The public works department at LSC360 supports developers in the planning, implementation and supervision of construction and infrastructure projects of all sizes, tackling the challenges of renovating existing buildings, CO2 neutrality and digitalisation.

Could you start by introducing us to the public works department at LSC360?

It employs around 30 people spread across four departments: three of which are responsible for studies and projects, and one for construction management.

Among the study departments, the “Grandes voiries” (major roads) department deals with road infrastructure: city roads, motorways, motorway junctions, road and rail platforms, trams, etc.

The “Engineering Structures” department deals with road and railway bridges, footbridges, wildlife crossings and civil engineering structures such as water towers, water catchments and retaining walls. It is also active in the field of river structures (landing stages) and lake structures, particularly in the context of international projects, such as in Dakar. This department also carries out numerous inspections of existing structures. These are diagnostic assessments to evaluate their state of repair and determine whether renovation or reinforcement work is necessary.

The Transport and Mobility Service develops mobility concepts for all modes of transport – pedestrians, cyclists, public transport – and at all levels – local, regional or national. It also draws up plans for school transport, parking, traffic calming and traffic regulations. The department supports urban planning projects, carries out road safety audits and traffic analyses, and contributes to the optimisation of public transport networks.

The “Direction des travaux” (construction management) department takes over the tasks once the studies have been completed and construction work has begun. It ensures that the work runs smoothly, supervises and monitors it on behalf of the client and acts as an interface between the client, the planning office and the various authorities.

Our main clients are public clients such as the Road and Bridge Authority, Luxtram or municipalities. We also work with construction companies, mainly at an international level. We manage projects from A to Z, from design to implementation planning.

Finally, we work closely with the other departments at LSC360, in particular the Environment & Sustainability department for CO₂ balances, the Geodata department for monitoring construction sites using instant as-built technology – data collection by drone, which is fed directly into the plans – and the Spatial Planning department in the context of urban planning projects that integrate mobility, such as PAG, PAP or planning competitions.

What are the biggest challenges you currently face in your areas of work?

The modernisation and maintenance of existing public infrastructure is one of them. There are currently around 1,300 road structures (bridges and tunnels) in the Grand Duchy. Most of these structures, which were built around fifty years ago, now require extensive renovation work to meet current standards and repair damage caused by ageing materials.  Reinforced concrete, which was widely used in the 1960s due to its ease of workability and durability, is exposed to mechanical, chemical and physical influences over time and depending on the environment, which must be taken into account as early as the design phase.

Another major challenge is sustainable mobility, in particular the integration of different modes of transport to reduce dependence on private transport in urban areas. Luxembourg has a particularly dense network of cycle paths, and we are actively working to expand it and connect it to areas that are still underdeveloped. This requires regular adjustments, such as widening roads or modifying existing structures, to ensure the smooth and safe coexistence of road users.

The integration of BIM is a key focus of our projects. Right from the early stages, we use 3D modelling to create plans, integrate existing environmental elements and monitor the development of structures throughout the construction phase. The aim is to deliver a digital model after completion of the construction work that corresponds to the finished structure and that the client can use for the maintenance and management of their infrastructure. The introduction of these digital tools is naturally accompanied by support for the teams in the form of targeted training to ensure efficient mastery of the new tools and methods.

What are you doing today in the area of materials to make projects more sustainable?

Our projects are designed from the outset to optimise material quantities and promote reuse. In road construction, for example, all excavated materials are systematically analysed so that they can be reused on site or recycled on other construction sites as far as possible. This approach makes it possible to reduce both the carbon footprint of projects and the amount of waste generated, while at the same time controlling costs.

In our civil engineering structures, we prefer to use materials with a low environmental impact wherever possible. In particular, we use steel produced in electric furnaces powered by green energy, low-carbon concrete, self-patinating steel and composite materials that intelligently combine the properties of steel and concrete. These choices not only enable us to reduce material consumption, but also to design structures with larger spans while ensuring robustness, durability and carbon neutrality.

What about the use of wood in civil engineering?

So far, there is little experience with the use of wood in infrastructure construction, and its long-term durability continues to raise questions. In the Nordic countries and Switzerland, wood is often used – either on its own or in combination with other materials such as concrete or steel – particularly for bridges or mixed structures made of wood and concrete or wood and steel. In Luxembourg, however, its use remains limited and is essentially restricted to lightweight structures such as footbridges.

Do you calculate the carbon footprint of your projects? And how important are these calculations in the decisions made by building owners?

We apply this approach systematically, in close collaboration with our Environment & Sustainability department, which also produces the EPD (Environmental Product Declaration), which lists quantified and verified information on the environmental impact of a product throughout its life cycle.

When presenting the preliminary design to the client, we provide them with a table listing several criteria and the advantages and disadvantages of each solution under consideration. The final decision then rests with the client.

How do you combine aesthetics, innovation and sustainability in your projects?

In infrastructure projects, the presence of an architect is rarely required. Therefore, except in special cases, our team takes on the design of the structures. We pay attention to the harmony between form, function and environment in order to design structures that are both aesthetic and functional and fit perfectly into their context. In addition, as already mentioned, we systematically integrate innovative materials with low environmental impact into our designs, in line with our commitment to sustainable infrastructure.

Advanced construction techniques such as prefabrication in the factory are an important lever for optimising structures. In addition, we are increasingly designing integral bridges – structures without bearings and expansion joints – which significantly reduce maintenance costs for the client, as these elements are usually subject to rapid wear and tear. In addition to these maintenance advantages, the integral bridge is a coherent static system that allows for better material optimisation.

Which recently completed projects would you cite as examples of your work?

The tram project has kept our teams very busy in recent years and continues to do so today. We have supported Luxtram in both the planning and execution phases of the first sections currently in operation and are proud to have contributed to this symbolic project, which has received great recognition at national level.

At the same time, we are involved in several motorway expansion projects on behalf of the Roads and Bridges Authority, with the aim of improving national mobility – a real challenge in the current context. We also designed the Esch-Micheville cross-border link, which connects Luxembourg in the south of the country with France. This project, which crosses the former ArcelorMittal site, is part of the wider redevelopment of this strategically important industrial wasteland.

We also carried out the studies for the new water tower in Kirchberg, whose structure blends perfectly into its surroundings. In addition, several of our international infrastructure projects – particularly in France and Africa – demonstrate our teams’ ability to adapt their expertise to different geographical, technical and cultural contexts.

Article published in Neomag 73 – Photo: © Picto communication partners – Fanny Krackenberger