1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Zagreb Cathedral was seriously damaged in the earthquake that hit Zagreb in March, 2020. The top of the southern tower broke and crashed down, while the northern tower was badly damaged. Because of high risk of collapsing and causing even greater damage to the Cathedral and surrounding buildings, it was necessary to remove the damaged part. Important and demanding phase of the removal has been conducted with blasting technology application. By small, directed explosive charges, connection anchors of the tower and lower loading stone coronet had been detached. Instantaneously, steel rope of counterweight mass lead sphere has also been cut. Blasting demolition technology is common practice during the earthquake recovery period and is applicable for demolition of whole or parts of damaged buildings. Blasting works that have been performed on the cathedral are unique because of safety limitations, its importance as a monument, altitude and rendering condition. The part of the bell tower that could collapse weighted about 36 tons, with a total height of 13.47 meters including its cross. This paper describes how design and technical solution were developed, how research and testing were carried out and how the blasting part of removal, immediately before tower lifting, was performed.