Yangmingtan Bridge Case Study Solution
1.1. The construction of the bridge
Yangmingtan Bridge was a major construction project of the Heilongjiang province. It is the longest river suspension bridge in the north of the Changjiang River in China, so the government gave it great attention. It breaking ground on 2009 December 5th and completed at a marvelous speed and opened to traffic on November 6th, 2011, with an estimated investment of 1.882 billion Yuan (about 300 million dollars) .
Considering the traffic around the bridge would increase, during the construction of the bridge, a synchronous traffic control project also started working, which became part of the bridge system. According to the news from government website of Harbin Construction Network …show more content…
On August 24, 2012, at around 5 o`clock in the morning, four trucks loaded with construction materials such as rocks and sand were driving on a section of the approach bridge of the Yangmingtan Bridge when the span collapsed. The collapsed girder was about 120 meters long and it was an overall collapse. Four trucks fall down with the deck, which caused 3 died and 5 injured . In the photos of the scene, we can see the deck was unbroken and there were almost no damage on bridge …show more content…
Consider these reasons, Chinese truck drivers always choose to take more cargo than legal provisions. So when designers design the bridge, this situation should definitely take into consideration. However, in this case, even if the design load was double the standard, it could make no difference because the trucks were overweight too much.
Eccentric load problem and overweight
The four trucks were totally more than 400t (for three of them were around 120t each and the fourth truck were about 50t) and the length of span was 120 meters. So the average load was more than 3t per meter, much bigger than the standard (1t per meter) above. According to the law of moment balance, and consider the parameter of the bridge, we can calculate the force and bending moment of each support