engleski

Development of Service-Life Prediction Models

The procedures for the determination of mechanical properties and structural stability are well defined and mathematically precise, while the durability of structures is still being determined empirically in most cases. International standards and various recommendations for reinforced concrete and prestressed structures design do not adequately define the durability conditions. Numerous cases of damaged reinforced concrete structures are evidencing the lack of such guidelines. Currently used approach is based on the awareness that similar to the determination of bearing capacity and deformability, the design process should include durability design as well. This means that environmental loads, relevant material parameters, numerical model and criteria for safety factors have to be defined during the design process. Unfortunately, not even one of these data is adequately solved in today's practice. Despite these shortages encountered in practice, the development of models for determination of service life is in continuing progress. It can be anticipated that service life prediction and associated assessment of durability will soon become a part of the project documentation and an integral part of the quality assurance. The paper presents an overview of existing models for the determination of concrete durability and service life prediction. Three groups of models, namely, empirical formulas, physical models and models based on elementary scientific laws are taken into the account. The emphasis is placed on the physical models, which are also used for the calculation of service life for the bridge structure exposed to the chlorides.

durability design; mathematical description; service life models

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