Experts Analyse the Rollover Accident of Wuxi Viaduct: Overload Accident is not Solution-free

 Experts Analyse the Rollover Accident of Wuxi Viaduct: Overload Accident is not Solution-free

On October 11, 2019, the site of the rollover accident of Wuxi viaduct in Jiangsu Province was being cleaned up. Visual Chinese Map

On the night of October 10, the bridge deck overturned at k135 of 312 National Road and Xigang road in Wuxi City, Jiangsu Province.

According to the official Weibo of Wuxi Municipal Government, there are three cars under the bridge and five cars on the bridge deck, including three cars and two trucks.

Up to the time of press release, the accident resulted in three deaths and two injuries.

Preliminary determination that the accident was caused by overload

Peng Weibing, a professor at Zhejiang University of Technology, and Dai Fei, an associate professor at West Virginia University, conducted a finite element analysis based on online public information, as well as photographs and videos of debris at the site of the collapse.

The team believes that the bridge accident can be initially identified as a serious overload and unbalanced load caused by overturning damage to the bridge.

Wuxi Accident Rescue Command also affirmed that the overturning of the overpass bridge is caused by the overloading of transport vehicles.

Some experts said that the accident was not caused by a single vehicle overload. Several overloaded trucks passed successively, causing the single-column pier deck to move like a seesaw and eventually roll over.

Zhang Qiwei, Professor of Bridge Engineering Department of Tongji University, told the Chinese Science Journal that according to the current design standards of highway bridges in China, the load level of the first-class highway vehicles is highway-I, which is equivalent to a 55-ton multi-axle vehicle plus several 20-ton vehicles in a fleet, and the vehicle spacing is more than 10 meters.

According to the on-site information, the truck carrying at least five 28 tons of cylindrical steel coils, plus the vehicle weight, the total weight of the truck and goods is more than 150 tons, that is to say, more than twice the maximum allowed by the industry standards.

Severely overloaded vehicles greatly exceed the design calculation load, especially when the overloaded vehicles walk in the side lane, they will produce a great overturning moment. If the overturning capacity of single pier bridge exceeds, it may lead to the overturning of the bridge. Zhang Qiwei said.

Overload will not cure, and there will be endless aftermath

According to incomplete statistics, at least 17 bridge collapses in China in the 12 years since 2000 have been attributed to truck overload.

Since 2010, there have been many accidents, such as the Shangyu Spring Hui Bridge accident in Zhejiang Province in 2011, the Qunli Viaduct accident in Harbin Third Ring Road in Heilongjiang Province in 2012, and the ramp bridge of Gansu-Guangdong Expressway in Heyuan, Guangdong Province in 2015.

Among them, on August 24, 2012, in the accident of Qunli Viaduct on the Third Ring Road, four overloaded trucks were driving on the outer side of the ramp of Honghu Road at the same time, which resulted in the side slip of the continuous steel composite beam of the bridge and the rollover of four trucks, resulting in three deaths and five injuries.

After the Gan-Yue Bridge accident in 2015, the Ministry of Transport and Communications issued documents to the provincial and municipal governments and issued a number of measures to further strengthen the control of illegal overloading of highways, strengthen the management of highway and bridge construction and maintenance.

However, the occurrence of the Wuxi accident shows that the hidden danger of bridge collapse caused by serious overloading has not been eradicated in China.

Overloading will lead to endless consequences! exclaimed some traffic experts who did not want to be named. The relevant departments should be called upon to study the incorporation of illegal overloading and transportation into the criminal law as soon as possible and start the legislative process.

Road administration alone is difficult to eradicate

Zhang Qiwei introduced that the Highway Management Regulations for Over-limit Transportation Vehicles, implemented by the Ministry of Communications in 2016, clearly stipulated the types, loads and driving requirements of over-limit vehicles, as well as the penalties for violations. When using over-limit vehicles for transportation, large pieces of transportation applications should be submitted to the highway management agencies. Within the permitted lanes, driving at the prescribed distances and speeds should be carried out.

Peng Weibing and others believe that from the perspective of urban management, the real-time monitoring and management of overloaded and overloaded vehicles should be further strengthened in the future.

In addition to strengthening the management of overloaded vehicles, in bridge design, improving the design calculation to make the bridge body more solid, is also a way to reduce bridge safety accidents. Peng Weibing and other suggestions need to further improve the anti-overturning calculation method of curved girder bridge; in addition, in the case of unpredictable load, the ultimate failure mode of structure (bridge) should be controlled in design to avoid overturning failure (brittle failure) occurring before strength ductile failure.

Although the state has large-scale transport regulations, illegal overloading still occurs frequently, and underground refitting factories still exist, which shows that it is difficult to eradicate the problem by road administration alone, and needs coordination of road administration, transportation, vehicle management and other departments in order to solve the problem. Zhang Qiwei was outspoken.

To solve the safety accidents caused by illegal overloading involves a broad consensus and cooperation of the whole society. It requires not only the bridge design and construction units to improve the safety indicators of the bridge, the supervision and management departments to strengthen the governance and improve the management efficiency, but also the transport owners to enhance safety awareness, avoid luck and stop illegal overloading transportation.

I hope this kind of accident will be eradicated as soon as possible in our country and provide a safe driving environment for road users.