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The coal-burning factories and locomotives, and automotive pollution provided many airborne chemicals that could attack steel. A truck driver and teenage girl are killed when suspension cables snap on a French bridge, with prosecutors saying the deadly collapse was apparently caused by … The cause of the fatigue stress was the cycling loading applied on the bridge over the four decades. A few hours after the collapse, the St. Mary’s Bridge was closed for safety as its design was similar to that of the Point Pleasant Bridge. This finding had significance, considering the extreme temperature changes in the region. On 15th December 1967, the Point Pleasant Bridge collapsed due to heavy traffic on the bridge. Once all the survivors had been rescued, and vehicles had been recovered, the operations shifted towards the removal of the collapsed structure. Login to The Constructor to ask questions, answer people’s questions, write articles & connect with other people. This analysis took into consideration static and dynamic loads. The length of the Point Pleasant Bridge was 681 m. The Point Pleasant Bridge was constructed at the cost of USD 1.2 million. On 15 th December 1967, the Point Pleasant Bridge collapsed due to heavy traffic on the bridge. Following this incident, the U.S. government brought several new reforms to check the functionality and safety of bridges across the nation. The composition of the atmosphere also played a critical role in the state of the steel. The two predominant factors were the application of tensile stress and the attack of pollutants on the steel. HONG KONG // Hong Kong authorities said they had launched an investigation after an air bridge collapsed at the city's airport, ripping the door off a Cathay Pacific plane and injuring a technician. The tensile stress came from traffic loads and thermal effects. The first factor was the use of higher-strength steel, which is more brittle than the mild steel typically used for structural steel and reinforced concrete construction. The exposed surface was thus left open to natural elements and created a built-in weakness. "No passengers or crew members were on the air bridge at the time. VIP members get additional benefits. Sorry, you do not have permission to ask a question, You must login to ask question. The study of high-strength steel in the environment determined that the combination of stress corrosion (due to tensile stress in a corrosive environment) and fatigue corrosion (induced by the oscillation of loading in the corrosive environment) led to the propagation of the crack in the eyebar and caused the failure of the eyebar and ultimately caused the collapse of the bridge. Beyond The Headlines: Memories of Mosul three years after ISIS, Beyond The Headlines: The UAE's tactic against food crisis, Beyond the Headlines: Iran's secret affair with Al Qaeda, Ethiopia's Abiy Ahmed – from Nobel Peace Prize to the brink of war. The National Bridge Inspection Standards were created in response to the collapse. Dozens fell off the edge, tumbling 45m to the ground below, resulting in 43 deaths. Eyebar chain greatly improved the bridge’s stiffness with less steel. Scour was eliminated because of the observations of the divers at the scene. The design was also evaluated, and the bridge did not provide any redundancy in the structural members that connected the suspension chain to the eyebars. 22nd August 2020 – (Hong Kong) At the Zhuhai Gongbei Port construction site, it is suspected that part of the pedestrian footbridge has collapsed, and Customs clearance services were once disrupted today. The design of the bridge was unique because it had high tension eyebar chains, rocker towers, and a unique anchorage system. The Point Pleasant Bridge was a suspension bridge. Key features of the Point Pleasant Bridge are described below: On a cold winter evening, the bridge suddenly collapsed due to the failure of the connection between the eyebar to the first joint on the north side of the bridge. Each bridge was to be inspected every two years. The reaction most prevalent to the cause of the collapse was found in the eyebar chains and pins. The system of inspection is broken down into a standard procedure. Towers of the bridge were supported on the rockers. Beyond The Headlines: How will Arab Americans vote in US presidential election. A 140-meter (459-foot) bridge has collapsed in northeast Taiwan, sending an oil tanker in the water and killing at least two people in fishing boats below. At least three fishing boats were crushed and a fuel truck plunged into the water. The bridge collapsed about 9:30 a.m. in Nanfangao, a tiny but often-crowded Pacific coast fishing village. This center works to identify inspection methods through the use of technology that includes laser measurement, monitoring systems, and ultrasonic tests. A different theory of the collapse found support in the metallurgical aspects of the eyebar chains and the consequence of both loading and the environment on the steel. