Research On Rupture Of Frost Heaving Corrosion Effects On Bridge Safety In Arid And Cold Area

China’s arid and cold areas at higher elevations, surrounded by mountains, due to the dry、cold、wind、temperature、strong ultraviolet and other climatic characteristics, formation of the freeze-thaw cycles、dry-wet alternating、hot-cold alternating、wind erosion and other typical natural climates. In the condition of natural and engineering,when Existing bridges far from the design of the life time, Their durability degradation and safety performance are seriously inadequate, Appears serious defects phenomena such as concrete blowup and corrosion、spalling and Steel corrosion,there is a great impact for the normal use of the bridge.Nowadays,the study on concrete blowup and corrosion diseases of bridge maintenance and management technology in dry-cold area of China northwest far behind other developed countries. In order to research the frost damage effects on safety performance of steel-concrete composite bridge, respectively, analysis from the aspects of bridge bearing capacity and durability; First analysis the mechanism on concrete frozen expansion and chlorine salt corrosion, summary the change law about concrete mechanical performance priority consist of frozen expansion crack、chlorine salt corrosion、frozen thaw denudation、steel rust、modulus declined and many other aspects of effects, do an accurate position on steel-concrete composite bridge to security,further,provides theory reference for bridge bearing capacity and durability design under effects of blowup and corrosion in northwest dry-cold area.Subject to Lian Huo high-speed highway bridges of Jiayuguan section,and priority research the Yezhugou bridge and beiganqu bridge,the main contents and conclusions are as follows:(1)Based on domestic and foreign trend of study on the durability, researching bridge diseases of the northwest dry-cold area, summarizing performances of blowup and corrosion in bridges, analysising produce causes and mechanisms to the frost damage on bridge in dry-cold area.(2)Combining mechanics knowledge,after the analysis of concrete damage mechanical properties and constitutive relations, preliminary numerical analysis was carried out on the frost heave corrosion damage and the simulation of finite element software, and compare the indicators changes of the bridge after the cold.(3)Based on the calculation principle of frost heave crack and the theory of steel component chlorine salt corrosion,the influence of the bearing capacity of bridge structure, and calculate the remaining bearing capacity of the damaged steel bridge structure.(4)Analysis the durable performance of the steel components under frost damage environment in dry cold region, estimating the bridge service life under the expansion crack corrosion damages and putting forward some effective prevention advices.