Evaluation of the vulnerability of existing building stocks under the impact of extreme natural hazards

• Applicant: Dr.-Ing. Jochen Schwarz
• Subject Area: Structural Engineering, Building Informatics and Construction Operation
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 278225923

The aim of the initial phase was the development of an engineering based evaluation system for the vulnerability of building stocks in their regional distribution under the impact of the natural hazards earthquake, flood, tsunami and wind and their combined consideration in the sense of a multi-hazard vulnerability. A key objective of the continuation phase is to refine and extent the developed models with the concept of the "LEGOization" of the existing buildings. The proposed sub-structuring of buildings in stories (including roof, basement and ceilings) allows the classification of the vulnerability and damage characteristics within the individual, unified separated building zones and the synthesis of representative building prototypes. In order to set the multi-hazard vulnerability in relation to the real hazard, exposure classes are defined which reflect the specific situation by the contributions of individual natural hazards at a site. On this basis, the dominance of the corresponding natural hazards can be evaluated and the consequences of individual hazard can be compared for different assumed occurrence rates. The extensive "field-oriented" data elaboration must be supplemented, replaced or preferably coupled with "Remote Sensing" technologies and the evaluation of aerial photographs for changing the situation and state (change detection) in different time windows. The impact intensity concept from earthquake hazard can be applied to other natural hazards, so that these can be combined with the characteristic damage to the building. The definitions of damage grades are extended with respect to damage patterns of roof construction and chimneys as independent substructures, which are particularly exposed at the top of the structure. Until now, the assessment of the vulnerability is global and focused on the whole building; it is foreseen to break down the evaluation on the locally differently affected building zones. Engineering and experience-based assignments of the most likely vulnerability classes and the identification of their uncertainty ranges have to be further differentiated for the transformation of the analytically-based fragility functions and have to be concentrated on sub-structured building zones. A hybrid approach has to be developed for damage prognosis combining empirical, analytical, and instrumental sources of information. The evaluation system has to be adapted in a way that the changes in the vulnerability due to temporally differently set events and sequences of identical and different natural hazards can be considered. The methodology developed for the simulation of building damage has to be applied to the natural hazards and their sequences. The aim here is to investigate the spreading of the impact side, building modeling and the final consequences for the damage prognosis. The developed elements have to be provided within a modular arranged databank structure leading to a "Conceptual damage simulation tool".

• DFG Programme: Research Grants