The various exchanges with the actors involved in a BIM supported infrastructure project (engineering specialists, contractors, operators, publishers, surveyors, economists, project owners) have shown a significant disparity in terms of motivation, understanding, acceptance and maturity with regard to digital techniques and innovations, as well as the contributions and changes they could generate.
Use case 5, entitled “Cost control through modelling”, brought together eight partners. These representatives of actors in the sector shared their standard practices for estimating, costing, monitoring and running an infrastructure project from a financial point of view.
The objective set by the working group was to understand how BIM will be able to model and manage the total cost of an infrastructure during the various phases of a project:
- Estimates, price studies
- Cost monitoring during the construction phases
- Cost monitoring during the operating and maintenance phase
All the elements, which are presented in the UC5 phase 1 deliverable, start from the assumption that a BIM forms the backbone of data exchanges between the various parties involved and the project phase.
Four reports have been drafted as part of phase 1. They present a map of the various parties, the most common financial organisation structure for the design/construction phase, the contractual interactions arising from a law or contract, and the tools available on the market to meet the needs of this phase.
A review of the state of the art summarised the lessons learned as regards the development of IFC alignments, Levels of Development (LOD), standards already in existence or under development, and research on price bases. Although IFCs have already existed for several years in the fields of buildings and bridges (the initial version, which remains incomplete, dates from 2004), the extension IFC alignment are still being developed. In phase 1, it was not possible to analyse the new standard BIMetre for the exchange of quantity surveying information, which was identified as being in the draft stage.
The costs and the way in which they are applied and evaluated during the design phase can be used to evaluate and control the project as a whole (total budget) and in detail: takeoffs/quantity/costs, catalogue/unit price. The information model must integrate the notion of total cost in order to obtain a financial view of a project across its whole lifecycle.
A list of elements that may be included in the cost has been drawn up. These elements are generally integrated into an article database or price catalogue. This database makes it possible to cover/rank the prices and make a link to the information model (notion of linking to the article code). Several questions arise from this:
- Should this price catalogue be standardised?
- Should this price catalogue be integrated into the information model or made external?
- Can the price catalogue change according to the design phase (initiation/preliminary design/basic design/design, etc.)?
Different levels of detail and terminology could be envisaged depending on the advancement of the operation, for example “Level of Price” (LOP): notion of level of price or cost on the same principle as the “Levels of Development” (LOD) in the information model (example: LOD 100 –> P 100/LOD 200 –> P 200/etc.).
As for the LODs in a BIM, the costs and prices do not have the same degree of precision as would be contained in these LOPs:
- Estimates, a range
- Calculated prices
- Sub-contracted prices (therefore from a contract)
- Replacement, maintenance and/or operating prices
After that, the LOPs are not linked to the LOD and their definition requires development in phase 2.
The discussions on the construction phase concerned the budget monitoring for a project, and how exchanges could be digitised.
Different levels of detail and terminology could be envisaged depending on the advancement of the operation, for example LOP: notion of level of price or cost in relation to the LOD in the information model (example: LOD 100 –> P 100/LOD 200 –> P 200/etc.).
It is easy to envisage two main types of BIM at this stage:
- A “tool” BIM in which all the data would be entered within the BIM; here we are talking about data leading to 5D. In this case, the BIM Manager has an overview of all the data. This tool BIM has a clearly defined scope and may be applied within a company/business/consortium;
- A “platform” BIM to which databases are linked. On an external database it would therefore be possible to find the following information:
- daily entry of advancement of work;
- unit prices of company X;
- organisation of checks, etc.
Each company would thereby retain the ability to make this information visible or not on the BIM and to the BIM Manager via filters.
This platform BIM would be applied where data is being shared (contractual notion) between different parties/companies.
For the purposes of budget control, a template known by all the actors involved in cost control must be put in place before or at the very beginning of the work. This template will tell the actors (the providers of information for budget control) what kind of information to submit, the desired frequency and the methods to use (tools, transmission circuits with validation, etc.). The template will comprise the following elements:
- definition of the geographical or functional subdivision of the project;
- cost database;
- organisation of entry and validation processes;
The discussions on this phase concerned the financial information fed back during the operating and maintenance phase that can be structured using a BIM organisation system.
The aim of the operator is to ensure that the approach taken by the designers/contractors incorporates, upstream, the operator’s own needs in terms of data format/attributes, and in terms of architecture.
The phase 1 work identifies the various stages of the lifecycle during which the operator interferes with the BIM and, for each stage, which data the operator needs and how urgently:
- Necessary attributes/what should be digitised?
- Static data (“as-built” inventory) and variable data (state of assets, record of inspections and maintenance operations)
- Which filters?
It pragmatically analyses the architectures proposed for the BIM platform as regards the Asset Management application, proposes areas for discussion on the development of the information model and identifies the principle challenges to be overcome to retain the advantages of the information model in the long run.