RELIABILITY OF REINFORCED-CONCRETE CYLINDRICAL-SHELLS

Reinforced concrete shells are structurally complex and closed-form mo dels for their various limit states of serviceability and strength eit her are not available or may be based on approximations and idealizati ons of behavior. Nonlinear finite-element techniques have made it poss ible to account for account for the complexities of reinforced concret e behavior in the inelastic range, to identify these limit states more accurately, and to assess the safety and reliability of concrete shel ls. Traditional reliability analysis methods are more convenient to ap ply when closed-form mechanical models of limit states are available. In the absence of such models, the reliability analysis can be perform ed by response surface methods that approximate the limit states by po lynomial surfaces obtained through finite-element analyses of the syst em at a set of predetermined experimental points. This paper presents the reliability analysis of a reinforced concrete containment structur e by the response surface method. Axisymmetric nonlinear finite-elemen t analyses were performed to define the limit surfaces and importance sampling was used for the calculation of limit state probabilities.