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During the exploitation period, the properties of reinforced concrete in structures constantly decrease, resulting in damage that directly affects serviceability of the structures. Initiation and development of damage are time-dependent phenomena accompanied by deteriorating processes, which are differently implied depending on the environment. The influence of environment is an important factor that determines type of damage and mode of propagation, and damage level depands on the exposure of structures elementsto aggresive action.

U radu je prikazan novi pristup koji omogućuje aktivno praćenje stanja konstrukcija i otkrivanje oštećenja na masivnim armiranobetonskim konstrukcijama, a utemeljen je na primjeni piezoelektričnih pametnih agregata. U matričnom je obliku izveden inovativni trodimenzionalni indeks oštećenja baziran na valićnoj dekompoziciji signala i energiji prostiranja valova. Iako se predloženi trodimenzionalni indeks oštećenja može koristiti za sve vrste armiranobetonskih konstrukcija, prije svega se ipak preporučuje za masivne infrastrukturne građevine. Pristup predložen u ovom radu teoretski je izveden za proizvoljni oblik armiranobetonskog elementa, te je numerički provjeren u raznim scenarijima variranjem geometrije armiranobetonskih elemenata, isto kao i položaja, veličine i rasprostranjenosti oštećenja. Kvazistatička analiza piezoelektričnih pametnih agregata modelirana je pomoću standardne metode konačnih elemenata, a u ovom je istraživanju uspješno primijenjena eksplicitna metoda konačnih elemenata za modeliranje prostiranja ultrazvučnih valova. Rezultati bazirani na numerički generiranim simulacijama upućuju na perspektivnost novog pristupa za nerazorno otkrivanje oštećenja pomoću trodimenzionalnih indeksa oštećenja., A novel approach to active structural health monitoring and damage detection of massive reinforced concrete structures using piezoelectric smart aggregates is presented in this paper. An innovative three-dimensional damage index, based on wavelet signal decomposition and energy of wave propagation, is derived in matrix form. Although the proposed three-dimensional damage index can be used for all types of reinforced concrete structures, it is primarily recommended for massive infrastructure buildings. The approach proposed in this paper is theoretically considered for an arbitrary shape of a reinforced concrete element, and it is numerically verified for various scenarios by varying the geometry of reinforced concrete elements, as well as the position, size and quantity of damage. Quasi-static analysis of piezoelectric smart aggregates is modelled using a standard finite element method, and the explicit finite element method is successfully applied in this research for modelling propagation of ultrasonic waves. The results based on numerically generated simulations indicate that the new approach to non-destructive damage detection using three-dimensional damage indexes is quite promising.