2,617 articles
Ordine degli Ingegneri
The Ordine degli Ingegneri (Order of Engineers) is the Italian professional order for engineers, a network of 106 provincial bodies that maintains the register of engineers and controls access to the profession.
Ordnance Survey
Ordnance Survey (OS), Great Britain's national mapping agency founded 21 June 1791 by the Board of Ordnance, maintains over 600 million geospatial features, the National Grid, and OSGB36 mapping data.
Øresund Bridge
The Øresund Bridge (Öresundsbron) is a combined railway and motorway link across the Øresund strait between Copenhagen, Denmark, and Malmö, Sweden, opened on July 1, 2000.
Oroville Dam
Oroville Dam is an earthfill dam on the Feather River in Butte County, California. At 770 feet (235 m) high, it is the tallest dam in the United States.
Oroville Dam crisis
The Oroville Dam crisis was a February 2017 emergency at Oroville Dam on the Feather River in California, in which spillway failures prompted the evacuation of about 188,000 people.
Orthotropic deck
An orthotropic deck, or orthotropic steel deck, is a lightweight steel bridge deck of rib-stiffened plate and floorbeams acting as one structure, developed in Germany in the 1930s for long-span bridges.
Oslofjord Tunnel
The Oslofjord Tunnel (Oslofjordtunnelen) is a 7,306-meter subsea road tunnel on European route E134 under the Oslofjord in Norway, opened in 2000 as part of the Oslofjord Connection.
Osterberg cell test
The Osterberg cell test, commonly called the O-cell test, is a deep foundation load test in which a sacrificial internal jack loads a pile from within.
Otford railway tunnel
The Otford railway tunnel, or Otford Tunnel, is a disused heritage-listed railway tunnel in New South Wales, opened in 1888 and closed to trains in 1920.
Ottoman aqueducts in the Balkans and Istanbul
Ottoman aqueducts are water-supply bridges and covered galleries built under Ottoman rule from the mid-sixteenth century onward, with the Kırkçeşme system, ordered by Süleyman the Magnificent in 1554, supplying Istanbul.
Ouachita River Lock and Dam No. 8
Ouachita River Lock and Dam No. 8 was a movable-wicket lock and dam on the Ouachita River at Calion, Arkansas, built by the U.S. Army Corps of Engineers in 1907 and 1916.
Ouse Valley Viaduct
The Ouse Valley Viaduct, also called the Balcombe Viaduct, is a brick railway viaduct in West Sussex carrying the Brighton Main Line over the River Ouse.
Outer Ring Road, Pune
The Outer Ring Road, also called the Pune Ring Road, is a circular access-controlled expressway being built around Pune, India, with construction beginning in 2025.
Outlet works
Outlet works are the structures and equipment in a dam through which controlled releases of reservoir water are made, via gates, conduits, and valves, distinct from spillways.
Output-based aid
Output-based aid, also called performance-based aid, is a results-based financing approach in which subsidies are paid to service providers only after verified delivery of services to poor households, mainly in developing countries.
Over Bridge
Over Bridge is a single-arch stone bridge over the River Severn at Gloucester, England, built between 1825 and 1830 to a design by Thomas Telford.
Overflow spillway
An overflow spillway, or ogee spillway, passes flood water over the top of a dam on a crest shaped to match a falling water sheet.
Overstrength
Overstrength is the ratio of a structure's actual lateral strength to the strength required by seismic design provisions, central to earthquake engineering because codes rely on reserve strength to prevent collapse.
Overtopping
Overtopping, or wave overtopping, is the passage of water from wave run-up over the crest of a seawall, dike, or breakwater, which can flood the hinterland and endanger people.
Overtopping protection
Overtopping protection is the armoring of a dam, most often an earthen embankment, so floodwater flowing over its crest does not erode it and cause a breach.
Overtoun Bridge
Overtoun Bridge, called the dog suicide bridge, is a road bridge over the Overtoun Burn near Dumbarton, Scotland, known for reports of dogs falling from its parapet.
Oxidation ditch
An oxidation ditch is a modified activated-sludge process that treats wastewater in a racetrack-shaped loop, using rotating aerators and long solids retention times to remove organic matter and nutrients.
Ozonation
Ozonation is a water treatment process that dissolves ozone into water to inactivate pathogens and oxidize contaminants; used in drinking water since 1893, notably at Nice, France.
Package treatment plant
A package treatment plant is a pre-manufactured wastewater treatment facility, built in a factory and shipped to a site, typically serving small communities or individual properties with flows between 0.01 and 0.25 MGD.
Padma Bridge (পদ্মা সেতু)
The Padma Bridge (পদ্মা সেতু), formally the Padma Multipurpose Bridge, is a 6.15 km road and rail bridge over the Padma River in Bangladesh, opened in 2022.
Pakistan Engineering Council
The Pakistan Engineering Council (PEC) is the statutory body that regulates engineering in Pakistan, licensing engineers and accrediting engineering programs under the PEC Act 1976 from Islamabad.
Palace Bridge
Palace Bridge, also known as Dvortsoviy Most, is a bascule bridge in Saint Petersburg that crosses the Neva River, linking the Winter Palace with Vasilievsky Island.
Pamban Bridge
The Pamban Bridge is a railway bridge in Tamil Nadu, India, connecting Rameswaram Island with the mainland; the original 1914 bridge was India's first sea bridge.
Panama Canal
The Panama Canal, also known as Canal de Panamá, is an artificial waterway across the isthmus of Panama linking the Atlantic and Pacific Oceans through locks, opened in 1914.
Panama Canal Authority
The Panama Canal Authority (Autoridad del Canal de Panamá, ACP) is the Panamanian public entity that operates the Panama Canal, taking over from the United States on December 31, 1999.