Evaluation of ground vibration induced by rail system

A series of field-measured data are used to characterize the ground vibration induced by the Taipei Mass Rapid Transit (TMRT) system on bridges. The measurements for analysis consist of various geological conditions with wide ranges of ground shear wave velocities. Both ground vibration beside bridge column and vibration propagation induced by TMRT are evaluated and then compared with those induced by the Taiwan High Speed Rail (THSR) system. Based on the analyses, the overall vibration level beside a bridge column is between 68 and 72 dB (ref. 1 micro-inch/sec). The overall vibration attenuation coefficients range from 2.1 _ 10_3/m to 5.3 _ 10_3/m, and the attenuation coefficient decreases with increasing ground shear wave velocity. The overall vibration influence distance increases with increasing ground shear wave velocity and is between 117 and 243 m. Meanwhile, the low and middle frequencies have the farthest influence distances for all soil types. Compared with the THSR, the vibration level and influence distance of the TMRT are lower. The attenuation coefficient of the TMRT on bridges is slightly higher than that of the THSR on both embankments and bridges. Further detailed discussions are also provided in the paper.