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China. Collapse of the Tacoma Narrows Bridge. However, it was not large enough to allow engineers to inspect the connection. The system of the eyebar consisted of two force bar members with rounded eyes at each end; the anchorage system consisted of reinforced concrete troughs filled with concrete; the towers were constructed on octagon-shaped piles of reinforced concrete. Also, the overall redundancy of the structure was poor. 1. The connection at the eyebar was not redundant because it consisted of only two pairs of eyebars. Also, the company lacked technical justification for the use of low safety factors against ultimate and yielding strength. It first verified with the military that no airplanes had passed through the vicinity at the time of the collapse. The stress calculations that had been prepared for the design were verified for assurance that the bridge met the engineering criteria that were used at the time of construction. The bridge was designed using the deflection theory. A total of 46 people lost their lives due to this accident. In 1996, the FHA created the nondestructive evaluation center in McLean, Virginia. Comments ( 0 ) Top Stories In 1968, the U.S. federal government enacted a procedure for national bridge inspection. The bridge was constructed as a continuous truss between anchorages. This change of symmetry caused uneven loads across the suspension spans. A towering bridge over a bay in eastern Taiwan has collapsed sending an oil tanker truck falling onto boats in the water below. The traffic on the bridge was crawling. We are investigating the cause of the incident," a spokesman from the Hong Kong Airport Authority said. The U.S. Bureau of Standards noted the fracture pattern on the eyebar. Live loads produced by a heavy vehicle would cause the hole in the eyebar to be placed in tension. He said the technician's condition was stable. When around three big trucks and 72 cars came to a halt, the bridge began to sway wildly and ultimately collapsed. Donald Trump's final week in the White House - latest updates, UAE has struck balance between lives and livelihoods, top official says, Emir of Kuwait accepts government's resignation, Watch: Dubai vaccination centre set up in 72 hours to boost Covid-19 fight, Cybersecurity jobs boom in UAE with starting salaries of Dh40,000 or more, UAE vaccination doses near two million mark, Neom: Saudi Arabia's $500 billion ‘megacity of the future’, US sends more B-52 bombers to the Middle East, Huge archaeological find in Egypt includes 50 mummies and a temple, Oman closes land borders as coronavirus cases rise, Beyond the Headlines: how Egypt's #MeToo movement is changing the country. A second worker was found dead Thursday evening after a work platform collapsed earlier at the construction site of the Hong Kong-Zhuhai-Macau bridge. On the night of 6 th November, a strong storm blew in the river where Tacoma Narrows Bridge was located. The tests sought to establish the natural frequencies of the bridge and to determine the excitation created by heavy vehicle use. Please follow the instructions below to allow notifications to be sent from The National. Some travellers crossing the border had to walk across the construction site to bypass the section affected by the incident. All affected passengers had left Hong Kong by Monday morning on alternative flight arrangements, she added. Also, the designers did not consider the effect of unsymmetrical loading on fatigue. One feature considered to be potentially faulty was the substructure of the bridge. Since then, the design load has been increased to the heavier AASHTO HS-20. The other factor was the low temperature that on the day of the collapse, was near to freezing temperature. The importance of this standardization is to allow the accurate rating and comparison of the bridges in the inventory. No one thought that a small, exposed surface flaw included in the design could have caused the fatigue failure and, ultimately, the collapse of the bridge. It was wide enough to provide an air space for pollutants to attack the steel. These tests concluded that the live loads were not excessive and that the loading caused some vibrations in the individual members of the structure. The warning came as … The construction of the Point Pleasant Bridge was undertaken with the adoption of the latest technologies and new construction materials of the time. The oil tanker that was traversing the bridge at the time fell into the water and caused a fire when it struck three fishing boats that were below the bridge. The narrow gap between the eyebar and the connecting pin made the problem worse. When the first eyebar failed, the entire connection was rotated and got separated from the eyebar. Some of them are discussed below: The U.S. Army Ordnance Group ruled out the possibilities of explosions and impacts. The built-in flaw in the eyebar led to the sudden propagation of the crack when the fatigue stress exceeded its limit. Plagued by the collapse of travel amid the coronavirus