scholarly journals Seismic Response of Resilient Bridges with SMA-Based Rocking ECC-Reinforced Piers

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6500
Author(s):  
Xiaogang Li ◽  
Ke Chen ◽  
Ji Chen ◽  
Yi Li ◽  
Dong Yang
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Damage Control ◽  
Ground Motions ◽  
The Self ◽  
Strong Earthquakes ◽  
Residual Displacements ◽  
Working Principle ◽  
Bridge System

Post-earthquake investigation shows that numerous reinforced concrete (RC) bridges were demolished because of large residual displacements. Improving the self-centering capability and hence resilience of these bridges located in earthquake-prone regions is essential. In this regard, a resilient bridge system incorporating engineered cementitious composites (ECC) reinforced piers and shape memory alloy (SMA) energy dissipation components, i.e., SMA washers, is proposed to enhance its resilience when subjected to strong earthquakes. This study commences with a detailed introduction of the resilient SMA-washer-based rocking bridge system with ECC-reinforced piers. Subsequently, a constitutive model of the ECC material is implemented into OpenSees and the constitutive model is validated by test data. The working principle and constitutive model of the SMA washers are also introduced. A series of dynamic analysis on the conventional and resilient rocking bridge systems with ECC-reinforced piers under a suite of ground motions at E1 and E2 earthquake levels are conducted. The analysis results indicate that the resilient rocking bridge system with ECC-reinforced piers has superior resilience and damage control capacities over the conventional one.

scholarly journals Finite Element Analysis for the Self-Loosening Behavior of the Bolted Joint with a Superelastic Shape Memory Alloy

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1592 ◽  
Author(s):  
Xiangjun Jiang ◽  
Jin Huang ◽  
Yongkun Wang ◽  
Baotong Li ◽  
Jingli Du ◽  
...  
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory ◽  
Computational Procedure ◽  
The Self ◽  
External Loading ◽  
Bolted Joint ◽  
Element Analysis ◽  
Dissipation Energy

A macroscopic constitutive model is proposed in this research to reproduce the uniaxial transition ratcheting behaviors of the superelastic shape memory alloy (SMA) undergoing cyclic loading, based on the cosine-type phase transition equation with the initial martensite evolution coefficient that provides the predictive residual martensite accumulation evolution and the nonlinear feature of hysteresis loop. The calculated results are compared with the experimental results to show the validity of the present computational procedure in transition ratcheting. Finite element implementation for the self-loosening behavior of the superelastic SMA bolt is then carried out based on the proposed constitutive model to analyze the curves of stress-strain responses on the bolt bar, clamping force reduction law, dissipation energy change law of the bolted joint for different external loading cases, and preload force of the bolt.

scholarly journals Study of SMA-dowelled timber connection reinforced by densified veneer wood under cyclic loading

2019 ◽  
Vol 275 ◽  
pp. 01015 ◽  
Author(s):  
Haoyu Huang ◽  
Wen-Shao Chang ◽  
Ke Chen
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Temperature Control ◽  
The Self ◽  
Damping Capacity ◽  
Conventional Steel ◽  
Energy Dissipation Capacity ◽  
Timber Connections

This study explores the dynamic behaviours of shape memory alloy (SMA)-dowelled timber connection with densified veneer wood (DVW) reinforcement, so as to provide resilience to the timber structure. The performance of the SMA bar under cyclic bending is firstly studied, and it is found that it has superior self-centring effect and large ductility compared with that of the steel. By testing the SMA-dowelled timber connections and the conventional steel-dowelled timber connections under cyclic loading at various displacement levels, it is shown that SMA can provide better self-centring effect and larger ductility to the connection. The DVW reinforcement can enhance the self-centring and improve the strength. However, the energy dissipation capacity of the SMA-dowelled timber connection is lower than that of the steel-dowelled connection because of the smaller hysteresis area of the SMA. In the further study, the effect of the temperature control on SMA should be investigated to improve the damping capacity of the SMA-dowelled timber connection.

