braces and self-centering viscous energy-dissipative braces

Hybrid braced frames (HBFs) emerge as an innovative seismic-resilient system, synergizing the strengths of buckling-restrained braces (BRBs) and self-centering viscous energy-dissipative braces (SCVDBs). This novel system has the potential to simultaneously manage three key seismic demand parameters: peak inter-story drift (PID), residual inter-story drift (RID), and peak absolute floor acceleration (PFA). Nevertheless, a dedicated seismic design method for HBFs is yet to be developed. This research proposes a performance-based seismic design (PBSD) method specifically tailored for HBFs. The method's core relies on energy decoupling in the HBFs using a proposed energy distribution factor (η). To validate the proposed design method, sets of 4-, 8-, and 12-story braced frames are designed using varied η. A comprehensive seismic performance evaluation is conducted, utilizing nonlinear static and nonlinear time-history analyses. The findings indicate that the HBFs, designed utilizing different values of η, consistently meet predefined performance objectives. Within the scope of this study, the η value of 0.5 is shown to be optimal, enhancing the structural resilience of HBFs against PIDs and PFAs while exhibiting excellent self-centering performance comparable to the self-centering viscous energy-dissipative braced frame (SCVDF). Additionally, the HBFs demonstrate superior control over PFA compared to pure buckling-restrained braced frame (BRBF) and SCVDF.

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.

Numerical study of the hysteretic behavior of energy dissipation braces based on Miura origami

Miura-ori pattern was adopted to form the tessellation design of slender braces to improve the energy dissipation capacity under the low-cycle repeated loading. The energy dissipation mechanisms of origami energy dissipation braces (OEDBs) and conventional square braces with equal bearing capacity were compared. Finite element models for hysteretic simulation were constructed and analyzed to figure out the influences of various geometrical design parameters on the hysteretic behavior of OEDBs. The results show that the OEDBs have an obvious improvement in the energy dissipation capacity compared to conventional square braces. The influence of parameters on energy dissipation capacity is quite different. The smaller folding angles, smaller aspect ratios, and larger width-to-thickness ratio play positive roles in improving energy dissipation performance rather than elastic stiffness. However, smaller slenderness improves both while the change of in-plane angle is sensitive to the hysteretic performance.

Shake Table Tests on RC Double-Column Bridge Piers with Self-Centering Energy Dissipation Braces

Shake Table Tests on RC Double-Column Bridge Piers with Self-Centering Energy Dissipation Braces

Experimental and mathematical model of the variable friction adaptive self‐centering energy dissipative brace

AbstractThe self‐centering energy dissipative (SCED) brace can limit the maximum story drift and eliminate residual drift during an earthquake. The inadequate reliability or excessive complexity of the energy dissipative system, the contradiction between the energy dissipative system and self‐centering system, the limited elongation capacity, and the difficulty in replacement and reuse are the main challenges faced by the existing developed SCED brace. To solve these problems, a variable friction adaptive self‐centering energy dissipative (VFA‐SCED) brace has been proposed. First, the details of the VFA‐SCED brace are introduced, and the force analysis of each component and the working mechanism of the brace are expounded. Then, the equations that govern the brace performance have been derived, key parameters and mathematical models have been identified. Finally, the feasibility of the new system was demonstrated with a set of experiments, in which five specimens with different key parameters were fabricated, tested, and analyzed. The test results show that the hysteretic curve of the VFA‐SCED brace is typically flag‐shaped, and there is almost no residual deformation after multiple cyclic loadings, which means that the brace has good energy dissipative capacity and self‐centering ability, replaceable and recyclable for each component, and stable working performance. The elongation capacity, friction, energy dissipative capacity, and self‐centering ability can be changed by adjusting the relevant key parameters of the spring and wedge block, and the proposed mathematical model can well predict the force‐deformation hysteresis of the brace with different parameters. The results show that the VFA‐SCED brace successfully avoids the main obstacles of previous SCED braces.

