2.Construction Methods, Contracts and Works
The Construction Methods, Contracts and Works department is involved in management aspects of underground infrastructure projects, and provides assistance to project owners involved in such projects: identification of possible challenges, risk management, definition of the roles and responsibilities of stakeholders, contractual assistance, cost and timeframe assessment.
The structures concerned are road and rail tunnels, guided transport tunnels and other underground infrastructures (laboratories, storage facilities).
The department contributes to the development of technical guidelines by capitalizing on the data collected in the course of its engineering missions and by observing industry practices.
It is a member of the French Association of Tunnels and Underground Space (AFTES). It also participates in the dissemination of knowledge through training courses.
The department’s scope of activity essentially covers the following four main areas:
- management of tunnel projects
- contractual practices
- control of costs and deadlines
- construction processes
Its main activities in each of these areas are presented below.
Management of tunnel projects
The department provides project owners with support in the management of underground infrastructure projects.
This support, from the preliminary design phases to the completion of the structure, requires a good understanding of the various stages of an infrastructure project, the roles and responsibilities of the various parties involved, and issues specific to underground design and construction. The challenge is to raise project owners’ awareness of the specific characteristics of a tunnel project.
The aim is to encourage their full involvement in management operations, so as to ensure the technical and economic feasibility of their project, control associated risks and ensure the quality of the structure built.
The department aims to share best practices in the profession, encourage project leaders to apply them, and promote new developments in favour of the ecological transition (eco-design, etc.). Digital transformation, and in particular the use of Building Information Modelling (BIM), is also leading to changes in practices and provides powerful tools to promote eco-design, for example. The department closely monitors these developments.
Contractual practices
The contracts established between the project owner and design offices, project managers or contractors, determine the organisation, the responsibilities of the parties involved, the expected content of the studies and work, and the share of risks. The quality of the project and the final work ultimately depends on the quality of these contracts.
This field requires a thorough knowledge of public procurement rules and national and international reference documents. In addition to the general rules that apply to all public contracts, it is important to be familiar with and develop contractual tools for design, project management, and construction contracts that are specific to underground works and which are subject to uncertainties.
The department is involved in drafting technical clauses specific to tunnel projects, assessing the structural aspects of a contract, and assisting with contract awarding. It also provides expertise in handling claims following the completion of works.
In this area, the department has significantly contributed to updating the guidelines for applying section 69 of the general technical clauses relating to underground works (in French) and to the Observatory of Contractual Practices set up by AFTES. Collaboration with project management representatives within the underground profession has also led to the publication of an information document on the monitoring of underground works projects, aimed at prime contractors (in French). This collaboration is now being extended to all project phases, within the framework of an AFTES working group on project management contracts.
Control of costs and deadlines
The uncertainty and risks associated with the cost of underground works are an obstacle to the implementation of certain projects, even if these projects are highly relevant from a functional point of view. To facilitate decision-making, it is therefore important to work on the reliability of financial estimates at every stage of the project.
In order to determine the costs and timelines for a tunnel project, it is necessary to have a detailed understanding of their underlying factors and mechanisms. This includes the breakdown of the client’s budget, the identification of the civil engineering costs according to the construction methods chosen, and assessment of how risks will be taken into account. As costs are closely linked to deadlines, this area also covers project planning, determining the unit rates for carrying out the work and site planning.
Data gathered from various projects has enabled the development of a methodology and specific internal tools for assessing excavation times (cycle calculation) and estimating civil engineering costs. They can be applied to structures excavated using conventional methods or tunnel boring machines, with different approaches. The information gathered has led to the publication of an information document on tunnel pricing(in French). This data acquisition is ongoing and is being extended to include repair work on existing structures (in conjunction with the Materials, Structures and Tunnel Durability department).
Construction processes
The organisation of the construction site must be taken into account early on in the design of underground structures, as it can have a significant impact in terms of safety, costs and deadlines.
This field includes knowledge of the technical construction processes appropriate to a given context and their implementation on site: methods, excavation equipment, cyclogram analysis, phasing of works, etc. More broadly, it covers all aspects of site organisation, associated logistics and safety requirements.
Contact us
Secrétariat : (+33) (0)4 72 14 34 50
Courriel : secretariat-gc.cetu@developpement-durable.gouv.fr
