The Study On Crack Width Calculation Methods Of Reinforced Concrete Structure

With the rapid development of our country's economic, the construction of harbours is booming. At the same time, people pay more attention to the cracks of reinforced concrete in harbour works. Because of the high asymmetry and low tensile strength of concrete, most concrete structure works with cracking actually. So cracking becomes one of the problems which is hard to be avoided. Not only Cracks affect appearance, but also impact the stiffness, durability, and impermeability of reinforced concrete structures. For this reason, the specific requirement for crack control was made in many countries'code.Crack width calculation is very important in cracks control. While the factors which impact cracking are numerous, there isn't a wide accepted formula to predict the maximum crack width. Therefore, this paper summarized the main causes of cracking, and then introduced the theory of crack calculation and the main formulas. After that, this paper gave some revision suggestions of the formulas in the Design Code for Harbour Engineering Concrete Structures.For the sake of efficiency and applicability, this paper attempted to use FEM software ANSYS to predict maximum crack width. This study used the nonlinear spring elements (Combine39) to simulate the bond-slip relationship between rebar and concrete which depends on Houde's bond-slip model. Then, this paper studied the FEM crack width calculation theory of Zhao Guo-fan, and used the secondary development tool in ANSYS——APDL programmer to add the crack width calculation function to the post-processing of ANSYS base on the improved formula. The comparison between the results of FEM method and empirical formula showed that this method is more accurate to predict the crack width under every step of load, and it's a useful supplement and development for the methods in existence, so it has an important application value in engineering.