Analysis Of Temperature Field For Concrete Cable-Stayed Bridge With Box Section And Its Influence On Construction Control

Temperature is a factor that can’t be ignored in bridge construction control. The temperature field of the bridge structure is affected by solar radiation, the impact location,wind direction, and many other environmental factors so that it changes extremely complex.In this paper, Chishi Grand Bridge of Xiarong Expressway is chosen as engineering background. The temperature field inside the box-section concrete cable-stayed bridge and its impact on the construction control is studied. The main work is as follows:With the construction site, the temperature sensors are laid in the key nodes of the key sections of the main beams, main towers and stay cables. Temperature data of a continuous period of 7 to 15 days are collected in some typical seasonal weather conditions and the distribution of temperature field in typical weather is also summarized. Meanwhile, analyzing the more uniform time period of day temperature field distribution of sections in each season,in order to provide a reference for determining temperature effects in real-time control of the construction site after taking construction control into consideration.In this paper, the equations of heat conduction sunshine temperature field analysis are systematically derived, and the boundary conditions equations are established. At the same time, using large-scale general finite element program ANSYS to analyze temperature field of the main town of thick-walled box sections and the main beam of thin-walled box sections,and then comparing the measured values and calculated values. The comparison results show that accurate results can be sufficiently applied on the project, using meteorological information to simulate temperature field of the box–section. The ANSYS model after validated can predict the temperature data within the scope of any node section and analyze data, providing a reference for the same type of concrete box structure temperature field analysis.Based on the measured temperature field, numerical method is applied on the temperature effect calculation of the main beam elevation and tower top deviation, to provide a theoretical basis for the construction control. Parameter sensitivity is respectively analyzed from the parameters of the main beam axis, the curvature of the main beam, the main toweraxial strain, curvature of the main tower, cable-stayed axial strain and the temperature difference between the beam and the cable. The results show that the axial strain and the temperature difference between the beam and the cable are the dominant factor of temperature effect. From the viewpoint of the bridge construction control, proposing the criteria of main tower and main beam uniform temperature field and providing a basis for judging construction control temperature.