Long-Term Deterioration of High Damping Rubber Bridge Bearing

Itoh, Yoshito; Gu, Haosheng; Satoh, Kazuya; Yamamoto, Yoshihisa

doi:10.2208/jsceja.62.595

Cited by 17 publications

(6 citation statements)

References 12 publications

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“…It starts from the surface and makes the rubber stiff and brittle and resulting in higher hardness, lower tensile strength, and shorter elongation. Itoh et al 8) , defined two regions of rubber from the used bridge bearing: outer and inner, and reported that the property in the outer region deteriorates but does not extend to the inner region. The thickness of the outer region is called the critical depth: dc which is proportional to the exponent of reciprocal of temperature as shown in equation (7): In Fig.6, the critical depth is approximatly 70mm from both the outer and inner surface of the body.…”

Section: (1) Test Proceduresmentioning

confidence: 99%

“…The difference in average temperature between the north area and FD No.3 in the south island is about 15°C 3) which might be the reason for this difference in elongation coefficient. The calculated critical depths by Itoh et al 8) at each site location are shown in Fig.9. They look close to the measured distribution of FD No.8, 9, 10, and 11 (from 55 to 74mm ) in Fig.9 except for the 3000H-14 years in the north area where the critical depth is 102mm.…”

Section: (1) Test Proceduresmentioning

confidence: 99%

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Investigation on Service Years of Large Rubber Marine Fenders

et al. 2017

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Estimating the life of rubber marine fender (fender) is an important concern in the maintenance of a port facility. From the supply record of the Circular-Shaped Buckling (CSB) fender with panel contact, the actual service life was from 15 to 35 years. The compression tests of the fenders returned from ports showed that the reaction forces increased moderately due to the years in service. Other than some visible signs such as cracks and deformations, invisible signs of aging including uneven buckling, increased reaction force, and the growth of cracks were observed. The material tests results indicated that the deterioration of physical properties were limited to the rubber surface; the center of rubber bodies were still considered to be elastic and flexible. The performance in the first compression cycle of the test showed that the used fender exhibited a higher reaction force than the value stated in the catalogue -that is a value equivalent to the average of the second and third compression cycles. This increased reaction force during the first compression cycle (after a long interval from it's last compression cycle), for example, if used as inventory stock, could potentially be a concern to the berth structure and/or the vessel's hull.

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Section: (1) Test Proceduresmentioning

confidence: 99%

Section: (1) Test Proceduresmentioning

confidence: 99%

Investigation on Service Years of Large Rubber Marine Fenders

et al. 2017

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“…The mechanical properties of the HDRBs change uniformly along the radial direction of the isolator in a relatively short time, until a stable equilibrium state is reached in the inner region bounded by an external critical depth, 5 the latter being an exponential function of the temperature. 6 The outer region is also affected by an oxidation process, related to time and depending on the amount of oxygen, which produces a degradation of properties whose effects diminish moving towards the critical depth. Moreover, the HDRBs considerably increase their horizontal and vertical stiffnesses for decreasing values of the air temperature through rubber crystallization due to prolonged exposure to cold weather, whereas their cyclic behaviour does not change significantly at high air temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…During the lifetime of the elastomeric (e.g., high‐damping rubber bearings [HDRBs]) and sliding (e.g., flat sliding bearings [FSBs]) bearings, representing some of the most widely used types of isolation systems, ageing and air temperature are important factors that affect the degradation of rubber and friction coefficient of the sliding surface, respectively. The mechanical properties of the HDRBs change uniformly along the radial direction of the isolator in a relatively short time, until a stable equilibrium state is reached in the inner region bounded by an external critical depth, the latter being an exponential function of the temperature . The outer region is also affected by an oxidation process, related to time and depending on the amount of oxygen, which produces a degradation of properties whose effects diminish moving towards the critical depth.…”

Section: Introductionmentioning

confidence: 99%

Effects of the long-term behaviour of isolation devices on the seismic response of base-isolated buildings

Mazza

2019

Struct Control Health Monit

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Summary Seismic isolation is widely used around the world for the protection of buildings, but its long‐term behaviour was not considered in detail in past seismic design of isolated structures. Nevertheless, the American seismic code has recently introduced an explicit procedure aimed at evaluating upper‐bound and lower‐bound values of isolation system properties. Yet there are few studies on the evolution and extent of the deterioration of elastomeric (e.g., high‐damping rubber bearings) and sliding (e.g., flat sliding bearings) isolators during their lifetime and on their impact on the seismic behaviour of the superstructure. To investigate this problem, six‐storey–reinforced concrete buildings, base isolated with high‐damping rubber bearings acting alone or in combination with flat sliding bearings, are designed without considering the variability of mechanical properties of the isolation system due to ageing and air temperature. Then, based on experimental results from accelerated ageing tests at high temperature, mathematical models are implemented to account for oxidation of elastomers and friction changes. The variability of mechanical properties at different mean temperatures, due to seasonal thermal variations, is also considered. Finally, fragility curves are developed for the base‐isolation system and superstructure on the basis of nonlinear dynamic analysis of the degraded test structures.

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Section: Introductionmentioning

confidence: 99%

Long-Term Seismic Response of Buildings With Isolation Devices Affected by Deterioration Effects

Mazza¹

2019

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

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Base-isolation technique has long been used worldwide but seismic codes generally do not take into account ageing and environmental effects on the evolution and extent of the deterioration of elastomeric (e.g. high-damping-rubber bearings, HDRBs) and friction (e.g. flat sliding bearings, FSBs) isolators during their lifetime and on their impact on the nonlinear seismic behaviour of the superstructure. The aim of the present work is to investigate the effects of variability of the mechanical properties of elastomeric and sliding bearings on the nonlinear dynamic response of base-isolated reinforced concrete (r.c.) framed structures, focusing the attention on ageing and air temperature effects. First, six-storey base-isolated r.c. framed structures are designed in accordance with the current Italian code in a high-risk seismic zone, considering nominal values of mechanical properties of the isolation system. Specifically, nine structural configurations are examined, considering two alternative arrangements: i) elastomeric base-isolation (EBI) systems, with three different elastomer compounds for the HDRBs (i.e. soft, normal and hard); ii) hybrid elastomeric-sliding baseisolation (ESBI) systems, with the aforementioned elastomer compounds of the HDRBs and two friction coefficients (i.e. low and medium) of the FSBs. Then, based on experimental results from accelerated ageing tests at high temperature, mathematical models are implemented to account for oxidation of elastomers and friction changes. The variability of mechanical properties at different mean temperatures, due to seasonal thermal variations, are also considered. The results of nonlinear time-history analysis are used to build fragility curves based on simple regression in the logarithmic space of structural response versus seismic intensity.

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Long-Term Deterioration of High Damping Rubber Bridge Bearing

Cited by 17 publications

References 12 publications

Investigation on Service Years of Large Rubber Marine Fenders

Investigation on Service Years of Large Rubber Marine Fenders

Effects of the long-term behaviour of isolation devices on the seismic response of base-isolated buildings

Long-Term Seismic Response of Buildings With Isolation Devices Affected by Deterioration Effects

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