簡易な点検に基づく既設橋梁の構造性能判定法の提案: 材料の維持管理から構造物の維持管理への転換へ向けて

摘要

One of the major issues for appropriate maintenance of existing bridges is how we can rationally assess the performances of existing bridges. The authors have newly developed damage inspection and performance evaluation methods based on short-range visual observation of small and medium span concrete bridges. Under the newly developed methods, information on damage observed during inspection, such as the kind of cracks, crack width and area of concrete spalling, are related to safety and serviceability performances, where each performance is categorized into one of three grades, namely Pass, Conditional Pass, and Fail, that are assigned 1 point, 2 points, and 3 points, respectively. The total point value obtained by adding up the number of points of each member, such as girders, slabs, piers, abutments, supports and road side barriers, is defined as Index for Structural Point (ISP), and the ISP represents the structural performance level for the whole bridge. Furthermore, the ISPs for a group of bridges can be practically used as index for considering priorities of measurements.%概要既設橋梁の維持管理において.橋梁の構造性能を把握することは重要な事項である。筆者らは.技術者が既設構造物の構造性能を簡易に評価できる手法を検討した。構造性能の判定には，近接目視点検から得られる，ひび割れ，かぶりの剥落，鋼材の露出•腐食などの外観損傷の種類，程度および損傷領域を指標に用いる。外観損傷を種類ごとに，損傷の程度に応じて区分し，損傷の程度と領域が構造性能に与える影響を検討し，構造性能を満足する状態，満足しない可能性がある状態，満足しない状態の3段階にグレーデイングした。構造性能は，構造性能ポイント(ISP)として数値化されるため，定量的な判断を行うことが可能となり，構造性能ポイントの経時変化により将来の構造性能の予測も可能となる。