The Monitoring And Local Mechanical Reseach Of Rotation Construction On Continuous Box Grider Bridge

The improvement of the national economy has promoted the rapid development of the transportion infrastructure,and the bridge engineering which is closely related to the complex traffic network is also in the pioneering and innovative stage.With the continous progress of science and technology,the construction process is also increasingly rich and mature,among the many bridges,the swivel bridge can cross the busy existing lines and has its unique advantages,which does not affect the construction schedule and ensure construction safety.Swivel bridge has broad prospects for application,and has certain value for research.In this paper,the(55+100+55)m continuous box grider swivel bridge over the railway is taken as an example,with the help of Midas civil and Midas fea software to simulate and analyze the swivel bridge's construction monitoring and local stress.According the actual construction of the bridge,using Midas Civil to simulate and analyze each construction stage of the beam,the extraced theoretical values are compared with the measured values,the data are analyzed and adjusted effectively to ensure that linear and stress of the beam within a reasonable range.Using the ball joint rotating method to do weighting test of the swivel T structure,the friction coefficient,imbalance torque,friction torque and eccentricity are obtained by analyzing the test results.Reasonable counterweight eliminates the adverse effects of eccentricity in order to ensure that the feet are in a floating state during rotation,reducing the traction of the rotating equipment during rotation to ensure that the bridge is safely swivel.Using Midas Fea to simulate and analyze the hydration heat of the lower cap,the two conditions of cooling tube and no cooling tube are considered.The temperature sensor is embedded at the center when the steel frame of the cap is bound,and the temperature at the center of the lower cap is recorded within 14 days after the concrete pouring.The temperature theoretical value of lower cap center is compared with the measured value,and the temperature field of the lower cap is monitored.Using Midas Fea to simulate and analyze the rotation system,the vertical displacement and vertical compressive stress of the ball joint are calculated and compared with the theoretical value to verify the correctness of the theoretical calculation and the vertical compressive stress distribution of the contact surface;The effects of different eccentricity on the vertical displacement of the ball joint,the lower cap,the horizontal and vertical compressive stress of the ball joint are analyzed,it can determine the eccentricity of the bridge safety range;Whether the prestressed steel in the upper cap can reduce the maximum compressive stress of the upper,lower platform,ball joint and make the rotation system more secure;The pile foundation is divided into different groups with the distance from the center of rotation,and the force of each pile foundation and the ratio of each grope are analyzed,the conclusion can be used as a reference for such problems.