Retrofit strategies for Existing STructures against prOgRessive collapsE (RESTORE)
Lead Research Organisation:
UNIVERSITY COLLEGE LONDON
Department Name: Civil Environmental and Geomatic Eng
Abstract
Man-made extreme events (i.e., terrorist attacks, impacts, explosions, and fires) can cause local damage to structures which may spread from element to element leading to the collapse of the entire structure or a large part of it, i.e., progressive collapse. These are among the most severe events in terms of casualties, economic losses, and societal impact, as has been made evident by several cases, e.g., the progressive partial collapse of the Champlain Towers in 2021.
The RESTORE project proposes an innovative framework to assess the progressive collapse risk of existing Steel and Reinforced Concrete (RC) buildings subjected to man-made hazards and design robustness- and resilience-enhancing solutions. The project investigates innovative retrofit solutions, including combinations of global and local interventions, aiming for a trade-off between benefits and drawbacks of both strategies, thus enabling effective retrofit interventions against multiple hazards. They will:
- ensure structural redundancy, mitigating progressive collapse risk against multiple-hazards (robustness)
- provide an alternative to the demolish-and-rebuild strategy, allowing for the re-use of existing structures and the reduction of environmental impact (sustainability and low CO2 emissions)
- have low invasiveness on the ordinary functions of the building during the installation (low business interruption)
- minimise the probability of collapse under extreme events (protection of human life)
- experience minimal damage that can be rapidly repaired (high resilience for strategic buildings)
The excellence of the research facilities and courses for young researchers of the host institution (UCL, ranked among the world's top 10 universities), the Supervisor's expertise, and the involvement in the project of academic partners and of a high-profile industrial collaborator (ARUP) guarantee a high scientific value, the completion of the project and the exploitation of the achieved results in practice.
The RESTORE project proposes an innovative framework to assess the progressive collapse risk of existing Steel and Reinforced Concrete (RC) buildings subjected to man-made hazards and design robustness- and resilience-enhancing solutions. The project investigates innovative retrofit solutions, including combinations of global and local interventions, aiming for a trade-off between benefits and drawbacks of both strategies, thus enabling effective retrofit interventions against multiple hazards. They will:
- ensure structural redundancy, mitigating progressive collapse risk against multiple-hazards (robustness)
- provide an alternative to the demolish-and-rebuild strategy, allowing for the re-use of existing structures and the reduction of environmental impact (sustainability and low CO2 emissions)
- have low invasiveness on the ordinary functions of the building during the installation (low business interruption)
- minimise the probability of collapse under extreme events (protection of human life)
- experience minimal damage that can be rapidly repaired (high resilience for strategic buildings)
The excellence of the research facilities and courses for young researchers of the host institution (UCL, ranked among the world's top 10 universities), the Supervisor's expertise, and the involvement in the project of academic partners and of a high-profile industrial collaborator (ARUP) guarantee a high scientific value, the completion of the project and the exploitation of the achieved results in practice.
Publications
Di Filippo R
(2023)
Quantitative integration of fire risk with life cycle analysis of building: The case of thermal insulation
in Journal of Building Engineering
Possidente L
(2023)
Fire Fragility Curves for Industrial Steel Pipe-Racks Integrating Demand and Capacity Uncertainties
in Fire Technology
Possidente L
(2023)
Dynamic Increase Factors for progressive collapse anaylsis of steel structures accounting for column buckling
in ce/papers
Possidente L
(2024)
Review of design approaches for steel columns subjected to localised fires: Insights from the 2nd generation Eurocode model
in Engineering Structures
Possidente L
(2025)
Fire response of steel frames retrofitted against progressive collapse
in Fire Safety Journal
Possidente L
(2024)
Dynamic increase factors for progressive collapse analysis of steel structures considering column buckling
in Engineering Failure Analysis
Possidente L
(2024)
Dynamic increase factors for progressive collapse analysis of steel structures considering column buckling
in Engineering Failure Analysis
| Description | Key Findings and Results: - Dynamic Effects in Progressive Collapse: The research investigated the importance of dynamic effects during progressive collapse scenarios. These effects play a crucial role; however, current recommendations for accounting for these effects in static analyses are insufficient. To address this, a new procedure for determining dynamic effects has been proposed. - Design of Retrofit Measures: The research examined several retrofit methods for existing structures to mitigate the risk of progressive collapse. It was demonstrated that certain retrofit strategies are more effective than others in specific conditions. Both global and local retrofit measures have been assessed for their effectiveness, with recommendations provided to identify the optimal retrofit strategy for each situation. - Effectiveness of Retrofit Measures for Long Duration Hazards: Retrofit measures designed using a progressive collapse approach, such as the column removal method, have proven effective in preventing fire-induced progressive collapse. - Development of a Probabilistic Framework: A probabilistic framework is currently being developed to further enhance the understanding and mitigation of progressive collapse risks. |
| Exploitation Route | Potential Applications of the Outcomes: - Dynamic Effects Procedure: The procedure for determining dynamic effects can be applied to real-world case study structures, enhancing their robustness against progressive collapse. Observations on the influence of column buckling on dynamic effects can be partially extended to other case study structures. - Retrofit Measures Procedure: The developed procedure for assessing the impact of retrofit measures on existing structures can identify critical situations, such as during the installation phase or in the presence of specific hazards. - Applicability and Implementation of Retrofit Measures: Insights into the applicability and implementation of retrofit measures against progressive collapse, and their interactions with other hazards, are invaluable for practitioners. These considerations help in designing optimal retrofit strategies that minimize business interruptions and mitigate adverse effects on responses to other hazards. |
