Study On The Influence Of Temperature In Construction Control Of Cable-stayed Bridges

Along with the development of long-span cable-stayed bridges, the construction control plays an increasingly significant role on the cantilever construction of cable-stayed bridge. However, temperature becomes an increasingly important factor that affects the accuracy of construction control, and delay time limit for a project as well, thereby affects schedule of the construction. Combined with the construction control of Yibin Zhongba Jinshajiang River Bridge, this thesis firstly presents briefly the calculation method of prestressed concrete bridges' temperature field caused by sunshine, based on theories of concrete structures' heat conduction, builds up two-dimensional unstable temperature field's finite element analysis models of cable-stayed bridge's girder and tower, according to the third of boundary conditions by using quadrilateral isoparametric element, simulates laws that girder and tower's temperature fields vary in the whole day, using Transient Thermal Analysis of ANSYS, one large-scale finite element software, analyze the laws of vertical temperature gradient of side-rib girders, and solve stresses caused by temperatures as well, using the thermal-stress coupled-field analysis of ANSYS. Secondly, the simplified calculation method of temperature effects on the construction control is discussed. According to the view of self-adaptive control for cable-statyed bridge, the parameters in thermal difference expressions of the cable-stayed bridge's girder, tower and inclined cables are identified on the basis of measured data by virtue of the least square method in modern cybernetics, and deformations and stresses which temperatures induce are calculated in some key construction stages as well, for the sake of showing temperature effects which can not be neglected. At the same time, one important issue is discussed home that the revision of elevation of formwork erection when taking into account temperature difference in construction controls, then the temperature laws are studied when every component of cable-stayed bridge are in different temperatures during different construction stages, consequently the scientific bases are provided for proper time for elevation and cable force measurement.