pandemic, arrivals to Hong Kong plummeted nearly 94% year on … This failure caused the Ohio tower to fall and resulted in the collapse of the West Virginia tower. A total of six fishing workers from Indonesia and the Philippines were killed in the incident, which also left 12 … Read more.. This lack of consistency indicated that the eyebar had a more severe susceptibility to stress corrosion and hydrogen embrittlement in the harder section of the material. Beyond the Headlines: how will the US election play out? It was the holiday season and people were shuttling back and forth between the two cities via the bridge. The growth of the crack was most likely due to stress corrosion. A similar design was used earlier in the St. Mary Bridge in West Virginia, which is also located on the Ohio river. Less than a week ago, another bridge collapse, this time in Shenzhen, next door to Hong Kong injured 19 people, five seriously, the China Daily reported. If the piers shifted, the towers would be out of alignment, inducing a sag in the cables. The substructure of the bridge was lacking the structural redundancy. Other improvements to bridge management include nondestructive evaluation methods. The 41 … The cross-sections of the eyebar revealed a number of small cracks, about the size of pinholes. All Rights Reserved. HONG KONG // Hong Kong authorities said they had launched an investigation after an air bridge collapsed at the city's airport, ripping the door off a Cathay Pacific plane and injuring a technician. The linkage of the eyebar chains to the suspension cables by a pin created a section of the material that could not be protected by paint. Calculations showed a 3% loss of steel due to this degradation of material. Country Point Pleasant Bridge Disaster: Collapse of the Eyebar-Chain Suspension Bridge, Mackinac Bridge: Construction of the Most Aerodynamically Stable Suspension Bridge. A team assembled to look into the accident on the multibillion-dollar Hong Kong-Zhuhai-Macau bridge which killed two workers and injured three … This sag would change the load distribution throughout the structure. Inspection of the wreckage showed corrosion in many sections of the bridge. Terrifying moment massive bridge suddenly collapses in a Chinese city 'due to severe flooding', sending cars into a raging river. The construction of the bridge started in 1920 and completed in 1928. However, the steel used was of unusually high strength, and its properties were not well known. However, the check for the safety of the bridge could not be verified due to the limitation on advancements in bridge engineering. Thus, as soon as the tower toppled over, all the spans of the bridge collapsed because it was constructed as a continuous truss between anchorages. Double airbridge collapse at Hong Kong damages CX A330. A Cathay spokeswoman said its aircraft was "slightly damaged" but would not comment on whether the home carrier will seek compensation from the airport authorities. A higher, not lower, factor of safety should have been used for this bridge. Reduced factors of safety, 2 against ultimate strength and 1.5 against yielding, were used in the original bridge design. Tests showed that the eyebar pin connection was susceptible to pitting corrosion due to water, hydrogen sulfide, and salt. VIP members get additional benefits. The twitterverse is showing the damage done at Hong Kong airport in a double airbridge collapse early last night. Become VIP Member. The format categorizes the superstructure, the substructure, and the deck of the bridge into a set range of values. The experts investigated many possible causes of the collapse. The works related to the pier foundation were carried out by the general contracting company of Pittsburgh, and the superstructure was constructed by the American bridge company of Pittsburgh. Hong Kong-Zhuhai-Macao Bridge breakwater design scientific, reasonable and safe, says top gov’t official by Kris Cheng 10:59, 10 April 2018 22:01, 31 March 2020 Print Beyond the Headlines: will vaccines help us return to normal in 2021? This theory implied that the pin cap would become responsible for resisting the lateral forces within the connection. The next morning, the bridge authorities closed the bridge for traffic after noticing that the bridge was undergoing severe undulating motions. Rocker towers were hinged at the bases to accommodate thermal deformations. It was first conceived … This exceedance would cause the eyebar to detach from the pin, allowing the connection to rotate and thus cause the collapse. In Taiwan, a huge 140 meter (459 feet) bridge collapsed in October of 2019, the event is known as the “Taiwan Bridge Collapse”. Hong Kong's rule of law has been pushed to the "brink of total collapse" after more than five months of protests, police have warned. This limit contrasted with higher factors of safety, 2.75 and 1.75 respectively, for an alternate conventional suspension design. It's one year since part of a motorway bridge outside Genoa collapsed, as cars and lorries sped across it. Collapse of the Tacoma Narrows Bridge: A Case Study, Petra Jordan: A World Heritage Site Under Risk. Further, no testing methods were developed to measure the strength of large eyebar chains. 