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79-470: On December 15, 1967, the Silver Bridge collapsed amid heavy rush-hour traffic, resulting in the deaths of 46 people, two of whom were never found. Investigation of the wreckage soon pointed to the failure of a single eyebar in one of the suspension chains as the primary cause — a finding noted in a preliminary report released within 10 months of the collapse. However, to explain why that eyebar failed —

158-458: A broadened scope to cover all modes of transportation, although most of its activities are still specific to highways. While AASHTO is not a government body, it does possess quasi-governmental powers in the sense that the organizations that supply its members customarily obey most AASHTO decisions. The voting membership of AASHTO consists of the Department of Transportation of each state in

237-473: A chain break occurring, say, in the center part of the span would have resulted in the towers falling in opposite directions, away from each other.) The bridge, which was designed in 1926–27, generally conformed to the engineering standards of its era, according to the investigation into the bridge's collapse, and the investigation's review of the original stress calculations underlying the design found no significant errors. A few years earlier, in 1923, AASHO ,

316-488: A failure triggered by a flaw just 0.1 inches (2.5 mm) deep, which led to a fracture — required significantly more time and effort to uncover, with the final accident report taking three years to complete. The collapse led to significant changes in the way bridges in the U.S. are inspected and maintained. The collapsed bridge was replaced by the Silver Memorial Bridge , which was completed in 1969. At

395-420: A final selection from the five remaining entries. Telford rejected all the remaining designs, arguing that 577 feet (176 m) was the maximum possible span. Telford was then asked to produce a design himself, which he did, proposing a 110-foot-wide (34 m) suspension bridge, supported on tall Gothic towers, costing £52,000. The Bridge Committee which had been set up to look at the designs sponsored

474-451: A national standards-setting organization, had released documentation to aid engineers in designing bridges — providing quality-control specifications and guidelines on topics such as computing forces and loads, types and properties of steel, and estimating future traffic levels. The bridge's eyebars, which used a new, stronger steel, offered a maximum allowable stress of 50,000 psi , significantly higher than most other steels then in use, and

553-411: A result of the thoroughness of the investigation, the cause of the disaster was precisely and indisputably found to be "a design that inadvertently made inspection all but impossible and failure all but inevitable. If ever a design was to blame for a failure, this was it." Petroski does not fault the bridge's designers, who were unaware of many of these hazards. Instead, he points to the future. "If there

632-737: A small rest area on the Ohio side of the river, along Route 7. The bridge has been designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers as its collapse ultimately led to the creation of the first national bridge inspection program in the Federal-Aid Highway Act of 1968 . Reviewing the collapse and subsequent investigation in his 2012 book To Forgive Design: Understanding Failure , engineering historian Henry Petroski finds it "a cautionary tale for engineers of every kind." As

711-673: Is a suspension bridge spanning the Avon Gorge and the River Avon , linking Clifton in Bristol to Leigh Woods in North Somerset . Since opening in 1864, it has been a toll bridge , the income from which provides funds for its maintenance. The bridge is built to a design by William Henry Barlow and John Hawkshaw , based on an earlier design by Isambard Kingdom Brunel . It is a Grade I listed building and forms part of

790-479: Is a standards setting body which publishes specifications, test protocols , and guidelines that are used in highway design and construction throughout the United States. Despite its name, the association represents not only highways but air, rail, water, and public transportation as well. Although AASHTO sets transportation standards and policy for the United States as a whole, AASHTO is not an agency of

869-426: Is anything positive about the Silver Bridge failure," he concludes, "it is that its legacy should be to remind engineers to proceed always with the utmost caution, ever mindful of the possible existence of unknown unknowns and the potential consequences of even the smallest design decisions." In his 1970 book Operation Trojan Horse , and in his 1975 book The Mothman Prophecies , Fortean author John Keel linked

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948-437: Is located about 4,300 feet (1.3 km) downstream (south) of the original. The bridge carries US 35 across the river and serves as a major crossing for people and goods traveling between Charleston, West Virginia , and Southern and Central Ohio . The speed limit on the bridge is 65 mph (105 km/h). No toll is imposed at either end. (collapsed) Clifton Suspension Bridge The Clifton Suspension Bridge

