著者

別府 万寿博 濵田 匠李 市野 宏嘉 相澤 武揚

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.67A, pp.890-903, 2021 (Released:2021-04-16)

参考文献数

25

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This study investigated the blast-mitigation effects of an aluminum honeycomb composite panel on the deflection of a target steel plate, by conducting a series of close-in explosion tests in which a fragment impact was considered. In the close-in explosion tests, aluminum was used as an upper sheet of the honeycomb panel, and the honeycomb panel was set on a steel plate. A steel ball was set at lower or inside of a spherical high explosive of Composition C-4 to simulate a fragment impact. The test results revealed that the position of a steel ball affected the perforation of the aluminum sheet and the blast-mitigation effect by the honeycomb panel.

著者

秦 吉弥 矢部 正明 野津 厚 葛西 昭 高橋 良和 松崎 裕 秋山 充良

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.63A, pp.265-278, 2017 (Released:2018-06-08)

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下記の論文は撤回されました.記秦吉弥,矢部正明,野津厚,葛西昭,高橋良和,松崎裕,秋山充良:臨時余震観測に基づく2016年熊本地震における西原村および南阿蘇村の被災橋梁に作用した地震動の評価,構造工学論文集,Vol. 63A,pp. 265-278,2017.撤回の理由2019年3月15日に大阪大学より公表された研究活動上の特定不正行為に関する調査結果において,本論文に対して第一著者による特定不正行為(ねつ造)が認定されたため,撤回した.

著者

大久保 一徳 大山 浩代 別府 万寿博 大野 友則 片山 雅英

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.53A, pp.1273-1283, 2007 (Released:2007-08-01)

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This study is to find the local damage and failure of concrete plate due to the contact and close-in explosion by C4 explosive. First, to examine the blast effects by C4 explosive, basic explosion tests were done. Then, the relation between the maximum overpressure and distance from an explosive source is formulated. Next, to examine the local damage and failure of concrete plate due to the contact and close-in explosion by C4 explosive, the small scale explosion tests were carried out. In tests, the concrete plates (50cm x 50cm square) were employed. And, to know the material model and parameter to be used for the hydro code AUTODYN, some of test cases were numerically simulated.

著者

桃木 昌平 蔡 華堅 塩谷 智基 小林 義和 宮永 孝志

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.57A, pp.959-966, 2011 (Released:2011-08-01)

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Ageing concrete structures have been significantly increasing. To sustain those, understanding the damages and decision the time and method of repairing is a crucial issue. Non-destructive testing (NDT) appears to contribute to this paramount issue, since it includes a variety of testing methods corresponding to the measurement scale. NDT also provides momentous information on the effects of repairing when the test is repeated after the repair work. In this study, seismic tomography, one of NDT methods, was applied for the damage quantification of full-scale concrete structures. The test was conducted both before and after repairing. The distributions of velocity led to a conclusion that the velocity variations represented well the effects of repairing.

著者

南波 宏介 白井 孝治 坂本 裕子

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.63A, pp.1163-1176, 2017 (Released:2018-06-08)

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In the case of impact analysis to verify structural integrity of existing steel structures of nuclear power plants (NPPs) against tornado missiles, one of the strain-base criteria regarding aircraft impact on NPPs described by US Nuclear Energy Institute is currently used. However, the technical bases for this methodology are not disclosed. In this report, to clarify a way to decide the response values and the penetration conditions for a steel plate when a tornado missile crashes steel plate and verify an accuracy of design methodologies, impact tests with the pipe shaped missile of 50mm diameter and 4mm wall thickness were executed at impact velocity 49m/s.

著者

豊田 淳 佐々木 貴信 荒木 昇吾 林 知行 有山 裕亮 後藤 文彦

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.65A, pp.799-806, 2019-03-15 (Released:2020-01-27)

参考文献数

14

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Cross laminated timber (CLT) is a new type of engineered wood panel consist of several layers of structural lumber boards stacked crosswise at 90° angles and glued together on their faces. It is possible to produce CLT panels of 3 m wide, 12 m long, and 270 mm thick. CLT is light-weight material which the unit weight of CLT made of Japanese cedar is about 1/6 of reinforced concrete, therefore it's has advantage in terms of the transport and construction works. The authors consider using CLT elements for bridge deck replacement instead of a concrete deck slab. The overview of the design and construction of the bridge deck replacement of an existing bridge using CLT srlabs is reported herein.

