Assessing the potential to use structure-borne sound to detect survivors in collapsed buildings

Abstract

When victims are trapped within a collapsed structure, it can be difficult to quickly locate survivors. Airborne sound tends to be highly attenuated hence there is greater potential to detect physical movement or signals from survivors by measuring the seismic response. Recent work has used Statistical Energy Analysis (SEA) and Finite Element Methods (FEM) to assess the feasibility of predicting structure-borne sound transmission across fragmented reinforced concrete structures. This has the potential to improve strategies for the detection of trapped survivors using structure-borne sound by search and rescue teams as well as seismic detection equipment. The main focus has been on vibration transmission between reinforced concrete elements that are in contact after the collapse. Laboratory experiments have been used to validate FEM models of reinforced concrete beam junctions with surface-to-surface contact conditions using Experimental Modal Analysis. This has given insights into the contact stiffness between reinforced concrete beams. FEM simulations of beams with surface-to-surface contacts as well as beam junctions with fragmentation at the junction indicate the potential to use SEA to give reasonable estimates of vibration transmission. This paper summarises the progress made to-date and considers the next steps that are needed in the research on this topic.