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And she's pledged some … What are the Installations Required in a Tunnel? The collapse prognosis of the bridge under a subsequent strong ground motion is then performed based on the updated model. Full story: Design features also indicated that the towers were protected from possible contact with a vehicle. Officials: Multiple Deaths After Bridge Collapse Associated Press. Testing showed that as the environmental temperatures decreased, the material was more susceptible to fracture. You will receive a link and will create a new password via email. Plagued by the collapse of travel amid the coronavirus pandemic, arrivals to Hong Kong plummeted nearly 94 per cent year on year in 2020 to just 3.57 … Beyond The Headlines: why superstorms are the new normal. Also, the bridge was not designed with a sufficient number of redundancies. Become VIP Member, Do you need to remove the ads? The Hong Kong–Zhuhai–Macau Bridge (HZMB) is a 55-kilometre (34 mi) bridge–tunnel system consisting of a series of three cable-stayed bridges, an undersea tunnel, and four artificial islands.It is both the longest sea crossing and the longest open-sea fixed link in the world. The center span broke and flipped over into the water below, carrying 64 people from the roadway. Three vehicles were caught in the bridge collapse, according to the prosecutor. They reported no holes around the piers or any signs of damage to the piers. The American bridge company didn’t make its calculations and test results public. Six people were missing after a bridge in Taiwan collapsed. After the collapse of the Point Pleasant bridge, the President of the United States created a task force on bridge safety. Please enter your email address. The stresses that occurred during the collapse were less than the maximum stresses identified in the design. Each joint contained two eyebars that connected to the suspension chains. The reassembly of the bridge showed evidence of a cleavage fracture in the eyebar on the Ohio side of the truss. The traffic on the bridge was crawling. The roof of Cellar Vall Llach, one of the leading wineries in Priorat, has collapsed due to heavy snows potentially destroying what remains of the 2018, 2019 and new 2020 vintages. After the vehicle passed, the connection would respond in compression to return to its original static dead load. To verify the fact that dynamic effects were not a factor leading to the collapse, vibration response, and dynamic stress amplification tests were performed on the St. Mary’s Bridge. The new procedure provided exact protocols to be followed, and inspectors were required to be evaluated and certified by the Federal Highway Administration (FHA). It was the second eyebar suspension bridge consisting of heat-treated eyebars, and a rocking base was constructed on the Ohio river. However, different opinions surfaced to justify the cause of this fracture. It was considered to be the most unique and cost-effective bridge. Hong Kong logs 3.57 million arrivals in 2020, lowest number on record. When the Point Pleasant Bridge was being constructed, the knowledge of long-term fatigue combined with the crevice corrosion was limited. It was also found that the eyebar was affected by the atmospheric conditions. There were two main contractors who were awarded the work. The loss of one element would lead to the collapse of the bridge. Beyond the Headlines: will Azerbaijan's victory in Nagorno-Karabakh lead to lasting peace? Point Pleasant Bridge, also known as Silver Bridge, was constructed over the Ohio River to provide the crossing for highway number-35 of the United States of America. This oscillation caused fatigue stress in the member and could, over time, lead to failure. One of these, it appeared, had grown into the 33 mm flaw that had initiated the fracture. This adjustment would cause a sliding friction to occur rather than a rolling friction. UP NEXT. The following points describe the key lessons from the failure of the Point Pleasant Bridge: A total of 46 people died due to the collapse of the Point Pleasant Bridge. It was possible for these forces to exceed the available resistance. This stress increase was considered in terms of an increased percentage of the original live loads. The evidence supporting failure by fatigue stress was based on changes in the live loads of the structure, which changed the orientation of the eyebars. Further examination of the eyebar showed a crack that had occurred during manufacturing. The suspending eyebar chain acted as the top chord of a variable-depth stiffening truss. TAIPEI: Taiwanese rescuers on Thursday (Oct 3) retrieved the body of the last missing person killed when a bridge collapsed two days ago, smashing onto fishing boats moored underneath. Beyond the Headlines: Stories from 2020 of Covid-19 and beyond. The vehicles removed from the wreckage