Time-dependent reliability analysis of corroded reinforce concrete beams in the atmospheric environment
School of Architecture and Urban Planning, Yunnan University
The limit state equation with random parameters is established based on the time-dependent model of reinforcement material performance and the degradation probabilistic model of shear strength and bending strength in corroded reinforced concrete beams under atmospheric environment. The probability density evolution equation which satisfies the limit state equation is obtained based on the principle of probability conservation, and the calculation method of time-dependent reliability for the degradation strength of beams is proposed by introducing absorbing boundary conditions. The probability density evolution process of objection function is shown and the time-dependent reliability of different diameters of stirrups and different depth of concrete cover is discussed by taking a simply supported corroded reinforced concrete beam subjected to symmetrical concentrated loads as an example. The results show that the degradation of mechanical properties of concrete members can be delayed by appropriate increasing the concrete cover depth and the stirrups diameter under the precondition that the beam has enough initial shear strength and bending strength. By comparing with 1 million Monte Carlo simulation results, it can be seen that the proposed method can obtain the analysis results with good calculation accuracy at the premise of paying less computational cost.