Study On Construction Monitoring Technology Of Three-span Steel Box Arch Without Center Pier Support Cable Lifting

Because the diameter and number of bridge spans are increasing,higher requirements are imposed on bridge construction technology and bridge construction control.Cable hoisting is widely used in bridge construction due to its unique advantages in large tonnage lifting and horizontal long distance transportation.For multi-span continuous arch bridges with multiple arch ribs in the transverse direction,the construction method of no-pillar support cable hoisting is adopted.The tower is arranged with the full width of the bridge,and transverse ribs are hoisted by the construction method of cable saddles.When different ribs are hoisted,due to the effect of the main cable and the buckle cable,the tower will be offset,and even a large torsion phenomenon will occur.The construction process needs to be accurately controlled.This paper takes the Yihengxiankuayulinhe bridge in Chongqing as the engineering support,and adopts flip-chip analysis method to perform simulation analysis of the construction process by the finite element software MSC.marc,to study the construction monitoring technology of this project and control the construction phase.In view of the characteristics of the cable lifting construction of the Yihengxiankuayulinhe bridge,the cable lifting process of the side ribs and middle ribs was selected for analysis.Calculating the main control parameters such as the force of main cable and buckle cable,pre-elevation of arch ribs,wind cable tension and tower offset in the construction phase,as the theoretical basis for on-site construction.Combing the change law of front and rear wind-cable tension and tower offset with the torsion effect of the tower,set a reasonable pre-bias for the tower to ensure the overall stability of the tower.Basing on the change law of buckle cable force and arch rib height at different temperatures in the closing and lifting stage,it shows that the temperature change has a significant effect on the elevation of arch ribs,and the temperature of the arch ribs should be strictly monitored during the hoisting process.Using the finite element software MSC.marc to build a tower calculation model and selecting 12 lifting conditions to check the bearing capacity and stability of the tower.After the trial hoisting process and the hoisting process of the rib(D-rib),the analyze data agree well with the actual results.Therefore,the simulation analysis method in this paper can be effectively applied to the actual construction control,guide the Yihengxiankuayulinhe bridge construction process,and provide reference for the construction monitoring technology research of similar projects.