Analysis On Temperature Field And Temperature Effect Of Double-slanted Tower Cable-stayed Bridge With Inter Cables

As urban bridges continue to improve their aesthetic requirements,new types of bridges continue to emerge.The double-slanted tower cable-stayed bridge with inter cable studied in this paper is a new type of bridge.The structure of the bridge is special and the temperature field changes are complicated,which will cause unfavorable temperature stress on the structure and even affect the normal use of the bridge.At present,there are few studies on the temperature field distribution of slanted bridge towers in China,and the temperature effect of the special-shaped cable-stayed bridges with inter cables is rarely studied.In this paper,the temperature field and temperature effects of this bridge type are studied in the context of actual engineering.The main contents and conclusions are as follows:(1)According to the research status of this type of bridge type at home and abroad,some problems in the research are put forward,and the research purpose and significance of this paper are pointed out.The main research contents of this paper are introduced.The basic theory of temperature field and temperature effect analysis of bridge structure is studied.The relevant boundary conditions of temperature field are determined by establishing solar radiation model,and the solar heat exchange formula of east-west inclined section is derived.(2)The temperature effect of the bridge structure under the annual temperature difference is analyzed by using the temperature difference of the system in the MIDAS software.Under the overall temperature difference,the cable force change of the cable between the bridge tower and the main beam is more obvious than the cable tension between the bridge tower.The main tower is affected more by the overall temperature difference than the secondary tower.The tower beam consolidation section and the cable tower consolidation lower section are the key sections of the pylon stress change.(3)The ANSYS calculation model was established to analyze the temperature field distribution of the bridge structure under the action of sunlight.Determine the unfavorable temperature field in which the structure is in the change in the sunshine duration.Calculate the temperature field results of the main beam with ANSYS and compare the measured values of the temperature.The accuracy of the calculation results was verified.The main temperature difference of the tower appears on both sides of the east and west.The maximum temperature difference of the secondary tower is 7 °C,and the maximum temperature difference of the main tower is-6.2 °C..The maximum temperature difference between the upper and lower edges of the steel beam is 17.4 °C,and the maximum temperature difference between the upper and lower edges of the concrete beam is 11.5 °C.(4)After loading the temperature field into the MIDAS model.The variation characteristics of cable force,structural stress and structural displacement of the cable in the temperature field of three sunshine hours are calculated and compared.The cable force variation of the M1~M8 stay cable showed a linear trend.The triangular zone formed by the lower tower column and the tower beam consolidation section of the main and auxiliary towers has a large stress,and is a position where cracks are more likely to occur.The maximum displacement of the pylons appears at the top of the tower and is generated by the 14 o'clock temperature field.The displacements in the X-axis direction and the Z-axis direction of the main tower are larger than those of the secondary tower.(5)The temperature effect characteristics of the stay cable are analyzed.The main tower is at the consolidation of the tower beam,and the secondary tower is subjected to a large tensile stress in the 1/2 anchorage zone.Sufficient compressive stress reserve shall be provided at this location.The degree of mutual influence of the major components is explored,and the influence of the main beam on each cable is the largest except for the cable itself.The main tower only has a greater impact on the cable tension of the M cable,and the influence of the secondary tower on the cable is relatively small.