A complete analysis of a nuclear building to nuclear safety standards

The nuclear standards impose on the designer the necessity of examining the loads, stresses and strains in a nuclear building even under extreme loading conditions, both due to plant malfunctions and environmental accidents. It is necessary then to generate, combine and examine a tremendous amount of data; really the lack of symmetry and general complication of the structures and the large number of loading combinations make an automatic analysis quite necessary. A largely automatized procedure is presented in view of solving the problem by a series of computer programs linked together as follows. After the seismic analysis has been performed by (SADE CODE) these data together with the data coming from thermal specifications, weight, accident descriptions etc. are fed into a finite element computer code (SAP4) for analysis. They are processed and combined by a computer code (COMBIN) according to the loading conditions (the usual list in Italy is given and briefly discussed), so that for each point (or each selected zone) under each loading condition the applied loads are listed. These data are fed to another computer code (DTP), which determines the amount of reinforcing bars necessary to accommodate the most severe of the loading conditions. The Aci 318/71 and Italian regulation procedures are followed; the characteristics of the program are briefly described and discussed. Some particular problems are discussed, e.g. the thermal stresses due to normal and accident conditions, the inelastic behavior of some frame elements (due to concrete cracking) is considered by means of an 'ad hoc' code. Typical examples are presented and the results are discussed showing a relatively large benefit in considering this inelastic effect