1027-454: Is often required to submit test results to state DOTs. For example, a contract for the construction of a highway bridge may require a minimum compressive strength for the concrete used. The contract will specify AASHTO Test Designation T 22, "Compressive Strength of Cylindrical Concrete Specimens," as the means of determining compressive strength. The laboratory performing T 22 will be required to be accredited in that test. AASHTO coordinates

1106-898: Is still in service. Other bridges of similar design include the earlier road bridge over the Menai Strait built by Thomas Telford in 1826; the Széchenyi Chain Bridge in Budapest , built in 1839–1849, destroyed in the closing days of World War II by retreating Germans in 1945, and rebuilt identically by 1949, with redundant chains and hangers; and the Three Sisters , three self-anchored suspension bridges in Pittsburgh of similar design and construction period (from 1924 to 1928), each with suspension chains consisting of at least eight eyebars per link. The eyebars in

1185-459: Is well known as a suicide bridge and is fitted with plaques that advertise the telephone number of Samaritans . Between 1974 and 1993, 127 people fell to their deaths from the bridge. In 1998 suicide barriers were installed on the bridge to prevent people jumping. In the four years after installation this reduced the suicide rate from eight deaths per year to four. Nicolette Powell , the wife of UK rhythm and blues singer Georgie Fame , formerly

1264-605: The Marchioness of Londonderry , jumped to her death from the bridge on 13 August 1993. In 1957 a RAF Filton -based RAF Vampire jet from 501 Squadron piloted by Flying officer John Greenwood Crossley flew under the deck while performing a victory roll before crashing in Leigh Woods , killing the pilot. The accident caused a landslip that led to the temporary closure of the nearby Portishead Railway . A helicopter from National Police Air Service Filton flew under

1343-458: The Society of Merchant Venturers following Vick's bequest. The trust was authorised to manage the bridge and collect tolls by acts of Parliament in 1952, 1980 and 1986. A toll is levied on vehicles, but the £0.05 toll that the act allows for cyclists or pedestrians is not collected. Human toll collectors were replaced by automated machines in 1975. The tolls are used to pay for the upkeep of

1422-735: The Society of Merchant Venturers , the Senior Sheriff of the City and County of Bristol and Thomas Daniel . The act allowed a wrought iron suspension bridge to be built instead of stone, and tolls levied to recoup the cost. The three trustees named in the act met on 17 June 1830 and appointed further trustees, bringing the total up to 23. There were additions to this number in the weeks which followed, so by early July 1830 there were 31 in all, although not everyone had been formally sworn in by that date. Others included Thomas Durbin Brice, Master of

1501-538: The A-side of a 1967 single. Also known as Shane’s bridge. Author James Tynion IV uses both the mothman and the bridge as a plot point in his ongoing comic The Department of Truth . The Silver Memorial Bridge is a cantilever bridge that spans the Ohio River between Gallipolis, Ohio , and Henderson, West Virginia . The bridge was completed in 1969 as a replacement for the collapsed Silver Bridge, although it

1580-530: The B3129 road. The bridge is a Grade I listed building . In November 2011 it was announced that a new visitor centre, costing nearly £2 million, was to be built at the Leigh Woods end of the bridge to replace the temporary building currently being used. The new facilities were scheduled to be completed before the 150th anniversary of the opening, which was celebrated on 8 December 2014. In December 2012 it

1659-487: The B3129 road. The idea of building a bridge across the Avon Gorge originated in 1753. Original plans were for a stone bridge and later iterations were for a wrought iron structure. In 1831, an attempt to build Brunel's design was halted by the Bristol riots , and the revised version of his designs was built after his death and completed in 1864. Although similar in size and design, the bridge towers are not identical,

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1738-647: The Bridge would be a fitting memorial, and started to raise new funds. In 1860, Brunel's Hungerford suspension bridge over the Thames in London was demolished to make way for a new railway bridge to Charing Cross railway station . Its chains were purchased for use at Clifton. A revised design was made by William Henry Barlow and Sir John Hawkshaw , with a wider, higher and sturdier deck than Brunel intended, with triple chains instead of double. It has been argued that

