Tottenham Court Road station
Crossrail’s use of BIM dates back several years, what new initiatives are underway?
With 77% of the physical construction complete we are in middle of the fit-out stage and using 3D models to manage progress and keep track of complex installations.
Typically, a Crossrail engineer and contractor engineer use an iPad running a lightweight 3D model to capture the progress of work in the 3D model and automatically calculate installation progress against the planned programme. This gives us an immediate grasp of quantities, in 5D, and an as-built record of what was built when.
When the project started Level 2 BIM was still a long way off, are you more compliant now?
We are close to Level 2. PAS 1192:4 came along too late for us, so we don’t use COBie directly, but we use all the principles and characteristics of it, in terms of spreadsheet data. We have an advanced common data environment, comprising three joined up databases, for document information, CAD and 3D, and GIS data, which goes beyond Level 2 requirements.
We set out early on the create a single asset breakdown structure and asset classification system, covering the 600,000 assets on the project, which provided a backbone for BIM information going from design, through construction and on into operation and maintenance.
Have you been trialling any new tech?
We opened a “BIM cave” at Canary Wharf that projects the 3D model onto the walls of a room to enable users to walk around stations, which has proved particularly useful in design reviews.
3D point cloud models are being used extensively, mapped onto the engineering design model to verify that the built asset is as expected. For example, we ran a point cloud survey of the completed station box at Woolwich Station, before the cladding was installed, to verify the dimensions and position information.
Millions of pounds has been saved using BIM on Crossrail
We are now looking at how Crossrail 2 can make use of point cloud data during design to map not just the route, but the built environment around it, and the geology underneath it, to create a virtual world to take right through the design process.
Have you recorded concrete time or cost savings resulting from the use of BIM?
That’s hard to calculate accurately, but I believe we have saved many millions of pounds building a railway in this particular way.
Government data has shown that on typical contracts, up to 8% of costs can be attributed to waste, one of our engineers told me that Crossrail is around the 2% mark, which in part, is down to our use of BIM for design coordination and clash detection.
There have also been measurable efficiencies in terms of getting better quality information leading to better decision making. BIM has also reduced risk and improved safety.
What have been your key lessons learnt?
Performing activities as workflows in a single relational database [built by US technology company EB] has been extremely efficient and saved us many millions of pounds a year paying for different software platforms.
The database handles £8.5bn of contract administration, all document control, PDF drawings, snagging, asset inventory and technical requests etc, and makes it easy to link up different activities. For example, photographs taken in the field can be linked to a particular asset ready for access on mobile devices.
Having all the information joined up in one place is hugely efficient and provides a single source of truth everyone can work to.
What would you do differently if you had to start over again?
We would be more prescriptive about how we receive asset information from suppliers and define precisely what we want. We have about 80 contractors submitting asset information, and although we gave a list of requirements for our operation and maintenance manuals, we did not produce a template for the data until more recently. It is important to get the right information in the right format.
What other learning will carry over to Crossrail 2?
We can only tell them where we have had battle scars. The key is to treat information as a valuable resource for decision making that you manage in the same way you would manage staff and equipment. You have to manage it from day one, rather than just focus on purchasing lots of software.
Have you noticed project stakeholders getting up to speed with BIM since the mandate was introduced in April?
Yes, the only people who seem to have a problem with BIM tend to be directors and senior managers who see it as a big cost and difficult to implement.
Our BIM Academy, set up by Crossrail and Bentley, has trained more than 2,800 contractor and design staff in the basics of our BIM systems and processes and how to use models. With 25 major design contracts and 80 contractors, it is much simpler to train them to use a single system so they understand the competencies required, rather than allow them to implement their own software.
The “carrot” is we pay for their Bentley software licence if they go through the training, then they can’t use the excuse that they can’t afford it.
This article first appeared on CM’s sister title BIM+