Enhanced design and experimental investigation of disc spring‐based self‐centering buckling‐restrained braces with a compounded combination mode

AbstractThe disc spring‐based self‐centering energy dissipation (SCED) brace is a high‐capacity resilient structural component, characterized by a flag‐shaped hysteresis curve, which can provide both damping and recentering capacity to a structure. However, the conventional design method for the disc spring‐based SCED brace cannot quantitatively take into account the friction effects induced by combined disc springs, which greatly limits the disc spring size selection and combination mode. To address this issue, the friction effect of the combined springs is quantified using an incremental energy method and then introduced into the existing design method. A fully assembled self‐centering steel buckling‐restrained brace (SC‐SBRB) consisting of an energy dissipation (ED) system and a self‐centering (SC) system is proposed. The SC system employs a combination mode of stacking multi‐section springs in parallel and compounding new and old springs together to provide the desired recentering capacity for the brace; however, it is distinguished by an appreciable ED capacity that is different from the SC devices in previously reported SCED braces. With the use of the energy method for the quantification of the spring friction, the differences between the mechanical properties of a group of old springs in earlier and recent tests were systematically analyzed to check their reliability and serviceability. A series of test procedures were sequentially conducted on a pure BRB brace and a pure SC brace, and then on the full SC‐SBRB. A fatigue test was also performed after the damaged brace was repaired. The experimental results demonstrate that the improved design can provide accurate estimations of the spring friction in the brace design, and that the proposed brace can exhibit a stable and favorable flag‐shaped hysteretic response with negligible residual deformations throughout the loading protocol. The old spring used in the tests was found to have stable and reliable mechanical properties and could be reused in a brace requiring repair after an earthquake.

Seismic performance of an assembled self-centering buckling-restrained brace with controllable initial stiffness

An innovative assembled self-centering buckling-restrained brace (ASC-BRB) with controllable initial stiffness is introduced. The brace consists of a self-centering system and an energy dissipation system. Unlike existing post-tensioned self-centering energy dissipation braces, whose initial stiffness has high uncertainty and is sensitive to machining errors, the proposed ASC-BRB can obtain highly controllable initial stiffness because of its unique working mechanism. Therefore, structural seismic response uncertainties can be reduced significantly. The configuration, working mechanism, and theoretical restoring force model of the ASC-BRB are first presented. Quasi-static tests are then conducted to examine the feasibility of the brace, and typical flag-shaped hysteretic behavior and stable energy dissipation capability are observed. The main components of the ASC-BRB keep intact after repeated loadings, except for the core plates, which are damaged; however, the core plates can be easily replaced. This observation highlights the superiority of the ASC-BRB in terms of damage concentration and high recoverability. The proposed theoretical restoring force model can accurately predict the hysteretic response of the brace, especially for the initial stiffness, with the predicted value being within 5 % of the experimental value. A simplified numerical model is developed and used in a parametric study conducted to examine the effects of two key design parameters on the brace behavior. Furthermore, the effect of machining errors on the initial stiffness of the ASC-BRB is studied. An analysis of steel frames with ASC-BRBs indicates that the ASC-BRB can effectively reduce the residual inter-story drift and help achieve a peak floor acceleration response comparable to that of the frame with BRBs. However, the peak inter-story drift is amplified owing to the lower initial stiffness of the proposed brace. On the basis of a system-level parametric analysis, recommended optimized design parameters of the ASC-BRB are presented to facilitate efficient control of structural seismic responses.

