Natural frequencies of prestressed concrete beams : theoretical prediction and numerical validation

The paper explores the effects of prestress forces on modal parameters of concrete beams. This ongoing research has the twofold purpose of deepening a task of structural identification and of investigating possible applications with significant technical relevance. Concerning the former aspect, it is still not clarified whether prestress forces should be included or not in standard identification-model-updating frameworks. On the other hand, a well founded theoretical model, able to catch the experimental evidence, would be desirable in order to explore the feasibility of dynamic methods for assessing prestress level and prestress losses in concrete beams.