Chongqing Egongyan rail bridge suspension rod fracture, what is the cause, can the bridge still operate?

2022-05-16 0 By

On January 19, 2022, Chongqing Rail Transit (Group) Co., Ltd. issued a statement saying that a sling lug screw on The Egongyan Rail Bridge broke on January 18. Chongqin Rail Transit will immediately launch an emergency plan and temporarily suspend the use of the Egongyan rail Bridge.So what exactly caused the boom to break?Is it possible that it was man-made?Will the rail bridge continue to operate in the future?Why did the boom break?Construction of the 1,650.5-meter-long Ergongyan Rail Bridge began in 2014 and began in July 2019. It is just 45 meters apart from the 1,650.5-meter-long Ergongyan Yangtze River Bridge.Although there are twin brothers, but there are obvious differences between the two Bridges, the Egongyan rail bridge is the subway train running bridge, the bridge deck is narrower, and the Egongyan Yangtze River bridge is wider, mainly for vehicles, the two are chongqing jiulongpo district and the nanan district of the two important connecting Bridges.Maybe many people don’t know is that male goose YanChangJiang bridge is began to open to traffic in 2000, it has been nearly 11 years, during the period of almost no anything related to quality problems, can the goose and rock bridge orbit, from started to now only less than 3 years, has been the boom fracture events, the occurrence of the incident,As a result, some sections of chongqing’s subway line were frozen and could not be used.This raises the question of whether the construction company may have cut corners when building the bridge and caused the boom to break.After the boom fracture, relevant researchers quickly threw themselves into the investigation of the cause of the event. After the investigation, some researchers came to the conclusion that the boom fracture is likely to be brittle fatigue failure. What is brittle fatigue failure?For example, a person’s physical quality itself is not very good, but also stay up late for a long time, eventually leading to physical problems, the possibility of sudden death, that is, internal defects, and then a series of external factors caused by the final consequences.The boom breaks for a similar reason.The reason for the defects of the boom is probably from these two aspects;The first aspect is likely to be the material problem, we can see from the fracture of a transverse of derrick, some place is relatively smooth, give a person a kind of very early without adhesion together feeling, this is on behalf of the derrick before fracture, the smooth part without any struggle and resistance performance, in plain English, that is, material defects, itself is injured,And then through the cumulative destruction, eventually lead to collapse.Another aspect is the installation Angle of the boom. As can be seen from the fracture diagram, the boom and the boom are not on the same vertical plane, which leads to the unbalanced force of the boom and the boom, resulting in some secondary stresses.Relevant professionals have studied the similar suspension bridge in the United States – the Golden Gate Bridge, found that the bridge from the completion and use of almost 80 years now, basically did not happen similar fracture events.The main reason is that the bridge is in addition to allow bridge longitudinal shake, lateral also allows for the bridge, and the goose and rock bridge allows only longitudinal shake orbit, which is the bridge to hold, but it is such a configuration, lead to the shear force produced by the bridge can’t ease away, make originally is not vertical opposite derrick is abruptly broken.However, from the beginning of the operation of the bridge to the occurrence of boom fracture, it is only about two and a half years, the adaptability of the boom can not be so poor, so some people think that it is largely the problem of the material itself.Can the Egongyan Bridge still operate?In fact, just broke a suspender, the impact on the bridge itself is not big, because the redundancy of suspension bridge is very strong, after a suspender fracture, it failed to bear the force will be apportioned to other suspender, but there are hundreds of suspender ah on a suspension bridge.And chongqing jiaotong university institute of civil engineering of the bridge engineering department shui-xing zhou, who after seeing the scene multi-angle photographs to surging news said, screw fracture should be material and the relationship between stress, may just need to change the screw, he also said that such a problem, need to other boom also to conduct a comprehensive inspection, lest appear such problem again.So now we just need to wait for the replacement of the screw by The Chongqing Rail Transit Group, make sure there are no other problems with the bridge and issue a statement before the Bridge can continue to be used.Goose and rock rail bridge will therefore leave hidden trouble maybe derrick fracture, some people will have psychological shadow, after all, a bridge after your problems there is a place, is likely to leave the bridge some pitfalls, like attached to tendons, bone fracture, a sling other sling may also because of under pressure overload, and bring about later also other sling fracture.If the subway you were riding on suddenly collapses due to the quality of the bridge, you could lose your precious life.In fact, we can rest assured that the bridge is the use of construction cableway traction new technology, as well as China’s first aerial cableway aerial lifting installation of steel box girder and its construction control new technology, and set up about 200 tons of damping device on the bridge.In addition, the construction company adopts the technical scheme of “cable-pull first and suspension cable after suspension”. The construction difficulty and technical level are quite high. For the construction of such a bridge, the technical personnel will do the utmost control and take all the existing possibilities into account, so as to do a good job in all aspects of the problem response measures.Although the boom broke this time, bridge expert Zhou Shuixing has said that the impact on the bridge is not significant.The main reason for this is that the suspension Bridges like Egongyan use bolts made of round steel with strong tensile strength. Relevant data show that the bearing capacity of the bolts made of round steel can reach an astonishing 1,500 tons or so.Even if this weight is exceeded, the screw will not break immediately, but will be stretched evenly and gradually thin due to the force.Moreover, in order to ensure the quality of suspension Bridges, generally when suspension Bridges are being built, the bearing capacity of suspension cables is far greater than the weight of the bridge, so as to avoid the failure of one suspender resulting in the failure of other suspenders and the eventual collapse of the bridge, because the loss caused by this is that no one can afford.The hundreds of screws of the Egongyan Rail Bridge are all made of such round steel. That is to say, once problems occur, the rest of the screws will share the force equally, but they will not be affected and therefore leave hidden dangers, so we do not have to worry too much.Put forward some Suggestions to strengthen efforts to detect the fracture from the boom in the picture can be seen in the smooth part, this boom is hidden trouble should have a certain amount of time, can bridge is responsible for personnel discovered the problem after the break, it is proved that our testing strength is not strong, hope to strengthen survey, to ensure that the goose and the safety of the rock bridge.2. Reduce the shear stress although only allows longitudinal shake to better fixed Bridges, thus increasing the driving stability of vehicles, but have to say, in order to prolong the service life of the bridge, we can draw lessons from the way the construction of the golden gate bridge, allow lateral sway, thus reducing the shear strength of suspension Bridges, avoid boom be broken.Conclusion: Egongyan rail Bridge is an important part of chongqing’s traffic circle. Its position in chongqing’s Bridges has long been self-evident. Although one suspender is broken, the other suspender is still in operation.And the bridge construction company has been timely in dealing with the relevant problems, a comprehensive inspection of the bridge, I believe that after all the problems are resolved, the bridge can continue to operate.