China News Service, May 15th. According to the "Guangdong Transportation" WeChat public account, Guangdong Transportation Group announced that the Humen Bridge will resume traffic at 9:00 on May 15th.
On the afternoon of May 5, the suspension bridge of the Humen Bridge experienced significant vertical bending vibration, the bridge management quickly launched an emergency plan, and the joint traffic police department took two-way traffic control measures in a timely manner.
On the morning of May 6, the expert working group of the Ministry of Transport went to the Humen Bridge on-site for guidance in time. The Guangdong Provincial Department of Transportation and the Provincial Communications Group have successively invited well-known domestic experts to review the comprehensive inspection, detection and safety assessment report of the suspension bridge, analyze and judge the causes of vibration, and discuss the vibration suppression plan.
The bridge manager immediately organized the design, inspection, construction and other units to conduct a comprehensive inspection, detection and safety assessment of the suspension bridge, commissioned three universities to carry out wind resistance research in parallel, and the design unit took the lead to work with the inspection, three universities, construction and other units on the suspension bridge. In-depth analysis of vibration causes, research and demonstration of vibration suppression measures.
The inspection unit integrated the past three years and the inspection and monitoring data issued an evaluation report on the structural safety of the suspension bridge of Humen Bridge. The evaluation showed that the technical status and bearing performance of the bridge structure remained stable. The vibration did not affect the structural safety. , Slings, main cable saddles, loose cable saddles, supports, expansion joints, etc. were not found abnormal. After a careful review, the invited expert group believes that the testing and monitoring items are complete, the methods are reasonable and standardized, and the data are credible. The evaluation conclusions of the testing unit and the design unit are agreed. The suspension bridge structure of the Humen Bridge is safe.
The invited expert group carefully reviewed the analysis of the vibration reasons and the vibration suppression measures of the submitted suspension bridge, and believed that the vibration causes were basically identified: The Humen Bridge is a long-span steel box girder suspension bridge, which is a typical flexible structure and is continuously installed along the side fences of the bridge. The water horse has changed the aerodynamic shape of the steel box girder, and under certain wind conditions, it induces vertical vortex-induced resonance of the suspension bridge; vortex vibration that lasts for a long time and has a large amplitude causes the bridge structure damping to decrease, even if the water horse is removed, Under certain wind conditions, vortex vibration occurred again on the no-load bridge.
According to the research results and the recommendations of the expert group, the management of the bridge took timely measures to suppress vibration, which mainly included installing dampers on the outer guardrail, improving the aerodynamic shape of the steel box girder, adding water tank weight and increasing the damping ratio. At present, the overall condition of the suspension bridge of Humen Bridge is stable and the vibration suppression effect is good.
On the evening of May 13, at the Humen Bridge Suspension Bridge Restoration Traffic Evaluation Meeting, the invited expert group believed that the Humen Bridge Suspension Bridge is structurally safe and the bridge management has taken vibration suppression measures and implemented the preparations before restoring traffic and agreed to resume traffic operations .