後施工プレート定着型せん断補強鉄筋の適用性の拡充
建設技術審査証明報告書(財団法人土木研究センター)改訂(2011年8月)の概要
府川 徹*1・本谷 幸康*2・岡本 晋*3・福浦 尚之*1・三桶 達夫*1・堀口 賢一*1・新藤 竹文*4
後施工プレート定着型せん断補強鉄筋(以下PHbと略記)は,RC構造物のせん断耐力向上を目的とする補強工法である。PHbの性能は実験結果に基づいて評価されるので,性能を発揮するための前提条件や適用範囲が定められている。それらに該当しない材料は使用できず,同じく該当しない構造物にはPHbの適用が困難であった。そのため,以下の適用性の拡充を盛り込んで,有効期限を迎える建設技術審査証明を改訂した。(1)SD295A・B,SD345 ,SD390のD13,D16,D19,D22 D25,D29,D32が使用可能となった,(2)せん断耐力の有効係数は,上限値を0.9として主鉄筋間隔と必要定着長(設計降伏強度で引抜けが生じないために必要な定着長)から定まる有効係数を使用できる,(3)半地下構造物・地上構造物の補強に対して,部材の応答変位と最大耐荷力が骨格曲線を侵さないことを確認できた場合に,せん断補強を目的として適用できる。
キーワード: | 後施工,せん断補強,高強度鉄筋,太径鉄筋,変形性能 |
*1 技術センター 土木技術研究所 土木構工法研究室
*2 土木本部 土木設計部
*3 成和リニューアルワークス(株) 工事統括部
*4 技術センター 土木技術研究所
Expansion of Applications for Shear Reinforcement with Anchor Plate for Post-construction Operations
Abstract for Revision of Construction Technology Review and Certification (August, 2011)
Tohru FUKAWA*1, Yukiyasu HONTANI*2, Susumu OKAMOTO*3, Naoyuki FUKUURA*1, Tatsuo MIOKE*1, Kenichi HORIGUCHI*1 and Takefumi SHINDOH*4
A shear reinforcement with anchor plates on both end for post-construction operations (hereafter described as PHb) has been developed. This new shear reinforcement not only increases the shear capacity but also is one of the easiest measures to employ for shear reinforcement after construction is completed. The method earned Construction Technology Review and Certification in 2005, although the variety of re-bars and the applicable reinforced concrete structures were both limited. The certification is revised in 2011 to expand its range of applications. The re-bars, varying from D13 to D32 and from SD295A・B to SD390 (Japanese Industrial Standards), can be applied to reinforced concrete structures to increase the shear capacity. The ratio of the shear capacity bore by PHb to the one bore by stirrups, which meet the general structural details, is increased up to 0.9 as maximum value. In former certification, the ratio was 0.8 as constant value. Moreover, the ratio can be calculated as a function using both the required development length according to the design yield strength of the re-bar and the distance between the primary re-bars. PHb also can be applied to semi-underground structures and upper-ground structures, as well as underground structures, so long as the response displacement and maximum load-carrying capacity of the structure member has not been exceeded the deformation capacity (skeleton envelope curve) .
Keywords: | post-construction operation, shear reinforcement, high-strength re-bar, thick re-bar, deformation capacity |
*1 Civil Structure and Material Research Section, Civil Engineering Research Institute, Technology Center
*2 Design Department, Civil Engineering Division
*3 Operation Supervisory Division, Seiwa Renewal Works Corporation
*4 Civil Engineering Research Institute, Technology Center
12 - REPORT OF TAISEI TECHNOLOGY CENTER No.44 2011