04 / HISTORY
Every failure taught us
to inspect again.
From the keepers of Roman aqueducts to boiler explosions, bridge collapses, the Sasago tunnel and drones: the history of inspection is a history of building systems out of failure.
Ancient
- 256 BC · China (Sichuan)
Dujiangyan irrigation system completed
Begun by the Qin official Li Bing to tame floods on the Min River, the system was completed around 256 BC. It divides the river rather than damming it and still irrigates about 668,700 hectares. An inscription attributed to Li Bing tells later keepers to straighten winding flows and deepen wide, shallow beds.
→ Infrastructure that lasts two millennia relies on maintenance rules handed down with it.
- 97 AD · Roman Empire (Rome)
Frontinus appointed curator aquarum
In 97 AD Emperor Nerva made Frontinus supervisor of Rome's aqueducts. His treatise De aquaeductu records how he compared intake and delivery on each line to expose illegal taps, and notes that leaks in buried conduits were hard to find. It also covers the masonry of arched sections and keeping tree roots away from the structures.
→ One of the earliest recorded cases of inspection by measurement and record-keeping rather than by eye alone.
Pre-modern
- 690 · Japan (Ise, Mie)
First Shikinen Sengu at Ise Shrine
The buildings of Ise Shrine are rebuilt every 20 years in a rite called shikinen sengu. The custom dates from the 7th century, with the first rebuilding in 690. The source records the 61st rebuilding in 1993.
→ A fixed renewal cycle renews skills as well as structures.
- c. 1224 · France (Strasbourg)
Œuvre Notre-Dame maintains Strasbourg Cathedral
The Fondation de l'Œuvre Notre-Dame has overseen the construction and upkeep of Strasbourg Cathedral since at least 1224. Medieval cathedrals kept standing workshops of masons who went on repairing them long after completion. The foundation's museum holds original sculptures, stained glass and the earliest plans.
→ A permanent maintenance body and preserved drawings underpin eight centuries of upkeep.
Industrial age
- 1831–1879 · United Kingdom / France
Physics behind eddy-current testing
Faraday discovered electromagnetic induction in 1831 and Foucault found eddy currents in 1851. In 1879 David Hughes showed that a coil's properties change with a metal's conductivity and permeability. These findings later became the basis of eddy-current testing.
→ Many inspection methods grew out of basic physics done for other reasons.
- 1850s–1865 · United States
Era of boiler explosions and the Sultana disaster
In the 1850s a boiler explosion occurred roughly every four days in the US. In 1865 the boiler explosion on the Mississippi steamboat Sultana killed more than 1,800 people, described as the worst boiler disaster in history.
→ Steam power spread faster than any system for understanding and inspecting it.
- 1866 · United States (Hartford, Connecticut)
Hartford Steam Boiler founded
Founded on 30 June 1866, the company paired boiler inspection with insurance, an idea from a Hartford technical club formed in 1857. Insurance gave owners a reason to accept inspection and helped guarantee its quality, with safety as the main goal.
→ Linking insurance to inspection gave inspection an economic engine.
- 1868 · United Kingdom
First magnetic crack detection
In 1868 S.M. Saxby used magnetic indications to look for cracks in gun barrels. William Hoke tried the same approach in 1917.
→ The idea of revealing hidden flaws through a physical effect starts here.
- 1879 · United Kingdom (Dundee, Scotland)
Tay Bridge disaster
On 28 December 1879 the Tay Bridge collapsed in a gale, killing everyone on the passing train: 59 known dead, up to 75 estimated. The inquiry pointed to a design without explicit wind allowance and poor castings, and found the bridge inspector was a bricklayer who re-tightened loose ties without reporting them to the engineer.
→ Inspection fails when findings never reach the people who can judge them.
- 1880 · United Kingdom
Wind-load standard for railway bridges
After the Tay disaster a Board of Trade commission set a design wind pressure of 56 psf (2.7 kPa) for railway bridges with a safety factor of four. Formal wind-pressure rules had not existed before.
→ Disasters produce numerical standards, which inspection then checks against.