An innovative seismic-resilient bridge with shape memory alloy-washer-based footing rocking RC piers

2020 ◽  
pp. 1045389X2096316
Author(s):  
Yue Zheng ◽  
Cheng Fang ◽  
Dong Liang ◽  
Ruiqin Sun
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Damage Control ◽  
Load Resistance ◽  
System Level ◽  
Superior Performance ◽  
Static Tests ◽  
System A ◽  
Fixed Base ◽  
Bridge System

This study proposes a new footing rocking pier which employs shape memory alloy (SMA) washers as its kernel elements. Apart from providing self-centering capability and energy dissipation, the SMA washers enable a “limited rocking” behavior for the pier, helping enhance the seismic resilience of the bridges. The study commences with quasi-static tests on SMA washer groups with various stack patterns. Subsequently, a 1/4 scale SMA-washer-based rocking pier specimen is tested. Following the experimental study, a bridge system adopting the SMA-washer-based rocking pier is carefully designed. An iterative seismic design approach is proposed for the rocking pier, followed by a system level analysis on the entire bridge system. A suite of ground motions corresponding to two intensity levels are considered. The performance of the innovative bridge is also compared with a conventional bridge with fixed-base piers. The results reveal that the new system exhibits superior performance to the conventional bridge in terms of pier damage control, which is achieved with acceptable sacrifice of other performance indices such as bearing displacement and peak drift ratio. A further parametric study suggests that the response of the bridge with the proposed pier is related to the load resistance and deformability of the SMA washers.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

scholarly journals Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2961
Author(s):  
Moein Rezapour ◽  
Mehdi Ghassemieh ◽  
Masoud Motavalli ◽  
Moslem Shahverdi
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Vertical Strip ◽  
Maximum Resistance ◽  
The Cross ◽  
Post Tensioning

This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

PRELIMINARY STUDY ON NOVEL BEAM-TO-COLUMN CONNECTION BASED ON SMA PLATE

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Michael CH Yam ◽  
Ke Ke ◽  
Ping Zhang ◽  
Qingyang Zhao
Keyword(s):  
Friction Coefficient ◽  
Energy Dissipation ◽  
Numerical Study ◽  
Numerical Models ◽  
Numerical Technique ◽  
The Self ◽  
Hysteretic Behavior ◽  
The Novel ◽  
Energy Dissipation Capacity ◽  
Preliminary Study

A novel beam-to-column connection equipped with shape memory alloy (SMA) plates has been proposed to realize resilient performance under low-to-medium seismic actions. In this conference paper, the detailed 3D numerical technique calibrated by the previous paper is adopted to examine the hysteretic behavior of the novel connection. A parametric study covering a reasonable range of parameters including the thickness of the SMA plate, friction coefficient between SMA plate and beam flange and pre-load of the bolt was carried out and the influence of the parameters was characterized. In addition, the effect of the SMA Belleville washer on the connection performance was also studied. The results of the numerical study showed that the initial connection stiffness and the energy-dissipation capacity of the novel connection can be enhanced with the increase of the thickness of the SMA plate. In addition, the initial connection stiffness and energy-dissipation behavior of the novel connection can be improved by increasing the friction coefficient or pre-load of bolts, whereas the increased friction level could compromise the self-centering behavior of the connection. The hysteretic curves of the numerical models of the connection also implied that the SMA washers may contribute to optimizing the connection behavior by increasing the connection stiffness and energy-dissipation capacity without sacrificing the self-centering behavior.

Experimental study on seismic performance of suspended ceiling components

2021 ◽  
Author(s):  
Yong Wang ◽  
Huanjun Jiang ◽  
Chen Wu ◽  
Zihui Xu ◽  
Zhiyuan Qin
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Seismic Vulnerability ◽  
Axial Loading ◽  
Deformation Capacity ◽  
Severe Damage ◽  
Strong Earthquakes ◽  
Static Tests ◽  
Load Carrying

<p>Suspended ceiling systems (SCSs) experienced severe damage during strong earthquakes that occurred in recent years. The capacity of the ceiling component is a crucial factor affecting the seismic performance of SCS. Therefore, a series of static tests on suspended ceiling components under monotonic and cyclic loadings were carried out to investigate the seismic performance of the ceiling components. The ceiling components include main tee splices, cross tee latches and peripheral attachments. All specimens were tested under axial loading. Additionally, the static tests of cross tee latches subjected to shear and bending loadings were performed due to their seismic vulnerability. The failure pattern, load-carrying ability, deformation capacity and energy dissipation of the ceiling components are presented in detail in this study.</p>

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