A new concept of isolation bearings for highway steel bridges using shape memory alloys

2005 ◽  
Vol 32 (5) ◽  
pp. 957-967 ◽  
Author(s):  
Eunsoo Choi ◽  
Tae-hyun Nam ◽  
Baik-Soon Cho
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Ground Motion ◽  
Residual Deformation ◽  
Steel Bridge ◽  
Ground Acceleration ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Isolation Device ◽  
Strong Ground

Conventional lead–rubber bearings (LRB) may have a problem of instability and unrecovered deformation with a strong ground motion. To improve the problems, this study proposed a new concept of an isolation device in which shape memory alloy wires were incorporated in an elastomeric bearing. This study illustrated the behavior of shape memory alloy in tension and discussed the variation of stiffness and stress on the hyteresis curves. A three-span continuous steel bridge was used for seismic analyses to compare the performance of lead–rubber bearings with the proposed bearings. This study showed that large residual deformation of LRB occurred even with a weak ground motion of peak ground acceleration (PGA) of 0.2g. The proposed bearings effectively limited the relative displacement of the deck when tested for the strong ground motions and almost recovered the original undeformed shape. However, the proposed bearing increases the demand on bridge columns compared with the LRB.Key words: shape memory alloy, lead–rubber bearings, seismic bridge analysis, isolation device, residual deformation.

Longitudinal seismic response control of long-span cable-stayed bridges using shape memory alloy wire-based lead rubber bearings under near-fault records

2017 ◽  
Vol 29 (5) ◽  
pp. 703-728 ◽  
Author(s):  
Shuai Li ◽  
Farshad Hedayati Dezfuli ◽  
Jing-quan Wang ◽  
M Shahria Alam
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Alloy Wire ◽  
Base Shear ◽  
Alloy Wire ◽  
Near Fault ◽  
Long Span ◽  
Lead Rubber Bearing ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

This article investigates the efficiency of a new generation smart isolation system, namely shape memory alloy wire-based lead rubber bearing, for the seismic response control of long-span cable-stayed bridge systems under near-fault ground motions. The constitutive model of shape memory alloy wire-based lead rubber bearings is coded and implemented into OpenSees as a new user element. This user element can accurately predict the re-centering capability and energy dissipation capacity of shape memory alloy wire-based lead rubber bearing under different excitations. The Sutong cable-stayed bridge in China, with a main span of 1088 m, is taken as an example. Results reveal that implementing shape memory alloy wires into lead rubber bearings can effectively increase the self-centering property and, as a result, reduce the residual deformation in shape memory alloy wire-based lead rubber bearings under near-fault ground motions. Shape memory alloy wires lead to an increase in the horizontal stiffness and energy dissipation capacity of shape memory alloy wire-based lead rubber bearings. The deck displacement is restricted effectively, and a superior structural performance is achieved in terms of the deck acceleration. Shape memory alloy wire-based lead rubber bearings can effectively reduce the base shear and base moment of the towers. However, it is observed that an increase in the shape memory alloy wire diameter may have negligible effect on the deck acceleration, tower base shear and moment, and in some cases, on the pier base shear and moment.

scholarly journals Earthquakes on the surface: earthquake location and area based on more than 14 500 ShakeMaps

2018 ◽  
Vol 18 (6) ◽  
pp. 1665-1679
Author(s):  
Stephanie Lackner
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Earthquake Location ◽  
Primary Concern ◽  
Ground Acceleration ◽  
Ground Shaking ◽  
Geographic Context ◽  
The Social ◽  
Strong Ground

Abstract. Earthquake impact is an inherently interdisciplinary topic that receives attention from many disciplines. The natural hazard of strong ground motion is the reason why earthquakes are of interest to more than just seismologists. However, earthquake shaking data often receive too little attention by the general public and impact research in the social sciences. The vocabulary used to discuss earthquakes has mostly evolved within and for the discipline of seismology. Discussions on earthquakes outside of seismology thus often use suboptimal concepts that are not of primary concern. This study provides new theoretic concepts as well as novel quantitative data analysis based on shaking data. A dataset of relevant global earthquake ground shaking from 1960 to 2016 based on USGS ShakeMap data has been constructed and applied to the determination of past ground shaking worldwide. Two new definitions of earthquake location (the shaking center and the shaking centroid) based on ground motion parameters are introduced and compared to the epicenter. These definitions are intended to facilitate a translation of the concept of earthquake location from a seismology context to a geographic context. Furthermore, the first global quantitative analysis on the size of the area that is on average exposed to strong ground motion – measured by peak ground acceleration (PGA) – is provided.

