Fast evaluation method for safety of train operation on bridge under impact of cars

Here, aiming at potential safety issues of train operation on a cross-line railway bridge after encountering car collision, a 32 meter-span T-shaped simply supported beam bridge in service was taken as the engineering background, a fast evaluation method based on transfer function was proposed using a combination of impact tests and numerical simulation. This method could use force hammer impact tests to collect time histories of impact force and dynamic response time histories of key positions of a bridge under impact. Impact force was taken as input variable and bridge dynamic responses was taken as output variables to solve bridge structure transfer function matrix. Fast Fourier transform (FFT) was performed for time histories of car impact forces, the transfer function matrix was dot-multiplied by input vector, inverse Fourier transform (IFFT) was performed for the obtained output vector to achieve dynamic response time histories of bridge impacted by car impacts. The applicability of the transfer function-based fast calculation method was verified by comparing its results to those obtained with finite element (FE) model. It was shown that in engineering field, this method avoids a large number of repetitive FE calculations and destructive tests ; it can quickly derive dynamic responses of bridge after being hit by cars, and realize fast evaluation of train operation safety on bridge. © 2024 Chinese Vibration Engineering Society. All rights reserved.