An experimental study on a novel reclaimed rubber compound for fiber-reinforced seismic isolators

Cilento, Fabrizia; Losanno, Daniele; Piga, L.

doi:10.1016/j.istruc.2022.09.009

Cited by 23 publications

(9 citation statements)

References 56 publications

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“…This works reports preliminary results on the vertical response of U-FREIs under vertical and multi-directional horizontal loads. Further developments include multiple values of the vertical pressure and of the shear modulus of the rubber (including reclaimed rubber compounds (Losanno et al, 2020;Cilento et al, 2022), as well as different shape of the bearings. Also, additional FEAs on elastomeric bearings needs to be carried out implementing different material models for the elastomer, including viscoelasticity, or compared with results obtained using phenomenological approaches (Vaiana et al, 2019;Vaiana and Rosati, 2023).…”

Section: Discussionmentioning

confidence: 99%

Vertical response of unbonded fiber reinforced elastomeric isolators (U-FREIs) under bidirectional shear loading

Galano

2022

Front. Built Environ.

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Fiber Reinforced Elastomeric Isolators (FREIs) were generally studied in unbonded configuration. Due to combined axial and shear loads, the contact area between the bearing and horizontal supports reduces with the horizontal displacement. As a result, both the vertical and the horizontal stiffnesses decrease with the horizontal deformation while also the vertical deformation increases. This paper presents the results of a large set of full-scale 3D Finite Element Analyses on unbonded fiber reinforced bearings with different geometries, subjected to combined axial and multi-directional shear loads. The main vertical response parameters were studied, namely the vertical displacement, the vertical stiffness, and the effective compressive modulus, thus highlighting the influence of both geometry and horizontal loading direction on the vertical response of the FREIs. Conclusion of this study demonstrate to what extent the combined influence of geometric properties and loading conditions affects the vertical response of elastomeric bearings with flexible reinforcements.

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Section: Discussionmentioning

confidence: 99%

Vertical response of unbonded fiber reinforced elastomeric isolators (U-FREIs) under bidirectional shear loading

Galano

2022

Front. Built Environ.

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“…The rubber shear modulus 𝐺 can be ranging from 0.4 to 1.1 MPa according to previous investigations depending on the manufacturing process of the compound. 28,62 The number and typology of the fibre layers can be obtained by imposing a satisfactory ratio of the vertical-to-the-horizontal stiffness of the isolators. (iii) Design procedure of the BI system: The isolators were sized according to the stability requirements for FREIs, which according to preliminary design criterion tend to remain stable for displacements smaller than half of their base dimensions.…”

Section: Design Of Base Isolation Systemmentioning

confidence: 99%

“…The design assumptions of this study are not limited to recycled‐rubber since the same target stiffness and performance objective can be obtained through both virgin‐ and recycled‐rubber 63 once stability limits are set according to the bearing geometry. The rubber shear modulus G can be ranging from 0.4 to 1.1 MPa according to previous investigations depending on the manufacturing process of the compound 28,62 . The number and typology of the fibre layers can be obtained by imposing a satisfactory ratio of the vertical‐to‐the‐horizontal stiffness of the isolators. Design procedure of the BI system : The isolators were sized according to the stability requirements for FREIs, which according to preliminary design criterion tend to remain stable for displacements smaller than half of their base dimensions 66 .…”

Section: Design Of Base Isolation Systemmentioning

confidence: 99%

“…25,26 As regard higher uncertainties in the mechanical properties of recycled-rubber, these authors recently investigated the influence of variability in RR-FREIs' properties, demonstrating low sensitivity of seismic fragility analysis due to significantly higher effect of masonry properties to be accounted in case of URM buildings. 27 Further development of RR-FREI technology would demand mechanical properties be duly characterized according to modern standards for rubber testing as recently done in Cilento et al 28 One of the key components in seismic risk assessment of buildings is the fragility analysis which is used for a probabilistic estimation of future losses. 29,30 Several studies had been carried out to evaluate the vulnerability of reinforced concrete (RC) buildings, steel buildings and bridges.…”

