Search

A self-centering energy dissipation (SCED) brace that utilized disc springs to provide self-centering capability and friction pads to dissipate energy was developed. Based on Bouc–Wen model and the working principle of SCED brace, a restoring force model is developed to describe the mechanical behavior of the brace. Comparisons between the cyclic loading tests and predicted results are conducted. Results show that the restoring force model can accurately predict both the energy dissipation and self-centering capabilities of SCED brace. A performance-based design method for frame structures with SCED braces is developed corresponding to the four-level seismic fortification objective, that is, no damage under minor and moderate earthquakes, replaceable or repairable under major earthquakes, and no collapse under mega earthquakes. A typical SCED braced steel frame was designed, and nonlinear time-history analysis was conducted to analyze the seismic performance and resilience of the braced frame. It is demonstrated that the SCED braced frame has superior resilience with small residual deformation under the moderate and major earthquakes due to the self-centering capability provided by the SCED brace. The collapse of the structure is also effectively avoided due to the stable energy dissipation and lateral stiffness provided by the SCED brace. [ABSTRACT FROM AUTHOR]

The ability of an idealized piecewise-linear restoring force model and a nonlinear mechanical model to describe the hysteretic performances of the pre-pressed spring self-centering energy dissipation braces was evaluated based on experimental data. The hysteretic behaviors predicted by these two proposed models were compared with the experimental results of a typical prototype brace, and the results demonstrated that the two models can explain the brace force-time responses, and that the nonlinear mechanical model is more effective in describing the stiffness transition and energy dissipation of the brace. The two proposed models can be used for the design of the pre-pressed spring self-centering energy dissipation brace specimens, and the nonlinear mechanical model may be more useful for designing the structures with the pre-pressed spring self-centering energy dissipation braces. An orthogonal experiment was applied to analyze the influences of the key parameters on the performances of pre-pressed spring self-centering energy dissipation braces based on the nonlinear mechanical model. The results indicate that the friction slip force of energy dissipation mechanism, the pre-pressed force of self-centering mechanism, and the post-activation stiffness significantly affect the hysteretic performances and equivalent viscous damping ratios of the bracing system, while the changes in other parameters only produce slight effects. The determination of the pre-pressed force of the self-centering mechanism should be coordinated with the friction slip force of the energy dissipation mechanism to achieve a better hysteretic performance of the pre-pressed spring self-centering energy dissipation brace. [ABSTRACT FROM AUTHOR]

The pre-pressed spring self-centering energy dissipation (PS-SCED) brace that combines the friction energy dissipation mechanism with a self-centering member comprising combination disc springs is developed and experimentally studied. The configuration of the proposed bracing system is presented and a Bouc–Wen model-based restoring force model is proposed to predict its hysteretic behavior. Two large scale PS-SCED braces with different length and different types of disc springs are designed, fabricated, and tested under low cyclic reversed loadings, and results demonstrate that the PS-SCED brace exhibits stable and repeatable self-centering hysteretic responses with effective energy dissipation capacity. The ductility of the proposed bracing system can be enhanced by employing the disc springs with bearing surface, and increasing the length of the tube members or segments of the disc springs. The symmetry of the bearing force in tension and in compression meets the design requirement for bracing elements. And the proposed restoring force model can accurately portray the hysteretic behavior of the PS-SCED bracing system. [ABSTRACT FROM AUTHOR]

A new type of bracing system composed of friction energy dissipation devices for energy dissipation, pre-pressed combination disc springs for self-centering and tube members as guiding elements is developed and experimentally studied in this paper. The mechanics of this system are explained, the equations governing its hysteretic responses are outlined and large-scale validation tests of two braces with different types of disc springs are conducted under the condition of low cyclic reversed loading. The experimental results demonstrate that the proposed bracing system exhibits a stable and repeatable flag-shaped hysteretic response with an excellent self-centering capability and effective energy dissipation throughout the loading protocol. Furthermore, the maximum bearing force and stiffness are predicted well by the equations governing its mechanical behavior. Fatigue and destructive test results demonstrate that the proposed bracing system can maintain stable energy dissipation and self-centering capabilities under large deformation cyclic loading even when the tube members exceed the elastic limit and that a larger bearing capacity is achieved by the system that has disc springs without a bearing surface. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The present study develops and experimentally verifies a new type of earthquake-resilient bracing system. The proposed pre-pressed spring self-centering energy dissipation (PS-SCED) bracing system combines friction energy dissipation devices between inner and outer tube members with a mechanism of pre-pressed disc springs that provides a self-centering capability and additional energy dissipation. Two large-scale PS-SCED braces with different types of inner tube members are designed, fabricated, and tested under low cyclic reversed loadings, and the results demonstrate that the PS-SCED braces exhibit stable and repeatable flag-shaped hysteretic responses with excellent self-centering capabilities, effective energy dissipation, large ultimate bearing capacity, and appreciable ductility. The residual deformation of the brace is controlled by adjusting the ratio of the initial pre-pressed force of the disc springs to the friction force provided by the energy dissipation devices. The energy dissipation and ductility of the PS-SCED brace constructed with a circular inner tube are better than those of the brace constructed with an X-shaped inner tube. A restoring force model for the PS-SCED brace is proposed, and the predicted hysteretic responses agree well with the experimental results. [ABSTRACT FROM AUTHOR]