Test of Novel Self-Centering Energy Dissipative Braces with Pre-Pressed Disc Springs and U-Shaped Steel Plates

ABSTRACT To control the residual displacement of the structure after strong earthquakes, this paper develops and validates a novel brace, i.e. the self-centering energy dissipative brace with pre-pressed disc springs and U-shaped steel plates (SCEDB-U). The pre-pressed disc springs are used for recovering nonlinear deformation and the U-shaped steel plates are used for dissipating energy. Initially, the configuration and working principle are described in detail. Then the analytical equations governing the cyclic behavior of the brace are derived. To confirm the concept, the large-scale bracing specimens are designed and manufactured for the quasi-static cyclic loading tests. In the tests, the varied parameters included the plate width of the U-shaped steel plates and the pre-pressure magnitude of the stacked disc springs. Besides, the high-fidelity three-dimensional finite element (FE) models of SCEDB-U are established. According to the experimental data, the SCEDB-U has typical flag-shaped hysteresis, which is characterized by excellent self-centering capability and stable energy dissipation ability. It also indicates that increasing the plate width of U-shaped steel plates can effectively improve the energy dissipation capacity, but may induce residual displacement; increasing the pre-pressure magnitude of disc springs could improve self-centering ability. The numerical results are in good agreement with the experimental data; hence, the FE models can be further utilized for parametric analysis, initial design and optimization.

Seismic Performance Assessment of a RC Bridge Retrofitted with SCEBs Under Near-Fault Pulse-Like Ground Motions

ABSTRACT A novel self-centering energy dissipation brace (SCEB) was developed to enhance the seismic resilience of bridges. In this paper, the replaceable SCEBs are installed between the double-column bent transversely and at the abutment longitudinally. Taking both the seismic safety and resilience into consideration, the seismic performance of bridges retrofitted by braces under near-fault (NF) pulse-like ground motions was evaluated by the probabilistic approach. Results show that the original and retrofitted bridges exhibit higher damage probabilities under NF pulse-like ground motions. The bridges retrofitted with SCEBs exhibit better seismic resilience than the bridges with buckling restrained braces when intensity measure increases.

Design recommendations for self-centering buckling restrained braces

Self-centering buckling-restrained braces (SC-BRBs) have typical flag-shaped hysteresis. Differing from conventional buckling-restrained braces (BRBs) which can result in significant residual drifts, the SC-BRB incorporates additional prestressing elements, so that it can recenter after earthquakes, which is critical for seismic resilience. Current seismic design procedures can be used to calculate the key properties of conventional braces (e.g. BRB), but they cannot be used to determine the additional hysteretic properties of SC-BRB braces. To achieve a comprehensive understanding of the performances of SC-BRB systems and develop their design recommendations, this paper conducted a parametric study of two typical SC-BRB systems, using a 12-story steel braced frame office building. Then, the overall behavior of the SC-BRB system was compared with those of a BRB system and two self-centering energy dissipative brace systems. The selection of SC-BRB properties appeared to be a tradeoff between demands on component properties and seismic performances. The criteria for proportioning the system were suggested. Numerical results showed that, although the SC-BRB systems had smaller residual drifts than the BRB system, they generated more significant high-mode effect than the other comparable systems.

Seismic performance of a shear-type energy dissipation brace: Experimental investigation and numerical analysis

In this study, a novel shear-type energy dissipation brace (SEDB) was proposed, which integrated multiple pieces of steel shear plates on a single brace. The brace stiffness and yield load can be adjusted by changing the number of pieces and layers of the steel shear plates, which is more flexible than the traditional shear-type dampers. Three configurations of SEDBs were developed, including the flat steel plate-SEDB (F-SEDB), F-SEDB without core tube and corrugated steel plate-SEDB (C-SEDB). The quasi-static cyclic tests were conducted on three SEDBs to investigate the seismic performance. Experimental results showed that the proposed SEDB can achieve a stable hysteretic behavior, especially by adopting the core tube to prevent global out-of-plane deformation. Meanwhile, the C-SEDB has a more stable energy dissipation performance due to the high out-of-plane stiffness of the corrugated steel plates. The design procedure of the SEDBs was developed. Meanwhile, a finite element model was established and verified by the experimental results. The influences of the height-thickness and height-width ratio of steel plates were systematically investigated, which benefited the application and offered suggestions in engineering design.