Writes Mark King, Severn Partnership

With the UK Government’s announcement in the summer of 2011, Building Information Modelling (BIM) is quickly becoming the buzz word in infrastructure for 2012.

Paul Morrell, the UK Government’s Chief Construction Officer, publicly told the construction sector to work more collaboratively and to use information technology such as BIM to support the design, construction and long-term operation and maintenance of its built assets. In the Government’s Construction Strategy, published in May 2011, it is stated that BIM is mandatory for all public sector construction projects over £5 million.

What is BIM?

To define BIM is very difficult, but it can be thought of as the process of creating, managing and sharing data to support decision making on a facility throughout its lifecycle. Much of this data can be centred on an intelligent 3D CAD model, which acts as a repository or database for all this information. This allows users to easily understand and interact with an almost endless amount of information and to plan and manage construction projects with greater flexibility for scope change and predictability on cost. Most importantly, BIM acts as a focus for ongoing management or maintenance of the assets for their useful life cycle. It is moving towards maintaining and updating one master record, utilised by multidisciplinary teams.

The benefits of storing all this information in a single BIM and sharing it with all stakeholders involved are that informed decisions can be made quickly and shared amongst everyone involved in the project. An example would be that, when an architect alters the type of window designed into a building, this amendment can be seen by the project engineer working on the same BIM in almost real-time and can be checked for any potential structural clashes. This approved alteration can then be quickly sent to the project team for final approval.

Severn Partnership has invested in the hardware and software to be fully BIM enabled. This entailed reviewing working practices, defining bespoke BIM survey specifications and testing compatibility with programs such as Autodesk Revit and ArchiCAD. With this, an upgrade in IT systems has also been achieved, improving software and hardware packages, to run large and detailed 3D point clouds & Revit files which can be a very computer-intensive process.

BIM in Brighton

With the cost of new construction rising, companies are turning to existing buildings for large scale refurbishment as a more cost effective alternative. As a survey company, Severn’s ability to laser scan and accurately 3D model existing facilities acts as the first stage in any retro-fit, refurbishment or renovation BIM project.

Projects such as the 3T’s development at West Sussex Hospital, Brighton, have based all new designs and engineering work on the as-built BIM created from scan data due to the lack of any existing digital CAD plans. Other industry sectors, such as sports and leisure, are making use of BIM and understand that running costs of structures across the whole lifespan of a building such as football stadiums can be reduced and made safer for the paying public.

A key element of BIM in railway infrastructure is its continuous use in the management and operation of the rail asset, especially with defined targets related to TOC’s timetables. The data requirement for the operation and management of rail should be clearly defined in the BIM project plan so that the necessary information can be gathered during the project so as to be ready once the construction phase has been completed.

Most BIM formats have been designed for building projects and much of the rail assets are in the form of stations, depots and storage facilities. The concept of BIM for the rail infrastructure track itself is fast developing and, although some argue there are issues that need to be overcome, the large expenditure in rail on projects such as High Speed 2 (HS2) and CrossRail are accelerating the development in BIM making it a “must” for the future.

Point clouds

Laser scanner technology and associated software has developed quickly in the twenty-first century, and the rail industry in recent years has seen the benefits. Laser scanned “point cloud” data, collected and processed by surveyors, has become a recognised format for the multi disciplined teams of rail design engineers.

One advantage of point cloud data is its ability to be 3D modelled more efficiently than 2D survey data. BIM software vendors such as Autodesk and Bentley are realising the growing importance of point cloud data within the process and have begun incorporating point clouds directly within their software. This saw Autodesk launch Revit 2012 with its own point cloud engine and saw Bentley purchase the popular point cloud software Pointools towards the end of 2011. Using the scan cloud directly within the BIM software enables building information models to be created faster and more accurately without the need for any reference to 2D drawings.

One example is the laser scanned point cloud data from Crewe railway station, turned into a building information model that can be modelled in Autodesk Revit software and populated with all the information important for the continued facilities management of the station asset. This is an example of a project that has been typically “Scanned to BIM” and will become more common across the rail industry with the development of specifications to suit.

Ultimately BIM will become the preferred vehicle through the various GRIP stages for survey, planning, design, construction, as-built and facilities management in rail.