Pre-pressed Spring Self-centering Energy Dissipation Research Articles

Assembled self-centering energy dissipation braces and a force method-based model

A pre-pressed spring self-centering energy dissipation (PS-SCED) bracing system has significant energy dissipation and re-centering abilities, although many welds result in a lengthy manufacturing process and reduce the machining accuracy to an unacceptable level. An assembled pre-pressed spring self-centering energy dissipation (A-PS-SCED) bracing system that uses disc spring groups to provide a re-centering ability and a friction device to dissipate energy, is presented in this paper to simplify production and maintenance. A novel force method-based (FMB) hysteretic analysis model governing the distribution of the internal force is proposed and verified by a numerical model of the A-PS-SCED brace and tests of the PS-SCED brace specimen. The simulation results indicate that the A-PS-SCED brace exhibits sufficient and steady energy dissipation and re-centering capacities. The FMB model agrees well with the numerical model with a maximum bearing force difference of 2% and has steady hysteretic responses under random excitations. The FMB model is used to determine the mechanisms of the stiffness and contact status change during a typical loading process. Additionally, the FMB model accurately predicts the cyclic loading test results of an existing PS-SCED brace specimen, and the average bearing force differences are 6% and 2% at friction force of 200 kN and 300 kN, respectively.

SEISMIC PERFORMANCE STUDY OF REINFORCED CONCRETE FRAME WITH SELF-CENTERING BRACES

A mechanical model is proposed accurately describe the hysteretic behavior of pre-pressed spring self-centering energy dissipation (PS-SCED) brace. The state variables are introduced to distinguish different stages of PS-SCED brace and then its mechanical responses are determined. The secondary development of the mechanical model is carried out based on ABAQUS. The simulation results of the developed PS-SCED brace element are compared with the test results of the brace, and the seismic performances of a 3-story reinforced concrete frame structure with PS-SCED braces are analyzed. The results indicate that the hysteretic curves obtained from the brace element simulation agree well with the test results, and the brace element is accurate enough to describe the mechanical performance of the brace under dynamic loads. The seismic energy dissipates sufficiently and the plastic deformation of the structure is controlled effectively by PS-SCED braces subjected to strong earthquake. Additionally, the residual deformations of frame structure with PS-SCED braces are reduced by 72.1%~92.1% compared with the original frame structure. The PS-SCED brace exhibits full hysteretic performances with good energy dissipation capacity and self-centering behavior, which significantly improves the seismic performances of reinforced concrete frame structures.

Development and experimental validation of a steel plate shear wall with self-centering energy dissipation braces

Abstract A new type of steel plate shear wall with self-centering energy dissipation braces (SPSW-SCEDB) was developed. Validation tests of the wall plate and the pre-pressed spring self-centering energy dissipation (PS-SCED) braces were conducted and a single-bay, single-story, 1:3-scale SPSW-SCEDB specimen was designed, fabricated, and tested under cyclic loadings. The results demonstrated that the SPSW-SCEDB exhibited a stable flag-shaped hysteretic response with high initial stiffness, appreciable ductility, and excellent self-centering and energy dissipation capabilities due to the synergistic effects of the wall plate and the PS-SCED braces. The proposed theoretical equations of the compressive force of the wall plate, the ultimate lateral load capacity, and the remaining restoring force of the SPSW-SCEDB were verified. The PS-SCED braces reduced the stiffness degradation of the wall plate and improved the lateral force resistance and the stability of the SPSW-SCEDB system. The wall plate provided more energy dissipation than the PS-SCED braces. The remaining restoring force of the PS-SCED braces should be as small as possible to maximize the energy dissipation of the PS-SCED braces while ensuring that it overcomes the compressive force of the wall plate.

Experimental study on component performance in steel plate shear wall with self-centering braces

Steel plate shear wall with self-centering energy dissipation braces (SPSW-SCEDB) is a lateral force-resisting system that exhibits flag-shaped hysteretic responses, which consists of two pre-pressed spring self-centering energy dissipation (PS-SCED) braces and a wall plate connected to horizontal boundary elements only. The present study conducted a series of cyclic tests to study the hysteretic performances of braces in SPSW-SCEDB and the effects of braces on the overall hysteretic characteristics of this system. The SPSW-SCEDB with PS-SCED braces only exhibits excellent self-centering capability and the energy loss caused by the large inclination angle of PS-SCED braces can be compensated by appropriately increasing the friction force. Under the combined effect of the two components, the SPSW-SCEDB exhibits a flag-shaped hysteretic response with large lateral resistance, good energy dissipation and self-centering capabilities. In addition, the wall plate is the primary energy dissipation component and the PS-SCED braces provide supplementary energy dissipation for system. The PS-SCED braces can provide up to 90% self-centering capability for the SPSW-SCEDB system. The compressive bearing capacity of the wall plate should be smaller than the horizontal remaining restoring force of the braces to achieve better self-centering effect of the system.

Seismic Assessment of Buildings with Prepressed Spring Self-Centering Energy Dissipation Braces

AbstractThe seismic performance of four- and eight-story steel buildings with prepressed spring self-centering energy dissipation (PS-SCED) braces was evaluated using a proposed nonlinear mechanica...

