Experimental assessment and analytical modeling of novel fiber-reinforced isolators in unbounded configuration

Losanno, Daniele; Sierra, Ingrid E. Madera; Spizzuoco, Mariacristina; Marulanda, Johannio; Thomson, Peter

doi:10.1016/j.compstruct.2019.01.026

Cited by 77 publications

(46 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The use of materials with low mechanical properties for the manufacture of RR-FRBs is possible, because these devices are adopted in an unbonded configuration where the bearing is free to roll off the supports when deformed in shear. A detailed description of the production technologies and the results of extensive experiments on the recycled rubber used for the manufacture of these bearings are contained in the work of Montella et al 9 Many studies that focus on compression and shear tests of FRBs have aimed to demonstrate the feasibility of using the bearings as base isolators (e.g., previous studies [10][11][12][13][14][15] ), but very few shaking-table tests have been used to address the response of buildings when base isolated with FRBs. 5,16,17…”

Section: Recycled-rubber Fiber-reinforced Bearingsmentioning

confidence: 99%

Bidirectional shaking‐table tests of unbonded recycled‐rubber fiber‐reinforced bearings (RR‐FRBs)

Losanno

Spizzuoco

Calabrese

2019

Struct Control Health Monit

Self Cite

View full text Add to dashboard Cite

Summary This paper describes the results of bidirectional shaking‐table tests performed on novel, low‐cost, and eco‐friendly recycled‐rubber fiber‐reinforced bearings (RR‐FRBs). The research aims to demonstrate the adequacy of square bearings made of recycled rubber when it comes to performing a base isolators in low‐rise residential buildings in developing regions of the world. The results of shear tests on RR‐FRBs are described in this paper as well as the response of a base‐isolated prototype building under bidirectional ground‐motion excitation. Compared with the results of a fixed‐base structure, the peak drift ratio, peak base shear, and peak acceleration on the different floors are significantly reduced for the base‐isolation system of the RR‐FRBs. The results of this work confirm the option of adopting RR‐FRBs as base isolators in real structures, with the stability of the devices under major bidirectional excitation requiring further investigation.

show abstract

Section: Recycled-rubber Fiber-reinforced Bearingsmentioning

confidence: 99%

Bidirectional shaking‐table tests of unbonded recycled‐rubber fiber‐reinforced bearings (RR‐FRBs)

Losanno

Spizzuoco

Calabrese

2019

Struct Control Health Monit

Self Cite

View full text Add to dashboard Cite

show abstract

“…(1) where is the compression modulus of the confined elastomeric compound, when fiber reinforcements are used [20]. For circular bearings, this equivalent compression modulus can be determined from Figure 1, where ( ) ( ) and , with as the Poisson's ratio of the fiber, is the shear modulus at a strain level of 20%, is the radius of the isolator, is elastic modulus of the fiber, is the thickness of the fiber reinforcement and is the bulk modulus of the rubber [18]. is the compression modulus for steel reinforced isolators defined as , where the shape factor is ( ), with as the diameter of the device and the thickness of each rubber layer.…”

Section: Analytical Modelmentioning

confidence: 99%

“…is the compression modulus for steel reinforced isolators defined as , where the shape factor is ( ), with as the diameter of the device and the thickness of each rubber layer. In a previous work [18], the authors developed an accurate analytical model capable of predicting both the horizontal and the vertical stiffness of U-FREIs. The main steps required to estimate the horizontal stiffness of FRBs are summarized below.…”

Section: Analytical Modelmentioning

confidence: 99%

“…Once the internal fibers have been preloaded, the tangent stiffness is practically the same according to pressure solution and FEM estimate. The stiffness change limit point is calculated assuming a rubber deformation of 3,5 % according to experimental results from a previous investigation [18]. With the bilinear model, the vertical displacement under design load is approximately two times higher than with linear model.…”

Section: Vertical Behaviormentioning

confidence: 99%

“…The aim of this paper is to compare the vertical and horizontal behavior of FREIs with different reinforcement, shape and geometry under cyclic and monotonic loads. This comparison will be based on the results of analytical model proposed by the authors in a previous investigation [18] and results of finite element analysis (FEM) available in literature [15].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analytical vs Numerical Determination of the Axial and Lateral Stiffness of Fiber Reinforced Isolators

Losanno¹,

Sierra²,

Calabrese³

et al. 2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

Self Cite

View full text Add to dashboard Cite

This paper presents the results of a numerical and experimental study aiming to define the vertical and horizontal stiffness of Fiber-Reinforced Elastomeric Isolators (FREIs). In FREIs, the conventional steel shims of laminated rubber bearings are replaced by flexible fiber reinforcements. The axial and lateral response of these bearings is influenced by the flexibility of these layers. This study describes results of an analytical model capable of providing an accurate estimation of the vertical and horizontal stiffness of the bearings under static and dynamic loads. Results of this analytical model are compared to output of finite element analysis (FEM) available in literature. The influence of the geometry of the isolator (i.e., strip and circular shape), its shape factor and type of reinforcement on the vertical and horizontal stiffness are discussed. Considerations are also given on the effects of the compressibility of the rubber on the axial and lateral response of the devices.

show abstract

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

Losanno

Ravichandran

Parisi

2022

Earthq Engng Struct Dyn

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Experimental assessment and analytical modeling of novel fiber-reinforced isolators in unbounded configuration

Cited by 77 publications

References 36 publications

Bidirectional shaking‐table tests of unbonded recycled‐rubber fiber‐reinforced bearings (RR‐FRBs)

Bidirectional shaking‐table tests of unbonded recycled‐rubber fiber‐reinforced bearings (RR‐FRBs)

Analytical vs Numerical Determination of the Axial and Lateral Stiffness of Fiber Reinforced Isolators

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

Contact Info

Product

Resources

About