Experimental validation of an eigenvalue problem-based inverse solution for damage detection in masonry minarets☆

Abstract

Historical, monumental, and artistic structures such as masonry minarets are vulnerable during dynamic events like strong winds and earthquakes due to their brittle materials and slenderness. Many of them have collapsed throughout history around the world. Structural Health Monitoring (SHM) is essential for regularly assessing the health of minarets, enabling early warning of potential collapse and informing preservation efforts. It is crucial to accurately indicate the occurrence and location of damage under practical conditions. An effective SHM method should be implemented, particularly considering simple sensor networks under ambient conditions. The study experimentally verifies an eigenvalue problem-based inverse solution designed for damage detection in high-rise buildings, applied here to a 3.625 m-high masonry minaret made of brick and mortar materials in a laboratory setting. A simple sensor network consisting of three uniaxial accelerometers is positioned along the height of the minaret. To circumvent the issue of limited measured degrees of freedom (DOFs), based on the installed sensor network, the minaret is modeled as a lumped mass system. Damage occurring between any pair of accelerometers can be detected based on the stiffness reduction in the simplified system. The results confirm that the inverse solution is promising for practical applications, as it enables accurate detection of typical damage modes using only the first two bending modes.