PRO-SIS
Policy objective: PO1 - A more competitive and smarter Europe by promoting innovative and smart economic transformation and regional ICT connectivity
Specific objective: SO1 - Developing and enhancing research and innovation capacities and the uptake of advanced technologies
Typology: Capitalization project
As part of the "CONSTRAIN" project, intervention strategies for reducing the seismic vulnerability of existing masonry buildings were developed and their effectiveness verified through a significant experimental campaign. Basically, the proposed strategies make it possible to obtain significant reductions in seismic vulnerability with interventions carried out from outside the buildings, without requiring the movement of people and things inside the buildings, with significant savings in economic terms but above all in terms of discomfort for people.
- This results in significant financial savings, but more importantly, it makes the intervention much more occupant-friendly. In the proposed project, we intend to develop a design methodology or guidelines and apply it to actual buildings that are planned for seismic retrofitting. The analytical and numerical procedures will be validated and calibrated on the investigations already carried out in the CONSTRAIN project.
Development and calibration of numerical algorithms (WP1)
The PRO-SIS project began with an in-depth analysis of the experimental tests carried out within the "CONSTRAIN" project, which investigated the effects of reinforcing historic masonry using GFRP mesh reinforced mortar coatings applied on one both sides (Fig.1).
Fig.1 - "CONSTRAIN" structural consolidation of masonry walls: application (a) and configuration for reinforcement on both sides (b), and on one side (c)
A thorough analysis of the response and damage evolution in the tested piers and spandrels was carried out. The analysis was followed by a critical and systematic discussion of the results with focus on strength, displacement capacity, stiffness degradation, accumulated and dissipated energy, and damping parameters. This allowed the identification of the response mechanisms of the system (Fig. 2) and the definition of reliable analytical models to quantify the effectiveness of the reinforcement through simple relationships suitable for practical use in structural design.
Fig.2 - Schematization of the main mechanical response mechanisms of the reinforcement system for the reduction of the seismic vulnerability of masonry buildings
To extend the validity of the identified behaviour patterns, advanced detailed numerical models were developed, calibrated and validated (using Abaqus and OOFEM software, Fig 3). This approach enabled a more in-depth analysis and interpretation of the interactions between masonry and the reinforcement system, and allowed the investigation to be extended to a wider range of scenarios with more complex configurations (different materials, geometries, and boundary conditions; Fig 4).
Fig.3 - Schematization of the two detailed numerical models: Abaqus (a) and OOFEM (b) and example of validation by comparison with experimental tests on masonry piers (c)
Fig.4 - Parametric analyses conducted on structural configurations of increasing complexity: examples of comparison between damage patterns that emerged from detailed simulations using the Abaqus (a) and OOFEM (b) software
The peculiarities and capabilities of various commercial software currently used in professional practice for the pushover analysis of masonry buildings (Midas GEN, Tremuri, PROSAP, SREMB) were investigated. The software models are based on different variations of the equivalent frame method with concentrated plasticity, and new robust methodologies were developed for implementing the studied reinforcement systems into this framework. The different operational strategies were systematically described, organized and compared.
Below are the research outputs:
Report 1.1 | Analytic model for dimensioning
Report 1.2 | Numerical models for the simulation of the behavior of reinforced elements/buildings
Report 1.3 | Results of case studies analysis of structural elements and entire buildings
Report 1.4 | Definition of parameters for simplified automatic calculation programs
Report D1.4.2 | Report on analytical and numerical modeling
Guidelines for the design and application of "CONSTRAIN" seismic strengthening (WP2)
In the second phase of the project, benchmark wall configurations of increasing complexity were identified, and simulated in different software. A comparison and critical discussion of the results was carried out, highlighting similarities and differences (Fig.5). For some configurations, the reliability of the simplified analyses was also assessed by comparing their results with those obtained from detailed modelling.
Fig.5 - An example comparing the results of the analysis of a masonry wall obtained using different calculation software based on equivalent frame models and a simplified analytical–mechanical method
In addition to several simple configurations of masonry piers, portals, single walls with one or more levels; a pilot building (also experimentally tested within "CONSTRAIN" project), and an entire building (Fig.6) were analysed by pushover analysis. Overall, the results showed good agreement among the different computational tools. The analysis of the latter case study also enabled a comparison of the effects of the intervention at the global building scale, considering varying levels of invasiveness (e.g. application on one side of the perimeter walls alone or of all the walls, application on both sides of all the walls).
Fig.6 - Comparison of the results obtained from the analysis of a real masonry building with the help of different calculation software (equivalent frame models)
All partners cooperated in the drafting of "Guidelines for the design and application of CONSTRAIN strategies". The document is structured in three different chapters, each dedicated to a specific role of the user: owners/managers of real estate and investors, designers and construction workers/work supervisors:
- Section for real estate owners/managers and investors: contains information on when structural reinforcement of existing buildings is necessary, identifies cases in which the "CONSTRAIN" system for seismic strengthening is recommended, and examines its economic aspects and applicability, including in buildings protected by conservational constraints.
- Secion for designers: describes the phases of the intervention design process, from the preliminary inspection of the building and the collection of significant data to the definition of the structural modelling strategy for the assessment of seismic vulnerability. The section also includes examples, instructions for the interpretation of the results obtained with different commercial software and finally presents the maintenance manual of the CRM system.
