Broughton Suspension Bridge was a suspended-deck suspension bridge

Suspension bridge

A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...

 built in 1826 to span the River Irwell

River Irwell

The River Irwell is a long river which flows through the Irwell Valley in the counties of Lancashire and Greater Manchester in North West England. The river's source is at Irwell Springs on Deerplay Moor, approximately north of Bacup, in the parish of Cliviger, Lancashire...

 between Broughton

Broughton, Greater Manchester

Broughton is an inner city area of Salford, in Greater Manchester, England. It lies on the east bank of the River Irwell and A56 road, in the northeastern part of the City of Salford, north-northwest of Manchester city centre and south of Prestwich. Broughton consists of Broughton Park, Higher...

 and Pendleton

Pendleton, Greater Manchester

Pendleton is an inner city area of Salford, Greater Manchester, England. It is about from Manchester city centre. The A6 dual carriageway skirts the east of the district....

, now in Greater Manchester

Greater Manchester

Greater Manchester is a metropolitan county in North West England, with a population of 2.6 million. It encompasses one of the largest metropolitan areas in the United Kingdom and comprises ten metropolitan boroughs: Bolton, Bury, Oldham, Rochdale, Stockport, Tameside, Trafford, Wigan, and the...

, England. It was one of the first suspension bridges constructed in Europe. On 12 April 1831 the bridge collapsed, reportedly owing to a mechanical resonance

Mechanical resonance

Mechanical resonance is the tendency of a mechanical system to absorb more energy when the frequency of its oscillations matches the system's natural frequency of vibration than it does at other frequencies...

 induced by troops marching over the bridge in step. A bolt in one of the stay-chains snapped, causing the bridge to collapse at one end, throwing about forty of the men into the river. As a result of the incident the British Military

British Armed Forces

The British Armed Forces are the armed forces of the United Kingdom of Great Britain and Northern Ireland.Also known as Her Majesty's Armed Forces and sometimes legally the Armed Forces of the Crown, the British Armed Forces encompasses three professional uniformed services, the Royal Navy, the...

 issued an order that troops should "break step" when crossing a bridge.

The bridge's construction has been attributed to Samuel Brown

Samuel Brown (Royal Navy officer)

Captain Sir Samuel Brown of Netherbyres KH FRSE was an early pioneer of chain design and manufacture and of suspension bridge design and construction. He is best known for the Union Bridge of 1820, the first vehicular suspension bridge in Britain.-Naval career:Brown was born in London, the son of...

, but this has been questioned; some sources have suggested that it may have been built by Thomas Cheek Hewes, a Manchester millwright

Millwright

A millwright is a craftsman or tradesman engaged with the construction and maintenance of machinery.Early millwrights were specialist carpenters who erected machines used in agriculture, food processing and processing lumber and paper...

 and textile machinery manufacturer

Textile manufacture during the Industrial Revolution

The industrial revolution changed the nature of work and society. Opinion varies as to the exact date, but it is estimated that the First Industrial Revolution took place between 1750 and 1850, and the second phase or Second Industrial Revolution between 1860 and 1900. The three key drivers in...

.

The bridge was rebuilt and used until 1914, when it was replaced by a Pratt truss pedestrian bridge, which is still in use.

Construction

In 1826 John Fitzgerald, the wealthy owner of Castle Irwell House (later to become the site of the Manchester Racecourse

Manchester Racecourse

Manchester Racecourse was a former racecourse in the City of Salford, Greater Manchester, England. Manchester Racecourse moved several times but remained within Salford in the 19th and 20th centuries...

), built at his own expense a 144-foot suspension bridge across the River Irwell between Lower Broughton and Pendleton

Pendleton, Greater Manchester

Pendleton is an inner city area of Salford, Greater Manchester, England. It is about from Manchester city centre. The A6 dual carriageway skirts the east of the district....

