ENHANCE
The project
Enhance is a €600,000 Prometeo project funded by Generalitat Valenciana aiming to develop a novel approach for retrofitting existing buildings based on hanging floors from the roof to ensure they comply with the latest structural robustness requirements.
KEY CHALLENGES
With the ever-increasing occurrence of extreme abnormal events, it is now well-recognised that there is a need for robust buildings that can withstand local initial damage without experiencing failure propagation. In fact, many design codes now explicitly require buildings in high-risk consequence classes to be designed with a sufficient degree of redundancy to ensure that the failure of a single component does not lead to disproportionate collapse.
Fortunately, thanks to the great research effort made in the field of progressive collapse over the last few decades, engineers already have several methods and solutions at their disposal to design new constructions. Nevertheless, the vast majority of that research is not applicable to existing building structures. In addition, the few retrofitting solutions proposed to enhance structural robustness tend to be overly invasive or complex to implement. Many of them are also local in nature and are thus generally ineffective. At the same time, most buildings worldwide were designed and built with little or no consideration for structural robustness. Many of these existing buildings are occupied by a large number of people or form part of critical infrastructure facilities, meaning that their collapse would result in catastrophic consequences for society. Simply replacing such buildings is not only unfeasible but also unsustainable, since it is essential to maximise the use of existing structures and even extend their lifespan as much as safely possible in the fight against climate change and resource scarcity.
There is an urgent need for efficient and practical retrofit solutions to improve the robustness of existing buildings.
THE SOLUTION
Torres de Colón in Madrid worked as a source of inspiration for a radical solution. The slabs of this building are hung from large beams from the top of the building by cables and at the same time are joined to the central core, which makes it a building with no columns directly supported by the foundations.
Based on this inspiration, a promising solution involves adding stiffening beams on the roof of buildings. Floor slabs would then be suspended from these beams in the event of the failure of one or more columns in the lower floors. The main advantage of this solution is that all the work associated with the reinforcement is concentrated on the roof with minimum intrusion into the building itself.
Despite this strategy having been mentioned previously, no research has been carried out to date that could result in its effective implementation in buildings.
OBJECTIVES
The overall aim of Enhance is to develop a novel approach for retrofitting existing buildings based on hanging floors from the roof to ensure they comply with the latest structural robustness requirements. This overall aim will be achieved through five specific objectives:
- Objective 1: To develop a risk-based approach for identifying situations in which the proposed retrofitting solution is beneficial.
- Objective 2: To define a framework for efficiently assessing the actual condition of the existing structure and establishing strengthening requirements to ensure the proposed retrofitting strategy functions as intended.
- Objective 3: To design the retrofit solution considering global aspects and local phenomena.
- Objective 4: To implement and validate the retrofitting technique in real buildings.
- Objective 5: To engage with industry and code-issuing entities, disseminate, communicate and exploit the project’s outcomes.
METHODOLOGY
Enhance is organised into five Work Packages (WP).
WP1. Determining advantageous situations and layout design.
WP1 is mainly concerned with the development of decision-support tools to ensure that the retrofit solution is only employed in situations whereby it would result in a positive expected benefit over the entire lifecycle of a building. The approach will consider different possible stiffening beam layouts and will be based on an in-depth consequence analysis of carefully defined generic cases accounting for desired levels of robustness and enhanced safety.
WP2. Framework for AI-supported condition assessment.
The proper functioning of the proposed retrofit solution relies on the activation of specific ALPs, which in turn relies on existing structural components satisfying certain strength and ductility requirements. As such, to ensure that the retrofitting technique is effective in practice, purposely designed condition assessment procedures will be developed in WP2. These will incorporate well-defined inspection techniques and AI-based data analysis methods.
WP3. Global design, local aspects and construction details.
WP3 will involve carrying out a detailed study of the behaviour of the retrofitted building before defining adequate steps for the design of the stiffening beams and related construction detailing. Since the stiffening beams will have to interact with the existing structure, the need to strengthen some of its elements will be considered. This will be accomplished by means of numerical simulations using micro- and macro-models.
WP4. Implementation and validation-testing on real buildings.
WP4’s most ambitious task will involve tests on two scaled retrofitted buildings to validate the new approach in real reinforced concrete and steel/composite structures. Computational modelling will then be performed to assess the behaviour of buildings in different event scenarios. The retrofitting technique will be included in building design thanks to the definition of simplified calculation models to facilitate their application in common industry practice.
WP5. Dissemination, communication, exploitation and outreach.
Since the retrofitting approach is novel, with significant potential for major scientific/technological impact, it will be of the utmost importance to carry out a thorough communication, dissemination, and exploitation campaign. We will engage with standards-issuing entities and private companies to spread the new retrofitting approach and communicate with different target audiences.
IMPACT
Enhance’s outcomes will have a high scientific, technological, and social impact by contributing to obtaining safer buildings, especially in events or situations that could have grave consequences for a building’s integrity. A large number of existing buildings now need to be adapted to robustness criteria defined in current codes and guidelines, and this project will consist of the most ambitious research performed to date in the field of retrofitting existing buildings to improve their robustness. The project’s outcomes are also intended to contribute to transforming the industry by providing a comprehensive framework with guidelines and software for carrying out the required analyses and structural design.