- Section for construction workers and work supervisors: provides detailed instructions on all application phases, from the initial inspection of the masonry to the execution and maintenance of the "CONSTRAIN" reinforcement. Each step is supported by illustrations, highlighting critical phases and common mistakes to avoid. The operational aspects for the correct implementation of the reinforcement intervention are also explained, supported by detailed drawings (Fig.7).
Fig.7 - Extract from the "CONSTARIN Guidelines" with some construction details of the "CONSTRAIN" reinforcement system for the structural consolidation of existing masonry buildings
Below are the research outputs:
Report 2.1 | Results of the analyses on various existing masonry buildings with the procedures of WP1
Report 2.2 | Graphic comparison of the results
Report 2.3 | Design of seismic strengthening CONSTRAIN
Report 2.4 | Guidelines for the design and implementation of the “CONSTRAIN” strategies
Pilot application on existing masonry buildings (WP3)
The last phase of the project the application of the proposed reinforcement strategy was designed for two "case study" buildings:
- in Italy, a social housing building dating back to the 50s has been identified (Fig.8a): it is a brick masonry structure on two levels plus basement. The structure was selected because it is a very common type of construction built in the past for social housing throughout Italy, designed by the Ministry of Public Works. In this case, the goal was to reinforce the building by limiting the invasiveness of the intervention inside as much as possible, so as to reduce the cost and inconvenience associated with the temporary relocation of tenants.
- in Slovenia, a historic building in the centre of Ljubljana (Fig.8b) dating back to 1885 has been identified: it is a brick masonry structure on three levels plus basement and attic. The building is subject to the protection of the external facades and some frescoes in some internal common areas (Fig.8b). In this case, the goal is to reinforce the building by intervening only from the inside, preserving the external facades.
Fig.8 - The two case studies: the building in Udine (a) and the one in Ljubljana (b)
For each of the two buildings, the technical documentation and original drawings were collected and the necessary inspection and survey operations were carried out. In-situ investigations were performed on the building in Udine, to acquire further information on the characteristics of the materials (Fig.9a). For the historic building in Ljubljana, on the other hand, in-depth inspections were carried out to verify the actual state and assess the consistency of the main structures in order to deduce their mechanical characteristics.
Fig.9 - Experimental investigations on the two pilot buildings: in-situ destructive tests on the building in Udine (a) and visual and detailed surveys on the building in Ljubljana (b)
The seismic vulnerability assessment of the two ‘case study’ buildings was carried out through global pushover analyses, adopting an equivalent frame model with concentrated plasticity using Midas Gen software for the building in Udine and 3Muri for the one in Ljubljana. The results showed that, in their current condition, the seismic capacity of both buildings is inadequate with respect to the requirements set by current regulations. The "CONSTRAIN" strengthening was then designed and new simulations were performed, allowing for a comparison between the structural performance before and after the intervention (Fig.10).
Fig.10 - The two numerical models developed for the seismic vulnerability analysis of the building in Udine (a) and Ljubljana (b)
In accordance with the specifications and construction details provided in the "CONSTRAIN Guidelines", the executive drawings of the two structures and of the strengthening interventions planned by the project were developed. The interventions were then quantified and economically evaluated. Finally, a price analysis of the intervention was carried out, together with a study of the direct and indirect costs, such as those related to the temporary relocation of occupants, also in comparison with traditional strengthening strategies.
Below are the research outputs:
Report 3.1 | Collection of drawings of selected buildings and description of characteristics
Report 3.2 | Results of the technical documentation collections on the pilot buildings
Report 3.3 | Assessment of the seismic vulnerability of pilot buildings
Report 3.4 | Executive design documents concerning the interventions on the pilot buildings
Report 3.5 | Economic comparison of proposed interventions costs versus usual costs
Report D3.5.2 | Final report on WP3 outputs
Dissemination and communication activities
In October and November 2025, a series of technical seminars and thematic conferences were held for the dissemination of the project results, addressed to:
- membersof professional associations (Engineers) - 8 meetings of 3 hours (4 in Italy, 4 in Slovenia)
- PA technicians, Civil Protection, National Association of Building Contractors - 6 meetings of 3 hours (3 in Italy, 3 in Slovenia)
Fig.11 - Cities where the seminars were held
Fig.12 - Seminar at the Order of Engineers in Pordenone (31. 10. 2025), a) and at the Chamber of Commerce in Ljubljana (11. 11. 2025, b)
Below are the research outputs:
Seminar slides | Design strategies and analysis of composite reinforced mortar (CRM) reinforcements for masonry buildings
In addition, the LP had the opportunity to communicate and disseminate the project activities in progress in the context of two international conferences in the field of civil engineering:
REHABEND Congress “Construction Pathology, Rehabilitation Technology and Heritage Management” (7-9 May 2024): presentation of the paper entitled “The strengthening of floor and roof masonry ring beams with fibre-based composite materials: experimental tests”
HIVIB Symposium “16th International Symposium on Human-Induce Vibrations and Seismic Influencer on Structures” (15-18 May 2024): presentation of the paper entitled “Seismic performance of CRM strengthened masonry: from experiments to analytic approach”
