task 3 - vulnerability assessment and risk evaluation methodologies
When assessing seismic vulnerability of buildings it is fundamental to establish the objectives purposed and in function of those, chose the most adequate strategy and tools for the assessment. The past development of a vulnerability index method formulation for the vulnerability assessment of masonry buildings has brought to attention the most important parameters that control building damage and must be surveyed individually. The substantial knowledge and work in Italy over the past 25 years, opens an opportunity to improve first and second level approaches supported by methodologies that introduce more detailed analysis, resulting from the good level of building stock information. It is intended to discuss and redefine the criteria of some of the most important aspects that should be assessed, such as the interaction amongst buildings (structural aggregates) and other overlooked building features [26].
For example aligned buildings, usually present connection problems of façade walls to orthogonal walls. The efficiency of the horizontal diaphragms and roof connections is also an important issue in the out-of-plane collapse mechanisms. From the Italian historical earthquakes [15,16], the majority of the damages were associated to out-of-plane collapses of masonry façade walls that at falling, consequently lead to a high death rates and blocked route access into the city mesh. Therefore two new approaches for the issue of seismic vulnerability assessment strategies for façade walls and masonry building aggregates will be developed and calibrated. For the seismic risk evaluation, hazard will be undertaken in a deterministic approach based on mascroseismic intensities, so it is possible to use and relate to the EMS-98 [19] damage scale.
Expected results:
The vulnerability approach that has been previously created [21] is a blend of the typological and conventional methods that bring out the best results for large scale assessments. Several midterm goals within this task are expected to be fulfilled:
When assessing seismic vulnerability of buildings it is fundamental to establish the objectives purposed and in function of those, chose the most adequate strategy and tools for the assessment. The past development of a vulnerability index method formulation for the vulnerability assessment of masonry buildings has brought to attention the most important parameters that control building damage and must be surveyed individually. The substantial knowledge and work in Italy over the past 25 years, opens an opportunity to improve first and second level approaches supported by methodologies that introduce more detailed analysis, resulting from the good level of building stock information. It is intended to discuss and redefine the criteria of some of the most important aspects that should be assessed, such as the interaction amongst buildings (structural aggregates) and other overlooked building features [26].
For example aligned buildings, usually present connection problems of façade walls to orthogonal walls. The efficiency of the horizontal diaphragms and roof connections is also an important issue in the out-of-plane collapse mechanisms. From the Italian historical earthquakes [15,16], the majority of the damages were associated to out-of-plane collapses of masonry façade walls that at falling, consequently lead to a high death rates and blocked route access into the city mesh. Therefore two new approaches for the issue of seismic vulnerability assessment strategies for façade walls and masonry building aggregates will be developed and calibrated. For the seismic risk evaluation, hazard will be undertaken in a deterministic approach based on mascroseismic intensities, so it is possible to use and relate to the EMS-98 [19] damage scale.
Expected results:
The vulnerability approach that has been previously created [21] is a blend of the typological and conventional methods that bring out the best results for large scale assessments. Several midterm goals within this task are expected to be fulfilled:
- Improvement and development of vulnerability assessment approach for the building typology – masonry – therefore evolving into more reliable vulnerability assessment models that can combine statistical and mechanical convergence, in the sense that they could lead to bidirectional validation by adjusting criteria by using the Bayesian theory;
- The use and implementation of such vulnerability assessments integrated into a macroseismic methodology based on the EMS-98 [19] damage scale will enable to put forward damage and loss scenarios, such as: collapsed and unusable buildings, human casualties, economic loss, for risk mitigation and management purposes;
- Creation of earthquake scenarios for the urban areas, enabling to estimate and forecast the direct and indirect consequences of economical and physical impact; establish and validate a modular approach for creating building vulnerability databases, damage and cost evaluation for other historical urban areas;
- Development of a new methodology for the seismic vulnerability assessment of masonry façade walls and building aggregates. In this new methodology, the seismic vulnerability of the façade will be evaluated through the individual assessment of a group of parameters, where each parameter evaluates one particular aspect related to the seismic response of a masonry façade wall. The proposed vulnerability assessment formulation will be based on post-seismic damage survey data and on the identification of constructive and technological parameters that most influence damage suffered by masonry building façades.
- All the database information associated to the assessment procedure developed for masonry façades and aggregates are integrated into the GIS application and can be periodically updated, allowing the mapping of different damage scenarios, risk reduction actions associated to definition of strengthening strategies of existing buildings.