Mechanical Performance Analysis of Long Span High-speed Railway Station Roofs Considering the Coupling Effect of Low Temperature and Extreme Snow Load
The steel roof of the high-speed railway passenger station is sensitive to temperature and has a high number of statically indeterminate times,which tends to cause collapse under low temperatures and snow cover in cold regions.To explore the mechanical performance of the irregular roof structure of a high-speed railway passenger station under the coupled effects of low temperatures and extreme snow loads,a finite element model of the roof is established by ABAQUS based on a high-speed railway station in a region of northeast China.The accuracy of the finite element model is verified by on-site monitor data.The impact of design temperature differences on the roof structure is studied,considering the frequent occurrence of extremely low-temperature weather on-site in recent years,and then the stress on the roof under extreme temperature differences is analyzed,considering different design snow load distribution methods.Moreover,the study explores the impact of extreme snow loads in cold regions and the stress state under the coupling of extreme snow loads and temperature differences.The results show that the stress changes in the curved edges of the roof are significant under different temperatures,and are more sensitive to temperature changes.Extreme temperature differences require attention to the stress changes of the members in this area.When designing the roof structure of a station building,attention should be paid to the influence of uneven snow loads caused by the height difference between the skylight and the surrounding roof on the internal force of the structure.Under extreme snow loads,the maximum stress bars of the roof is close to yielding,and the maximum vertical displacement is also near the allowable value in the specifications.Considering the coupling of extreme snow load and extreme cooling,the maximum tensile stress and maximum vertical displacement of the designed snow load and temperature difference coupling roof increase by 47.1%and 50.2%respectively,and the stress exceeds the designed steel strength.When designing the steel roof of large-span high-speed railway stations in cold regions,the influence of the coupling of the two should be fully considered.
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