- 1905 · United States (Brockton, Massachusetts)
Grover Shoe Factory boiler explosion
On 10 March 1905 a boiler explosion levelled the Grover Shoe Factory in Brockton, killing 58 and injuring 117. Thousands of boiler explosions had occurred in the US and Europe during the 19th century, and this one made the case for boiler laws.
→ Major accidents turn voluntary inspection into legal duty.
The History of ASME's Boiler and Pressure Vessel Code — ASME
- 1911–1915 · United States
ASME Boiler and Pressure Vessel Code
ASME's Boiler and Pressure Vessel Code was conceived in 1911; its first edition, the 1914 Edition, was published in 1915 as a single 114-page book.
→ It set the pattern of an industry body writing shared rules for design, fabrication and inspection.
The History of ASME's Boiler and Pressure Vessel Code — ASME
- 1929–1934 · United States
Magnetic particle testing goes industrial
In 1929 Victor de Forest and Foster Doane achieved the first industrial magnetic particle crack detection and founded Magnaflux in 1934. Railroad inspectors were already using oil and chalk to reveal cracks, an early form of penetrant testing.
→ Field tricks plus commercialisation turned NDT into a trade.
- 1929 · Soviet Union
Sokolov's ultrasonic flaw detection
In 1929 Sergei Sokolov studied ultrasonic detection in metals and in the early 1930s demonstrated a through-transmission flaw technique, though poor resolution limited its practical use.
→ A working principle can take years to become a field tool.
- c. 1930 · Germany
Industrial radiography
X-rays, discovered by Röntgen, spread first in medicine. Around 1930 Richard Seifert adapted the equipment for industrial use with welding institutes.
→ Welded construction created the need to see inside joints.
- 1933–1948 · Germany
Förster and eddy-current testing
In 1933 Friedrich Förster used eddy currents to measure conductivity and sort ferrous parts, founding his company in 1948, which still operates.
→ Fast non-contact checks for near-surface flaws entered industry.
- 1940–1942 · United States
Firestone's practical ultrasonic testing
In 1940 Floyd Firestone filed for the first practical ultrasonic testing method, granted on 21 April 1942 (US 2,280,226). In 1949 Josef Krautkrämer and Karl Deutsch independently began building ultrasonic flaw detectors.
→ Pulse-echo ultrasonics remain the basis of thickness gauging, now also carried by contact drones.
Modern
- 1967 · United States (Point Pleasant, WV – Ohio)
Silver Bridge collapse
On 15 December 1967 the Silver Bridge over the Ohio River collapsed in rush-hour traffic, killing 46. A single eyebar in a suspension chain fractured suddenly from a defect only about 2.5 mm (0.1 in) deep.
→ A tiny flaw in a non-redundant member can bring down a whole bridge.
Happy 50th Anniversary, National Bridge Inspection Standards — FHWA
- 1971 · United States
National Bridge Inspection Standards enacted
Following the Silver Bridge collapse, the NBIS were enacted on 27 April 1971, requiring inspections at least every two years by appropriately trained inspectors.
→ The starting point of modern bridge inspection: a national interval and qualified inspectors.
Happy 50th Anniversary, National Bridge Inspection Standards — FHWA
- 1979 · United States
NBIS extended to all public-road bridges
In 1979 the NBIS scope expanded from Federal-aid bridges to all bridges on public roads.
→ Wider scope multiplies the demand for inspectors and money.
Happy 50th Anniversary, National Bridge Inspection Standards — FHWA
- 1983 · United States (Greenwich, Connecticut)
Mianus River Bridge collapse
On 28 June 1983 a span of the I-95 Mianus River Bridge fell, killing three. Drains blocked during roadwork a decade earlier let water rust the pin-and-hanger assemblies until a hanger cracked. Connecticut had 12 engineers inspecting 3,425 bridges, and this one had passed an inspection nine months before.
→ Hard-to-reach details plus too few inspectors let even visible rust go unaddressed.
