Study On Dynamic Test Technology Of Road Bridge

Dynamic properties of the bridge parameters to acquire, for the analysis of wind and seismic performance of the bridge structure, the natural frequency of checking the bridge structure and mode shapes, quickly and accurately evaluate the health of the bridge played a supporting role data, while helping to bridge the dynamic early detection of disease, reduce repair and maintenance costs, strengthen the management of the bridge, the bridge structure to ensure performance and ensure safety of life and property has an important practical significance.Recognition of traditional dynamic characteristics parameters in the recognition process need to give impetus to test the response time curve and exciting force data, which measures the use of modal analysis, frequency response calculated at each test point between the exciting force function, resulting in the frequency domain data is calculated based on the dynamic characteristics parameters of the bridge structure or function of the pulse response between the various excitation force to obtain dynamic characteristic parameter structure is calculated based on the number of domain data. In practical engineering, large-span bridge structure environment excitation method is often used in the dynamic properties of the test can not be collected exciting force signal, so the traditional dynamic characteristic parameter identification methods can not directly dynamic response under ambient excitation conditions in obtaining bridge dynamic characteristic parameter structure, the need for ways to bridge dynamic characteristics selected parameters to be optimized.Based on the random decrement technique, to obtain the free decay response of the structure in response to ambient random excitation conditions, and on this basis, in the free decay response condition, calculate the theoretical program type and frequency of vibration of bridge structures using wavelet transform theory formation. In frequency identification on the basis of the results derived been calculated based on the theory of bridge structures at all levels of the free decay signal damping ratio method.Finite element analysis model, combined with practical engineering design optimization of dynamic measurement points, and bridge the environmental incentive to give power to the bridge structure response data for each measurement point, get free decay method based on dynamic random decrement measured response data points, men calculate the vibration mode, frequency and damping ratio of the bridge structure.Finally, this paper studies the impact of the bridge structure factor theory works under the car test excitation conditions used in the calculation, and a continuous box girder bridge, for example, the test car were calculated by the impact factor of the bridge.