Study On The Temperature Field And Temperature Effect Of Fish Belly Complex Cross Section

Fish-bellied box sections are widely used in bridge structures.The applicability of the temperature gradient specified in the Chinese bridge code to this section is still uncertain.The current temperature gradient and temperature stress studies carried out on fish-bellied sections are still rare.Based on the temperature theory,this paper partition the fish-belly complex cross-section to simulate the temperature boundary and to study the temperature field and temperature stress.The main contents are as follows:(1)According to the theories of solar physics,astronomy and heat transfer,considering the occlusion of the fish-belly cross-section under the action of sunlight,the partition temperature boundary is used to solve the problem,and the Power exponent model,ASHRAE model,and Hottel model are chosen to calculate the solar radiation.The transient temperature boundary expressions of each location are obtained,and the slope sky effect is carefully solved to determine the thermodynamic boundary.The special section temperature field verifies the method’s effectiveness with an inclination angle of β=90°.The influence law of the inclined surface of the inclined web on the temperature field is explored,and the optimal inclined web inclination angle based on the extreme value of the temperature field boundary is obtained.(2)Relying on the actual engineering,the transient temperature boundary of the fish-belly cross-section is obtained based on the Power exponent model and the partition algorithm.The temperature field of the fish-belly cross-section is numerically simulated based on the finite element method and verified by comparison with the field measured data.According to the local climatic conditions,the unfavorable temperature field distribution of the fish-belly box section is determined,and a temperature gradient form suitable for the fish-belly section is proposed.(3)A fish-belly cross-sectional temperature field correction method based on the response surface method is proposed.The feasibility of the approach is verified by comparison with the measured temperature.The results show that the physical meaning of the temperature parameters corrected by this method is clear,and the correction results are promising.On this basis,the temperature stress of the fish-belly section beam is studied in three cases.The results showed that under the action of the temperature difference in sunlight,the fish-belly section roof and the junction between the top and the web appeared apparent tensile stress,which is easy to cause the roof of the bridge deck cracking.