A fire-resistant setting method for automobile combustion in long-span suspension bridges

Abstract

The invention provides an automobile burning resistant setting method of a large-span suspension bridge. The method specifically comprises the following steps that firstly, on the basis of the shortest destroying time of a sling fire disaster, the most dangerous fire scene of the suspension bridge is determined, and ultimate bearing capacity of the sling and the automobile burning ultimate state of the suspension bridge are obtained; secondly, fire-resistant performance of fire-proof materials with different heat conductivity coefficients is compared, and it is determined that aluminium silicate serves as the fire-proof materials wrapped outside a suspension bridge main cable and the sling; thirdly, the aluminium silicate is wrapped on the main cable and the sling for thermal analysis, and a value taking interval of the thickness of a fire-proof layer wrapped outside the sling and the main cable; fourthly, temperature of sections, at different heights, of the sling is lower than the ultimate temperature when the sling is destroyed, the protecting height of the sling can be obtained, temperature field distribution of the sections of the different positions of the main cable in the longitudinal direction in the ultimate state is calculated, the temperature of steel wires at the outermost layer of the main cable is prevented from being overhigh, and a protecting range of the main cable is obtained. The automobile burning resistant setting method can be popularized to bridges of other cable systems, and has large practical engineering application value.

Description

technical field [0001] The invention relates to the field of bridge and culvert engineering in the transportation industry, in particular to a method for arranging automobile combustion and fire resistance of a large-span suspension bridge. Background technique [0002] As an important traffic channel in the city, the suspension bridge has shared the huge traffic flow. The risk of vehicle combustion in bridge operation is increasing. Once a vehicle combustion emergency occurs, it will not only cause heavy casualties, but also cause bridge traffic to be paralyzed. At the same time, the main cable and Suspenders are crucial components of bridge structures. Due to the huge tensile stress they bear, the tensile ultimate bearing capacity and elastic modulus of the main cables and suspenders will be greatly reduced under the action of automobile combustion fires, thereby shortening the service life of suspension bridges. The sharp drop will increase the difficulty of bridge repair...

AI Technical Summary

Problems solved by technology

[0002] As an important traffic channel in the city, the suspension bridge has shared the huge traffic flow. The risk of vehicle combustion in bridge operation is increasing. Once a vehicle combustion emergency occurs, it will not only cause heavy casualties, but also cause bridge traffic to be paralyzed. At the same time, the main cable and Suspenders are crucial components of bridge structures. Due to the huge tensile stress they bear, the tensile ultimate bearing capacity and elastic modulus of the main cables and suspenders will be greatly reduced under the action of automobile combustion fires, thereby shortening the service life of suspension bridges. The sharp drop will increase the difficulty of bridge repair, and the loss will be immeasurable

At present, a large number of theoretical calculations and analysis of building fires and related fire tests have been carried out at home and abroad. For the fires in long-span steel-concrete composite suspension bridge structures, the main research focuses on the use of finite element numerical simulation calculations to analyze bridge structures in fire. The mechanical performance response under the action did not obtain the most dangerous fire scene and the corresponding ultimate bearing capacity of the suspension bridge according to the specific fire location, and did not further propose the fire resistance setting method of the suspension bridge in the most dangerous scene

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