著者

武田 慈史 河西 良幸

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.57A, pp.1225-1238, 2011 (Released:2011-08-01)

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The purpose of this paper is to propose impact response calculation method using response spectrum based on identical impulses. For that purpose, the relationship between momentum of missiles and associated impact impulse were at first analyzed based on previous collision experiments due to hard and soft missiles, and hard missiles through shock absorbing installations such as sand and rubble. As a result, conservation of momentum proved to be realized on the whole and therefore the impulse necessary for calculation can be easily decided based on the momentum of missiles. Consequently, diagrams of impact response spectrums based on identical impulses were originally proposed and successfully applied to three cases. In conclusion, the calculation method can easily and rationally evaluate impact responses of structures.

著者

川西 寛 丸山 收 三木 千壽

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.62A, pp.459-471, 2016 (Released:2017-04-24)

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The study analyzes the impact that bridge inspection expenses with close visual technique have on municipalities' finance and verifies measure for promoting efficiency of their ongoing bridge inspections. It clarifies that the annual expences of bridge inspection operations by majority of municipalities surpass their mean bridge maintenance expenditures for the past 5 years. Also it shows that measure called collective ordering has the effect to the efficiency of an order procedure and supervision duties, but that just has a small effect to the cost reduction. While their bridge inspection operations pay for themselves, their challenges are how to efficietly implement the bridge inspection operations given a fiscal constraint.

著者

俵 道和 二井谷 教治 芦塚 憲一郎 綾野 克紀

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.65A, pp.615-623, 2019-03-15 (Released:2020-01-27)

参考文献数

15

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In this study, wheel load running fatigue test was conducted on a slab specimen produced with concrete replacing crush sand with blast-furnace slag fine aggregate. By comparing with the results of a similar wheel load running fatigue test on concrete using crushed sand, the influence due to the difference in fine aggregate for concrete was evaluated. It was confirmed that concrete using blast-furnace slag fine aggregate has enough fatigue durability compared to concrete using crushed sand. It was also confirmed that concrete using blast-furnace slag fine aggregate can be evaluated with the proposed S-N prediction formula by considering the effects of the main reinforcement and transverse reinforcement and sorting out the values from the past experiments.

著者

下里 哲弘 長坂 康史 矢吹 哲哉 有住 康則

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.62A, pp.559-570, 2016 (Released:2017-04-24)

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Recently, corrosion damage on those steel bridges has been often reported. In particular, a section loss and a plate thickness reduction are concentrated in bridge girder ends, and the damage leads bridge failure in the worst case scenario. Since it is estimated that the corrosion damage of steel bridges greatly increases, effective and efficient repair methods are required. This study focuses on the repair method with carbon fiber sheets for shear panels. As a result of tests, the good specimen of shear strength, load carrying capacity and elongation performance, has been proven to be with low elasticity adhesives.

著者

小川 徹 阿部 和久 紅露 一寛

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.54A, pp.114-123, 2008 (Released:2008-08-01)

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The paper attempts to enhance the VOF-basedfinite element method for snow deformation problem by taking into account the deposition process. The variation of snow shape due to the deposition is modeled by involving the supply from snowfall in the advection equation of the VOF function. The snowfall process is described by simplified advection and diffusion models. The developed method is verified through a comparison with a semianalytical solution for a one-dimensional deposition problem. Besides, the simulation of Nakamura's experiment for snowpack with an embedded beam is achieved. Based on these analyses the significance of snow deposition process and deformation hardening in the mechanical behavior is discussed.

著者

Yan Yang Shozo Nakamura Baochun Chen Takafumi Nishikawa

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.58A, pp.777-784, 2012 (Released:2013-04-19)

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China timber arch bridge is a special bridge type, in which the arch ring is woven from two polygonal arch systems. There are more than 100 such bridges survived in Fujian and Zhejiang Provinces. Its traditional construction technology handed down from ancient to today generation by generation through oral teaching has been listed in the Urgent Safeguarding List of Intangible Cultural Heritage by UNESCO in 2009 because it is now at a risk of disappearing. To record down the technique is one of the key issues to preserve the intangible cultural heritage. This paper gives the general description of China timber arch bridges and discusses their traditional construction technology.

著者

吉田 善紀 小林 裕介 和田 一範

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.61A, pp.532-543, 2015 (Released:2015-05-22)

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In this research, we proposed the power storage device by energy harvesting from the bridge vibration, for the monitoring system to detect the bridge and predict a tendency toward deterioration of the bridge. We made the prototype monitoring system charging system and verified the operations at the existing bridge. This prototype system demonstrated to measure displacement and temperature at fixed intervals, and the dynamic response of the bridge to passing trains by using only power generated from the bridge vibration.

