Experimental Modal Analysis of U-Shaped Adobe-Mudbrick Wall Units

Abstract

Millions of people around the world live in traditional adobe-mudbrick houses which are at significant risk of damage and collapse due to earthquakes. To improve the earthquake resistance of traditional adobe-mudbrick structures, a research program is being undertaken at the University of Technology, Sydney, which involves the shake table testing of scale model (l :2) u-shaped adobe wall units with different structural reinforcement systems. Experimental Modal Testing and Analysis (EMTA) has been carried out prior to and during the shake table testing in order to obtain the natural frequency of each test specimen (to allow proper dynamic similitude) and to study the stiffness, strengthening effects and dynamic behaviour of different specimens. This paper describes the Experimental Modal Testing and Analysis of two adobe-mudbrick specimens, focusing on the procedure and outcomes for impact excitation (using a modal hammer).