Research On Detective Methods Of Engineering Structural Crack And Its Experiments

The nondestructive detection of large-span structures and high-rise buildings get more and more attention in academic studies and engineering field. In China, the detection, identification assessment and strengthening research work of the reinforced concrete structures were started late, and the security of the existing structure evaluation standard is not perfect. Therefore, further studies of the detection of reinforced concrete structures, safety evaluation, and reinforcement areas were necessary.In this paper, according to the requirements of concrete structures quality, the contents of the concrete structure inspection was described, and various detection methods for reinforced concrete structures based on the summary details on concrete flaw detection methods was introduced. Meanwhile, through the application of carbon fiber as the concrete cracks smart sensor, the detection tests to analyze the specimen changes in crack width was conducted. Specific studies were outlined below:1. The formation of cracks in engineering structures and the dangers was described. Several common methods of non-destructive testing of concrete defects was presented and compared to each other. Meanwhile using the carbon fiber intelligent layers as the intelligent detection were selected as the major research method.2. The carbon-fiber-Intelligent pre-engineering test pieces were manufactured and the three-point bending tests were conducted. The measured parameters changed with the increasing of load variation, and either the relationship between the change of resistance rate and the strain or the relationship between the rate of resistance change and the incision open end displacement relations was analyzed and explained in detail. The empirical formulas for notch tip opened displacement were presented.3. The different three-dimensional finite element models, were created by using of ANSYS finite element software combining with the theory of fracture mechanics. And the three-dimensional structures with initial cracks in power-mechanical coupled field were simulated. The stress intensity factors and the resistance change rate in different conditions were obtained in simulations.4. The improved damping least squares were selected to fit the empirical formulas of the calculation of stress intensity factors. The sub-end opening displacement of the incision and the correctness of the formulas were verified by using these test data.