Study On Bridge Turnaround Construction Monitoring Technology Based On Binocular Visual Measurement

With the substantial improvement of road traffic in China,more and more bridge projects need to cross the existing lines.The traditional construction technology will hinder the operation of the existing lines,especially the construction of crossing the railway.Frequent points in the construction stage will affect the operation and safety of the railway.At present,the rotating construction technology is an effective way to solve the existing line engineering.In the process of rotating construction,in order to ensure engineering quality and structural safety,rotating construction monitoring is very important.The monitoring of swivel construction is generally divided into weighing test before swivel,whole process attitude monitoring during swivel,fine adjustment after swivel and final attitude confirmation,and reliable whole process monitoring means are the key to swivel construction monitoring.As a non-contact measurement method,binocular vision measurement has the advantages of continuous measurement and high precision,which is widely used in agriculture,industry,biomedicine and other fields.Based on binocular vision measurement technology,combined with the actual swivel project,this paper puts forward the swivel construction monitoring technology based on binocular vision measurement,and explores its application effect and economic benefit in swivel construction monitoring.Details and results are as follows :(1)Based on the principle of binocular vision measurement,combined with the engineering field environment,the binocular camera,calibration board and notebook computer are used as the basic equipment,and the solid circle is used as the target.Based on Python platform and Open CV vision library,the measurement system is built and tested.The test error meets the accuracy requirements of rotating construction monitoring,and lays the foundation for further application in practical engineering.(2)In the weighing test,the conventional displacement meter needs to contact the measured object,the probe is easy to wear and tear,and the calibration environment is strict.In this paper,the weighing test technology based on binocular vision measurement is proposed.By relying on the field test of the project and comparing with the traditional displacement meter,the results show that the average error of binocular vision measurement is less than 0.2 mm,and the measurement data of the displacement meter show the same trend.The correct parameters(unbalanced torque,eccentricity,friction torque,static friction coefficient)of the weighing test can be obtained,and then the weight distribution scheme is determined to reduce the risk of turning tilt.(3)In this paper,aiming at the problems of limited monitoring data,expensive equipment(about 100,000 to 400,000 yuan)and professional station measurement in the whole process of supporting foot displacement monitoring during swivel,a whole process monitoring technology of supporting foot displacement during swivel based on binocular vision measurement is proposed.By relying on the engineering field test and comparing with the traditional total station,the results show that the average error of binocular vision measurement is not more than 0.18 mm,which can realize the whole process monitoring of supporting foot displacement without interfering with the swivel construction and meet the requirements of monitoring accuracy.And has high economy(compared with total station can save about 80 % of the equipment cost).After rotation,the maximum deviation of alignment is not more than 12 mm through field measurement of alignment and internal force data and comparison with the theoretical data of finite element model.The stress deviation does not exceed 10 %.It shows that the final posture of the bridge after rotation meets the requirements of closure and structural safety.