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Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

DOI： 10.2208/jscejj.24-00024

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

The purpose of this study was to understand the effect of the applied surface treatment method on the corrosion environment of rebar on an existing RC structure supplied with water from the back not in a severe corrosive environment. In order to evaluate corrosion possibility, electrochemical monitoring, moisture and chloride ion content were conducted using mortar specimens under various conditions. As a result, in the case without carbonation, low possibility of corrosion was confirmed regardless of the environment conditions and whether or not the surface coating was applied. On the other hand, in the case with carbonation, the corrosion suppression effect was different depending on the type of surface treatment. In addition, the corrosion suppression effect could not be confirmed for the case with surface coating regardless of the environmental conditions.

DOI： 10.2208/jscejj.24-00061

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/ut49729.2023.10103374

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3151/jact.20.254

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.matdes.2022.110556

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Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

DOI： 10.2208/jscejoe.78.2_i_301

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Publishing type：Part of collection (book)   Publisher：CRC Press  

DOI： 10.1201/9780429279119-277

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3151/jact.19.226

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DOI： 10.1080/15732479.2019.1676792

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.conbuildmat.2019.116908

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

This special session was intended to introduce the latest ICT in the maintenance of coastal structures and to widely discuss the expectations and issues regarding application of the ICT in construction and maintenance of coastal infrastructures. Through three presentations of research papers, two presentations related to the topics and the panel discussion regarding the applications of ICT, it was confirmed that the new technologies were effective to solve the technical problems of construction and maintenance of infrastructure. However, it was also confirmed that it would be necessary to improve the procurement system and to propose the evaluation method of benefit by introducing the ICT.

DOI： 10.2208/jscejoe.75.i_1031

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DOI： 10.1016/j.conbuildmat.2017.07.173

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Reformation projects for existing protective and mooring facilities in harbors have recently shown rapid increase to meet new requirements due to changes in social and economic situations. Accordingly, it is required to setup a design framework that is not the same as those for a new construction, but there are no guidelines available how to execute facility reformation design.<br>&nbsp;In this paper, we collected 262 facility reformation projects nationwide in Japan and performed case analyses focusing on motivation and methods of reformation. As a result, we showed the current situations of existing port facility reformation that was urgently responded to the requests corresponding to the change in social situations. Also, we clarified typical problems during reformation design such as changes in verification methods from the originals and difficulty in structural performance evaluation of an existing structure. In addition, we showed the basic of the reformation design and the prospects to solve the problems for the reformation design of existing port facility.

DOI： 10.2208/jscejoe.73.I_426

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DOI： 10.1201/b17618-254

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DOI： 10.1201/b17618-220

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DOI： 10.3151/jact.12.187

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DOI： 10.1201/b17394-14

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DOI： 10.1504/IJSTRUCTE.2013.050765

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

The port facilities have been recognized as emergent supply transporting base in order to provide assistance for rehabilitation of disaster-affected areas. A system to evaluate the residual structural performance of the damaged facilities is required to judge whether the facility can be used or not. This paper deals with the residual structural performance of RC superstructure of open-type wharf damaged by earthquake. From the results of loading tests on the 1/4 scaled model, the failure process and the residual load carrying capacity of the RC superstructure after the earthquake are investigated.

DOI： 10.11532/structcivil.59A.91

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DOI： 10.3151/jact.10.151

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Structural behavior and residual structural capacity of 2-way reinforce concrete (RC) slabs against punching shear failure were investigated through static loading tests after falling-weight impact loading tests. It was found that punching shear capacity of RC slabs damaged by repeated impact loads slightly decreases compared with non-damaged slabs just before the occurrence of punching shear crack. It was also found that punching shear capacity rapidly declines after formation of cracks due to punching shear at the bottom surface of the slabs. Based on the test results, the method to evaluate punching shear resistance of RC slabs subjected to repeated impact loads was proposed. Furthermore, the applicability of the proposed method to 1-way slab was examined.