1817-507: The Brooklyn Bridge's construction, it was discovered that some substandard steel wire had been installed in the cables. To compensate, 150 more good steel wires were added to each cable, supplementing each's 5,434 wires. The designer's son, Washington Roebling, decided the safety factor may have been reduced, but remained more than sufficient. The two towers that supported the two suspension chains rose nearly 131 feet (40 m) from

1896-610: The Clifton Bridge Bill which became an act , the Clifton Suspension Bridge Act 1830 ( 11 Geo. 4 & 1 Will. 4 . c. lxix), when the bill received royal assent on 29 May 1830. The act appointed three trustees to carry through the purposes of the act, with powers to appoint more up to a total not exceeding thirty five or less than twenty. The three trustees named in the act were the Master of

1975-542: The Clifton tower having side cut-outs, the Leigh tower more pointed arches atop a 110-foot (34 m) red sandstone -clad abutment. Roller-mounted "saddles" at the top of each tower allow movement of the three independent wrought iron eyebar chains on each side when loads pass over the bridge. The bridge deck is suspended by 162 vertical wrought-iron rods in 81 matching pairs. The Clifton Bridge Company initially managed

2054-492: The Silver Bridge collapse to alleged sightings of the Mothman . The story was adapted as a film by the same name , released in 2002. Author Jack Matthews wrote a novella, Beyond the Bridge , written as the diary of an imaginary survivor of the disaster starting a new life as a dishwasher in a tiny West Virginia town. Honky tonk singer-songwriter and West Virginia native Ray Anderson released "The Silver Bridge Disaster" as

2133-435: The Silver Bridge offered little to no redundancy, as each chain link consisted of just two eyebars in parallel. (Each bar was 45–55 feet long and 2 inches thick; bars were joined together at the eyeholes using cylindrical pins 11.5 inches in diameter.) These eyebars were made of a new, higher-strength steel (more than twice the tensile strength of other steels of that era), which meant fewer eyebars per link were needed to achieve

2212-604: The Society of Merchant Venturers, George Daubeny, John Cave, John Scandrett Harford , George Hilhouse, Henry Bush, and Richard Guppy. The first full meeting of the trustees was held on 22 June 1830 in the Merchants Hall in Bristol. Alderman Thomas Daniel was in the chair. 86 people had committed £17,350, an average of just over £200 each. These funds raised during the first few months of 1830 were not sufficient for

2291-552: The United States, as well as those of Puerto Rico and the District of Columbia . The United States Department of Transportation has a non-voting associate membership. Some noteworthy AASHTO publications are: In addition to its publications, AASHTO performs or cooperates in research projects. One such project is the AASHTO Road Test , which is a primary source of data used when considering transport policies and

2370-512: The attic rooms, and that they overhung the river much as Tudor houses would overhang the street. In the 1760s a bill to replace the bridge was carried through parliament by the Bristol MP Sir Jarrit Smyth . By the early 18th century, increase in traffic and the encroachment of shops on the roadway made the bridge fatally dangerous for many pedestrians. A new bridge, designed by James Bridges and finished by Thomas Paty

2449-431: The bridge deck is suspended by eighty-one matching vertical wrought-iron rods ranging from 65 feet (20 m) at the ends to 3 feet (0.91 m) in the centre. Composed of numerous parallel rows of eyebars connected by bolts, the chains are anchored in tunnels in the rocks 60 feet (18 m) below ground level at the sides of the gorge. The deck was originally laid with wooden planking, later covered with asphalt, which

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2528-543: The bridge during a search in 1997. On 12 February 2014 the bridge was closed to traffic due to wind for the first time in living memory. On 11 July 2024, there was a discovery of human remains on the Clifton Suspension Bridge . The bridge was closed to all traffic and all pedestrians during a manhunt that led to the arrest of a murder suspect. AASHO The American Association of State Highway and Transportation Officials ( AASHTO )

2607-469: The bridge for major annual events has continued each year since then. On 26 November 2003, the last Concorde flight (Concorde 216) flew over the bridge before landing at Filton Aerodrome . In April 2006, the bridge was the centrepiece of the Brunel 200 weekend, celebrating the 200th anniversary of the birth of Isambard Kingdom Brunel. At the climax of the celebration a firework display was launched from