Experimental and numerical studies on a novel shape-memory alloy wire–woven trusses capable of undergoing large deformation

2019 ◽  
Vol 30 (15) ◽  
pp. 2283-2298
Author(s):  
Zhixiang Rao ◽  
Xiaojun Yan ◽  
Xiaoyong Zhang ◽  
Bin Zhang ◽  
Jun Jiang ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Deformation ◽  
Residual Deformation ◽  
Shape Memory Alloy Wire ◽  
Static Compression ◽  
Recoverable Strain ◽  
Alloy Wire ◽  
Assembly Method ◽  
Finite Element Analysis Simulation

Currently, most wire-woven trusses are fabricated with traditional metals such as steel and aluminum, thus the deformation ability is constrained due to the low yield strain of common metals. Shape-memory alloy is a kind of smart material which can bear large recoverable strain while producing hysteresis. Due to the unique capacity of large deformation and remarkable damping property of the shape-memory alloy, a novel lattice trusses assembled by superelastic shape-memory alloy coil springs was proposed. Furthermore, the treatment processes to prepare the shape-memory alloy coil springs and the assembly method to fabricate the shape-memory alloy wire–woven trusses were also introduced. The quasi-static compression under different maximum deformation and temperatures was performed to investigate the mechanical and thermal responses of the proposed shape-memory alloy wire–woven trusses. Cyclic compression tests were also performed to study the functional fatigue of the shape-memory alloy wire–woven trusses. The proposed wire-woven trusses can undergo up to 80% deformation by compression and recover without evident residual deformation after unloading. Finite element analysis simulation of representative volume element under different deformation was presented. Analytical modeling of the stiffness of shape-memory alloy wire–woven trusses was also carried out. Both the numerical and analytical methods can predict the stiffness within a small deviation.

Seismic Performance of Concrete Bridge Piers Reinforced with Hybrid Shape Memory Alloy (SMA) and Steel Bars

2019 ◽  
Vol 14 (01) ◽  
pp. 2050001
Author(s):  
Jize Mao ◽  
Daoguang Jia ◽  
Zailin Yang ◽  
Nailiang Xiang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Performance ◽  
Residual Deformation ◽  
Steel Reinforcement ◽  
Bridge Piers ◽  
Dissipated Energy ◽  
Concrete Bridge ◽  
Loss Of Function ◽  
Hybrid Reinforcement

Lack of corrosion resistance and post-earthquake resilience will inevitably result in a considerable loss of function for concrete bridge piers with conventional steel reinforcement. As an alternative to steel reinforcement, shape memory alloy (SMA)-based reinforcing bars are emerging for improving the seismic performance of concrete bridge piers. This paper presents an assessment of concrete bridge piers with different reinforcement alternatives, namely steel reinforcement, steel-SMA hybrid reinforcement and SMA reinforcement. The bridge piers with different reinforcements are designed having a same lateral resistance, or in other words, the flexural capacities of plastic hinges are designed equal. Based on this, numerical studies are conducted to investigate the relative performance of different bridge piers under seismic loadings. Seismic responses in terms of the maximum drift, residual drift as well as dissipated energy are obtained and compared. The results show that all the three cases with different reinforcements exhibit similar maximum drifts for different earthquake magnitudes. The SMA-reinforced bridge pier has the smallest post-earthquake residual displacement and dissipated energy, whereas the steel-reinforced pier shows the opposite responses. The steel-SMA hybrid reinforcement can achieve a reasonable balance between the residual deformation and energy dissipation.

scholarly journals Relationships between macroseismic intensity and peak ground acceleration and velocity for the Vrancea (Romania) subcrustal earthquakes

2021 ◽  
Vol 64 (4) ◽  
pp. SE432
Author(s):  
Iren-Adelina Moldovan ◽  
Angela Petruta Constantin ◽  
Raluca Partheniu ◽  
Bogdan Grecu ◽  
Constantin Ionescu
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Empirical Relationship ◽  
Macroseismic Intensity ◽  
Ground Acceleration ◽  
Ground Motion Parameters ◽  
Motion Parameters ◽  
Subcrustal Earthquakes ◽  
Strong Ground