Seismic performance evaluation of steel frames with pre-pressed spring self-centering braces

Pre-pressed spring self-centering energy dissipation (PS-SCED) braces with flag-shaped hysteretic responses are expected to undergo large deformation while re-centering to their origin, providing a self-centering capability for the structures. Three 4-, 8-, and 16-story braced frames with PS-SCED braces were analyzed to assess their seismic performances in comparison to conventional steel braced frames (CSBFs) and buckling restrained braced frames (BRBFs). Detailed analytical models of the PS-SCED braces were implemented and seven suites of ground motions with three different hazard levels were used to assess the structural performances with respect to interstory drifts, residual deformations, and peak floor accelerations during earthquakes. It was shown that the CSBFs underwent larger average responses than the BRBFs and the PS-SCED braced frames. The interstory drifts and peak floor acceleration responses of the frames with the BRBs were comparable and often better than those of the frames with the PS-SCED braces due to their high energy dissipation and simpler hysteretic cycles; the difference in the performance of these two braces tended to decrease with the increase in the seismic hazard level and the building height. The PS-SCED braces reduced the residual deformations more effectively than the BRBs and CSBs.

Hysteresis analysis of pre-pressed spring self-centering energy dissipation braces using different models

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.

Seismic performance and damage analysis of RC frame–core tube building with self-centering braces

This paper examines the seismic responses of a reinforced concrete (RC) frame–core tube building with pre-pressed spring self-centering energy dissipation braces (PS-SCEDBs). The PS-SCEDB is a passive energy dissipation device with disc springs and friction pads. Parameters of PS-SCEDBs installed on the structure are designed according to the principle of equivalent stiffness, based on the parameters of a buckling-restrained brace (BRB) equipped on the original RC frame–core tube structure. The constitutive models of self-centering flag-shaped and bilinear elastoplastic hysteresis for PS-SCEDBs and BRBs, respectively, are developed and experimentally verified. The seismic performance of RC frame–core tube structures with PS-SCEDBs and BRBs, respectively, are studied and compared using non-linear time history analysis. Results show that the PS-SCEDB can substantially reduce residual drift ratios of a concentrically braced building while still capable of effectively controlling the peak inter-story drift ratio and damage of components adjacent to braces under rare earthquakes. The structure with PS-SCEDBs can effectively dissipate seismic energy without increasing damage to beams, columns, and shear walls.

Cyclic behaviors of steel plate shear wall with self-centering energy dissipation braces

The present study develops and numerically verifies a new type of earthquake resilient system. The proposed system combines a steel plate shear wall with infill panel connected to beams only and pre-pressed spring self-centering energy dissipation (PS-SCED) braces that provide the self-centering and additional energy dissipation capabilities. The mechanics of this system is explained and the equations governing its stiffness and strength are also presented. A simplified model is proposed to simulate the hysteretic behaviors of the PS-SCED braces, and comparisons with experimental results demonstrate that the proposed model can effectively describe the hysteretic responses of the bracing system. The hysteretic behaviors of the proposed system and the effects of the infill panel and the PS-SCED braces parameters on the system performance under cyclic loadings are analyzed. Results indicate that the proposed system exhibits a flag-shaped hysteretic response with large stiffness, high strength, excellent self-centering and energy dissipation capabilities. The initial stiffness and yield force of the system are well predicted by the governing equations. The energy dissipation capability of the system is mainly affected by the PS-SCED braces, and the system with the self-centering ratio of 0.7 or more can limit the residual deformation to the tolerance for new steel building when the inter-story drift ratio reaches 2%.

Behaviors Comparisons and Prediction of Pre-Pressed Spring Self-Centering Energy Dissipation Braces

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.

Hysteretic Analysis Model for Pre-pressed Spring Self-Centering Energy Dissipation Braces

AbstractA restoring force model is proposed that is applicable for predicting the hysteretic behaviors of the pre-pressed spring self-centering energy dissipation (PS-SCED) braces. Two Bouc-Wen mod...

Experimental behavior and analysis of self-centering steel brace with pre-pressed disc springs

Quasi-static reversed cyclic loading tests and finite element analyses of a pre-pressed spring self-centering energy dissipation brace are conducted. The proposed steel bracing system combines a mechanism of pre-pressed disc springs for self-centering with friction devices for energy dissipation. The mechanics and the basic equations governing the design and distribution of internal force are presented. The results demonstrate that the bracing system exhibits stable and repeatable self-centering hysteretic responses with effective energy dissipation, and no residual deformation occurs when the initial pre-pressed force of disc springs is greater than the friction force provided by the energy dissipation devices. The forces at the surface of the inner and outer tubes are distributed as expected. The inverse calculation method is proposed to predict the hysteretic responses employing the strain data, the comparative analyses of behaviors obtained from experiments, finite element analyses, and inverse calculation are conducted, and good agreements are observed.

Development and experimental verification of a pre-pressed spring self-centering energy dissipation brace

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.

Hysteretic behavior studies of self-centering energy dissipation bracing system

This paper presents a new type of pre-pressed spring self-centering energy dissipation (PS-SCED) bracing system that combines friction mechanisms between the inner and outer tube members to provide the energy dissipation with the pre-pressed combination disc springs installed on both ends of the brace to provide the selfcentering capability. The mechanics and the equations governing the design and hysteretic responses of the bracing system are outlined, and a series of validation tests of components comprising the self-centering mechanism of combination disc springs, the friction energy dissipation mechanism, and a large scale PS-SCED bracing specimen were conducted due to the low cyclic reversed loadings. Experimental results demonstrate that the proposed bracing system performs as predicted by the equations governing its mechanical behaviors, which exhibits a stable and repeatable flag-shaped hysteretic response with excellent self-centering capability and appreciable energy dissipation, and large ultimate bearing and deformation capacities. Results also show that almost no residual deformation occurs when the friction force is less than the initial pre-pressed force of disc springs.