Classification of Collapsed Buildings for Fast Damage and Loss Assessment

Abstract

Fast and reliable identification of collapsed buildings is essential in case of earthquake disasters in urban areas. Airborne laserscanning offers the possibility to fulfil this task. Based on height measurements, geometrical surface models of buildings can be generated with this technology. Comparing the undamaged pre-event models with those recorded after an earthquake, the location of collapsed buildings and the dimension and characteristic of their damage can be obtained. The knowledge about typical damage types of collapsed buildings is necessary to interpret the changes found between the pre- and post-event building models. As existing building damage classifications don’t meet the requirements of this novel technique, observations and reports of building collapses were analysed. This leads to a new classification system of collapsed buildings and the definition of the so-called “damage catalogue”. The damage catalogue is a composition of different damage types of entire buildings typically occurring after earthquakes and it contains the observed dimensions of the geometrical features such as volume reduction or inclination change for each damage type. Besides the detectability of these geometrical features in airborne laserscanning data, the differentiation of the damage types takes effects on casualty numbers and on different search and rescue needs into account. The damage catalogue was developed by evaluating the associated database, which contains the characterisation of real damaged buildings by the defined geometrical features. The paper includes the conception of the damage catalogue and of the associated database, their use for the described reconnaissance technique and their further application possibilities.