構造工学論文集 A
Online ISSN : 1881-820X
最新号
選択された号の論文の120件中1~50を表示しています
構造工学一般・計算力学
構造安定・耐荷力
設計工学
振動・振動制御
地震工学
橋梁耐震
橋梁制震・免震
流体関連振動・風工学
維持管理
  • 窪田 真之, 玉越 隆史, 河野 晴彦, 増田 安弘, 加藤 豊, 星隈 順一
    2017 年 63A 巻 p. 450-463
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    Weathering steel bridges have been constructed in the region where little salt is found. But these days, some of these bridges are much corroded. To estimate the condition of bridge site in detail, our group started exposure testing using weathering steel ball. The advantage of using steel ball is, because of this shape, the condition of bridge sites can be estimated in all direction.
  • 野口 恭平, 白土 博通, 井伊 悠, 秦 聡一朗, 八木 知己
    2017 年 63A 巻 p. 464-475
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    The deterioration of a bridge is promoted by water on the surface. On the other hand, some water drops due to condensation are expected to run down bridge surfaces and then wash off salt on the surfaces. Therefore, it is important to estimate the salt amounts on bridge surfaces considering the washing-out effect of condensation drops to achieve effective maintenance. The authors sought to estimate the amounts of water formed on steel bridge girders on the basis of the 1-D heat conduction equation, and investigate the conditions for a water drop to run down a surface and the amount of salt removed by a drop. The salt amounts calculated on surfaces were decreased with the washing-out of condensation drops.
  • 尾上 紘司, 藤井 堅, 真鍋 幸男, 大田 耕平, 米倉 亜州夫
    2017 年 63A 巻 p. 476-482
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    Surface preparation is very important in re-painting of steel structures so as to extend the effective term of corrosion prevention. Though grinding or blasting have been widely used to remove rust and old coating film on steel surface, both these methods have some difficulties in completion of rust-removal and cause some problems such as dust scattering, noise, etc. This paper presents the laser cleaning method which instantaneously sublimes/evaporates the rust on the surface of steel structure. It is concluded from the experimental results that laser cleaning can remove not only rust but also salt on the steel surface . The basic data is provided for further dissemination of laser cleaning.
  • 坂本 貴大, 石川 敏之
    2017 年 63A 巻 p. 483-492
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    Recently, for the repair of corroded or fatigue damaged steel members, bonding patch plate have been proposed and applied. One of the concerns of this method is prevention of debonding of patch plate, because the shear and peel stresses in adhsive layer concentrate at the end of patch plate. In this study, the equation for calculation of stresses in adhesive in single lap joint under tensil or bending condtion. Furthermore, the tensile test and bending test of single lap joint were carried out to evaluate the debonding condition with applying the adhesive stresses. As a result, it was shown that the energy release rate and principal stress calculated by the adhesive stresses are able to evaluate the debonding of patch plate under tensile load or bending.
  • 青木 康素, 松本 理佐, 石川 敏之, 河野 広隆, 藤林 美早
    2017 年 63A 巻 p. 493-502
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    While the use of plate bonding method to repair or strengthen steel structures started to be accepted, the influence of temperature state of steel members on the reinforcing effect of plate bonding method and endurance of bonding are concerned. In this research, steel and CFRP plates are bonded on to the lower surface of bottom flange in main girder and onto the lower surface of orthotropic steel deck plate in service, and strains on the patch plates during the adhesive curing and applying the traffic loading were measured. As a result, it was found that the adhesive layer were completely cured under the service. Furthermore, it could be observed that the strain transfer ratio in the case of bonded patch plates on the bottom flange was constant through the season, while the strain transfer ratio in the case of bonded patch plates on the deck plate was depended on the season.
  • 内田 大介, 森 猛, 武下 美那, 宮崎 晴之, 木村 直登
    2017 年 63A 巻 p. 503-516
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    When functions of bearings in steel I-girder bridges are lost due to generation of rust and so on, it is known that fatigue damage is prone to occur there. Some methods for improving fatigue durability of this part have been proposed and actually applied, but the most suitable countermeasure and the specific structural detail are not clarified yet. This study aims at improving fatigue durability of the bearing in existing steel bridges by relatively easy repair methods which are adding a vertical stiffener, finishing the weld toe and deepening weld penetration of the welds between sole plates and lower flanges. Effects of above-mentioned methods have been examined through stress measurement tests, fatigue tests and FE-analyses on model specimens.
