3D Laser Scanner Technology Application In The Bridge Deformation Research

The uninterrupted measurement of 3D laser scanner overcomes the defect of traditional discontinuous measurement.3D laser scanner has high speed of measurement,can get panoramic three-dimensional model,possesses strong details expression and anti-environment disturbance capability,which is widely used in architectural modeling,cultural relics protection and other fields.Presently,the application trend of 3D laser scanner gradually develops from modeling to deformation monitoring.3D laser scanner can obtain continuous point cloud data and has the effective analysis of the deformation.In this paper using 3 D laser scanner to explore of bridge deformation,mainly do the following:(1)Because deformation monitoring needs to establish a control network of high precision,set up two options: one,two geodetic quadrilateral;Two,the geodetic quadrilateral and triangle according to the actual situation.Through GPS observation of the practical field and analysis of data processing results,the precision of the option two is higher than that of the option one.;the mean square error of relative length of control network is in accordance with the requirements of the forth class precision of GPS control network.(2)The influence factors of 3D laser scanner accuracy have many: resolution,scanning distance.First the scanner resolution is explored.Study of three kinds of resolution: 0.0384°(vertical)×0.0128°(horizontal);0.0192°×0.0192°;0.0192°×0.0096°,scanning time is respectively 9,13,26 min,the longer the time,the greater the resolution.Data processing result shows that the scanning effect improves with increase of resolution,decrease of point cloud interval and the rise in the numbers.But in practice,the choice is decided by need.This paper test chooses the scan resolution of 0.0192°×0.0192°.Then have a ranging analysis of arranged monitoring point.At the same station,set scanning times for three and each time 13 min,extract monitoring point coordinates of 3 D laser scanner under different distances,calculate the mean square error of point position and get the quadratic multinomial between the distance and the mean square error.Within the scope of the 40 m,the mean square error of point position is less than 12 mm,reaching the precision of the forth class deformation monitoring.(3)There are a variety of errors using 3D laser scanner to monitor.Data processing error mainly has coordinate transformation a nd splicing error.According to the different error sources,the matching model of higher precision and the weakening measures are put forward.(4)Analysis of bridge deformation should be periodically,thus three phases of monitoring are performed before and after.When the loads,deformation condition is relatively complex,mainly analyzing the change of the vertical the Z value.The result of 1st stage is similar to that of 2nd stage due to relatively close the load;The first phase is compared with the third,the second and the third,clearly the deformation amount increases as the load increases.Similarly seen from the pier deformation,the deformation value also increased with the load increasing.This test explored the 3D laser scanning technology in the application of bridge deformation monitoring research and provide the reference for 3D laser scanner in the aspect of bridge deformation monitoring in the future.