Saddle Without Pre-partial Construction Of The Steel-concrete Composite Beam Suspension Bridge Process Time-varying Effects Analysis

Suspension bridge, a multi-hyperstatic and flexible structure, whose construction method is special. Due to the geometrically nonlinear load-deflection relationship, it is very sensitive to the influence of temperature and creep and shrinkage of concrete. In order to make the actual condition in the state of construction and completion approximate the designed ideal state best, time-dependent affection, as a sensitive factor, must be taken into studying conscientiously and then modifying in time.The calculation theories is systematic explained, the method of the line-type of completion state, zero-stress length of suspender is put forward by analysing the stress of the suspension bridge built by non-pre-bias of cable-addle. The fabrication length of the main cable, initial cable construction state and initial cable height, the stress of main tower in the stage of erecting stiffening-girder and anchor span strand jack time and displacement is systematically discussed by analytical iterative method based on mechanics of suspension bridge and the FEM method based on finite displacement theory.The paper employs the mathematic model of creep and shrinkage of concrete. Basing assumption of plane cross section, applying the aging theory and the finite element method, subtracting the portion of creep and shrinkage of concrete from the measured strains, then the real elastic strains of concrete is obtained. Analysing temperature loads effect, applying the heat-conduction theory and Fourier equation of heat-conduction, assuming border temperature function, the transient temperature field of structure is solved and the practical calculation method of temperature stress is obtained.Based on the project of LanChanGiang steel-concrete overlapping stiffening girder suspension bridge built non-pre-bias of cable-addle in XiangYun-LinChang Highway in YunNan Province, the cause of the pylon tower deviation and calculation method is studied during the whole process-from nake tower to constructing the catwalk, to hanging the cable, to erecting the stiffening girder. It analyses the time-dependentaffection, and puts calculation method of the elastic stresses of concrete forward. Combining the characteristics of the project and the Geographical environments, the temperature measurement scheme of tower> catwalk and main cable is given. By studying on the calculation method for temperature control, the formula for the worst-case temperature gradient is put forward. On the basis of the principle of invariable of zero-stress length of suspender, it solves that the slack of suspender under temperature loads and provides the detailed method of the cable adjustment of the suspender. The influence of the temperature and creep and shrinkage of concrete on stiffening girder and the state under dead loads is analysed. It assures the stress of tower, the unbalanced force between the cables and the maximum stress is under control through the real-time control and adjustment of anchorage cable tension, the stress of suspension cable and the level of stiffening girder. And the line-type of the state under dead loads is accorded with the designed requirement.The application in this project proves that the theory, the calculation method and the analytical method of time-dependent in this paper is reliable and valuable The conclusion in this paper provides references to design, construction and construction control of long span-suspension bridge.