Section: Introductionmentioning

confidence: 99%

“…As regard higher uncertainties in the mechanical properties of recycled‐rubber, these authors recently investigated the influence of variability in RR‐FREIs’ properties, demonstrating low sensitivity of seismic fragility analysis due to significantly higher effect of masonry properties to be accounted in case of URM buildings 27 . Further development of RR‐FREI technology would demand mechanical properties be duly characterized according to modern standards for rubber testing as recently done in Cilento et al 28 …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Seismic fragility models for base‐isolated unreinforced masonry buildings with fibre‐reinforced elastomeric isolators

Losanno

Ravichandran

Parisi

2022

Earthq Engng Struct Dyn

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Unreinforced masonry (URM) buildings are highly vulnerable to seismic ground motion, calling for quantitative risk assessment and mitigation programmes in different earthquake‐prone countries to reduce future losses. Despite the effectiveness of base isolation technology in reducing seismic response of buildings, the high costs of conventional isolators prevent their application to low‐cost housing in developing countries. Fiber‐reinforced elastomeric isolators (FREIs) have been recently developed as low‐cost isolators suitable for application to URM buildings. The structural performance assessment of base isolated URM buildings using FREIs can be a sustainable solution for a large‐scale mitigation of seismic risk. In this context, the present study presents the seismic fragility analysis of both fixed‐base and base‐isolated URM buildings. Five URM building archetypes were considered to account for variation in geometry and building configuration. A number of static pushover analyses and nonlinear time history analyses were carried out to assess the capacity and demand of the selected buildings, respectively, while considering the uncertainties associated with material properties, capacity model, damage state and earthquake ground motion. The fragility curves were developed for both fixed‐base and base‐isolated configurations of the different archetypes. The results show that the probability of slight to moderate damage to fixed‐base URM buildings is significantly higher than their base‐isolated counterparts, demonstrating that FREIs significantly improve their seismic performance. These outcomes address further research in promoting the development of FREIs to reduce the vulnerability of URM buildings in developing countries.

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Phenomenological modeling of fiber‐reinforced elastomeric isolators at multiple lateral deformation levels

Montalto,

Konstantinidis,

Ankem

2024

Earthq Engng Struct Dyn

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Unbonded fiber‐reinforced elastomeric isolators (FREIs) are a cost‐effective seismic isolation technology that uses lightweight fiber‐fabric reinforcement and forgoes the attachment plates connecting the isolators to the supports. These devices exhibit a complex nonlinear mechanical behavior under lateral deformation, which has typically been represented by uniaxial phenomenological models. In this paper, a new model, called Pivot Bouc–Wen model, is proposed to address the shortcomings of existing numerical models and obtain a better prediction of the response over the whole range of motion. The model has been formulated with the objective of providing (a) improved interpretability of the model parameters, (b) adequate energy dissipation prediction at multiple deformation levels, and (c) stable response at large deformations. The model combines a nonlinear elastic spring and a Bouc–Wen element with a modified pivot hysteresis rule to capture the lateral response of the isolators at different deformation amplitudes. Initial values for the model parameters are recommended based on existing analytical formulations of the quasi‐static lateral response of FREIs and data corresponding to 36 cyclic tests from 12 different experimental programs. The proposed and existing models are compared in their ability to predict the lateral cyclic test results from a previous experimental study. The models are further compared via response history analyses of idealized one, two, three and four‐story base‐isolated shear buildings subjected to 30 ground motions at different intensity levels. The results highlight the importance of capturing the hysteretic response of the isolators at multiple deformation levels and not only at the maximum expected displacement.

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An experimental study on a novel reclaimed rubber compound for fiber-reinforced seismic isolators

Cited by 23 publications

References 56 publications

Vertical response of unbonded fiber reinforced elastomeric isolators (U-FREIs) under bidirectional shear loading

Vertical response of unbonded fiber reinforced elastomeric isolators (U-FREIs) under bidirectional shear loading

Seismic fragility models for base‐isolated unreinforced masonry buildings with fibre‐reinforced elastomeric isolators

Phenomenological modeling of fiber‐reinforced elastomeric isolators at multiple lateral deformation levels

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