Research On Tracking Simulation Calculation Of Self-anchored Suspension Bridge With Cable-stayed Buckle Hanging Construction Method

With the rapid development of national economy,China’s infrastructure construction changes with each passing day,and bridge construction technology continues to innovate.self-anchored suspension Bridges are favored by project builders because of their beautiful appearance,strong site adaptability and economy.The main span of self anchored suspension bridge is more than 600 meters,and it is unprecedented to build with "Cable-Stayed Buckle Hanging",the mechanics characteristics of structure in the process of its construction has been far beyond the traditional experience,or simple structural mechanics analysis can be judged,establish "Cable-Stayed Buckle Hanging" model of finite element method for the key component in the process of its construction,the mechanical properties of key nodes track simulation,monitoring and control is the guarantee bridge construction safety and engineering quality presses for solution of technical problems.In this paper,based on the construction in progress,the simulation technology of "Cable-Stayed Buckle Hanging Method",the reasonable calculation of completed bridge and the mechanical characteristics of the structure in the construction process are systematically studied.The main contents of this paper are as follows:(1)Research on Modeling Technology of Cable-stayed-suspension Composite Structure.Based on the theory of finite element and the basic principle of construction mechanics,with the aid of numerical analysis software Midas/civil,this paper discusses the numerical modeling technology of "Cable-Stayed Buckle Hanging Construction Method" self anchored suspension bridge,and realizes the simulation of coexistence of cable-stayed suspension system and cable-stayed system.In this paper,the "temperature method" is used to simulate the top push of the saddle of the main cable,and the "rigid element" is used to simulate the sliding saddle.Combined with the "element life and death method",it is proposed that the unstressed cable length control is the main method,and the "external force" simulation is used to simulate the tension process of the single cable element.(2)Research on the reasonable completion state of self anchored suspension system.Based on the principle of the internal force balance method,the reasonable completion status of the self-anchored suspension bridge is calculated.Based on this,it is compared with the designed bridge parameters to verify the correctness and effectiveness of the established numerical model.Finally,the non-linear iterative method is used to accurately calculate the stress-free configuration of key components such as tower beams and cables,which provides technical guidance for construction.(3)Research on simulation technology of steel box girder hoisting.The side-span jacking simulation of the steel box girder is used to check the reaction force of the pier and the stability against overturning.The mid-span suspension installation simulation of the steel box girder,and the mutual verification with the monitored values can reflect the actual force situation of the bridge;According to the closing deviation in the middle section of the steel box girder,This chapter calculate the coordinated adjustment value of tension and weight,the relationship between push distance and thrust through sensitivity analysis to formulate a reasonable adjustment plan,to achieve the high-precision closure of the bridge;Finally,Raise the main beam in preparation for subsequent high-position structural system conversion,this chapter calculates the reasonable amount of stay cable and the operation sequence by using the influence matrix method and the constraint function to obtain the optimized construction plan.(4)Research on bridge structure conversion simulation technology and construction structure mechanics characteristics.In order to realize the reasonable transformation from the cable-stayed system to the suspended cable system,based on the principle of dual control of force and displacement,This chapter s Simulate the force characteristics of bridge members under different working conditions,and focus on analyzing the internal forces and deformation trends of key working conditions such as main cable installation,sling tension and uninstallation.According to the results of parameter sensitivity analysis,establish the cable strand sag adjustment formula,and review the baseline cable adjustment line and empty cable shape,cable clamp stakeout point and other parameters;The above finite element model simulates the construction process,and calculates key control parameters such as tension length,ejection distance and ejection timing,and internal force of the structure,so that the entire construction process is safe and controllable,and each index meets the design requirements.The rationality of simulation technology and construction scheme is verified by comparing the simulation results with the monitoring results.Finally,the paper summarizes the similarities and differences between the mechanical properties of the system transformation of "Cable-Stayed Buckle Hanging Method" and the traditional method,and provides references for the design and construction of similar projects in the future.(5)The system transformation of "Cable-Stayed Buckle Hanging Method" has the following characteristics: 1)The main tower of the middle span sling in the traditional tensioning method has the characteristic of deviation to the middle span,while the "cable-stayed hanging method" may present the opposite trend;2)The bridge tower always bears a large pressure value(it is not easy for the tower limbs to appear tensile stress),so the allowable deviation of the bridge tower is relatively large.The main purpose of saddle pushing is to release the unbalanced force and improve the stress on the weak surface of the main tower;3)The cable tension makes the unloading ability of the cable force of the middle span cable stronger than that of the side span,which leads to the main tower inclining to the shore side more and the main tower’s stress is disadvantageous.Therefore,the cable force should not be too large before the system conversion.