Canada’s largest road project demonstrates the value building information modelling can offer to highways, a sector that has tended to lag behind others in using the technology.
When work started on Canada’s biggest highway project, the Port Mann/Highway 1 upgrade, the H5M joint venture of Hatch Mott MacDonald and MMM Group made an early resolution to use building information modelling (BIM) extensively. But in 2008 BIM adoption was still scarce in the highways sector.
“None of us were calling it ‘BIM’ at the time,” says Hatch Mott MacDonald project director Chris Mealing.
“We just set out to use an integrated 3D modelling environment to do all of the civil design and support the structures design. Although we did much of our structural detailing in 2D, design configuration and geometry were largely developed using data extracted from the BIM model.”
“Although we did much of our structural detailing in 2D, design configuration and geometry were largely developed using data extracted from the BIM model”
Chris Mealing, Hatch Mott MacDonald
Port Mann/Highway 1 is a CA$2.46bn (£1.57bn) project encompassing 37km of highway widening along Highway 1, a major trunk road forming part of the Trans-Canada Highway.
Designed to quell heavy congestion and meet traffic needs forecast to 2031, the five year programme includes the reconstruction of 13 interchanges, addition of two new interchanges, and construction or rehabilitation of over 42 onshore bridges - all while maintaining uninterrupted traffic flow.
H5M used Autodesk’s Civil 3D to create a single integrated model of the entire 37km transport corridor, incorporating grading, layout, geometry and alignment. H5M also modelled existing infrastructure such as drainage culverts, power lines and sewers.
This was achieved through a combination of high resolution orthorectified photographs and on-site laser scans. This extensive modelling process was essential due to the congested areas through which the existing Highway 1 passes.
“The project was done in a highly urban environment, so there was a continuous process of managing conflicts,” says Mealing.
“It was like fitting 10 pounds of stuff into a five pound bag.”
The core project-wide model was developed within the first six months of the job, and was then continuously refined over a two year period to support the detailed design process, with more development as construction progressed.
The team added increasing levels of detail to resolve ever more specific constraints and conflicts - early modelling of major alignments and sewers gave way to subsequent modelling of ancillary elements such as junction boxes, street lamps and minor drainage elements.
“The challenge is finding the appropriate level of modelling for the job you’re working on, and the methods the contractor is going to employ”
Chris Mealing, Hatch Mott MacDonald
“There’s potentially an infinite amount of detail to be filled in, and some judgment required on what level of detail is appropriate for each element,” says Mealing.
As well as resolving the interaction between old and new infrastructure, the model greatly aided all parties in planning and understanding construction sequencing.
“One of the real powers of BIM is the ability to visualise what you’re building,” says Mealing.
“At the most basic level, that helps us to understand how all the pieces fit together - which is often the challenge with complex geometry and staged construction.”
The enhanced visualisation made possible by BIM was invaluable for ironing out the most challenging parts of the project. The team created sequential visualizations of the construction stages of particularly complex areas, such as the B1627 bridge complex where a bridge, sewer, embankment and tunnel all converged. These sets of visualisations were then used to assist the project’s design and build contractor in developing their detailed staging and temporary works.
Investment Corporation, a Crown
Corporation of the Province of
Consultant: H5M joint venture,
comprising Hatch Mott
MacDonald and MMM Group
The design and build contractor was given managed access to the model so that it could extract data for its own purposes, such as entering the data into total stations during set-out and using Trimble’s BladePro control system for grading operations. Data was also extracted from the model for quantities, and as a basis for traffic simulations.
However, all of this data sharing did not always come easy. “The highways industry in British Columbia at the time was using a range of different software,” says Mealing. Standardised BIM tools for roads have only become ubiquitous since the project started, he says.
“We had to get over a hump to get everyone working in the same native model at the same time. There’s a lot of pre-planning and organisation needed around data exchange -a key lesson to take forward is that it’s very important to have upfront discussions about who gives whom what, and in what format.”
However, with 13 sub-contractors working together as an integrated “super design team”, overcoming that hump was worth the effort.
“The collaboration we needed would have been practically impossible if we hadn’t been working in a common data environment,” says Mealing.
With the right software and data exchange processes in place, the collaborative aspects of BIM still hark back to traditional ways of working.
“The act of going through the design and coordinating with people doesn’t feel much different from before, but the pace at which you can move forward - considering the complexity of the design - is the difference with BIM,” says Mealing. “We’re able to do very complex things much more quickly, and look at a greater range of options, and keep people better up to speed.”
That time efficiency, even in the face of great complexity, is what Mealing cites as the chief benefit of BIM on Port Mann/ Highway 1.
“Like any design and build project, we were working to an extremely demanding timeline,” he says.
Despite the success of Port Mann/Highway 1 - which is due for total completion by the end of 2014 - the use of BIM on roads projects is still a developing practice. “We’re in the awkward teenage years of BIM on heavy civils,” says Mealing. “
The challenge is finding the appropriate level of modelling for the job you’re working on, and the methods the contractor is going to employ.”
Unlike in other sectors, highways projects have traditionally benefited from on-site judgment calls around many aspects of finished grading, and ancillary elements such as street lamp placement. Human common sense therefore still needs to be in the mix alongside BIM, Mealing says.
Experience gained on Port Mann/Highway 1 has helped Hatch Mott MacDonald to better consider where projects should sit on the spectrum between highly detailed BIM and a combination of indicative BIM and traditional methods - particularly in the case of brownfield sites.
“We need to ensure that we’re making the most intelligent use of the model,” says Mealing. “As
an industry, we’re continuing to figure out where the value is.”