Research On Fuzzy Time-varying Reliability Of Serviceability Limit State For Structural Members Of Steel Reinforced Concrete (SRC)

The effect of fuzziness of failure criteria, deterioration of resistance and change of the maximum load during different purpose reference periods is comprehensively considered in analyzing reliability in serviceability limit state for structural members in this paper, the concept of fuzzy time-varying reliability is presented, which make the reliability of structural members more consistent with the actual situations and can predict failure time of structural members.To calculate the fuzzy time-varying reliability, the static fuzzy reliability is calculated firstly and then considering the effect of time, thus different purpose reference periods can be obtained, that is the fuzzy time-varying reliability of structural members.The improved Monte Carlo method is presented to calculate the fuzzy reliability, in this method the deduction of complex mathematical formula is unnecessary to calculate standard deviations of variables, the multiple samples of random variables achieved by a computer is merely necessary, then an adequate precise solution is obtained, which can provide a simple and effective method for fuzzy reliability.The deterioration of resistance and changes of the maximum load during different purpose reference periods must be considered in calculating time-varying reliability. To apply the loads defined in the load code, the effect of different purpose referenceperiods to reliability is taken into account by amending those loads in this paper. The deterioration regularity of resistance for SRC bending members has not been seen so far, so the related research achievements of RC structural members are approximately used in this paper.Applying the method mentioned above, the fuzzy time-varying reliability of serviceability limit state about crack width is analyzed for a simply supported SRC beam, and some valuable conclusions are obtained.