Procjena ponašanja konstrukcija u graničnim uvjetima rada

Assessment of structural behaviour in limit state operating conditions

Structures are designed according to their purpose taking into account all relevant service life requirements, which are usually related to a factor of safety, material properties, service life conditions and of course service life prediction. Structure may be sometimes exposed to unexpected conditions, let say adverse or hazard conditions. These conditions may cause failures making structure incapable to perform the function for which it has been designed. The task is to make an assessment of the structure behaviour at mentioned conditions and decide if the structure is capable for further operation. This means the assessment should provide an answer if the structure has sustained irreparable damage. Therefore, the main objective is to provide an assessment of structure behaviour, by comparing of the parameters like stress, strain, crack occurring, etc., caused by certain load level and temperature at this unexpected limit state with those allowed by material properties. To assess structural behaviour in operation at limit state, the following research sub-objectives should be accomplished: testing of material properties for the different environmental conditions; definition of impact energy as well as the determination of the crack driving force and life assessment of structural elements; evaluation of the semi-rigid structural joints/connections behaviour; development of a numerical algorithm for optimization of semi-rigid framed structures; creep buckling simulations of composite beam-type structures; proper constitutive modelling at limit operating conditions (i.e. plasticity, damage, thermomechanical coupling); application of new materials to be used at limit state – nanocomposites. Targeted structures are single and multi storey steel buildings, rigs, high-power electrical transmission towers, ship structures, etc.