Research On Rapid Detection Method Of Bridge Damage Based On Portable Sensing Equipment

The traditional direct bridge detection method is to directly measure the vibration of the bridge structure by installing sensors on the bridge structures,so as to obtain the dynamic response characteristics of the bridge structure.The indirect detection method of bridge structure is to install sensors on the axle of the vehicle passing the bridge through the coupling effect of vehicle and bridge,and indirectly extract the dynamic response characteristics of the bridge structure s from the acceleration response information of the vehicle crossing the bridge.The indirect bridge detection method not only has the advantages of rapidness,economic and no need to block traffic,but also can avoid the difficulties of dealing with massive storage data in the later stage of detection.its limitation is that the acceleration sensor installed at the wheel axle position is easy to damage and not easy to maintain and replace.Therefore,in order to make the indirect bridge damage detection method effectively applied in the actual bridge engineering detection,this paper systematically studies the indirect damage detection method based on vehicle-bridge coupling and the main work was as follows:Improve the existing indirect damage detection method of bridge.On the assumption that difference approximation is valid,the coupling vibration model of vehicle body and wheel is introduced by substructure method to modify the vehicle-bridge coupling model.The coupling vibration relationship of bridgewheel-body is studied when the wheel-body system is in low frequency.The proposed method could prove theoretically that the feasibility of extracting the damage information of bridge structure from the vibration response information of vehicle body.A road roughness acquisition method based on vehicle acceleration is proposed.The difficulty of the improved indirect damage detection method is to determine the excitation frequency of the bridge pavement to be tested in advance.In order to solve this problem,this paper studies road roughness acquisition based on vehicle acceleration.The roughness of bridge pavement is analyzed by power spectral density function,and the excitation frequency of bridge pavement is determined.This paper proposes a method to extract the characterist ic deflection from the dynamic response of the vehicle body.In order to extract the damage informat i on of bridge structure from the dynamic response of vehicle body vibration,this paper studies the characterist ic deflection used to evaluate the health index of bridge structure in the indirect bridge damage detection method based on vehicle-bridge coupling.And the calculat ion process of extracting the characterist i c deflection from the measured value of the vehicle body vibration respon se informat ion is introduced in detail.Before selecting the portable sensing equipment for bridge damage detection,the calibrat ion experiment of the port able sensing equipment is carried out.And through vehicle-bridge coupling experiment,the damage condition of remove the transverse girders under the bridge was identified by using the portable sensor equipment.The experimental results show that the indirect damage detection method based on portable sensor equipment can effectively and quickly identify the damage of bridge structure.