Research And Design On Stress Monitoring System Of Bridge Intelligent Bearing

The bridge bearing in a bridge is used to withstand the loadings which come from the superstructure, and pass them onto the bridge pier. The bridge bearing should be able to adapt to the rotation and displacement of the superstructure when it is subject to various loading conditions, the change of temperature, and the shrinkage or creep of concrete, without generating any additional stresses in the superstructure. The internal stress of the bridge bearing represents the condition of the bridge bearing and the safety of the whole bridge. In this thesis, sensor technique, data acquisition technique and virtual instrument technique are integrated to detect the internal stresses of the bridge bearing. Detailed procedures for developing the internal stress detecting system are proposed. The system is validated by performing laboratory loading tests on a model bridge bearing. The research work provides important theoretical foundation and experimental basis for developing the intelligent bridge bearing with the self-monitoring function.The main research work includes:(1) Detailed analysis and study on the existing sensor techniques and products which are used to measure the pressure distribution. Combined with the practical application conditions of bridge bearing, a kind of thin film piezoresistive sensors is chosen as the data acquisition nodes of system.(2) Developing hardware with the selected sensor. Designing and manufacturing the signal measuring circuit, signal condition circuit and data acquisition circuit. Building the hardware platform of data acquisition system combined with the specific environment conditions.(3) Designing and developing the upper computer of data acquisition system using the virtual instrument technology, including data acquisition module, analysis module, user interface and data storage module.(4) Conducting the nonlinear correction of data acquisition system combined with bearing stress test conditions, designing the sensor layout, carrying out the complete and systemic loading tests on a model bridge bearing.