. The bridge was a source of great local pride, as the Menai suspension bridge

Menai Suspension Bridge

The Menai Suspension Bridge is a suspension bridge between the island of Anglesey and the mainland of Wales. Designed by Thomas Telford and completed in 1826, it was the first modern suspension bridge in the world.-Construction:...

 had only opened that year and suspension bridges were then considered the "new wonder of the age".

1831 collapse

On 12 April 1831 the 60th Rifle Corps

King's Royal Rifle Corps

The King's Royal Rifle Corps was a British Army infantry regiment, originally raised in colonial North America as the Royal Americans, and recruited from American colonists. Later ranked as the 60th Regiment of Foot, the regiment served for more than 200 years throughout the British Empire...

 carried out an exercise

Military exercise

A military exercise is the employment of military resources in training for military operations, either exploring the effects of warfare or testing strategies without actual combat...

 on Kersal Moor

Kersal Moor

Kersal Moor is a recreation area in Kersal, within the City of Salford, in Greater Manchester, England, consisting of eight hectares of moorland, bounded by Moor Lane, Heathlands Road, St...

 under the command of Lieutenant P. S. Fitzgerald, the son of John Fitzgerald. As a detachment of 74 men returned to barracks in Salford by way of the bridge the soldiers, who were marching four abreast, felt it begin to vibrate in time with their footsteps. Finding the vibration a pleasant sensation some of them started to whistle a marching tune, and they began to "humour it by the manner in which they stepped", causing the bridge to vibrate even more. The head of the column had almost reached the Pendleton side when they heard "a sound resembling an irregular discharge of fireams". Immediately, one of the iron columns supporting the suspension chains on the Broughton side of the river fell towards the bridge, carrying with it a large stone from the pier to which it had been bolted. The corner of the bridge, no longer supported, then fell sixteen or eighteen feet into the river, throwing about forty of the soldiers into the water or against the chains. As the water was only about two feet deep at that point none of the men were killed, but twenty were injured, including six who suffered severe injuries including: broken arms and legs, severe bruising, and contusions to the head.

Cause

An investigation found that a bolt in one of the stay-chains had snapped at the point where it was attached to the masonry of the ground anchor. There was criticism of the construction method used, as the attachment to the ground-anchor relied on one bolt rather than two, and the bolt itself was found to have been badly forged. A number of other bolts were also bent but had not broken. It emerged that three years previously the distinguished Manchester engineer, Eaton Hodgkinson

Eaton Hodgkinson

Eaton A. Hodgkinson was an English engineer, a pioneer of the application of mathematics to problems of structural design.-Early life:...

, had expressed some doubt about the strength of the stay-chains, as compared with that of the suspension chains. He had said that they should be rigorously tested, but they were not. It also came to light that some time before the accident one of the cross bolts had started to bend and crack, although it was believed to have been replaced by the time of the accident. The conclusion was that, although the vibration caused by the marching had precipitated the bolt's failure, it would have happened sooner or later anyway.

Aftermath

The collapse of the bridge caused something of a loss of confidence in suspension bridges, with one newspaper report at the time commenting:

From what happened on this occasion we would greatly doubt the stability of the great Menai Bridge (admirable as its construction is), if a thousand men were to be marched across in close column, and keeping regular step. From its great length, the vibration would be tremendous before the head of the column had reached the further side, and some terrific calamity would be very likely to happen.

This did not stop the building of more suspension bridges, and the main consequence of the collapse was that the British military introduced the order to "break step" when soldiers were crossing a bridge. French soldiers too were ordered to break step on bridges, but nevertheless the Angers Bridge

Angers Bridge

Angers Bridge, also called the Basse-Chaîne Bridge, was a suspension bridge over the Maine River in Angers, France. It was designed by Joseph Chaley and Bordillon, and built between 1836 and 1839...

 in France collapsed in a storm in 1850, killing over 200 soldiers.

Broughton Suspension Bridge was rebuilt and strengthened but, according to the Imperial Gazetteer of England and Wales (1870-72), it was propped with temporary piles whenever a large crowd was expected. The suspension bridge remained in use until 1914, when it was replaced with a steel Pratt truss pedestrian bridge.