Experimental Investigation on Ageing Behaviors of Rubbers Used for Bridge Bearings

Itoh, Yoshito; Gu, Haosheng; Satoh, Kazuya; Kutsuna, Yukihiro

doi:10.2208/jsceseee.23.17s

Cited by 16 publications

(10 citation statements)

References 14 publications

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“…Deterioration of bearings is partially accounted for by reducing the area of the steel dowels using Equation 3. However, it has also been observed that elastomeric bearing pads undergo oxidation due to prolonged exposure (Itoh et al, 2006). Therefore, stiffness of the bearing pad (K = GA p /t p ; A p : area of pad; t p : thickness of pad) is updated with time in accordance with the results in Itoh & Gu (2009):…”

Section: Deterioration Mechanisms and Their Modelingmentioning

confidence: 85%

Towards Risk-Based, Multi-Hazard-Resistant Design of Bridges

Kameshwar¹,

Padgett²

2014

Structures Congress 2014

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This paper proposes an object oriented consequence based framework for lifecycle risk assessment to aid design of bridges subjected to multiple hazards while considering the effects of structural deterioration. Such a framework constitutes an essential foundation for a transition to multi-hazard risk-based design. In the proposed framework, losses, i.e. consequences of damage such as cost or downtime, are introduced to provide a common performance metric for multiple hazards. Surrogate models are used to condition loss potential upon the intensity measure(s) of the hazards and structural design parameters. The loss estimates are coupled with hazard information to obtain expected annual losses from each hazard. The fragility of the bridge and consequently the expected annual loss change with time due to aging of the bridge; this time dependent feature is also accounted for in the proposed framework. As a case study, the proposed framework is applied for multi-hazard design of multi-span simply supported (MSSS) concrete girder bridges in coastal South Carolina, which is susceptible to earthquakes and hurricanes induced wave and surge loads in addition to corrosion. The framework's applicability in facilitating safe and economical lifecycle based design is shown by investigating the effect of variation in design parameters and structural deterioration on the lifecycle costs (LCC). The effect of deterioration on lifecycle performance of bridges under different hazards is studied along with relative contribution of each of the hazards towards total expected loss and its variation with time.

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Section: Deterioration Mechanisms and Their Modelingmentioning

confidence: 85%

Towards Risk-Based, Multi-Hazard-Resistant Design of Bridges

Kameshwar¹,

Padgett²

2014

Structures Congress 2014

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“…Environmental factors like oxygen exposure, heat, and sunlight, which deteriorate physical properties of rubber bearings such as elasticity and strength, are usually not considered during the design process of rubber bearings. Understanding the degradation of the material properties is considered essential in their lifetime prediction [1][2][3]. As the service temperature rises, molecular changes take place, resulting in a loss of mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

“…Oxidative degradation is the most important factor that determines durability in most engineering applications, including bridge rubber bearings, where the oxygen availability is limited by diffusion [2][3]. Itoh, et al [3,7] have evaluated the evolution of tensile mechanical properties (such as elongation at break and tensile strength) of different types of rubber compounds used for bridge bearings exposed to different ageing tests, including thermal oxidation, ozone, low temperature ozone, ultraviolet radiation, salt water, and acid rain.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Thermal Ageing on the Mechanical Properties of Natural Rubber-based Compounds Used for Rubber Bearings

Guzmán

Vásquez

Moreno

2021

J. Eng. Technol. Sci.

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Molecular changes due to high temperatures, sunlight, and oxygen, deteriorate the physical properties of rubber compounds, yielding additional crosslinks and molecular chain breakdown. Since oxidative degradation is the most important factor that determines the durability of rubber components, this study evaluated the mechanical behavior of rubber compounds exposed to accelerated thermal ageing. Therefore, three carbon black-reinforced natural rubber-based compounds typically used for rubber bearings were exposed to thermal oxidation and their mechanical properties under typical loading states were assessed through standardized tests. Significant differences were found due to thermal ageing in the compressive modulus, compression set, and creep compliance in compression, exhibiting a stiffening effect caused by additional crosslinks. However, no significant differences were observed in hardness, which is a superficial measurement and a typical test in the rubber industry to characterize rubber compounds. Therefore, the assessment of ageing in rubber bearings should not be limited to a hardness test, which is required in design standards but also addresses compressive, cyclic, and transient tests. The results obtained in this study can be considered in the design process of rubber bearings by limiting the allowable compressive stress and creep deflection due to ageing effects.

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“…Firstly, these are intended to measure changes in the elastomer at the (elevated) service temperature or, secondly, these can be used as accelerated tests to estimate the degree of change, which would take place over much longer times at normal ambient temperature 1 . A series of accelerated exposure tests were performed by Itoh 2 , et al on various rubber materials including high damping rubber (HDR) to investigate the degradation due to different environmental factors. It was found that the thermal oxidation is the most predominant degradation factor affecting the HDR material.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Life of an Elastomeric Component: A Stochastic Model

Das¹,

Chaudhuri²

2011

DSJ

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Life of equipment has been an area of great importance to engineers, however, largely unexplored. In the case of elastomers, this becomes more critical because of faster degradation in properties of the elastomers, and thereby performance of the elastomeric item, when compared to metals-the degradation referred to as aging of the elastomer. The present work focuses on the development of a stochastic model for estimating life of a vibration isolator, which finds many defence applications, to attenuate noise and vibration from the machinery. A majority of the vibration isolators use rubber for attenuation, and therefore, the life of the isolator invariably depends on the life of the rubber. The methodology of life estimation has been based on the Arrhenius theory of chemical kinetics and is applicable where the material degrades relatively faster at higher temperature so that the degradation rates can be studied. Statistical techniques have been applied to arrive at a reliable estimation. The method can be used for reliable estimation of storage life of elastomeric products, and thereby help to maintain cost-effective inventory.

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Experimental Investigation on Ageing Behaviors of Rubbers Used for Bridge Bearings

Cited by 16 publications

References 14 publications

Towards Risk-Based, Multi-Hazard-Resistant Design of Bridges

Towards Risk-Based, Multi-Hazard-Resistant Design of Bridges

The Effect of Thermal Ageing on the Mechanical Properties of Natural Rubber-based Compounds Used for Rubber Bearings

Estimation of Life of an Elastomeric Component: A Stochastic Model

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