Diagnostic methodological approach: innovative aspects for masonry structures

Nowadays it is widely shared an increasing attention toward the built heritage, which mainly comprises the historic buildings, but also includes the more modern structures that are often characterized by severe decay, as well. In fact, a new concept of town development, primarily based on life quality, has lately required the refurbishment, retrofitting and preservation of buildings and urban areas, by specific intervention criteria and methodologies, especially whenever historical and architectural values are involved. Within this scenario, the knowledge is a prominent issue. Specifically, the knowledge - i.e. the qualification of historic features, materials and construction techniques, structural and functional modifications, and state of conservation of the building and its components - is the necessary preliminary phase for the assessment of residual performances and, thus, the definition of appropriate refurbishment/maintenance works. It should be underlined that the variety of available investigation approaches and methods requires the knowledge process to be carefully organized, in order to optimize times and techniques, as well as to continuously verify the consistency of the qualification needs with the history, the technical/ technological features, and the state of conservation of the building. In fact, the uncritical application of methods and techniques seldom leads to a satisfying outcome, because data might be meaningless and/or not correlated toward a comprehensive analysis for the design development. Nevertheless, it should be observed that despite the diffuse awareness of basic alteration mechanisms and the wide availability of diagnostic tools, the definition of practices and procedures for diagnostic investigation, according to a multidisciplinary approach, is still challenging, in order to support and guide professionals and operators in the field of building refurbishment. A missing systemic vision generally implies the development of high specialism, which might prevent from the correlation of several investigated aspects. Besides, there are limited normative standards about technical procedures to evaluate the conditions of existing buildings. As a result, it is reasonable to carry out all the possible tests in order to better complete the performance assessment. Finally, since there are limited prescriptions on testing methods, application procedures and data interpretation routines, the investigation to assess the quality of materials and structures is mainly based on discretion, experience and expertise. From the analysis of the methodologies for an investigation programme, the present contribution points out the definition of a knowledge framework as decision making support where choices and expected results are consistent. Particularly, it is possible to review and update the well established structure of a diagnosis and intervention process, with reference to the following macro tasks: Basic Knowledge, Data Management, Preliminary Analysis and Pre-Diagnosis, Further Knowledge, Diagnosis, Project, Intervention, Intervention Assessment, and Maintenance. Each macro task will be further specified in sub-tasks in order to point out the links of the decision flow with the available data bases (atlases of construction typologies, materials, pathologies, investigation methods and techniques) and the technical legislation codes. The complexity of structural systems and characteristics within the building heritage, as well as the variety of involved disciplines, require the definition of diagnostic tools from two points of view: on the one hand, the systematisation of the up-to-date knowledge; on the other hand, the structuring of the diagnostic testing programme, in terms of procedures, tools, application and interpretation routines.