Efficient digital modelling cutting major project costs

It may be a rule of thumb that the larger a rail project is, the more its costs are expected to increase. In Sydney, the construction of the Sydney Metro CBD and Southwest is expected to increase by $3 billion, a 25 per cent increase on the initial costing of $11.5 to 12.5bn. Indeed, the Grattan Institute estimates that every 10 per cent increase in a project’s size is associated with a 6 per cent higher chance of an overrun, and that any overrun that occurs will be 3 per cent larger.

So when you are building the most expensive rail project in the world, the cost overruns could be gigantic. Already, the HS2 project in the UK is estimated to cost as much as £106bn ($208bn), however, the project delivery authority has been told to find at least £500 million in digital efficiencies.

To do so, HS2 Ltd have looked to apply digital best practice in data and modelling requirements, with the requirement to meet PAS 1192 Building Information Modelling (BIM) standards. This standard mandates a fully collaborative 3D BIM, including electronic project and asset information, documentation and data.

Implementing these requirements joint venture Skanska Costain STRABAG (SCS), which has been awarded the civil works contract for the 250km southern section between London and Birmingham. The section, and the project as a whole, will carry the fastest trains in Europe and over 30,000 passengers a day. During early contractor involvement, SCS had to formulate and achieve approval of a conceptual design scheme of 26km of railway within 14 months. To meet the client’s BIM demands, SCS needed to accommodate existing British railway systems and 6,000 utility assets, not to mention the 20km of tunnels, bridges, and five kilometres of earthworks.

Using BIM software from Bentley systems, SCS created a library of components within ProjectWise and OpenBuildings Designer to enable a distributed workforce of six companies including 550 staff across four countries.

“We have 59 nationalities, so quite diverse cultures on the team, and we like to think BIM is the common language we all speak,” said Peter Ruff, head of BIM for SCS.

The SCS team used Assetwise to connect asset information to the design model, so that operations and maintenance could be involved early. This led to an integrated BIM system which allows for real-time access to trusted information.

“We wanted to make sure that everyone, designers and contractors, can use this information,” said Ruff.

The use of Bentley systems in this early stage enabled early clash detection within the project and when interacting with the numerous outside stakeholders. This has already saved an estimated £1 million. Design review time was also reduced by having models and data in a single digital location, which saved £500,000 and the time cost of searching for information spread across multiple systems.

Using a connected digital environment also improved costing processes, an area of focus for SCS, said Ruff.

“One of our key areas that we wanted to improve was our 5D approach, where we use the BIM models to estimate and price from.”

A structured digital data environment ensured consistency and transparency for all stakeholders, enabling further accuracy. This led to a £300,000 saving in a 50 per cent reduction in design changes and 75 per cent less resources used than planned.

Moving forward from the early contractor involvement stage, the SCS team are looking to their BIM strategy underlying the information model which can be used throughout the project lifecycle.

“Using Bentley solutions has allowed us at SCS to realize our mission statement of creating a project that will be seen as the ‘Digital Blueprint of Future Infrastructure Projects’” said Ruff. “They have allowed us to create, manage, and leverage intelligent BIM models and the data housed within them on a complex project and see a significant increase in productivity, efficiencies, and collaboration between a large team and a multistage contract.”

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