were checked for explosives, and structural members were inspected for signs of damage due to explosives. The brittleness of the steel connection, and thus its susceptibility to sudden fracture, was enhanced by two factors. As the loads redistributed in the eyebar chain, the eyebar heads and the connecting pins would rotate. This shift could have been induced by sediments around the piers being washed away (known as scour), a deficiency in the foundation that would cause the anchors and piers to move, or an impact to the piers from a water vessel. The boarding bridge for a Cathay flight bound for Nagoya in Japan suddenly collapsed after all of the 262 passengers had boarded the aircraft last night, according to the Hong Kong Airport Authority and the airline. Before this law, bridges were not consistently inspected. When the bridge was designed, the loading was based on the American Association of State Highway and Transportation Officials (AASHTO) H-15 specifications for a 15-ton truck with 106 kN on the rear axle and 27 kN on the front axle. A technician who was trapped in the falling bridge at the time was injured. Its objectives were to identify the cause of the failure of the bridge, to figure out how to fund a new bridge in an efficient manner, and to define a system of standards that would ensure the safety of the bridges in the country. One opinion cited evidence for fatigue stress, whereas another one explained the cause as a combination of stress corrosion and corrosion fatigue. A sidewalk and a vehicle lane on the south side, instead of two vehicle lanes on the north end, caused this lack of symmetry. The hardness was not uniform throughout the thickness of the material. The bridge connected two major cities of Ohio and West Virginia, and provided direct access to their respective state capitals. These factors made the high-strength steel vulnerable to the propagation of cracks and reduced the time for these cracks to occur. It was the holiday season and people were shuttling back and forth between the two cities via the bridge. Studies were conducted to identify the influence of the environment on the material. However, there was no evidence that calculations were made for the correct dynamic loading. It was determined that the stress reversal was unique to a few eyebars because the vehicle lanes were not centered on the roadway. Bridge Collapses in Taiwan; Oil Truck Plunges Moments Away From Crossing Several fishing boat workers were among at least a dozen people injured when the bridge… Lost your password? The six-lane, Hong Kong-Zhuhai-Macau Bridge is 34 miles long and includes an underwater tunnel that goes for four miles. Plagued by the collapse of travel amid the coronavirus pandemic, arrivals to Hong Kong plummeted nearly 94 per cent year on year in 2020 to just 3.57 million, the lowest number on record for the once-mighty tourism hub.The provisional numbers, published by the Hong Kong Tourism Board on Friday, marked a precipitous drop from the 55.9 million people welcomed in 2019, a year in which … Beyond the Headlines: How will Joe Biden change US policy in the Middle East? The use of all rear bridges has been suspended for inspection, the official said, adding that passengers however would continue to board aircraft via the head bridges that are normally used by first class travellers. The eyebar would still be vulnerable to failure even if the resulting stress did not exceed the yield strength of the material. The rear bridge then smashed into the head bridge, which was connected to the first class cabin, ripping a door off the A330 aircraft. Sign Up to The Constructor to ask questions, answer questions, write articles, and connect with other people. Golden Gate Bridge: Construction of One of the Longest Suspension Bridges in the World, Chenab Bridge: Construction of the World’s Highest Rail Bridge, Austin Dam Failure: One of the Biggest Disasters in US History. © 2009-2020 The Constructor. Hong Kong leader Carrie Lam warned that what Hong Kong is experiencing now is actually worse than the 2008 global financial crisis. However, certain characteristics suggested the cause of the failure of the material. The Hong Kong – Zhuhai – Macao Bridge (HZMB) will be one of the longest cross-boundary sea- crossing road infrastructure in the world providing a direct land transport connection between two shores of the Pearl River Delta, linking Hong Kong in the east to Macao and Zhuhai in the west. The combination of uneven loading and changes in stress levels caused the pins to shift. This response was important because the Ohio River played a major role in the transportation of freight, and the wreckage prevented ships from navigating the waterway. Tests of different eyebars showed a consistent composition between the specimens, which indicated that the fractured eyebar was not unique. Stress concentration and fatigue can be a dangerous combination to cause the failure of a bridge. College of Civil Engineering, Fuzhou University, Fuzhou, China.

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