2686-407: The bridge had a design safety factor of 1.50, within engineering norms. Investigators into the collapse found no indication that the bridge had been overloaded, even on the day it failed. Despite the bridge's age and the heavy traffic on it at the time of its collapse, the load it was carrying was found to be within its normal capacity; and the location where the failure occurred was at less than half

2765-403: The bridge towers are not identical in design, the Clifton tower having side cut-outs whilst the Leigh tower has more pointed arches and chamfered edges. Brunel's original plan proposed they be topped with then-fashionable sphinxes , but the ornaments were never constructed. The 85-foot-tall (26 m) Leigh Woods tower stands atop a 110-foot (34 m) red sandstone-clad abutment. In 2002 it

2844-460: The bridge under licence from a charitable trust. The trust subsequently purchased the company shares, completing this in 1949 and took over the running of the bridge using the income from tolls to pay for maintenance. The bridge is a distinctive landmark, used as a symbol of Bristol on postcards, promotional materials, and informational web sites. It has been used as a backdrop to several films and television advertising and programmes. It has also been

2923-507: The bridge's main piers. They featured a "rocker" design, which allowed them to tilt slightly at their bases in response to unbalanced loading on the bridge, or to changes in chain length due to temperature change. Prior to their use on the Silver Bridge, rocker towers had been used on a similar bridge in Brazil and, before that, on two large bridges in Europe. Although the rocker towers required

3002-488: The bridge's suspension chains to keep them upright, their ability to tilt allowed the towers to minimize bending stresses — which standard, fixed-base towers must be designed to resist — resulting in a simpler tower design that used less material than fixed towers, and cost significantly less to build. Early into the collapse investigation, the rocker towers provided a significant clue as to the failure's cause and location. Investigators noticed that both towers had fallen during

3081-460: The bridge, as he did not believe a single-span bridge of such length could be constructed. His son chose to ignore his advice. A ceremony to mark the start of the construction works was held Monday 20 June 1831. Work started on blasting of St. Vincent's Rock, on the Clifton side of the gorge. Four months later work was halted by the Bristol riots , which took place after the House of Lords rejected

3160-445: The bridge, including the strengthening of the chain anchor points, which was done in 1925 and 1939, and regular painting and maintenance, which is carried out from a motorised cradle slung beneath the deck. By 2008 over 4 million vehicles crossed the bridge each year. In February 2012, the bridge trustees applied to the Department for Transport to increase the toll to £1, subsequently implemented on 24 April 2014. On 1 April 1979,

3239-518: The bridge. After the passing of the act for the Great Western Railway reestablished financial confidence, work resumed in 1836, but subsequent investment proved woefully inadequate. Despite the main contractors going bankrupt in 1837, the towers were built in unfinished stone. To enable the transfer of materials, a 1,000-foot-long (300 m) iron bar, which was 1.25 inches (32 mm) in diameter, had been drawn by capstan across

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3318-497: The bridge. The celebrations also saw the activation of an LED -based lighting array to illuminate the bridge. On 4 April 2009, the bridge was shut for one night to allow a crack in one of the support hangers to be repaired. On 23 May 2012, the London 2012 Olympic Torch relay crossed over the bridge, where two of the torchbearers came together in a "kiss" to exchange the flame in the middle of Brunel's iconic landmark. The bridge carries four million vehicles per year, along part of

3397-443: The chains, vertical suspension rods were hung from the links in the chains and large girders hung from these. The girders on either side then support the deck, which is 3 feet (0.91 m) higher at the Clifton end than at Leigh Woods so that it gives the impression of being horizontal. The strength of the structure was tested by spreading 500 tons of stone over the bridge. This caused it to sag by 7 inches (180 mm), but within

3476-470: The collapse, a strong indication that a suspension chain had broken — since neither tower could stand upright without the support of intact chains. (The towers themselves showed no sign of failure.) And the fact that both fell eastward (toward the West Virginia side) clearly indicated a chain break occurring somewhere west of the tower on the western side (i.e., Ohio side) of the bridge. (By contrast,

3555-411: The construction. Despite this Brunel produced a new proposal costing £10,000 less than Telford's design and gained support for it in the local press. James Meadows Rendel, William Armstrong and William Hill also submitted new, cheaper proposals, complaining that the committee had not set a budget. In 1831 a second competition was held, with new judges including Davies Gilbert and John Seaward examining

