道路橋は法令に従い，全部材に対して5年に1回の頻度で，近接目視を基本とする定期点検を実施しているが，全部材の近接目視には必要な人的負担や費用的負担が大きいという課題がある．特に同一部材を多数有し，近接目視が容易でない部材が複数存在する吊構造形式の橋梁は，その課題による影響が顕著であり最適な点検が求められている．本論では，吊構造形式の橋梁に多数配置されている鋼床版縦桁支承に着目し，将来の点検省力化を念頭に，鋼床版縦桁支承が腐食等の原因により固着化した場合における，橋の構造安全性への影響を把握するため解析的に検討を実施した．検討の結果，鋼床版縦桁支承のみ耐力を超過するものの，その他の部材では耐力以下に留まっており，固着化による橋の構造安全性に及ぼす影響は小さいことを確認した．

In accordance with laws and regulations, periodic inspections are conducted once every five years for all embers　of road bridges, based on close visual inspection. However, the labor and cost burdens required for close visual　inspection of all members are significant. In particular, cable-supported bridges that have many similar members and many members which are hard to be inspected in close proximity require optimal inspections.In this paper, steel deck bearings, which are installed in large numbers in suspension bridges are selected as study targets, and an analytical study to understand the effect on the structural safety of bridges when the steel deck bearings become unmovable due to corrosion or other causes are conducted, with a view to reducing the labor required for future inspection of the steel deck bearings. As a result, it was confirmed that only the steel deck bearings yield, while other members remained elastic range, and that the effect of the unmovable bearings on the structural safety of the bridge was small.

耐震補強工事において，局部座屈強度向上を目的に補剛材を箱型断面部材に片側施工高力ボルトにて接合した箇所において箱断面内部のバルブスリーブの腐食が確認された．バルブスリーブの腐食によりボルト軸力の低下が懸念されたため，腐食模擬試験及びFEM解析によりバルブスリーブの腐食が残存軸力に及ぼす影響について検討した．また，腐食促進試験によりバルブスリーブの耐食性を確認するとともに，実橋において超音波軸力測定を行った．これらの結果，バルブスリーブが腐食により減肉することでその程度に応じて残存軸力が低下することが分かった．一方で，実橋におけるボルト軸力計測により現時点においては軸力に影響のある腐食までは至っていないことを確認した．

Corrosion was identified in valve sleeves that connect stiffeners to box members to improve local buckling strength in seismic retrofit work. Due to a concern about the bolt axial force reduction according to the corrosion, a corrosion simulation test and FE analysis were performed to investigate the effect. In addition, the corrosion resistance of valve sleeves was confirmed by the corrosion acceleration test, and axial forces were measured by ultrasonic waves on the bridge site. As a result, it was found that the residual axial force decreased according to the degree of corrosion on the valve sleeve. On the other hand, the axial force of the bolts on the on-site bridge was confirmed to have sufficient axial force. On the other hand, it was confirmed that the current corrosion is not in severe condition to affect the bolt axial force.

本四高速道路では，鋼床版のデッキプレートとUリブとのすみ肉溶接部のビード（以下「Uリブ溶接ビード」という．）に生じる亀裂を対象に，赤外線サーモグラフィカメラを用いた温度ギャップ検知による疲労亀裂検出技術で疲労点検を2014年度から実施している．本四高速道路は多数の鋼床版を有していることから，設計年度や構造ディテール，累積大型車交通量などを考慮して点検対象箇所を選定し，開発した点検システムを用いた点検を実施してきた．点検に用いている温度ギャップ装置についても，現場条件や効率性の観点から点検撮影方式や通信方式の改良及び自動亀裂検知ソフトの開発も実施してきた．本稿は，これまでの温度ギャップ装置による疲労点検の実績，現状での温度ギャップ装置の性能と計測条件及び，温度ギャップ装置の今後の展望について報告する．

In the Honshu-Shikoku Bridge Expressway, fatigue inspection using an infrared thermography has been conducted to find fatigue cracks occuring on weld beads between deck plates and trough ribs by detecting temperature gaps since 2014. The Expressway has a large number of steel decks. Therefore, the inspection using developed system has been conducted by selecting inspection targets based on design year, structural detail, and cumulative large vehicle traffic volume. For the Temperature-Gap system, improvements of capture method and data transmission and development of automated crack detection software were conducted in terms of site environment applicability and working efficiency. This paper reports the past results, the current performance and measurement conditions, and the future direction of the Temperature-Gap device.

長大橋の鋼床版上の舗装は，基層に水密性が高く，かつたわみ追従性に優れたグースアスファルトが使用され，表層に耐久性に優れた改質アスファルトが使用されている．明石海峡大橋では，供用後10年が経過した頃から，舗装表面に橋軸方向に連続したひび割れやポットホールなどの変状が発生，増加している．そこで，明石海峡大橋の舗装に発生した変状についてFEM解析等により発生要因を推定し，その結果に基づいた舗装材料の選定及び試験施工を実施した．本稿は，長大橋舗装の長寿命化を目的として実施した舗装補修の取組について報告するものである．

On the steel deck of long-span bridges, the guss asphalt which has a high watertightness and deflection followability has been used as a base course, and the improved asphalt which has a high durability has been used as a surface course. In Akashi-Kaikyo Bridge, degradations such as longitudinal crack and pothole were observed and the number of degradation have increased.Therefore, we presumed the cause of the degradations by FEM analysis. Then, we chose pavement materials based on the presumption and carried out test constructions.This paper reports the approach of pavement repair to prolong the service life of long-span bridge's pavement.