In-situ measurement and analysis of subway-induced environmental vibrations and the effectiveness of vibration-source suppression methods

Human comfort inside a building that encounters subway-induced vibrations is analyzed with in-situ measurement, taking a six-story masonry building near a subway line in Shanghai as an example. Relative parameters in three directions are measured and analyzed after replacing a new kind of high elastic fastener or slowing down the average speed of trains, respectively. The results indicate that: a. subway-induced vibrations mainly cause the vibration of floor slabs in the vertical direction. The level of vertical vibration is related to the resonance frequencies of the floor slabs, and the values gradually decreaseon higher stories, as seen in the fact that the vibration level on the 6th floor slab is 5 dB lower than that of the 1st floor. b. The horizontal vibration level of the floor slabs is mainly affected by the structure's higher modes. The level will exceed the limited standard values under certain special conditions, so more attention needs to be paid on human comfort in horizontal directions. c. The new kind of high elastic fastener can reduce the floor slabs' vertical vibration level by nearly 10 dB, but it amplifies the longitudinal vibration level and has little effect on the transverse vibration levels inside the building. d. By slowing down average train speed, human comfort in three orthogonal directions inside the building is enhanced, with the peak values of the vertical vibrations reduced by nearly 8 dB and the horizontal vibrations by 30 dB at maximum. Thus, it can be used to control the vibration level of nearby buildings in sensitive regions when combined with other effective methods. ©, 2015, Nanjing University of Aeronautics an Astronautics. All right reserved.