Probabilistic model of torsion capacity of randomly corroded circular steel tube

The torsion capacity is one of the key parameters of circular steel tubes (CSTs). Corrosion can obviously decrease the torsion capacity of CSTs. The aim of this work is to quantify the influence of corrosion on the torsion capacity. The applicability of derived conclusion for CSTs with different D/t ratio is investigated. The random local corrosion which is most common in accrual condition is adopted. The geometrical imperfection on the torsion capacity of corroded CSTs is also revealed. The corroded thickness tc/t is assumed to follow different probabilistic distributions and then the influence of distribution model is analyzed. The changing rule of residual torsion capacity along with mass loss ratio is presented. The probabilistic distribution model of reduction factor of torsion capacity Θ followed normal distribution and the analytical method to determine the probabilistic distribution model is proposed and verified. The numerical case indicated that the analytical method can accurately predict the random model of Θ.