The main concepts underlying the application of modelling to the assessment of structural behaviour are examined. Criteria for safety and performance evaluation, modelling assumptions, analysis techniques and validation procedures are discussed. The papers submitted to this theme are briefly reviewed, stressing the major contributions.
On examine les concepts principaux subjacents à l'application de la modelisation au jugement du comportement structural. On discute les critères pour l'evaluation de la securite et performance, les hipothèses de la modelisation, les techniques d'analyse et les procedes de validation. Les communications soumises a ce thème sont brièvernent passees en revue, en accentuant les contributions majeures.
Die wichtigsten, der Anwendung der Modellierung fuer die Bewertung des strukturellen Verhaltens zugrundeliegenden Begriffe werden untersucht. Kriterien fur die Sicherheits- und Ausfuehrungsabschatzung, Modellierungsannahmen, Techniken fuer die Analyse, und Verfahren zur Gueltigkeitsbestatigung werden diskutiert. Die zu diesem Thema eingereichten Referate werden kurz besprochen, unter Betonung der Hauptbeitrage.
Rock Engineering concerns a broad field of activities, such as those related to civil, mining and petroleum engineering, as well as to the earth sciences (Rocha 1983). The economic development and the improvement of the quality of life have led to interventions in the environment of unprecedented dimensions, such as those in the fields of the land and marine environment (geology and geotechnology, marine geology, natural hazards, earthquakes), of the natural resources (dams, reservoirs, mines), and of the transportation networks (roads, bridges, etc.). Rock masses support structures (foundations, slopes, tunnels, wells and caverns). The object of rock engineering is therefore the planning, design, construction, maintenance and rehabilitation of the above indicated structures. Owing to their nature, and to the presence of joints and faults, rock masses are generally heterogeneous and discontinuous media, with complex, anisotropic, non-linear behaviour. Furthermore, the processes of their formation and alteration in time led to installation of complex states of strain and stress. Rock engineering should therefore be viewed within the framework of the relations between Man and environment. When intervening in the environment with the purpose of developing, modifying or protecting it, the engineer starts, in a first phase, by monitoring the environmental variables which may be of interest. A modelling phase will follow, in which the engineer develops the models for the interpretation of the monitoring results and for evaluation of the planned intervention. The design of the intervention is the third phase, and finally the implementation of the intervention is the fourth phase. As each intervention modifies the environment, to start a new intervention we should return to the first phase, i.e., to the monitoring of the modified environment. This cycle thus continues indefinitely (Oliveira & Pedro 1992, 1993). Modelling in rock engineering is therefore an important phase in the cycle of the intervention in the environment, which essentially provides support for monitoring and design activities. Both these activities require the assessment of the structures behaviour either to control their operation or to evaluate the design solutions. The assessment of the behaviour of the structures in rock masses is supported by appropriate criteria, models and methods of analysis. In recent decades, however, important steps have been made towards the separation of concepts concerning the criteria, models and methods of analysis, as well as towards the unification of those concepts for the different types of structures (Borges & Castanheta 1983, Rocha 1978, ICOLD 1984, 1987, 1993). In the following sections of this report the scope of the theme will be defined, the papers presented will be briefly reviewed, and some questions which seem to deserve further discussion will be selected.