Quarterly Report of RTRI

PAPERS

Investigation of the Bearing Damage Progression Starting from Cone Creep of a Railroad Axle Journal Bearing

Takafumi NAGATOMO, David G.TOTH

2006 Volume 47 Issue 3 Pages 119-124
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.119

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Journal bearing cone "creep" phenomena, leading to cones which "spin" on a railroad axle journal, can potentially be a cause for wear and a source of heat generation. It is, however, still unknown how rapidly an axle and bearing deteriorate after the initiation of the cone creep. A cone creep simulation test using a full-scale railroad bearing was conducted in a laboratory to investigate the bearing damage progression starting from cone creep. Test results gave changes in bearing temperature, vibration, and dimensional clearances between the axle journal diameter and the cone bore, due to cone creep.

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Development of Creep Decreased Axlebox Suspension of Cone-Shaped Multi-Layer Rubberspring

Minoru SUZUKI, Shogo MAMADA, Masanori HANSAKA, Takayuki SHIMOMURA, Mik ...

2006 Volume 47 Issue 3 Pages 125-131
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.125

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An axle-box suspension spring manufactured with a steel and rubber multilayered structure was developed to minimize the maintenance workload and to reduce the weight of a bolsterless bogie designed nearly twenty years ago. However, the rubber material deteriorates due to aging, especially creep phenomena that cause a loss in spring height, and eventually requires axle-box height adjustment. Optimizing the mix proportions of the rubber compound elements such as a carbon black, an anti-oxidation stabilizer, enables a stable axle-box height to be maintained and could decrease creep phenomena by 40%. We have also verified that the developed rubber spring ensures vehicle dynamic properties equivalent to the current rubber material.

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Mechanism and Countermeasures of Coarse Aggregate Spalling in Aged Concrete Tunnel Linings

Sohei NISHIO, Takahiko SASAKI, Yoshiyuki KOJIMA

2006 Volume 47 Issue 3 Pages 132-137
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.132

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A number of defective conditions such as coarse aggregate spalling are visible on cast-in-place concrete tunnel linings covered with accumulated soot emitted by steam locomotives. It is apparent that such defects have mainly occurred at construction joints or honeycombing existed since the beginning of the concrete construction. We conducted a study into the mechanism of such defects; hence, this paper describes the results of the study and countermeasures to cope with such defects.

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Detection of Concrete Spalling Using Active Infrared Thermography

Hisashi TANAKA, Seiichi TOTTORI, Tatsuya NIHEI

2006 Volume 47 Issue 3 Pages 138-144
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.138

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Active infrared thermography is a method to detect concrete spalling by heating the surface of the concrete using irradiation devices, such as halogen lamps, xenon arc lamps and far-infrared irradiation devices. We carried out irradiation tests of plain plate specimens using all of these devices and compared the results with those obtained by transient heat-conduction analysis. Specimens with artificial voids were then prepared for active infrared thermography using a xenon arc lamp and subjected to a laboratory test. A field test carried out on an actual viaduct to prove the effectiveness confirmed that active infrared thermography could detect concrete spalling accurately.

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Integrity Evaluation Method for Spread Foundation Piers with Dominant Bending Modes

Hiroshi HAYA, Kuniyuki MINEGISHI, Nobumasa MIZUNO, Satoshi NARUI

2006 Volume 47 Issue 3 Pages 145-149
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.145

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The Impact Vibration Test is now regarded as a major method to evaluate the conditions of bridge substructures. However, because of its low rigidity, the conditions of circular section piers cannot be evaluated by this test. In other words, because bending vibration is superior in these piers, it is difficult to evaluate the conditions of the bearing capacity of the foundation. First, this paper proposes how to estimate the standard values of the natural frequency of the circular section piers. Secondly, the Vertical Impact Vibration Test was tried to measure the vertical natural frequency. As a result, the validity of both evaluation techniques was verified.

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Durability Evaluation Based on Buckling Characteristics of Corroded Steel Deck Girders

Ichiro SUGIMOTO, Yusuke KOBAYASHI, Atsushi ICHIKAWA

2006 Volume 47 Issue 3 Pages 150-155
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.150

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More than half of steel railway bridges are aged over 60 years. The number of steel railway bridges which needs replacement will increase in the near future, and an accurate evaluation of durability of these bridges is required. In such a situation, it is very important to examine load carrying capacity limit state of railway steel riveted girders. Therefore, in order to estimate durability behavior of them, an actual railway girders were examined and tested. Moreover, some nonlinear analyses were executed using an analytical model which takes corrosion into consideration. By using the new method proposed by us, it is possible to evaluate durability of railway riveted steel bridges better than by the current method.

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Ground Vibration Characteristics Induced at High-Speed by Shinkansen and Evaluation Method for Speed Dependency

Hidehumi YOKOYAMA, Kimitoshi ASHIYA, Naoyasu IWATA

2006 Volume 47 Issue 3 Pages 156-161
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.156

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An average increment of Shinkansen-induced ground vibration has already been estimated for the entire Shinkansen network using previous measurement results; however, the degree of train-speed dependency varies considerably along the same line. Therefore, an evaluation method for the train-speed dependency at each point along a given line is required to estimate the cost and extent of any necessary countermeasures. This paper starts with a discussion of Shinkansen-induced ground vibration characteristics. Then we propose an evaluation method for the train-speed dependency of train-induced vibration using simple models of the ground dynamic characteristics, excitation force, and the effect of periodic axle load.

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Noise Reduction Effect of Noise Barrier for Shinkansen Based on Y-shaped Structure

Kaoru MURATA, Kiyoshi NAGAKURA, Toshiki KITAGAWA, Shin-ichiro TANAKA

2006 Volume 47 Issue 3 Pages 162-168
Published: 2006
Released on J-STAGE: December 20, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.162

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Sound barriers have been widely adopted and installed to reduce noise levels at locations adjacent to Shinkansen tracks. A number of different types of sound barriers with specific configurational features have been developed, but a quantitative evaluation of their advantages has yet to be clarified. In this paper, scale-model experiments were conducted on sound barrier configurations, the positioning of sound-absorbing materials, and a new type sound barrier that was fitted with an acoustic tube array on its upper surface. Sound barriers with effective configurations (Y-shaped sound barriers with absorbing materials and acoustic tube arrays) were proposed based on the experimental results. Furthermore, the authors verified the effectiveness of the proposed barriers by means of field tests with running Shinkansen vehicles.

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