  • 石川 敏之, 田村 隆佳, 奥村 徹, 松村 寿男, 内山 宗久, 藤井 通之
    2017 年 63A 巻 p. 517-526
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    In the welded joint, a tensile residual stress introduced by the weldeing is reduced when the crack initiates and propagates. Therefore, if the residual stress near the weld joint can be measured, it will be the fatigue crack detection method. Recently, residual stress in steel members is able to be measured by X-ray diffraction method on site. Therefore, in this research, a residual stress measurement using X-ray diffraction method is proposed for the detection technique of fatigue crack. To confirm the proposed methods, specimens of out-of-plane gusset joint and the specimen of joining between orthtorpic steel deck and U-shaped rib were tested under cyclic loading with measureing the residual stress. In the results of fatigue tests, the chaninging of the residual stress near the weld joint by the initiation and propagation of fatigue crack was observed by the proposed technique in all cases.
  • 松本 理佐, 田辺 篤史, 小山 雅弘, 坂野 昌弘
    2017 年 63A 巻 p. 527-540
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    Many fatigue cracks were found at the connections between girder-floor beam and girder-way in a simple supported composite girder bridge. The fatigue cracks occur in 40 years. Thus this fact implies that the fatigue cracks may occurred due to poor connection details. Therefore, fatigue retrofitting is planned for the bridge. This study is aiming to clarify the effects of retrofitting on stress reduction by FEA with sub-modeling technique of the bridge and its retrofitting. FEA results showed that retrofitting by splicing with weld bead removal can reduce local stress under 10% of original, and that retrofitting for the top of web-gap plates and vertical stiffeners could reduce local stress to 60-70 % of original.
  • 田中 博文, 松本 麻美, 原田 祐樹, 桶谷 栄一
    2017 年 63A 巻 p. 541-549
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    The axle-box acceleration (ABA) is regularly measured by the track inspection car in major Japanese railway operators. We developed a new technique for managing rail corrugation by making use of the ABA measured by the track inspection car. Concretely, we analyzed the relation between the ABA data and the rail surface roughness data measured on the ground. Furthermore, we examined the influence of the measurement axle in the bogie and the train running speed of the ABA on the detection accuracy of the rail corrugation by using the ABA. As a result, we have confirmed that the rail corrugation can be managed efficiently by using the ABA measured by the leading axle of the bogie in case where the track inspection car runs with a usual speed.
  • 坂本 寛章, 近藤 政弘, 朝倉 俊弘
    2017 年 63A 巻 p. 550-558
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    Cyclic load by train causes subsidence of railway level in tunnels, which is due to ground deformation under roadbed concrete. In this study, to develop a method for quantitative evaluation of train running stability on the slab track, a method to survey roadbed concrete by vibrating with small-sized vibration exciter was proposed. Vibration characteristic of roadbed concrete with accelerometers fixed around the vibration location was also evaluated. Then the correlation with progress of track disorder considered to be correlated with the soundness of roadbed concrete and the vibrational energy provided in vibration tests was verified, and a method for evaluation with the correlation was proposed.
  • 小屋 裕太郎, 小西 拓洋, 関屋 英彦, 牧田 通
    2017 年 63A 巻 p. 559-569
    発行日: 2017年
    公開日: 2018/06/08
    ジャーナル フリー
    In strain measurements for bridge maintenance, determining the position of the travelling vehicles is important because the strain response significantly vary depending on the position of the travelling vehicles. However, the conventional methods were not able to determine the position in a road width direction of the travelling vehicles accurately. This paper proposes the method to determine the position in a road width of that using image processing technique. In order to verify the proposed method, field measurements in a bridge in service were performed. Based on the experimental results, the proposal method was able to achieve accurately vehicle travelling position with practical processing speed.
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