- 1987 · United States (New York)
Schoharie Creek Bridge collapse
On 5 April 1987, during a record spring flood, the Thruway bridge over Schoharie Creek collapsed and ten people died. Investigators blamed scour under pier three and judged riprap protection, inspection and maintenance inadequate.
→ Foundations under water are a blind spot for visual inspection.
- 1988 · United States
NBIS adds fracture-critical and underwater inspection
In 1988 the NBIS added requirements for fracture-critical bridges and bridges needing underwater inspection; 1993 added reporting on follow-up actions, and 2004 defined qualifications and training for team leaders and programme managers.
→ Inspection rules grow by accretion, one failure mode at a time.
Happy 50th Anniversary, National Bridge Inspection Standards — FHWA
- 1988 · United States (Hawaii)
Aloha Airlines Flight 243
On 28 April 1988 about 18 feet of a Boeing 737's upper fuselage tore away in flight and a flight attendant was killed. The NTSB found fatigue cracking at many rivet holes in a lap joint, worsened by corrosion on a 19-year-old aircraft flying in coastal air. It also faulted a maintenance programme, including night-time inspections, that missed the damage.
→ Ageing structures demand inspections that catch many small, distributed flaws.
- 2000 · United Kingdom (Hatfield)
Hatfield rail crash
On 17 October 2000 a rail fractured under a train at Hatfield, killing four. Rolling contact fatigue had produced multiple surface cracks. Railtrack did not know how many similar defects existed, imposed more than 1,800 emergency speed restrictions and began nationwide rail replacement.
→ Without a network-wide picture of condition, one failure forces precautionary restrictions everywhere.
- 2002 · United Kingdom
Railtrack replaced by Network Rail
Disruption and rising costs after Hatfield led the government to put Railtrack into administration; Network Rail took over in 2002. Investigators found that comprehensive written procedures masked serious gaps in maintenance staff's experience. In 2005 Network Rail was fined £3.5 million under health and safety law.
→ Procedures on paper are no substitute for competent inspectors.
- 2007 · United States (Minneapolis)
I-35W Mississippi River bridge collapse
On 1 August 2007 the bridge collapsed in rush hour, killing 13 and injuring 145. The NTSB named undersized gusset plates (about 13 mm thick) as the primary cause, with added deck concrete (about 20% more static load) and construction materials as contributors. Photos from a 2003 inspection showed bowing in the gussets that was not acted on.
→ Inspection images help only if someone interprets them.
- 2012 · Japan (Ōtsuki, Yamanashi)
Sasago Tunnel ceiling collapse
On 2 December 2012 nearly 150 ceiling panels fell in the Sasago Tunnel on the Chūō Expressway, killing nine. Adhesive anchor bolts pulling out was named the direct cause, and hammer-sounding tests were done only after a visual anomaly and had not been carried out since 2000. In 2013 tests, 113 of 183 remaining bolts pulled out below the 4-tonne design load.
→ Showed the danger of relying on visual checks and skipping hands-on testing.
- 2013 · Japan
Japan's 'first year of infrastructure maintenance'
The year after Sasago, 2013, was declared Japan's first year of infrastructure maintenance, and a basic plan for extending infrastructure life was adopted.
→ National policy shifted from repair-after-failure to preventive maintenance.
- 2014 · Japan
Japan mandates five-yearly close-visual inspection
MLIT issued an amended Road Act ordinance on 31 March 2014, effective 1 July 2014, requiring bridges (about 700,000) and tunnels (about 10,000) to be inspected every five years, based on close visual inspection.
→ A nationwide mandate exposed shortages of inspectors and money, creating demand for drones and other support technologies.
道路の老朽化対策に関する省令・告示の公布について — 国土交通省（2014年） · 笹子トンネル天井板落下事故 — Wikipedia（日本語）
- 2015 · Japan
Expressway Renewal Project begins
From fiscal 2015 a large-scale renewal and repair programme for Japan's expressways began as the Expressway Renewal Project.
→ Inspection findings became the basis for major renewal investment.