DOI： 10.11532/structcivil.58A.967

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

&amp;nbsp;In this paper, the deterioration process of coastal protection facilities was investigated using inspection data obtained according to &quot;Manual on Maintenance of Coastal Protection Facility for Life Cycle Management&quot;. Utilizing the data, transition rates, which are considered as deterioration speed of facilities, were calcurated by Markovian chain model. As a result, it was found that the facilities which have a high transition rate exists in certain ratio regardless of type of facility or construction site. As future tasks, it is necessary to make a database of facilities regarding construction year, structural type and record of inspection or repair, and revise the manual from the viewpoints of inspection items, evaluation method, classification of degree of soundness, and deterioration prediction.

DOI： 10.2208/jscejoe.68.I_510

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&nbsp;This study reports the applicability of mechanoluminescent (ML) sensor to crack detection of concrete under dark-field. ML sensor could emit a visible light when the crack formed in concrete under dark-field. There was a linear relationship between the time-integra ted value of ML intensity and the energy required for the crack formation and propagation, which wa s estimated by load-CMOD curve obtained from bending tests on concrete beams. Based on fracture mechanics of concrete, the mechanism of luminescent of ML sensor was examined.

DOI： 10.2208/jscejmcs.67.430

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Language：Japanese   Publisher：Institute of Industrial Science The University of Tokyo  

&nbsp;&nbsp;&nbsp; RC slabs extracted from an open-type wharf were tested in order to evaluate the relationship between visually judged deterioration grades and load carrying capacities. Based on the statistical analysis on the relationship between deterioration grades and load carrying capacities, the probabilistic evaluation method of the load carrying capacities of RC members was proposed as quantitative evaluation method of residual structural performance of existing port RC structures. [This abstract is not included in the PDF]<br>

DOI： 10.11188/seisankenkyu.63.411

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Publishing type：Research paper (scientific journal)  

DOI： 10.1061/(ASCE)CC.1943-5614.0000142

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2208/jsceje.66.399

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.11532/structcivil.56A.644

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DOI： 10.1504/IJMIC.2009.027072

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Language：Japanese   Publisher：The University of Tokyo  

DOI： 10.11188/seisankenkyu.60.204

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Other Link： https://jlc.jst.go.jp/DN/JALC/00314451253?from=CiNii

Language：Japanese   Publisher：Japan Concrete Institute  

The authors proposed an idea of "replaceable" slab for open-type piled piers to simplify maintenance work such as inspection, repair and renovation, resulting in reduction of life cycle costs of the piers. In this study, new beam-slab joint systems were proposed to realize the replaceable slab based on results of loading tests on models of beam-slab structures.

DOI： 10.3151/coj1975.46.2_33

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Other Link： https://jlc.jst.go.jp/DN/JALC/10017875218?from=CiNii

Language：English   Publishing type：Research paper (international conference proceedings)  

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DOI： 10.2208/jsceje.62.341

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

While lots of harbor structures have been constructed, some of them are reaching the ends of design service life. The number of structures at which remedial actions are required will be increasing rapidly. To meet the increasing number of degraded structures, strategic maintenance and repair methods should be implemented to realize life extension and structural performance recovery, resulting in minimization of life-cycle costs.<BR>In this paper, the method is proposed to evaluate proper life-cycle scenario of deteriorated open-type wharf from the viewpoint of life-cycle cost. The change in load carrying capacity of RC members due to rebar corrosion is taken into account. Based on the calculated results, life-cycle scenarios with different repair plans were discussed from the viewpoints of recovery of load carrying capacity and the relevant life-cycle cost.

DOI： 10.2208/prooe.22.199

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.conbuildmat.2003.10.008

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DOI： 10.2208/jscej.2004.767_143

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Language：English   Publisher：Japan Concrete Institute  

One of the important factors for compressive stress-strain curves of concrete is the localization of failure. The stress-strain curve of concrete strongly depends on the aspect ratio of the concrete specimen; therefore, a unique stress-strain curve is not adequate to express the softening behavior of concrete. To overcome the problem related to the localization of failure, a series of uniaxial compressive tests of concrete specimens was conducted. From the measured energy distribution, the failed specimen was assumed to be composed of 2 or 3 zones. Then, an equation for an envelope curve involving a characteristic of compressive strength of concrete was formulated so as to match the experimental curve of each zone. Combining 2 or 3 proposed equations considering the extent of each zone could express the experimental stress-strain curve of the specimen regardless of the aspect ratio.

