The United States is home to over 617,000 bridges, 42% of which are at least 50 years old, and 7.5% of which are classified structurally deficient. More than 54,000 bridges need to be either repaired or replaced. Confrontingly, 178 million trips are taken across these potentially dangerous structures every day.
Technology for design, engineering, construction, and asset management has advanced significantly in recent years. To date, this technology has, however, yet to be commonly applied to bridge construction and rehabilitation in North America, Australia, and many otherwise technologically advanced nations. While the private sector is tackling similar asset management pressures with 3D Building Information Modeling (BIM), the public sector is still working toward digital transformation, and exploring the opportunities and benefits afforded by BIM for bridge design, construction, rehabilitation, and asset management.
Fostering Industry Change
Several Departments of Transportation (DOTs) are exploring the use of Bridge Information Modeling (BrIM), BIM and 3D modeling. In 2018, the Iowa DOT established the BIM for Bridges and Structures Pooled Fund Initiative. The objective of the Initiative is to: “Develop a National Standard for open exchange of modeled bridge and structure data to be used for design to construction and fabrication, with the ultimate goal of updating and using the data throughout the life of the structure.”
Twenty DOTs from right across the nation are now involved in the Initiative, along with the Federal Highway Administration, the American Association of State and Highway and Transportation Official, and various industry organizations.
As part of the Initiative, Utah’s DOT has undertaken 10 road projects that featured 3D models and is completing a major roadway reconstruction with three bridges utlizing 3D modeling. With early adopters in the US already paving the way, BIM and 3D modeling will take hold gradually over the next decade – as they have done in other parts of the globe.
A Global Perspective
The Nordic countries have embraced the use of BIM in their transport projects for years. So, it comes as no surprise that Norway’s 643m Randselva Bridge is the world’s longest bridge to be constructed using only 3D modelling – without a single 2D paper drawing. By closing the gap between the traditional and the modern, the project paves the way towards a more efficient and cost-effective future for the broader construction industry.
It was the Norwegian Public Roads Administration that encouraged the use of a 3D model for the Randselva Bridge. In other projects when BIM models were used, the Administration had seen a significant reduction in costs, due to fewer errors and change requests. So, in 2012, the Administration published a design model manual for road projects. Today, the Norwegian Administration is collaborating with industry to help ensure the transition to BIM-only infrastructure projects is as smooth as possible. As a result, Norway is the world leader in drawing-free infrastructure projects. Finland is a close second.
It is not only the Nordic countries that have adopted the use of BIM. Governments across the globe are recognising the value of 3D modelling. For instance, the Taiwan Government’s Public Construction Commission is now asking for the implementation of BIM in large public construction projects valued over NT$200 million (approx. USD$6.7m). Similarly, transport authorities in France, Germany, Italy, Poland, and the United Kingdom are all considering setting standards for the use of 3D models on infrastructure projects.
The move towards the use of BIM and 3D modeling for public infrastructure projects like bridges is being made to capitalize on its many benefits. Data-rich and exceptionally precise, 3D models provide the meticulous information needed to streamline and de-risk the entire lifecycle of an infrastructure project, from design, planning and materials procurement, through to fabrication and erection of structural steelwork, and ultimately, asset management.
Integrating data from all design disciplines and simplifying team communication streamlines the design process by checking fit ups and identifying clashes, so that fabricators deliver accurate steelwork. Precise structural steel detailing confirms that a structure is not only geometrically correct, but that it is constructible and erectable, and that fabrication is practical.
When clashes and rework are eradicated, scheduling certainty is assured, which tightens up construction timeframes, and therefore costs. In fact, the use of 3D models can reduce a project’s timeframe by up to 12%.
A data centric model also enables the production of deliverables not possible in the traditional 2D approach. For example, a 3D model can efficiently track weld data for high security projects, such as ID numbers, weld links, types of welds, specific notes and more. 3D detailing is able to identify, track, manipulate and extract any steel member, bolt, weld or any other element within the model.
While a 2D process is unable to visually track productivity, 3D models can help to streamline reporting. For example, DBM Vircon is able to extract color coded progress updates via access to the model, or snapshots of the model. These are clear and concise and demonstrate progress within the model, as well as any associated deliverables. BrIM also enables 4D planning for the scheduling of complex build sequences.
The benefits that BrIM delivers extend far beyond the construction of new infrastructure on greenfield sites. For example, 3D modeling can leverage the power of laser scanning and drones to scan an existing structure. The point cloud can then be used to back model the structure. This is particularly helpful when it comes to as-built structures that require rehabilitation—like the 54,000 bridges in the United States that need to be either repaired or replaced.
Handing over a BrIM model once construction is complete for ongoing asset management and the monitoring of bridge health is an indisputable long-term benefit for DOTs. For example, the data-centric model can be used to plan required maintenance, manage hazards, and help prevent serious incidents—all of which helps to prolong the lifecycle of a bridge and reduce the costs of operators. In addition, a BrIM model can be used to devise safe routes for heavy trucks during scheduled maintenance, improving the road safety and freight mobility. Extending BrIM to asset management eliminates the need to manually enter data on bridge health during in-service inspections, saving both time and cost.
By investing in 3D modelling, the enhanced constructibility of a project pays for itself many times over.