[en] An anaylsis procedure that can be used to evaluate the performance of light water reactor steel containments subject to pressure and temperature loadings beyond the design basis is presented. The potential failure modes in steel containments are identified. Results of experiments on 1:32-scale models and a 1:8-scale model of free-standing steel containments are reviewed. The general shell failure mode for steel containments is discussed, including a proposed evaluation criterion for failure. Appropriate methods for calculating the structural response of steel containments are also described. Methods for evaluating the leakage potential of penetrations are discussed in a companion paper