DOI： 10.3151/jact.2.395

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

長期にわたる供用を経た海岸保全施設の状態を定量的に評価し, 老朽化の進行に伴う機能・性能の低下を精度よく予測することが, 施設の機能維持やストックの有効活用の点から必要である. 本論文では, まず三面張り式防潮堤および消波ブロック被覆ケーソン式護岸の老朽化実態の調査事例を紹介した. これらの調査から得られた施設の性能低下の進行程度を, 確率論的アプローチであるマルコフ連鎖の手法を取り入れてモデル化することを試みた. その結果, マルコフ連鎖に基づく変状進行モデルは, 性能低下の実態を再現する手法として十分適用できることがわかった.

DOI： 10.2208/proce1989.50.911

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Publisher：Japan Society of Civil Engineers  

This paper describes a newly developed flexible joint structure for submerged tunnels. This joint called Crown-seal joint can absorb larger deformation in a submerged tunnel element than other types of flexible joint Crown-seal joint mainly consists of rubber, which was reinforced by plastic fibers. For investigating its applicability to actual submerged tunnels, some experiments were conducted using a full-scale model of tunnel section including Crown-seal joint. From the experimental results, it was confirmed that no abnormal deformation and local distortion were observed on the surface of rubber even if displacement at the joint occurred in the direction parallel and perpendicular to the tunnel element Furthermore, watertightness of the joint was verified through the seepage tests utilizing water pressure.

DOI： 10.2208/prooe.18.587

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Publisher：Japan Society of Civil Engineers  

Some methods regarding stress calculation etc. of a caisson have to be updated because they follow the former conventional ones. In this study, improvement of the structural design method to a caisson was examined on the following two points.<BR>(1) Reduction in the span length of wall and slab.<BR>(2) Effect of filling sand in a caisson chamber on bending moment induced in a wall.<BR>As a result, essential data to rationalize of structural design methods were obtained. The main findings were summarized as follows:<BR>(1) The span length of wall and slab could be reduced, because fixed supporting points existed in the haunch region.<BR>(2) Due to resistance of filling sand, bending moment of a side wall became smaller than that without filling sand when loads were applied to the wall.<BR>Moreover, diagonal pull-off tests were carried out on hooks for suspension of a caisson. The equation of design shear capacity of concrete around the hooks for suspension was reviewed, and a modified equation was proposed based on the test results.

DOI： 10.2208/prooe.17.259

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Despite the fact that harbor structures are extremely vulnerable towards chloride induced deterioration, study on residual structural performance of corroded steel pipe pile pier is still limited. Authors have previously proposed an evaluation method of residual structural performance based on the judgement result of deterioration by versatile structural analysis software. However, a simpler method without conducting structural analysis is appreciated when deciding the maintenance priorities of different piers. In this study, authors proposed evaluation methods of residual structural performance by introducing artificial intelligence to estimate both the area ratio and distribution image of damaged beams. In order to overcome the problem of misrecognition in unlearned piers’ shapes, a new idea of image processing is hatched by considering the relative distance of beams. As a result, the shapes of unlearned piers are correctly recognized and the estimate accuracy for damaged beams are confirmed.

DOI： 10.11532/jsceiii.1.j1_132

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Appropriate maintenance should be conducted for harbor structures due to their vulnerability towards chloride induced deterioration. We have already proposed an evaluation method of residual structural performance based on the judgement result of deterioration by versatile structural analysis software. On the other side, a simple evaluation method without structural analysis is also demanded when deciding the maintenance priority of several piers. In this study, evaluation methods of residual structural performance introducing artificial intelligence to estimate the damaged area ratio towards assumed external force are proposed. The estimation accuracy of artificial intelligence models are verified and damage estimation for piers with random deterioration distribution are conducted. As a result, for both models utilized numerical information and image showed high estimation accuracy, and the image model can also grasp the damage distribution as well as the damaged area ratio.

