Verification of Operational Performance for Simply Supported Box Girder in High Speed Railway Based on GB-SAR

To solve such problems as difficulties in installing data acquisition equipment, unstable data transmission and low work efficiency existed in the traditional test methods for operational performance parameters in high speed railway bridges, using non-contact, high-precision and high-frequency measurement technology of ground-based radar to verify the operational performance of 31.5 m prestressed concrete double-line simply supported box girder for Beijing-Shanghai high speed railway. Results showed that when the speed of the EMU was more than 300 km•h-1 and was running with passengers, the natural frequency of the bridge was 6.823 Hz, the ratio of deflection to span was 1/7 150~1/9 450, the rotation angle at girder end was 0.33‰~0.43‰. The vertical amplitude of the beam body was 0.13 mm and the lateral amplitude was 0.07 mm under single-line running condition, and the measured dynamic coefficient was less than the operation dynamic coefficient. The verification results based on ground-based radar are consistent with those of traditional methods, and the operation performance parameters of simply supported box girder are close to the usual values stipulated by relevant specifications. Ground-based radar can easily, quickly and efficiently verify the natural vibration frequency, mid span deflection, beam end angle, operation dynamic coefficient, mid span vertical amplitude and lateral amplitude of high speed railway bridge, which provides a new method for the operational performance verification of simply supported box girder of high speed railway in China. © 2020, Editorial Department of China Railway Science. All right reserved.