task 4 - mechanical methods for the vulnerability assessment and uncertainty analysis
Masonry building aggregates result from the progressive transformation of the urban tissue. There are various features that define the earthquake response of such building aggregates, such as: shared mid-walls of adjacent buildings, staggered floors, masonry heterogeneity, openings, building plan and height interaction. Therefore, since the reliable global response is not due to structurally independent units (buildings), it is a very actual debate on how to foresee the behaviour of building aggregates under earthquake action and identify structural fragilities and promote seismic protection measures.
Inherently mechanical models for the vulnerability assessment of masonry buildings take into account the uncertainties of the structural parameters and the damage limit states. The main goal in this task is to achieve a bilinear model for the capacity spectrum for masonry buildings as an analytical function of a few numbers of geometrical and mechanical parameters [28]. Applying a suitable procedure for the uncertainty propagation, the statistical moments of the structural capacity is obtained as a function of the statistical moments of the input parameters, showing the role of each in the results. Using the capacity spectrum method [29], the vulnerability analysis can be carried out with respect to a certain number of random damage limit states which depend on the building parameters [30].
Fragility curves can be derived taking into account the uncertainties of each quantity involved. Additionally it will include the introduction of the uncertainty associated to the response spectrum and the analysis of the model error contributions. With the vulnerability analysis of building aggregates, fragility curves and consequently damage distributions can be estimated using the procedure to be developed and compare this approach to the macroseismic methods developed in task 3. This task is coordinated and supervised by Humberto Varum. Professor Alex Barbat is the consultant that will be integrated into this task for his accumulated research on structural analysis of masonry.
Expected results:
The proposed model will be based on the capacity spectrum method and represents a strong procedure in the structural behaviour assessment of masonry building aggregates. The main expected results within this task are essentially:
Masonry building aggregates result from the progressive transformation of the urban tissue. There are various features that define the earthquake response of such building aggregates, such as: shared mid-walls of adjacent buildings, staggered floors, masonry heterogeneity, openings, building plan and height interaction. Therefore, since the reliable global response is not due to structurally independent units (buildings), it is a very actual debate on how to foresee the behaviour of building aggregates under earthquake action and identify structural fragilities and promote seismic protection measures.
Inherently mechanical models for the vulnerability assessment of masonry buildings take into account the uncertainties of the structural parameters and the damage limit states. The main goal in this task is to achieve a bilinear model for the capacity spectrum for masonry buildings as an analytical function of a few numbers of geometrical and mechanical parameters [28]. Applying a suitable procedure for the uncertainty propagation, the statistical moments of the structural capacity is obtained as a function of the statistical moments of the input parameters, showing the role of each in the results. Using the capacity spectrum method [29], the vulnerability analysis can be carried out with respect to a certain number of random damage limit states which depend on the building parameters [30].
Fragility curves can be derived taking into account the uncertainties of each quantity involved. Additionally it will include the introduction of the uncertainty associated to the response spectrum and the analysis of the model error contributions. With the vulnerability analysis of building aggregates, fragility curves and consequently damage distributions can be estimated using the procedure to be developed and compare this approach to the macroseismic methods developed in task 3. This task is coordinated and supervised by Humberto Varum. Professor Alex Barbat is the consultant that will be integrated into this task for his accumulated research on structural analysis of masonry.
Expected results:
The proposed model will be based on the capacity spectrum method and represents a strong procedure in the structural behaviour assessment of masonry building aggregates. The main expected results within this task are essentially:
- Development of a mechanical model for the vulnerability assessment of masonry building aggregates. The analytical formulation will allow the interpretation of uncertainties that affect the capacity spectrum and the damage limit states and will be calibrated resourcing to parametric studies;
- The capacity spectrum method on which the proposed model is based represents a strong alternative to other vulnerability simplified methodologies and will allow a bilateral validation with macroseismic methods;
- The implementation of an automatic procedure to create fragility curves for different building typologies within the masonry type;
- Development of an assessment procedure for building aggregates using a mechanical method without overlooking features linked to uncertainty.