Cosgrove aqueduct is a navigable cast iron trough navigable aqueduct that carries the Grand Union Canal over the River Great Ouse, on the borders between Buckinghamshire and Northamptonshire at the northwest margin of Milton Keynes in England. The present structure was built in 1811, to replace a previous brick structure that had failed. When the present structure was erected, it was known as the "Iron Trunk". The structure has two cast iron trough spans, with a single central masonry pier. The abutments were constructed in masonry but have been refaced in brick during the twentieth century. The trough is 15 feet (4.6 m) wide, 6 ft 6 in (1.98 m) deep, with a total length of 101 feet (31 m). The canal surface is about 40 feet (12 m) above the surface of the river. There are large approach earthworks about 36 feet (11 m) high above the valley floor and 150 feet (46 m) wide, with a total length of half a mile (800m).
The Grand Junction Canal (later absorbed into the Grand Union Canal) required to cross the course of the River Great Ouse, the lowest point between the summits at Tring and Braunston. Initially flights of locks, four at the southeast and five at the northwest, were used to allow the canal to descend to cross the river on the level, and this arrangement came into action in 1800. However William Jessop, the canal company’s engineer, designed a three-arch brick viaduct so that the canal could cross at a higher level, reducing the water loss and delay in locking down to river level. His structure was opened on 26 August 1805, but a section of the canal embankment collapsed in January 1806; this was repaired, but the aqueduct structure itself collapsed in February 1808, severing the canal.
Although Jessop is sometimes blamed for the failure of the first structure, the collapse actually led to a legal dispute with the original contractor. The issue went to trial, with damages eventually being awarded to the Grand Junction Company for loss of trade while the canal was out of action, and the cost of the replacement aqueduct.
The second structureedit
As a temporary measure the lock system originally installed was brought back into use, and Benjamin Bevan, an engineer employed by the canal company, designed a replacement structure. By this time, cast iron trough aqueducts designed by Thomas Telford for the Pontcysyllte Aqueduct and elsewhere, had become proven, and Bevan adopted the system for his structure. However, the canal was then operating as a wide canal in contradistinction to some northern narrowboat canals, so that the troughs had to be substantially larger and stronger than elsewhere. The cast iron units were cast at the Ketley foundry at Coalbrookdale; the company had already been involved with Telford on the Longdon-on-Tern Aqueduct. They were transported to Cosgrove by the canal itself, and assembled and erected at site. The new structure was completed in January 1811.
Structural detailsedit
To resist the substantial additional loading of a wide canal, Bevan designed the floor sections to be arched, providing additional strength; in addition there are arch ribs built in with the trough side plates to give additional shear strength The towpath is cantilevered from one side, as at Froncysyllte, and supported by diagonal struts. There is a cattle creep in the embankment either side of the main structure, which is used by pedestrians.
Labrum, E A, Civil Engineering Heritage, Eastern and Central England, Thomas Telford (1994).
Lewis, Peter R., Disaster on the Dee: Robert Stephenson's Nemesis of 1847, Tempus (2007).
External linksedit
A location map of several famous cast iron aqueducts
A brief description
April 23, 2024
cosgrove, aqueduct, confused, with, massachusetts, cosgrove, aqueduct, navigable, cast, iron, trough, navigable, aqueduct, that, carries, grand, union, canal, over, river, great, ouse, borders, between, buckinghamshire, northamptonshire, northwest, margin, mil. Not to be confused with Cosgrove Aqueduct Massachusetts Cosgrove aqueduct is a navigable cast iron trough navigable aqueduct that carries the Grand Union Canal over the River Great Ouse on the borders between Buckinghamshire and Northamptonshire at the northwest margin of Milton Keynes in England The present structure was built in 1811 to replace a previous brick structure that had failed When the present structure was erected it was known as the Iron Trunk The structure has two cast iron trough spans with a single central masonry pier The abutments were constructed in masonry but have been refaced in brick during the twentieth century The trough is 15 feet 4 6 m wide 6 ft 6 in 1 98 m deep with a total length of 101 feet 31 m The canal surface is about 40 feet 12 m above the surface of the river There are large approach earthworks about 36 feet 11 m high above the valley floor and 150 feet 46 m wide with a total length of half a mile 800m Cosgrove AqueductThe Cosgrove aqueductCoordinates52 04 07 N 0 50 01 W 52 0687 N 0 8336 W 52 0687 0 8336OS grid referenceSP800417CarriesGrand Union CanalCrossesRiver Great OuseLocaleCosgroveMaintained byBritish WaterwaysCharacteristicsTrough constructioncast ironPier constructionBrickTotal length101 feet 31 m Width15 feet 4 6 m Height60 feet 18 m Water depth6 feet 6 inches 1 98 m Traversable 15 ft but in a Narrowboats only canal sectionTowpathsNE SideNo of spansTwoPiers in waterOneHistoryDesignerBenjamin BevanOpened26 August 1805RebuiltJanuary 1811Location Contents 1 Origins 2 The second structure 3 Structural details 4 See also 5 References 6 External linksOrigins editThe Grand Junction Canal later absorbed into the Grand Union Canal required to cross the course of the River Great Ouse the lowest point between the summits at Tring and Braunston Initially flights of locks four at the southeast and five at the northwest were used to allow the canal to descend to cross the river on the level and this arrangement came into action in 1800 However William Jessop the canal company s engineer designed a three arch brick viaduct so that the canal could cross at a higher level reducing the water loss and delay in locking down to river level His structure was opened on 26 August 1805 but a section of the canal embankment collapsed in January 1806 this was repaired but the aqueduct structure itself collapsed in February 1808 severing the canal Although Jessop is sometimes blamed for the failure of the first structure the collapse actually led to a legal dispute with the original contractor The issue went to trial with damages eventually being awarded to the Grand Junction Company for loss of trade while the canal was out of action and the cost of the replacement aqueduct The second structure editAs a temporary measure the lock system originally installed was brought back into use and Benjamin Bevan an engineer employed by the canal company designed a replacement structure By this time cast iron trough aqueducts designed by Thomas Telford for the Pontcysyllte Aqueduct and elsewhere had become proven and Bevan adopted the system for his structure However the canal was then operating as a wide canal in contradistinction to some northern narrowboat canals so that the troughs had to be substantially larger and stronger than elsewhere The cast iron units were cast at the Ketley foundry at Coalbrookdale the company had already been involved with Telford on the Longdon on Tern Aqueduct They were transported to Cosgrove by the canal itself and assembled and erected at site The new structure was completed in January 1811 Structural details editTo resist the substantial additional loading of a wide canal Bevan designed the floor sections to be arched providing additional strength in addition there are arch ribs built in with the trough side plates to give additional shear strength The towpath is cantilevered from one side as at Froncysyllte and supported by diagonal struts There is a cattle creep in the embankment either side of the main structure which is used by pedestrians See also edit nbsp United Kingdom portal nbsp Transport portal Canals of the United Kingdom History of the British canal systemReferences editLabrum E A Civil Engineering Heritage Eastern and Central England Thomas Telford 1994 Lewis Peter R Disaster on the Dee Robert Stephenson s Nemesis of 1847 Tempus 2007 External links editA location map of several famous cast iron aqueducts A brief description Milton Keynes and the aqueduct Retrieved from https en wikipedia org w index php title Cosgrove Aqueduct amp oldid 1219383728, wikipedia, wiki, book, books, library,
