Structural analysis and design of a nuclear power plant building for aircraft crash effects

The object of this investigation is to assess the effect of a large commercial airplane crashing perpendicularly on to the surface of a spherical reactor building dome. This investigation is related to a project currently in execution. Practical solutions of the postulated case, which vary in the degree of engineering effort used, are shown. Based on safety consideration the various solutions are discussed from the viewpoint of penetration, cracking and collapse modes of failure, where, primarily, the carrying capacity of the structure under an equivalent statical load is considered. The performed investigations include:

1. (a) Calculation of the failure load following the yield line theory;

2. (b) Calculation of the sectional forces using the linear-elastic shell theory and subsequent design by the ultimate strength method;

3. (c) Calculation of the failure load, establishing of the failure mechanism and distribution of sectional forces using the plastic shell theory;

4. (d) Calculation using a three-dimensional FEM program with plastic capabilities; this includes the collapse load, the failure mechanism and the distribution of sectional forces.

A discussion of the resultant forces and the configutation of the critical section is given for the various methods used. The evaluation of the carrying capacity of the structure with respect to load is based on energy considerations. It is attempted to compare such results, to evaluate possible simplifications in the used solutions, and to give some recommendations for the practical design and for the development of structural details.