FEM Analysis On Crack Process Of Concrete Cover Caused By Stirrup Corrosion

Durability of reinforced concrete structures as a result the main form of structural damage caused by steel corrosion. Steel corrosion occurs, its volume is about rust corrosion amount of 2 to 4 times (the coefficient of the product according to the final form of corrosion varies), volume expansion of corrosion products around the concrete to be squeezed, as the further corrosion development, resulting in corrosion products gradually increased concrete cover cracks in tension until the protective layer Splitting broken cause spalling.After the cracking of reinforced concrete, reinforced concrete corrosion protective layer on the aggravated damage, corrosion effects will eventually lead to the destruction of protective layer of concrete structures severely affect its durability.Practical engineering small diameter of stirrups, and the cover thickness is less than longitudinal reinforcement, so the steel corrosion in concrete response to the beginning starting with stirrups, and the extent of corrosion of stirrup reinforcement ratio of longitudinal force to be serious.This article only considers the role of corrosion expansion stirrups, stirrup under the concrete characteristics of non-uniform corrosion, combined with vertical force on the reinforcement of existing research results, analysis of corrosion products obtained as expansion of Er Shi stirrup stirrup concrete surface does not produce mathematical expressions such as radial displacement, and conclusion is drawn that stirrup corrosion rate and the stirrups of the concrete surface the quantitative relationship between radial displacement;Consider the stirrup corrosion protection layer after the destruction of concrete in different forms, with Ansys finite element software, based on the aforementioned theory as the basis for use of the stirrup to impose uniform corrosion expansion of concrete around the displacement method, not cracking the test specimen (Different hoop diameter, the spacing, the thickness of protective layer with different combinations) for corrosion cracking simulation study.Based on the foregoing analysis of the finite element software, the results with stirrup corrosion protective layer of concrete damage caused by the law, and the result obtained stirrup corrosion cracking of concrete cover stirrup corrosion rate formula;After the above theory analysis and finite element simulation study, concluded the following conclusions:under the same conditions, reducing the stirrup diameter, increasing the spacing to increase the thickness of the crack could delay the protective layer.