Experimental Study on Safety of Bridge Deck using UFC

In recent years, the occurrence in steel deck welds of fatigue cracks caused by deformation arising from vehicle travel has become conspicuous, and costs required for maintenance such as inspection and repair are rising. In response to this situation, the authors developed waffle-type slabs that use ultra high strength fiber reinforced concrete (UFC) for high durability and light weight on a par with that of steel slabs. Thus far, stress verification by finite element method (FEM) analysis and verification of safety against fatigue through wheel load running tests have been conducted. In the present study, load testing was performed on test specimens after subjecting them to the wheel load running test, for the purpose of identifying the failure mode and verifying safety in terms of fracture strength. As a result, the failure mode was identified as flexural failure, and the specimens were confirmed to have load-bearing capacity 7.5 times the design wheel load.近年，鋼床版の溶接部に車両の走行に伴う変形に起因する疲労き裂の発生が顕在化しており，点検や補修など維持管理に必要なコストが増加する傾向にある。そこで，筆者らは超高強度繊維補強コンクリート（UFC）を用い，耐久性が高く，しかも鋼床版並みに軽量なワッフル型UFC床版を開発している。これまでに，FEM解析による応力度の照査や輪荷重走行試験による疲労に対する安全性の検証を行っている。本研究では，破壊モードの確認および破壊耐力に対する安全性の検証を目的として，輪荷重走行試験後の試験体を用いた載荷実験を行った。その結果，破壊モードは曲げ破壊であり，設計輪荷重の7.5倍の耐力を有することを確認した。