Experiment and Probabilistic Prediction on Mechanical Properties of Corroded Prestressed Strands under Different Strain Levels

Abstract

At present, prestressed structures are widely used in offshore buildings and bridges. After corrosion, the prestressed structure’s mechanical properties decline, significantly reducing the structure’s bearing capacity and threatening the prestressed system’s safety. Therefore, it is necessary to study the variation of mechanical properties of corroded prestressed strands. In the past, researchers mainly studied the rusty prestressed strands in the state of no stress, which is different from the prestressed strands in the actual structure. It can provide many benefits to study how the strain level affects the corrosion of prestressed strands. In this work, the mechanical properties of corroded prestressed steel strands under different strain levels were tested by experiment. The results show that the existence of strain will increase the corrosion amount, but the effect of strain on the corroded strand’s mechanical properties is not uniform. The mechanical properties of strands decrease linearly with increase of corrosion amount, but the dispersion is large, so the probability method is more suitable. The probabilistic prediction model of corroded strands’ mechanical properties is proposed in this paper, and the prediction results are compared with the experimental results. The prediction results are consistent with the test results, and the range of prediction results is narrower than the test results. But the prediction result of elongation does not align well with the experimental work.