DOI： 10.2208/jscejoe.76.2_i_600

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We have already clarified the residual structural performance of corroded beam by loading test of specimen. However, the validity of simulating real corroded beam by electrical corrosion method and reliability of using scale-down specimen are still need to be discussed. In this study, load tests for real corroded beam and electrical corroded specimen on same scale are first conducted to verify the effect of different corrosion methods. The effect of scale factor is also verified afterwards by comparing the actual scale specimen and the scale-down one. As a result, electrical corroded specimen tends to have higher rigidity modulus over real corroded beam, and scale-down specimen shows the possibility of higher rigidity modulus during post-yield region even with higher deterioration degree towards actual scale specimen due to show strain-hardening effect easily.

DOI： 10.2208/jscejoe.75.i_827

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Language：Japanese   Publisher：土木学会海洋開発委員会  

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Further maintenance should be conducted for pier due to its vulnerability towards chloride induced deterioration. However, research for residual structural performance and seismic performance of corroded pier is still limited. Since significant cost and time is needed for regular detailed survey to evaluate the residual structural performance of corroded pier, relatively simple evaluation method becomes necessary, especially for private businesses. In this research, load tests for specimens with different deterioration degrees are conducted, relationship between deterioration degree and residual structural performance is clarified. Introducing the results of the tests to versatile structural analysis software, simple evaluation method of residual structural performance is proposed. By reflecting the judgment result of deterioration degrees of a real corroded pier to structural analysis model, seismic damage area and level could be relatively easily and quantitatively shown.

DOI： 10.2208/jscejoe.74.i_55

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Other Link： http://id.ndl.go.jp/bib/031261714

Language：Japanese  

DOI： 10.2208/jscejoe.74.I_234

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Steel pipe piled piers are exposed to severe corroding salty environment and they should be more appropriately maintained. However, few researches have been conducted on the residual structural and seismic performance of corroded piers. The objective of this study is to clarify the effect of corroded steel bar at the RC superstructure and the junction area between superstructure and the steel pipe on the structural performance of the entire pile-supported structure. This study has been developed through the laboratory loading tests and numerical analyses. From the experiment and analysis, it is confirmed that corrosion on the superstructure has impact on the residual structural performance. However, corrosion on the reinforcement bar in haunch has minor impact on the whole behavior.

DOI： 10.2208/jscejoe.73.i_408

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The objective of this study is to analytically clarify the effect of steel bar corrosion on the seismic performance of the entire pile-supported structure, and to then propose an appropriate maintenance method for pile-supported structures with steel bar corrosion, based on the analytical results.<br> First, a steel corrosion model using RC beams was proposed and verified. Then, the structural performance of the corroded RC beams was analyzed. Concurrently, loading experiments of the RC beams were conducted to verify the analyses. After confirming the validity of the analysis, the constitutive law of RC beams with various corrosion patterns was calculated by cyclic loading analysis. The seismic performance of the pile-supported structure with several combinations of this constitutive law was analyzed to clarify the relationship between local steel bar corrosion and the seismic performance of the whole structure. Finally, an appropriate maintenance method was proposed based on the analytical results.

DOI： 10.2208/jscejoe.71.i_173

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DOI： 10.2208/jscejoe.70.I_834

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DOI： 10.2208/jscejoe.68.I_336

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DOI： 10.11188/seisankenkyu.64.591

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DOI： 10.2208/jscejcm.68.220

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DOI： 10.2208/jscejoe.67.I_655

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DOI： 10.2208/jscejoe.67.I_400

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Language：Japanese   Publisher：日本コンクリート工学協会  

既往の研究において提案した衝撃荷重を受ける鉄筋コンクリートはりの最大支点反力と最大変位の算出方法について,計算値の妥当性および計算値に影響を与える要因を検討するため,断面寸法や引張鉄筋比,支間長等をパラメータとした鉄筋コンクリートはりの重錘落下式衝撃載荷実験を行った。その結果,最大変位の計算値は概ね実験値に対応するのに対し,最大支点反力の計算値は,はりと重錘の質士比やはりの支間長等によって影響を受け,必ずしも実現象を適切に表せないことが判明した。そこで,実験結果より各要因が最大支点反力へ及ぼす影響を定士的に示し,これらの影響を考慮した最大支点反力の補正式を提案した。

