During construction of viaduct "Stara Susica" on the highway Zagreb - Rijeka in Croatia due to unpredicted mistakes in the execution works sudden fall of prestressed prefabricated beam girder (30 meters long and around 100 tons weight) had happened. During the fall the girder hit the column in its second third of height and caused significant damage of reinforced concrete column. Preliminary visual inspection implied only local damage of surface concrete of the column cross-section, without the indication of deeper structural damage. The combination of nondestructive techniques (ultrasonic pulse velocity and impact echo method) was used for the assessment of column structural damage, which had shown significantly greater structural damage of concrete, with deeper cracks detected within the concrete column than firstly visible from the surface. The combination of nondestructive methods gave a better image of structural damage, considering the size and depth of damage, which was the base for the design project of the column repair (choice of repair methods, technology and materials). In this case study nondestructive evaluation improved both the efficiency and accuracy of column inspection and justified its application in the structural damage assessment.
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