The goal of this paper is to develop a new empirical relationship between observed macroseismic intensity and strong ground motion parameters such as peak ground acceleration (PGA) and velocity (PGV) for the Vrancea subcrustal earthquakes. The recent subcrustal earthquakes provide valuable data to examine these relationships for Vrancea seismogenic region. This region is one of the most active seismic zones in Europe and it is well-known for the strong subcrustal earthquakes. We examine the correlation between the strong ground-motion records and the observed intensities for major and moderate earthquakes with Mw ≥ 5.4 and epicentral intensity in the range VI to IX MSK degrees that occurred in Vrancea zone in the period 1977-2009. The empirical relationships between maximum intensity and ground parameters obtained and published by various authors have shown that these parameters do not always show a one-to-one correspondence, and the errors associated with the intensity estimation from PGA/PGV are sometimes +/-2 MSK degree. In the present study, the relation between macroseismic intensity and PGA/PGV will be given both as a mathematical equation, but also as corresponding ground motion intervals. Because of the intensity data spreading and errors related to mathematical approximations, it is necessary to systematically monitor not only the acceleration and velocity but also all the other ground motion parameters. The mathematical relation between these parameters might be used for the rapid assessment of ground shaking severity and potential damages in the areas affected by the Vrancea earthquakes.

Comparative study of two types of self-recovery shape-memory alloy pseudo-rubber isolator devices under compression–shear interactions

2019 ◽  
Vol 30 (15) ◽  
pp. 2241-2256 ◽  
Author(s):  
Suchao Li ◽  
Chenxi Mao
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shear Failure ◽  
Three Dimensional ◽  
Residual Deformation ◽  
Shear Loading ◽  
Wire Mesh ◽  
Type I ◽  
Rubber Isolator ◽  
Deformation Recovery

Two types of novel shape-memory alloy-based devices with three-dimensional isolation potential and deformation recovery abilities were developed. These two types of isolators, which are called shape-memory alloy pseudo-rubber isolators, were both created with martensitic shape-memory alloy wires through weaving, rolling, and punching processes, but they underwent heat treatment at different fabrication stages and for different durations. A series of mechanical tests were performed on these two types of shape-memory alloy pseudo-rubber isolators to investigate their properties under compression, shear, and combined compression–shear loading at room temperature. The restorable shear limit was then investigated, and the corresponding shear failure mechanism was discussed according to a tension test of one thin layer of the shape-memory alloy wire mesh. Subsequently, the deformation recovery ability of the shape-memory alloy pseudo-rubber isolator with residual deformation was tested through heating on a thermo-control stove. Finally, the mechanical-property stabilities, energy-dissipation abilities, and recovery abilities were compared between the two types of shape-memory alloy pseudo-rubber isolator devices. The experimental results indicated that both types of shape-memory alloy pseudo-rubber isolators had excellent residual deformation recovery abilities, and the type-I shape-memory alloy pseudo-rubber isolator device had more stable mechanical properties than the type-II shape-memory alloy pseudo-rubber isolator. The type-I shape-memory alloy pseudo-rubber isolator device is thus an ideal candidate for traditional three-dimensional isolators.

Design of Shape Memory Alloy Damper for Base Isolated Structure

1997 ◽  
Author(s):  
Krzysztof Wilde ◽  
Paolo Gardoni ◽  
Yozo Fujino ◽  
Stefano Besseghini
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Base Isolation ◽  
Hysteretic Behavior ◽  
Isolation System ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
Smart Base Isolation

Abstract Base isolation provides a very effective passive method of protecting the structure from the hazards of earthquakes. The proposed isolation system combines the laminated rubber bearing with the device made of shape memory alloy (SMA). The smart base isolation uses hysteretic behavior of SMA to increase the structural damping of the structure and utilizes the different responses of the SMA at different levels of strain to control the displacements of the base isolation system at various excitation levels. The performance of the smart base isolation is compared with the performance of isolation by laminated rubber bearings to assess the benefits of additional SMA damper for isolation of three story building.

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