CASE C01 · US · 2016
ミネソタ州交通局(MnDOT):39橋での段階的ドローン点検研究(ブラトニック橋ほか)
MnDOTは2015〜2017年、州内39橋で点検用ドローンを段階的に試した。費用は平均40%下がり、全長約2.4kmのブラトニック橋では約5.9万ドルから約2万ドル、8日から5日に減ったと報告している。一方で、従来より高くついた橋もあり、打音などの触れる作業や狭い部位には対応できなかった。
| 設備の持ち主 | Minnesota Department of Transportation (MnDOT) |
| 実施 | — |
| 場所 | Duluth, Minnesota, United States (plus Nielsville, St. Paul and Stillwater) |
| 機体 | senseFly albris (prototype inspection UAS); Flyability Elios tested in Phase 3 |
| センサー | RGB still/video camera (90° tilt), thermal infrared, ultrasonic proximity sensors |
これまで
スヌーパー車(橋面から桁下へ届くクレーン)にバケットやロープで点検員を乗せる方法。通常は車線規制が必要。
ドローンでは
GNSSなしでも飛べる点検用ドローンで、鋼アーチ・トラス・暗渠などを撮影し、熱画像も取得した。
結果
| 指標 | 値(原文の言語) | 性格 |
|---|---|---|
| inspection cost (Blatnik Bridge) | about US$59,000 conventional (excluding mobilisation/travel) vs about US$20,000 with UAS | 報告値 |
| inspection duration (Blatnik Bridge) | 8 days with four snoopers and an 80-ft lift vs 5 days with UAS | 報告値 |
| safety / traffic | some lane closures curtailed or eliminated (not quantified) | 報告値 |
| average cost saving (Phase 1–2 research) | 40% on average; savings from avoided access ranged US$540–21,000 per bridge | 報告値 |
| bridge-by-bridge cost (12 bridges analysed) | e.g. Structure 62504: $3,660 → $1,020; Structure 27831: $2,580 → $540; but Structure 19538 cost more with UAS ($1,080 → $1,860) | 報告値 |
注意点・限界
- Not every bridge was cheaper: on Structure 19538 the UAS-assisted inspection cost more than the traditional one, and cost analysis covered only 12 of 39 bridges.
- Drones cannot perform hands-on tasks such as cleaning, sounding, measuring or tactile testing, so they supplement rather than replace the inspector.
- The albris was not collision-tolerant enough for very tight spaces (box girders, small culverts); a caged drone was trialled next.
- Figures come from MnDOT's research summary of a phased pilot, not from a full programme rollout.
- Large drones could not enter some confined spaces, and operation still required substantial training and skill.
出典
- MnDOT improves on award-winning use of drones for bridge inspectionMinnesota Department of Transportation Research Services 本文確認
- Benefit: MnDOT UAS bridge inspections saved 40% on average (ITS Knowledge Resources 2019-B01369)U.S. DOT ITS Joint Program Office 本文確認
- Cost: UAS-assisted vs traditional bridge inspection costs (ITS Knowledge Resources 2020-SC00448)U.S. DOT ITS Joint Program Office 本文確認
参照確認日: 2026-10-22