China News Service, Beijing, May 8 (Reporter Sun Zifa) A reporter learned from the China Earthquake Administration on the 8th that the Guangdong Earthquake Administration used a strong vibration monitoring system to analyze the "5.5" Humen Bridge vibration event. The preliminary results show that the main structure of the box girder of the Humen Bridge There was no obvious impact in this incident.
Schematic diagram of the location of the measuring point of the strong vibration monitoring system of the Humen Bridge. Photo courtesy of Guangdong Earthquake Administration
On the afternoon of May 5, obvious vibration occurred on the deck of the suspension bridge of Humen Bridge. Excessive amplitude of the deck affected driving comfort and traffic safety, and abnormal jitter occurred again that night. The strong vibration monitoring system deployed by the Guangdong Provincial Earthquake Administration on the Humen Bridge completely recorded the changes in the acceleration value of the bridge during this vibration event. The bureau then quickly organized relevant units in the industry to collate the observation data of the strong vibration monitoring system, and carried out analysis and assessment of the seismic safety and health status of the bridge from three aspects of acceleration, displacement and structural spectrum.
Observation data of the strong vibration monitoring system shows that from 13:00 on that day, the vertical acceleration and displacement monitoring data of the box girder of the bridge have changed significantly, reaching about 2-6 times the daily vibration amplitude, and the maximum vertical displacement reaches 44.61 cm. After 19 o'clock on the same day, the vibration was significantly reduced. From the change of the acceleration power spectrum, the main natural vibration frequency of the bridge box girder structure did not change significantly before and after the event. During the event, the vibration energy was mainly concentrated at 0.362 hertz (Hz). Preliminary analysis results show that the main structure of the bridge box girder has not been significantly affected by this vibration event.
The strong vibration monitoring system has been applied to 14 key projects. Photo courtesy of Guangdong Earthquake Administration
It is understood that the Humen Bridge Strong Vibration Monitoring System is a unit of the Guangdong Seismological Bureau commissioned by Guangdong Humen Bridge Co., Ltd. It was completed in 2010 and has 17 measurement points and 36 channels. The key part. The strong vibration monitoring system is equipped with a self-developed major engineering earthquake safety monitoring and evaluation software system, which can realize real-time alarms for earthquakes, impacts, vibrations and other emergencies, and quickly judge the health status of the bridge structure operation, serving the seismic research of major projects, After the earthquake (vibration) rapid assessment and routine maintenance and reinforcement. At present, the strong vibration monitoring system has been demonstrated in 14 major projects including the Hong Kong-Zhuhai-Macao Bridge, Humen Bridge, Xinfengjiang Reservoir Dam, Shenzhen Diwang Building, etc. (Finish)