Research On Application Of Key Technologies In Inclinometer Measurement Of Bridge Deflection

With the increasingly status of bridges in transportation,the operation safety of bridges has become crucial,and the measurement of deflection can reflect the safety of bridge structures.Compared with the traditional method of deflection measurement,the tilt measurement method has unparalleled advantages.However,the measurement error range of this method has not been studied explicitly.This method has not been popularized.To solve this problem,the main works of this dissertation are:First,according to the principle of deflection measured by the inclinometer,choose the most easy to use,most easy to promote deflection calculation model-segmented superposition model,and used this model as the basis for the measurement method of error.Two sources of measurement error were determined based on the deflection calculation model: segmentation error and inclinometer accuracy.Two error sources are analyzed separately,and the hypothesis that the measured value of the inclinometer accords with the normal distribution is proposed and verified by experiments.Second,to comprehensively calculate the impact of the two sources of error on the final deflection measurement error,this dissertation uses a simple supported beam as an example.The Monte Carlo method was used to analyze the sampling distribution of the measured values of the deflections of the simple beam after considering the inclination measurement accuracy under different segment numbers,and the average,standard deviation,95% probability interval,etc.of deflection measurement distribution were obtained.Determine the error.Third,the application of error analysis was used a continuous rigid frame bridge as an example,the deflection curve under various conditions were analyzed,based on this,consider the use of three different angle accuracy of the inclinometer and different number of segments,calculated using an inclination sensor to measure the deflection at mid-span deflection.Based on the results of the error(mean,standard deviation,and 95% probability interval)of different angular accuracy sensors used in different segmented cases,the sensor accuracy and segmentation method for different working conditions are indicated.Fourth,the use of inclinometer for the laboratory bridge model and continuous rigid frame bridge actual measurement experiment,at the same time,the measurement results and the traditional deflection measurement method results to verify the correctness and practicality of the error analysis.The research in this dissertation provides measurement error analysis method and sensor selection and placement methods for inclinometer measurement method.The analysis of measurement errors before practical measurement provides guidance and predictability for the measurement results and this will be helpful for the further promotion of this method.