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10641654

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10641790

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Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)  

DOI： 10.11188/seisankenkyu.59.267

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10640954

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Language：Japanese   Publisher：港湾空港技術研究所  

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Language：Japanese   Publisher：国土技術政策総合研究所  

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Language：Japanese   Publisher：港湾空港技術研究所  

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It is necessary to quantitatively evaluate effect of repair works to deteriorated structures to do the effective maintenance management. A basic examination has been executed about the effect of repair for each method. However, due to lack of accumulation of actual data concerning re-deterioration after repairing, quantitative evaluation of the effect of repair is not realized yet. In this research, a calculation model to quantitatively evaluate the effect of repair works to concrete structures damaged by chloride attack was examined against surface protection method and patching method. Based on the actual data collected from existing concrete structures repaired by surface coating method or cross-section recovery method, chloride-preventive property of each coating material was analyzed to achieve quantitative evaluation of the effect of repair. Furthermore, the method of quantitatively evaluating the effect of repair was proposed to calculate chloride concentration inside repaired concrete structures.

DOI： 10.2208/jsceje.62.832

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Language：Japanese   Publisher：日本コンクリート工学協会  

本研究は,塩害を受けた既存RC構造物を対象に,部材内に発生する鉄筋腐食のばらつき,および腐食による鉄筋の力学的性質の低下とそのばらつきを実験的に把握した。その結果,腐食による鉄筋の質量減少率は,コンクリートに生じた欠陥の影響によってばらつきが大きくなるものの,かぶりの増加にしたがって低下する傾向であった。また,腐食による平均断面減少率が大きくなるほど,断面積の変動係数は大きくなった。さらに,腐食した鉄筋の強度および伸び能力は,断面形状の不均一性により引張力の作用状態が異なるために,ばらつきが大きくなった。

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RC桟橋上部工から切り出した試験体の劣化調査と曲げ載荷試験を行い,劣化度と構造性能の関係を調べた。初期剛性の低下は外観調査による劣化度判定によってほぼ評価できたが,耐荷性の評価には主鉄筋の平均断面減少率と降伏強度およびヤング率の低下を考慮する必要があった。健全部では,発錆限界を超える塩化物イオン濃度でも鉄筋の腐食はほとんど確認されず,ジャンカ等の初期欠陥が鉄筋腐食の主な原因であった。

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10640424

Language：Japanese   Publisher：日本コンクリート工学協会  

短繊維を混入することで,RCはりのせん断特性が改善されることが確認されている。この改善効果を利用して,防波堤や護岸に用いられるケーソンのフーチング長を長くすることができれば,マウンド支持力や堤体安定性の点から,コストダウンにつながる可能性がある。そのため,短繊維を混入したフーチングを実寸大でモデル化した試験体を用いて載荷実験を行い,せん断補強効果の確認ならびにフーチング長の検討を行った。加えて,フーチングを有するケーソンの経済性を検討することで,最適なケーソン寸法の評価を試みた。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10640384

J-GLOBAL

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：日本コンクリート工学協会  

通常の鉄筋コンクリート部材は,気中環境下の疲労に比べ水中環境下では微細な骨材によるすりへり影響を受けるために疲労抵抗が低下する事が知られている。最近開発された超高強度繊維補強コンクリートによる曲げ疲労試験を,気中および水中の環境下で比較試験しこれらの環境の相違が曲げ疲労特性に与える影響を明らかにした。また,超高強度繊維補強コンクリート特有の疲労機構について検討を行い,設計に有用となるS-N曲線を求めた。

