Experts talk about suspension bridges: as long as the wind does not exceed the design range, safety need not worry
On the afternoon of May 5, the suspension of the Guangdong Humen Bridge's suspension bridge surface was relatively large, and the amplitude was relatively obvious, which caused discomfort to driving. To ensure traffic safety, the traffic police department has adopted traffic control measures to fully close the two-way traffic of the suspension bridge.
More than Humen Bridge. On April 26, Wuhan Parrot Island Yangtze River Bridge's bridge body waved like waves; in September 2013, the Hangzhou Bay Cross-sea Bridge also experienced bridge body shake ...
What are the advantages of suspension bridges? Will the sway of the bridge affect safety? Science and Technology Daily reporter interviewed Zhou Jiang, chief engineer of China Railway Siju Group Municipal Engineering Co., Ltd. on the 5th.
Zhou Jiang believes that the suspension bridge is a type of bridge whose main cable is the main load-bearing structure, and the stiffening beam is “hanged” on the main cable by a sling. Because the stiffening beams are hung by many slings at a certain interval, the bending moment they bear will not increase due to the increase of the span, that is, the span restricts the stiffening beams much better than other bridge types, so the suspension bridge is capable of spanning The largest bridge type.
He talked about the visual effects of suspension bridges being softer than arch bridges, cable-stayed bridges and beam bridges. Its ability to resist wind vibration mainly depends on the cross-sectional form and lateral rigidity of the beam. The cross-sectional form of the beam refers to the formation of a good streamline shape (such as a flat steel box beam with an air nozzle) or a ventilation coefficient (such as a steel truss beam), lateral rigidity to the gravity of the stiffening beam, cross-sectional characteristics, and sling spacing. The ability to resist crosswinds.
"Suspension bridge is a kind of super statically indeterminate structure, there are many factors that affect the ability to resist wind and vibration." Zhou Jiang believes that the modern suspension bridge of wind resistance design specifications, as long as the wind does not exceed the design allowable range, its structural safety is not to worry about .
At the same time, he also mentioned that swaying occurred, although the bridge structure is safe, but the driving may be affected, so it should be temporarily closed for testing to ensure safety.
According to the bridge professionals of Humen Bridge, it is normal for the bridge to sway under special wind conditions. Generally, the swaying of the bridge deck is relatively large.
Our reporter Long Yuemei Ye Qing