著者

南波 宏介 吉田 篤

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.67A, pp.849-863, 2021 (Released:2021-04-16)

参考文献数

26

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The development of a large cube container for low-level radioactive waste is necessary in order to ensure the efficient disposal of radioactive waste. Because waste disposal facilities are required to undergo a safety assessment in case of severe accidents, such a disposal container needs to be tested for impact resistant performance. In this study, a pre-simulation for a cube container previously designed, was carried out in order to decide the test conditions. The drop test conducted, used a full-scale container at its corner edge orientation. During the test, the lid bolts broke and the lid fell out. Taking into consideration these results, as well as the numerical analyses, the study proposes a container structure with improved impact resistant performance.

著者

石原 佳奈 楊 曜華 長山 智則 中村 俊敬 蘇 迪

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.68A, pp.275-288, 2022 (Released:2022-03-31)

参考文献数

24

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Rapid structural evaluation of bridges after earthquakes is imperative to recover quickly. While structural displacement is an essential indicator, direct measurement is difficult. Indirect estimation of displacement by numerical integration of measurement acceleration is inaccurate due to integration errors. In this research, estimation of displacement by only using acceleration measurements is proposed. Extended Kalman filter (EKF) assuming a simple non-linear hysteretic behavior and a genetic algorithm to identify parameters of the non-linearity are combined to achieve the displacement estimation. The displacement estimation capability of the proposed method is confirmed with simple models and a nonlinear RC pier model simulating an E-defense shaking table specimen.

著者

日高 菜緒 橋本 尚史 中村 真貴 馬越 一也 野中 哲也 小畑 誠

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.69A, pp.637-647, 2023 (Released:2023-04-11)

参考文献数

16

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In this paper, a method to semi-automatically construct an analysis model from point clouds of steel truss bridges is proposed. The authors proposed practical analysis models of truss bridges based on structural experiment and reproduction analysis of end sway bracing. For efficient seismic reinforcements enormous existing bridges, it is necessary to construct analysis models efficiently. Therefore, point clouds that represented 3D features of targets are used to construct analysis models without using drawings. The proposed method is applied to point clouds of end sway bracing in a truss bridge and verified its accuracy based on structural experiments and reproduction analysis.

著者

飯土井 剛 前島 拓 子田 康弘 宮村 正樹 上田 洋 石田 哲也 岩城 一郎

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.67A, pp.659-672, 2021 (Released:2021-04-16)

参考文献数

11

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The objective of this research is to investigate future maintenance methods focusing on water behaviors in the PC superstructure of the road bridge that has been in service for 23 years after construction under severe chloride environment. In the detailed investigations from 8 years ago, it was found that this bridge was deteriorated by corrosion of epoxy coated reinforcing bars and remarkable pop-out of concrete inside box girders due to the action of water. After various countermeasures to control water inside concrete, it was revealed that no remarkable deterioration was found in 2019. Based on these results, the maintenance methodology from the viewpoint of water was proposed.

著者

荒木 昇吾

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.57A, pp.890-899, 2011 (Released:2011-08-01)

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Durability of timber bridges is improved by using concrete decks, because it substitutes a roof. In this case, dead load is increased but this disadvantageous point is canceled by making the timber-concrete composite girder. In Japan, Design Criteria for this type of timber bridges have been developed in 2002 at Nagano Prefecture. And this bridge had been constructed for the first in 2003. In this paper, the improvement method for this type of timber bridge is suggested, that is to product a composition precast girder that has T-beam cross section with the web made of timber and the upper flange made of concrete. And the advantage is discussed from the viewpoints of cost reduction and labor saving.

著者

イアムラオー ピーラサック 藤掛 一典 大野 友則

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.56A, pp.1189-1195, 2010 (Released:2010-08-01)

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Blasting demolition techniques of reinforced concrete (RC) buildings are quite popular in Europe and the United States. However, if the blasting demolition techniques are applied to RC buildings in Japan, there is serious concern that excessively arranged reinforcement, which is required in earthquake resistant design, may disturb the blasting demolitions. In this study, therefore, the experimental demolition of RC column specimens with C4 explosives was performed, in which the amount of explosive used, the longitudinal reinforcement ratio and shear reinforcement ratio were chosen as experimental parameters. Finally the damage of RC column specimens after blasting was investigated qualitatively and quantitatively.

著者

渡辺 浩

出版者

公益社団法人 土木学会

雑誌

構造工学論文集 A (ISSN:1881820X)

巻号頁・発行日

vol.63A, pp.718-724, 2017 (Released:2018-06-08)

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Ekki is native to the western Africa. As it is considered to have great durability, great many Ekki members were imported in1990s. However bridge made of Ekki had dropped in 1999. It was recognized that suitable maintenance was required for Ekki bridges. Durability performance of Ekki is important, however there are few information about it. The aim of this study is to investigate long-term decaying behavior of Ekki bridge members. Suspension bridge which has Ekki deck members was diagnosed in 12, 16 and 25 years passed after construction. Valuable information about decaying behavior and diagnosis were obtained.