Research On Construction Monitoring Technology Of Cable-stayed Swivel Bridge

In the construction of bridges that need to cross deep water areas,steep canyons,or cross existing lines,the use of swivel construction has obvious advantages over other construction methods,because the swivel construction method can be constructed without brackets,so it is not subject to Venue restrictions.The construction method using the swivel construction method can cross a river or line that cannot be stopped or a valley that is difficult to cross using traditional methods,and the construction materials and equipment are simple,the construction is easy,the construction is fast and efficient,the structural stress state is easy to calculate,and the engineering cost is low advantage.Therefore,the monitoring of the swivel construction of the bridge is an important content to be studied in this subject.The unbalanced moment of the bridge is analyzed,the counterweight is calculated according to the unbalanced moment,and the relevant parameters of the rotation are calculated.The overall stress distribution and deflection of the bridge body are closely related to the dead load cable force after the bridge is built.The maximum displacement of the cable-stayed bridge tower and beam(the horizontal displacement of the tower and the vertical deflection of the beam)is taken as the goal to optimize the cable force,and the influence matrix method is used to complete the The cable force is adjusted.Using the empirical formula in "Code for Wind Resistance Design of Highway Bridges",the anti-overturning stability and flutter critical wind speed of Lianchi Street cable-stayed swivel bridge were studied.The longitudinal stability calculation under consideration of wind resistance and the longitudinal stability under consideration of wind lift were studied.The calculation results show that the anti-overturning stability coefficient of the cable-stayed bridge at the maximum cantilever state before turning is 14 and meets the design requirements.Based on the grey predictive control theory,the construction control predictive theory of hybrid beam cable-stayed bridge type is proposed.It is also applied to the cable-stayed swivel bridge on Lianchi Street.The results show that the control structure obtained by the prediction system agrees with the actual data by more than 90%,indicating that the system can be adapted to this bridge.This bridge adopts the swivel construction method,uses MIDAS Civil to establish the full bridge model,analyzes and calculates the stress and deflection of the beam body,and also provides a basis for selecting the monitoring section.The monitoring points of each monitoring type of the bridge are analyzed and arranged.Using monitoring methods,the line shape,stress and cable force of the bridge before and after each construction period were monitored in real time,and the measured value was compared with the theoretical value to guide the control construction.Through effective monitoring,the main beam line shape and the The stress state meets the design requirements.Finally,through monitoring and calculation of the whole project of the bridge rotation,the results show that the error between the predicted value and the theoretical value of the stress and line shape of the main beam in each construction stage is within the allowable range,which can meet the design accuracy requirements.The monitoring and forecasting data of the construction process of Helong indicate that the line shape and stress meet the design requirements,which can ensure the smooth closure of the bridge.Pre-monitoring and related tests on the construction of the bridge's swivel construction and the post-rotation Helong construction can effectively know the post-rotation construction of the bridge.