Vibration measurement of long-span floors in high-speed railway station

• Published in: Journal of Vibroengineering Vol. 20; no. 7; pp. 2705 - 2719
• Main Authors: Zhang, Zhiqiang, Ma, Fei, Zhang, Bill
• Format: Journal Article
• Language: English
• Published: 01.11.2018
• ISSN: 1392-8716; 2538-8460
• DOI: 10.21595/jve.2018.19841

High-speed rail stations have long-span floor structures stretching over rail tracks and platforms. These long-span floor structures are prone to vibration caused by large crowds. Current floor vibration design guidelines lack specific provisions addressing this type of structures. There is a need to study the crowd excitation and the vibration performance of the long-span floor structures. A field testing study was recently conducted in China’s newly constructed Xi’an North Railway Station, and results of the study is discussed in this paper. The output-only method was used for modal testing, where vertical accelerations were recorded at a grid of fifty locations on the floor panels and analyzed to obtain the natural frequencies, mode shapes, and damping ratios of structural vibration modes. Vibration measurements were taken and analyzed at a variety of load cases, which included operating cases at the floor sections in use to assess vibration performance of the floor structure, and several experimental cases at the floor sections not yet in use to investigate the effects of crowd size and walking and jumping frequency on floor vibration. It was found that under most operating conditions, the floor structural vibration didn’t exceed the commonly accepted design limits. Thus, the vibration control design of the floor structure is deemed satisfactory. Under certain coordinated crowd movements (e.g., walking and jumping at certain frequencies), resonance occurred, and vibration levels exceeded the threshold for acceptance. The crowd excitation frequency has a greater influence than the crowd size on floor vibration responses.