A method for monitoring the dynamic deflection of beam structures based on strain modes

Abstract

The invention discloses a girder structure dynamic deflection monitoring method based on a strain mode. The method is characterized in that a strain sensor is adopted for carrying out strain testing on a vibrating girder structure to obtain dynamic strain data, a strain mode shape is worked out through a cross-correlation function of the dynamic strain data, a displacement mode shape is worked out through a strain-displacement conversion relation, then, displacement mode coordinates are worked out through the dynamic strain data and the strain mode shape, finally, a real-time deflection line of the girder structure is obtained by superimposing the worked-out displacement mode coordinates on the displacement mode shape, and therefore monitoring of the dynamic deflection is achieved. According to the method, on the premise of guaranteeing precision, the dynamic deflection of the girder structure can be monitored through simple equipment at a low cost.

Description

technical field [0001] The invention relates to the field of bridge health monitoring, in particular to a method for monitoring the dynamic deflection of a bridge based on a strain mode, and the monitoring result is used to evaluate the service state and safety performance of the bridge. Background technique [0002] In the bridge health monitoring, the deformation of the bridge structure is an important index to evaluate the safety of the bridge, and it is also one of the key parameters of the bridge monitoring. As a description form of deformation, deflection can establish an internal relationship with the stiffness of the bridge, and then can effectively evaluate the service state and safety performance of the bridge. In particular, the dynamic deflection of the bridge is the most real-time embodiment of the bridge's stress and deformation. By monitoring the dynamic deflection, the dynamic characteristics of the bridge structure and the impact coefficient of the vehicle ...

AI Technical Summary

Problems solved by technology

However, these measurement methods require independent measurement equipment, which increases the amount of data and increases the cost of monitoring

Especially for bridges in special environments, due to the complex operating environment, it is often very difficult to directly install displacement sensors for direct measurement of deflection

At the same time, these methods can only measure the deformation of a certain or a limited point. If you want to obtain the real-time deflection curve of the entire bridge, you must use interpolation or fitting methods to obtain the real-time deflection of the bridge at a certain moment. deflection line

However, the interpolation or fitting method ignores the vibration effect of the bridge structure under the vehicle load, so it is difficult to measure the real-time deflection curve of the bridge.

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