An iconic building overlooking the Liège landscape, the Citadelle Hospital is undergoing an ambitious refurbishment operation. Entrusted to bureau greisch for structural engineering as well as building services & energy, this large-scale project aims to strengthen the institution’s energy resilience while ensuring the continuity of its hospital activities, with four main objectives:
- Reduce the hospital’s overall energy consumption after the works,
- Verminder de milieu-impact van de infrastructuur als geheel,
- Improve comfort for patients and staff,
- Preserve and enhance the existing structures.
One of the project’s major challenges lies in organising the construction works: the hospital must remain fully operational throughout.
Rehabilitation of primary networks
The technical installations of the Citadelle Hospital are ageing, highly energy-consuming, and no longer suited to current constraints (climate change, electrification of vehicle fleets, etc.). The Citadelle therefore intends to rethink its primary networks: power supply and emergency power, heating, cooling, and the various water and medical fluid networks. With this first component, the goal is to go further than simply replacing one system with another. The aim is to redesign these systems to meet today’s requirements and the evolving modes of patient care. A first technical programming phase has already helped identify priority interventions based on technical, financial, and environmental urgency. The preliminary design phase now focuses on the parts of the primary networks that are essential for commissioning the new care units forming the third component of the project. The primary fluid networks will be transformed into highly reliable systems, ensuring better resilience of the installations: in case of maintenance or intervention, only limited sections will be affected.
To maintain hospital operations, the old networks will remain active while the new ones are installed. These new systems will be integrated into innovative technical façade modules located at the ends of each wing and concealed behind the new continuous external skin of the renovated façades. Unlike the old installations, which ran from the centre of the building to the ends of the wings, the new networks will be decentralised, placed at the ends of the care units and running towards the centre of the hospital. Once the modules are fully operational, the transition to the new installations will be carried out gradually and safely, minimising any impact on hospital activities.
Façade refurbishment
The second component concerns the complete refurbishment of the façades: replacement of window frames, improvement of thermal insulation, and installation of a new outer skin along with a structure integrating passive solar-shading functions and photovoltaic production.
This delicate undertaking includes an in-depth structural study, particularly of the existing architectural concrete elements that act as sun-breakers. Following an extensive multi-criteria analysis carried out by the entire design team, the decision to dismantle these concrete elements became evident, making way for a new, durable, and energy-efficient façade envelope.
Development of new care units
In parallel, the project provides for the development of new Neonatology and Paediatrics units. These will offer new modular hospital spaces tailored to the evolving needs of the institution.
Implementation of a dynamic commissioning system
A 3D BIM model of the hospital structure involved in the project has been created as an integrated design tool, at the request of the client. Various surveying techniques were used to produce an accurate model of the existing building, including drone-based laser scanning and point cloud conversion.
Since the start of the project-and therefore before construction works-a real-time commissioning system has ensured precise monitoring of the technical installations (heating, dual-flow ventilation, medical fluids, hot and cold water, low- and high-voltage electricity). This tool helps anticipate potential deviations and continuously optimise energy performance.
The different components of the project follow distinct study timelines: preliminary design for the primary networks, permit procedures for the façades, preparation of tender documents for the development of the care units, and ongoing commissioning of existing installations.
The actors of the project
- Project Owner: CHR Citadelle, Procurement Department
- Project Authors: AAGG simple partnership, composed of Assar Architects, Henri Garcia Architecture, and Bureau greisch
- Special Techniques, Energy & Sustainability, Structural Stability, and Commissioning: Bureau greisch