Calculation And Analysis Study On Crack Width Of Corroded Reinforced Concrete Flexural Members

Crack is one of the main incentives of bearing capacity decline and durability failure to reinforced concrete structures. In view of this, problems of crack are paid widespread attention by domestic and international engineering, and a series of ways and means to control crack are proposed by them, in which crack width checking is a common method. At the same time, a lot of engineering examples have been shown that crack width development of service engineering structures is influenced by steel corrosion to some degrees. But the precedent of being directly introduced the factor of steel corrosion into the relevant industry specifications is not existent yet. In order to inquire into whether steel corrosion will produce an assignable impact on the structural cracks of practical engineering and the applicability of corrosion crack computation in different specifications, the following tasks are carried out from the aspects of theoretical summaries, normative comparisons and experimental data analysis:The basic theories of load crack width of reinforced concrete members internationally at present is introduced. The bond mechanism between steel bar and concrete as well as the differences in bond properties between round steel and twisted steel are expounded. So as the influence of reinforcement corrosion on the bond degradation performance. The crack morphology development process and their respective features under external loads between ordinary reinforced concrete and corroded reinforced concrete flexural members are described.The computational formula of crack width of reinforced concrete flexural members with different specifications are arranged. The differences from various perspectives of mainly parameters including methods of controlling crack width, theoretical foundations, load value,stress, effective reinforcement ratio and concrete cover thickness with different standards are analyzed and compared.Combined with the existing experimental data, the theoretical values of crack spacing and crack width of the test beam based on crack formula under different specifications arecalculated. The relationship between the ratio of theoretical and measured values and corrosion degree are curved fitting of regression analysis with a related software. According to the fitting results, the applicability of crack width modes under different specifications to the test beam crack is comparatively analyzed. A factor concerned with corrosion influence is introduced to modify the formula for calculating the crack of reinforced concrete beam. The correction coefficient expression for crack width of corroded reinforced concrete beam based on the applicable norm is proposed.