| Sectors | Construction |
| Description | Other researchers have used the findings as a reference or to motivate their assumptions/statements in their published research. Aspects on dynamic effects and retrofit measures are currently being considered in relevant projects at Arup. |
| First Year Of Impact | 2024 |
| Sector | Construction |
| Impact Types | Societal Economic |
| Title | Algorithm for evaluating dynamic effects in progressive collapse scenarios |
| Description | An algorithm/database was developed to determine factors to account for dynamic effects in simplified static analysis. Generalization is achieved through a novel procedure that allows for deriving factors that apply to the full building structure or a portion of it. |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2024 |
| Provided To Others? | No |
| Impact | The algorithm produced graphs that can be employed in the design practice. In addition, the procedure to limit the zone of application of factors, allows for deriving factors that comply with the format provided in current design standards. |
| Title | Algorithm for influence of retrofit measures on structural stability |
| Description | An algorithm was developed to account for the effect of the installation of retrofit measures on the stability of existing structures. Generalization is achieved through a procedure that allows for accounting for the effects on the structure for different loading conditions. |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2024 |
| Provided To Others? | No |
| Impact | The algorithm allowed for defining capacity curves of retrofitted structures accounting for load redistributions during the installation phase.In addition, the procedure allows for analysing potential collapse or failures during the installation phase depending on the loading conditions. |
| Description | Dynamic effects and fire-induced progressive collapse of steel structures |
| Organisation | University of Trento |
| Country | Italy |
| Sector | Academic/University |
| PI Contribution | My research team contributed with our expertise on progressive collapse and numerical modelling. Our group leads the collaboration, scheduled and prepared the research outputs. We provided access to the computational facilities at UCL for performing numerical analyses. |
| Collaborator Contribution | The research team at University of Trento contributed with their expertise in fire engineering, and supported research including a master student in the research activities. |
| Impact | Publications: 1) https://doi.org/10.1002/cepa.2387 2) https://doi.org/10.1016/j.engfailanal.2024.108209 3) https://doi.org/10.1016/j.firesaf.2025.104371 4) Progressive collapse of steel frames subjected to parametric fire curves in https://doi.org/10.30779/cmm_SIF24 |
| Start Year | 2022 |
| Description | Project outcomes communication at International conferences |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Dissemination of the outcomes of the research at two international conferences, namely Eurosteel 2023 in Amsterdam (NL), SECED 2023 in Cambridge (UK), SiF 2022 in Coimbra (PT) and CONFAB 2024 in London (UK). Questions followed the presentation and there was the opportunity to meet prominent researchers and discuss research outcomes and future collaborations. |
| Year(s) Of Engagement Activity | 2023,2024 |
| URL | https://www.eurosteel2023.org/ |
| Description | RECENT RESEARCH RESULTS USING OPENSEES |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | About 60 researchers, practitioners, students and interested persons attended online (40) and in person (20) a workshop on recent developments with the software OpenSees, in which the current major outcomes of the RESTORE project were presented. Questions and discussion followed the presentation, and the participants and organizers showed interest in re-proposing similar workshops in the future. |
| Year(s) Of Engagement Activity | 2024 |
| Description | Seminar on major outcomes of RESTORE project at ARUP - focus on dynamic effects |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Professional Practitioners |
| Results and Impact | During the Non-Academic placement at Arup, a seminar for dissemination of the RESTORE project was organised. PhD Luca Possidente presented the recent developments and major outcomes of the RESTORE project to the team dealing with blast and impact, focusing on aspects of their interest. About 20 professional practitioneers attended in person or online. Questions and discussion followed the seminar, and the participants showed interest. |
| Year(s) Of Engagement Activity | 2025 |
| Description | Seminar on major outcomes of RESTORE project at ARUP - focus on existing structures |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Professional Practitioners |
| Results and Impact | During the Non-Academic placement at Arup, a seminar for dissemination of the RESTORE project was organised. PhD Luca Possidente presented the recent developments and major outcomes of the RESTORE project to the team dealing with existing structures, focusing on aspects of their interest. About 20 professional practitioneers attended in person or online. Questions and discussion followed the seminar, and the participants showed interest in possible future collaborations. |
| Year(s) Of Engagement Activity | 2024 |
| Description | Seminar on major outcomes of RESTORE project at UPV |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | During a research visit at UPV Universitat Politècnica de València, a seminar for dissemination of the RESTORE project was organised at ICHITECH. PhD Luca Possidente presented the recent developments and major outcomes of the RESTORE project . About 60 researchers, students and interested persons attended online and in person. Questions and discussion followed the seminar, and the participants and academics showed interest in possible future collaborations. |
| Year(s) Of Engagement Activity | 2024 |
| Description | Summer school on "Structural Robustness and Resilient Infrastructure against Extreme Hazards" |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Attendance at Summer School on Structural Robustness and Resilient Infrastructure against Extreme Hazards, held at the University of Naples Federico II, Italy. |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://www.dist.unina.it/-/57355888-structural-robustness-and-resilient-infrastructure-against-extr... |