3634-718: The deaths of three drivers. In 2007, the I-35W Mississippi River bridge disaster in Minneapolis , Minnesota, resulted in 13 deaths. In early September 2009, the failure of an eyebar in the San Francisco–Oakland Bay Bridge was discovered during a scheduled closure, resulting in an emergency repair to reinforce the failed member. A memorial was installed in Point Pleasant to commemorate the 46 bridge-collapse victims. A scale model of

3713-564: The engineering qualities of the proposals. Thirteen designs were submitted; Telford's was the only one in which the chains achieved the weight per square inch required by the judges but it was rejected as being too expensive. The winner was declared to be a design by Smith and Hawkes of the Eagle Foundry in Birmingham. Brunel had a personal meeting with Gilbert and persuaded him to change the decision. The committee then declared Brunel

3792-409: The entire structure was inevitable since all parts of a suspension bridge are in equilibrium with one another. The damage to the link would have been difficult to see during inspection of the bridge: Inspection prior to construction would not have been able to notice the tiny crack ... the only way to detect the fracture would have been to disassemble the eye-bar. The technology used for inspection at

3871-517: The expected tolerances. During this time a tunnel was driven through the rocks on the Leigh Woods side beneath the bridge to carry the Bristol Port Railway to Avonmouth . The construction work was completed in 1864–111 years after a bridge at the site was first planned. On 8 December 1864, the bridge was lit by a combination of four electric arc lamps , magnesium flares and limelights for its ceremonial opening ceremony. This

3950-458: The federal government; rather it is an organization of the states themselves. Policies of AASHTO are not federal laws or policies, but rather are ways to coordinate state laws and policies in the field of transportation. The American Association of State Highway Officials (AASHO) was founded on December 12, 1914. Its name was changed to American Association of State Highway and Transportation Officials on November 13, 1973. The name change reflects

4029-534: The first modern bungee jumps were made from the bridge by members of the University of Oxford Dangerous Sports Club . In 2003 and 2004, the weight of crowds travelling to and from the Ashton Court Festival and Bristol International Balloon Fiesta put such great strain on the bridge that it was decided to close the bridge to all motor traffic and pedestrians during the events. The closure of

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4108-549: The gorge. A contract was placed with Dowlais Ironworks to supply 600 tons of bar iron, which was to be transported to the Copperhouse foundry to be forged into bar chains. By 1843 funds were exhausted and another £30,000 was needed. As the work had exceeded the time limit stated in the act, all work stopped. Brunel suggested building a deep water pier at Portbury , which would make the bridge an essential road link, but funds for this scheme were not forthcoming. In 1851,

4187-550: The ironwork was sold and used to build the Brunel-designed Royal Albert Bridge on the railway between Plymouth and Saltash . The towers remained and during the 1850s intrepid passengers could cross the gorge in a basket slung from the iron bar. Brunel died in 1859, without seeing the completion of the bridge. His colleagues in the Institution of Civil Engineers felt that completion of

4266-405: The maximum "live" load it was designed to handle when the collapse began. The bridge failure was due to a defect in a single link, known as eyebar 330, on the north of the Ohio subsidiary chain, the first link below the top of the Ohio tower. A small crack was formed through fretting wear at the bearing, and grew through internal corrosion, a problem known as stress corrosion cracking . The crack

4345-557: The older bridges to remain in service, but with tighter weight restrictions. Most heavily used bridges of this type have been replaced with bridges of more modern design. The collapse inspired legislation to ensure that older bridges were regularly inspected and maintained; however, aging infrastructure is still a problem in the United States. In 1983, the Mianus River Bridge in Greenwich, Connecticut , collapsed, causing

4424-401: The operation of the bridge. They paid £50 each year to the trustees who gradually purchased the shares in the company. The revenues from tolls were minimal initially as there was not much traffic; however, this increased after 1920 with greater car ownership. In 1949 the trustees purchased all the outstanding shares and debentures. The bridge is managed by a charitable trust, originally formed by