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10639720

Language：Japanese   Publisher：日本コンクリート工学協会  

鉄筋腐食が生じたRC部材の構造性能に関して,一定軸力作用下において正負交番水平荷重を受けた場合の耐荷性およびじん性を評価した。その結果,鉄筋の腐食程度に応じてRC柱の構造性能は低下し,軸力作用下における部材の構造性能は,鉄筋の局所的な腐食に影響されることがわかった。また,RC柱の耐荷性は主筋の腐食により,じん性は,特に帯筋の腐食に影響された。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10639750

J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

This paper describes experimental results of shear capacity of concrete beams reinforced by PVA short fiber. Loading test was carried out on reinforced concrete beams with PVA short fiber by changing fiber type, fiber content, shear reinforcement ratio, effective depth, and shear span-to-effective depth ratio. As a result, it was confirmed that shear capacity is improved by mixing PVA short fiber and that the increase in shear capacity is influenced by fiber content and specimen size.<br>The fiber was confirmed to effectively act in tied-arch beams. Therefore, an equation to estimate shear capacity for reinforced concrete beams with small shear span-to-effective depth ratio was modified by using the breaking point stress of tension softening curve and the effective depth of beam to express the capacity of the beams reinforced by PVA short fiber.

DOI： 10.2208/jscej.2004.774_123

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Language：Japanese   Publisher：日本コンクリート工学協会  

橋梁等に軽量コンクリートを用いた場合,施工の合理化,地盤への影響軽減,地震時慣性力の低減などの面でメリットがあり,設計の合理化やコストの縮減が図られる。本研究では,軽量コンクリートを橋脚に適用することを想定し,軽量コンクリート柱部材が軸力下において正負交番水平荷重を受けた場合の構造性能を,耐荷性,じん性,塑性ヒンジ長,エネルギー吸収能などの観点から評価した。また,道路橋示方書に基づいた設計が可能であるかについても検討を行った。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10639132

J-GLOBAL

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Language：Japanese   Publisher：日本コンクリート工学協会  

表面被覆による補修後14年が経過した桟橋上部工の補修効果に関する調査結果について報告した。また,補修を施したRC部材の長期間の構造性能を把握するために,表面被覆を施したRCはりの劣化状況と構造性能の関係について実験的検討を行った。その結果,塩害が生じたRC構造物に表面被覆を施す場合,コンクリート内部の塩化物イオンを除去する対策,あるいは電気化学的な補修対策を講じなければ,補修効果の長期にわたる持続は期待できないこと,また,表面被覆を施したRCはりの耐荷性および変形性は,腐食による鉄筋の断面減少を考慮することで評価が可能であることが確認された。

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10639153

Language：Japanese   Publisher：日本コンクリート工学協会  

PVA短繊維混入によるひび割れ分散性改善の定量評価を目的に,混入率をパラメータとした鉄筋コンクリートの一軸引張実験を行った。その結果,PVA短繊維混入によりコンクリートのひび割れ分散性の改善が確認できた。加えて,平均ひび割れ間隔を引張軟化曲線の折曲がり点応力で整理することで,一軸応力状態におけるPVA短繊維を混入したコンクリートのひび割れ幅の減少を低減係数として評価することができた。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10639118

Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

This paper presents the experimental results on T-shaped reinforced concrete beam-to-column joint with corroded rebars. Rebars at the joint were subjected to accelerated corrosion by means of the electrolytic technique. The degree of corrosion was monitored by electrochemical methods. Then flexural and shear loads were repeatedly applied to the joint. Decrease in load-carrying capacity due to corrosion was evaluated by taking into account the cross-sectional loss of rebar and degradation of bond performance between rebars and concrete at the joint. It was clarified that local horizontal displacement of the column was affected by deterioration of bond performance.

