Time-Dependent Reliability Analysis of Corroded Steel Beam

The time-dependent reliability of corroded steel beam was investigated. Nine groups of specimens were subjected to accelerate corrosion by the outdoor periodic spray test and monotonic tensile test. The surface profile of corroded steel plates and the 3D data of corrosion depth were measured by the three-dimensional non-contact surface topography instrument (PS50 3D). The probability distribution of corrosion depth and nominal yield strength of corroded steel plates were studied. Finally, a probabilistic limit state equation for corroded steel beams was established and the time-dependent failure probability and reliability index of corroded steel beams was calculated by Monte Carlo simulation method (MCS). The results of study show that the corrosion depth on steel plate surface and nominal yield strength of corroded steel plate conformed to the normal distribution. With the increase of corrosion time, the average, the standard deviation of the corrosion depth and relative yield strength increased while the mean of relative yield strength, nominal yield strength, nominal ultimate strength, the elongation decreased. The reliability index decreased rapidly with corrosion time, which shows that the reliability of steel structures under the aggressive environmental should be caused attention.