4503-555: The original Silver Bridge was on display at the Point Pleasant River Museum. An archive of literature about the bridge was also kept there for public inspection. On the lower ground floor, the museum displayed an eyebar assembly from the original bridge. The museum closed on July 1, 2018, due to significant fire damage. The future of the Silver Bridge exhibit is not known. https://www.pprivermuseum.com/ Another eyebar example has been erected for public viewing at

4582-463: The possibility that the failure of one bar would not have led to disaster." By comparison, the Brooklyn Bridge used suspension cables made up of thousands of individual wires each to provide the cables a relatively high safety factor of six. Such a cable also has an extremely high level of redundancy, with the failure of a single wire having almost no effect on its overall strength. During

4661-426: The required strength to support the bridge (earlier such bridges often used four or more eyebars per link). However, with only two eyebars per link, the failure of one of them would hugely increase the loading on the other, making failure of a suspension chain — and the collapse of the entire bridge — far more likely. Accident investigators found that "[h]ad there been three or more eyebars per link, there would have been

4740-424: The second Reform Bill , which aimed to eliminate some of the rotten boroughs and give parliamentary seats to Britain's fast growing industrial towns such as Bristol. Five to six hundred young men were involved in the riots and Brunel was sworn in as a special constable . The riots severely dented commercial confidence in Bristol; subscriptions to the bridge company ceased, and along with it, further construction of

4819-468: The size and technology of these revisions was so great that the credit for its design should go to Barlow and Hawkshaw. The towers remained in rough stone, rather than being finished in the Egyptian style. Work on the bridge was restarted in 1862. Initially a temporary bridge was created by pulling ropes across the gorge and making a footway of wire ropes with wood planks held together with iron hoops. This

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4898-751: The structural design of roads. Much of AASHTO's current research is performed by the National Cooperative Highway Research Program (NCHRP) which is administered by the Transportation Research Board (TRB), a division of the National Academy of Sciences, Engineering, and Medicine . AASHTO re:source, formerly the AASHTO Materials Reference Laboratory (AMRL), accredits laboratories. Accreditation

4977-506: The time of the Silver Bridge construction, eyebar bridges had been built for about 100 years. Such bridges had usually been constructed from redundant bar links, using rows of four to six bars, sometimes using several such chains in parallel. An example can be seen in the Clifton Suspension Bridge , designed by Isambard Kingdom Brunel having chain eyebars that are redundant in two dimensions; this early suspension bridge

5056-404: The time was not capable of detecting such cracks. The collapse focused much-needed attention on the condition of older bridges, leading to intensified inspection protocols and numerous eventual replacements. There were only two bridges built to a similar design, one upstream at St. Marys, West Virginia , and the notably longer Hercílio Luz Bridge at Florianópolis , Brazil . The St. Marys bridge

5135-456: The upkeep of the bridge. The French Revolutionary Wars broke out soon after the design was published, affecting trade and commerce, so the plans were shelved. In 1811 Sarah Guppy patented a design for a suspension bridge across the gorge but this was never realised and was not submitted to the later competition. By 1829, Vick's bequest had reached £8,000, but it was estimated that a stone bridge would cost over ten times that. A competition

5214-640: The venue for significant cultural events such as the first modern bungee jump in 1979, the last Concorde flight in 2003 which flew over the bridge, and a handover of the Olympic Torch relay in 2012. It is unknown when the first bridge was constructed across the Avon in Bristol, but the first stone bridge, Bristol Bridge , was built in the 13th century. It had houses with shopfronts built on it to pay for its maintenance. A 17th-century illustration shows that these bridge houses were five storeys high, including

5293-408: The winner and he was awarded a contract as project engineer. The winning design was for a suspension bridge with fashionably Egyptian -influenced towers. In 2010, newly discovered letters and documents revealed that, in producing his design, Brunel had not taken advice from his father, Sir Marc Isambard Brunel , who had offered to help. The elder Brunel had recommended including a central support for

5372-472: Was announced that the bridge had received £595,000 of funding from the Heritage Lottery Fund to improve the visitor centre. The University of Bristol Special Collections holds substantial records related to the bridge. Letter books of the trustees of Clifton Suspension Bridge dated 1831–1862 are held at Bristol Archives (Ref. 12167/42-44) ( online catalogue ). Although similar in size