DOI： 10.2208/jscej.2003.732_63

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Language：Japanese   Publisher：日本コンクリート工学協会  

近年,港湾のケーソン式構造物に対する施工の省力化の要求が高まっている。これに対し,著者らは孔あき鋼板をずれ止めに用いた新形式のハイブリッドケーソンを提案した。本研究では,ケーソンを構成する孔あき鋼板リブを用いた合成版を対象としたはり試験体の正負曲げ載荷試験を行った。試験結果より,合成はりの耐荷力,剛性およびひび割れ性状を明らかにし,最適な設計手法を検討した。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10638421

Language：Japanese   Publisher：日本コンクリート工学協会  

鉄筋が腐食した鉄筋コンクリート部材の力学性能に関する基礎的知見を得るため,電食により腐食程度を変化させたRCはりの正負交番載荷試験を行った。その結果,腐食によるはりの耐荷性およびじん性の低下は,腐食に起因する鉄筋とコンクリート間の付着性能の低下,せん断補強筋の腐食と繰返し載荷によるコアコンクリートの拘束効果の低下が原因であることが考えられた。また,主筋およびせん断補強筋の腐食が力学性能に及ぼす影響について検討し,それぞれの鉄筋腐食がRCはりのじん性に及ぼす影響とその機構について考察した。

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Language：Japanese   Publisher：日本コンクリート工学協会  

コンクリート部材は,せん断荷重下において脆性的に破壊するため,これに対する適切な補強が必要である。一般に,補強材としてせん断補強鉄筋が用いられるが,それに加えて,または代えてビニロン短繊維を混入することによるせん断補強効果を検討した。ビニロン短繊維の混入率およびせん断補強鉄筋比を変化させた鉄筋コンクリートはりを作製し,単調曲げせん断載荷試験を行った。その結果,ビニロン短繊維混入率とせん断補強鉄筋比の相関により,破壊モードやせん断耐力改善効果が異なることが確認できた。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10638437

Language：Japanese   Publisher：Japan Society of Civil Engineers  

When a concrete specimen is subjected to uniaxial compression, the failure is often localized. Therefore, the identical stress-strain relationship is not adequate to express the softening behaviors of concrete structures. In this study, a series of uniaxial compression tests of concrete specimens has been conducted. A failed specimen was divided into three zones by the local strain obtained from strain gauges attached to an embedded acrylic bar. Subsequently, the stress-strain relationships of concrete at each zone have been formulated. By combining these stress-strain relationships, the average stress-strain relationship of a whole specimen considering the localization of failure in compression can be proposed.

DOI： 10.2208/jscej.2003.725_197

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

The influence of ASR damage on structural performance was investigated through reversed cyclic loading tests on five RC column specimens by situating under influence of ASR for 3.5 years. It was found that load carrying capacity and ductility of ASR damaged columns were almost the same as those of sound ones. However, there were some differences in the mechanical properties between damaged and sound RC columns, such as the process and state of failure, absorption capacity of seismic energy, etc. Moreover, the PC confinement method was confirmed to be effective to strengthen ASR damaged columns from the viewpoints of load carrying capacity and ductility.

DOI： 10.2208/jscej.2002.704_129

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Language：Japanese   Publisher：日本コンクリート工学協会  

海洋コンクリート構造物の表面への海生生物の付着が,構造物の耐久性向上に及ぼす効果を明らかにすることを試みた。実海洋環境下に約2年間暴露した供試体を用いた試験の結果,コンクリート表面に付着した海生生物がその緻密な付着層により,コンクリート内部への塩化物イオンの浸透を抑制し,ひいては,内部鉄筋の腐食速度を低減していることを明らかにした。また,生物付着という要因を性能設計手法に取り入れ,構造物の耐久性に及ぼす効果を定量的に評価することを試みた。

CiNii Books

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10637352

Language：Japanese   Publisher：港湾空港技術研究所  

CiNii Books

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Language：Japanese   Publisher：国土交通省港湾技術研究所  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：国土交通省港湾技術研究所  

CiNii Books

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

In this study, the propagation behaviors of elastic waves in concrete were investigated through both experimental and theoretical approach. As a result, the size and the amount of aggregate in concrete were key factors for the propagation behaviors of elastic waves. Furthermore, it was clarified that the pulse velocity was also related to the characteristics of cement-paste matrix. In addition, the condition of the aggregate-matrix interface and the existence of microcracks resulted in the changes in the frequency characteristics of the elastic waves propagated through the concrete.

DOI： 10.2208/jscej.1999.627_223

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Country：Japan

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Country：Japan

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Country：Japan

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