- 2018 · Italy (Genoa)
Ponte Morandi collapse
On 14 August 2018 a 210 m section collapsed in a rainstorm, killing at least 43. Deterioration of the stays and internal tendons is cited as the main factor; corrosion had been found in 1990s inspections, and a February 2018 meeting reported average tendon section losses of 10–20%. Road cracking and abnormal stay behaviour had been flagged before the collapse.
→ Known deterioration still kills if decisions and action lag behind inspection.
- 2020 · Italy (Genoa)
Genoa-Saint George Bridge opens
The Morandi bridge was demolished rather than repaired (February–June 2019); the replacement began on 25 June 2019 and opened on 3 August 2020.
→ Rapid replacement did not settle questions about how existing bridges across Europe are inspected.
The drone era
- 2000 · Japan (Mount Usu, Hokkaido)
Unmanned helicopter observes Mount Usu eruption
In spring 2000 the government asked for a Yamaha R-MAX unmanned helicopter to observe the Mount Usu eruption because manned helicopters could not safely get close. It helped measure ash deposits and improve mudslide forecasts. The R-MAX had been developed for crop spraying on Japan's small farms.
→ An early proof that unmanned aircraft can look where people cannot safely go.
- 2011 · Japan (Fukushima)
Unmanned helicopters monitor radiation at Fukushima
After the 2011 Tōhoku earthquake and nuclear accident, Yamaha R-MAX helicopters measured radiation inside the no-entry zone around Fukushima Daiichi.
→ Unmanned aircraft took on measurement in environments hazardous to people.
- 2013 · China (Shenzhen) / global
DJI Phantom launched
DJI released the first Phantom on 7 January 2013 and the camera-integrated Phantom 2 Vision in October 2013; the Phantom 4 added obstacle avoidance in March 2016. Cheap camera drones put aerial inspection within reach of many service firms.
→ Mass-market drones, not bespoke aircraft, made drone inspection widespread.
- 2014 · United States (California)
Skydio founded
Three MIT alumni founded Skydio in 2014. It released the R1, which used 12 cameras to perceive its surroundings, in 2018 and the Skydio 2 in October 2019.
→ Autonomous flight reduced reliance on pilot skill for close-in inspection.
- 2015 · Japan
Japan's Civil Aeronautics Act defines unmanned aircraft
The amended Civil Aeronautics Act, in force from 10 December 2015, defined unmanned aircraft and set flight rules.
→ A legal definition gave commercial drone inspection a path to permits and approvals.
- 2022 · Japan
Japan's national drone pilot licence begins
Japan's national certification for unmanned aircraft pilots began in December 2022.
→ State-certified pilot skill becomes a benchmark for procuring and managing inspection work.
- 2023 · United States
Skydio X10 and autonomous inspection
Announced in September 2023, the Skydio X10 carries a 50 MP camera claimed to resolve 0.1 mm detail and a thermal camera, can build 3D models on board without a connection, and can fly autonomous missions from a self-charging dock. Its 3D reconstruction has been used to inspect Royal Canadian Navy ships.
→ Drone inspection is moving from taking pictures to autonomous data capture and modelling.
英語・日本語で検索し、Wikipedia（英・日）、公的機関（FHWA、国土交通省）、業界団体・企業の公式史（ASME、HSB）、技術史記事（UniWest）の本文をWebFetchで取得して確認した事実だけを記載した。WebFetchは本文を取得後に要約モデル経由で回答するため、reviewScopeのfull_textは『本文ページを取得して該当箇所を確認した』の意味で用いる。検索結果は抜粋を返さなかったため、検索結果だけに基づく項目は置いていない。調査途中でセッションの検索・取得上限に達したため、依頼にあった項目のうち中国・日本の城郭石垣や橋の維持、ヘリコプターによる送電線巡視、初期のUAV点検、Flyability Elios、ドローン・イン・ア・ボックス、レベル4飛行の解禁日、八潮市道路陥没事故（2025年1月）と下水道のドローン調査、ロープアクセス（IRATA）の成立年は未確認のため収録していない。伊勢神宮の式年遷宮は参照資料が1993年の第61回までしか記していないため、それ以降は書いていない。