5451-607: Was built in 1769 and 1776. Resentment at the tolls exacted to cross the new bridge occasioned the Bristol Bridge Riot of 1793. Other crossings were considered, but were restricted by Admiralty rules that stipulated that any bridge had to be at least 100 feet (30 m) above the water to allow the passage of tall-masted warships to Bristol Harbour . To achieve this, any bridge constructed between Bristol Bridge and Avon Gorge, from Hotwells to Ashton Gate , would require massive embankments and viaducts. The alternative

5530-534: Was built to a higher safety factor than the West Virginia bridge and had greater redundancy, with each suspension chain using an array of four eyebars per link, compared to just two per link for the Silver Bridge. But in 1991, the Florianópolis bridge was closed due to high levels of corrosion. Following extensive renovation, it reopened in December 2019. Modern non-destructive testing methods allow some of

5609-483: Was discovered that this was not a solid structure but contained 12 vaulted chambers up to 35 feet (11 m) high, linked by shafts and tunnels. Roller-mounted "saddles" at the top of each tower allow movement of the chains when loads pass over the bridge. Though their total travel is minuscule, their ability to absorb forces created by chain deflection prevents damage to both tower and chain. The bridge has three independent wrought iron chains per side, from which

5688-556: Was held to find a design for the bridge with a prize of 100 guineas . Entries were received from 22 designers, including Samuel Brown , James Meadows Rendel , William Tierney Clark and William Hazledine . Several were for stone bridges and had estimated costs of between £30,000 and £93,000. Brunel submitted four entries. The judging committee rejected 17 of the 22 plans submitted, on the grounds of appearance or cost. They then called in Scottish civil engineer Thomas Telford to make

5767-400: Was immediately closed to traffic and was demolished by the state in 1971. (A small truss bridge remained to allow access to an island in the river.) The Hi Carpenter Memorial Bridge was later built to replace the demolished bridge. The Hercílio Luz Bridge remained in active service until 1991. Although both it and the Silver Bridge used the same type of high-strength steel for the eyebars, it

5846-528: Was in Gloucestershire , outside the City of Bristol, until the 1830s) and Leigh Woods in Somerset. Although there was little development in the area before the late 18th century, as Bristol became more prosperous, Clifton became fashionable and more wealthy merchants moved to the area. In 1793 William Bridges published plans for a stone arch with abutments containing factories, which would pay for

5925-413: Was only about 0.1 inches (2.5 mm) deep when the link failed, breaking in a brittle fashion. When the lower side of the eyebar failed, all the load was transferred to the other side of the eyebar, which then failed by ductile overload . The joint was then held together only by three eyebars, and another slipped off the pin at the center of the bearing, so the chain was completely severed. A collapse of

6004-484: Was renewed in 2009. The weight of the bridge, including chains, rods, girders and deck is approximately 1,500 tons. Two men were killed during the construction of the bridge. In 1885, a 22-year-old woman named Sarah Ann Henley survived a suicide attempt off the bridge when her billowing skirts acted as a parachute and she landed in the thick mud banks of the tidal River Avon at low tide; she subsequently lived into her eighties. The Clifton Suspension Bridge

6083-512: Was the earliest use of external electric lighting in Bristol. However, the lighting levels were inconsistent and the magnesium lamps were blown out by the wind. The custom of lighting the bridge has continued with more recent events, although later thousands of electric light bulbs were attached to the bridge instead of flares. In 1860 the Clifton Bridge Company was set up to oversee the final stages of completion and manage

6162-411: Was to build across the narrowest point of the Avon Gorge, well above the height required for shipping. In 1753 Bristolian merchant William Vick had left a bequest in his will of £ 1,000 (equivalent to £190,000 in 2023), invested with instructions that when the interest had accumulated to £10,000 ( £1,920,000 ), it should be used for the purpose of building a stone bridge between Clifton Down (which

6241-429: Was used by the workers to move a "traveller", consisting of a light frame on wheels, to transport each link individually, which would eventually make up the chains supporting the bridge. The chains are anchored in tapering tunnels, 25 metres (82 ft) long, on both sides of the bridge and plugs of Staffordshire blue brick infilled to prevent the chains being pulled out of the narrower tunnel mouth. After completion of

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