BIM creates a valuable overview of a 37,500 sqm. project

CG Jensen is one of Denmark's leading contractors. The company employs more than 600+ people and is responsible for some of Denmark’s largest port and infrastructure projects with customers such as the Danish Road Directorate and Banedanmark. They are also involved in various large building and development projects, including Rødovre Port, a 37,500 sqm. new district that is under construction in a suburb to Copenhagen.

CG Jensen helps builders through all phases and in all conceivable forms of construction projects in Denmark and abroad."We must match everyone in all aspects of technology and consulting," says Henrik Graversen, engineer and project manager at CG Jensen, Anlæg Vest. "Our employees mainly consist of engineers, but we also employ machine operators who are trained from the ground up without a technical background – so we embrace a wide range of people.”

Experimenting with BIM

Helicopter platforms, amusement rides, construction and port projects. You almost lose your breath when you hear about the many different projects that CG Jensen is involved in - and as a recent add on CG Jensen now also have their own horticultural department. Although CG Jensen currently only uses BIM in selected projects, Henrik Graversen believes that BIM and 3D models create value for all parties involved.

“When we work for eg. Banedanmark, there are a lot of procedures around safety, grounding of machines and more. With BIM, we are able to prereview step by step how the construction process will proceed on the site, and how far there is between the machines and the tracks' overhead electrical lines, which is essential when working with railways. I find excavators as 3D objects on the web and adjust them so that they look real. In our industry we are used to get this type of work procedure descriptions go back and forth between CG Jensen and our client many times before it is approved, but at Rødovre Port it went through the first time around. This is definitely because of the preparation we have done in 3D based on point cloud scans. We gathered everything in one Archicad file, where we could take measurements in the model if we were in doubt,” Henrik Graversen explains.

500+ homes 12 minutes from downtown Copenhagen

It's not just the number of projects CG Jensen are involved in that takes your breath away. It’s also the scope and Rødovre Port is a good example. The 37,500 sqm. combined residential and commercial building is currently under construction and borders up to Rødovre S-station that is just a 12 minute train ride from Copenhagen Central Station. Henrik Graversen emphasizes that it is difficult to build close to existing infrastructure, since everything has an impact on the stability of the track, just as everything must be life-proof for 120 years.

“At the Rødovre Port project BIM has been an insanely powerful tool. Initially we took the point cloud survey into Archicad – first just to get an overview of the area and the construction site. Subsequently, we have added more to the model,” says Henrik Graversen. “BIM is not just 3D, but a kind of backbone that makes it possible to coordinate design, calculation, simulation and visualization. At Rødovre Port, we have modeled all the piles and all the anchors, which were placed crosswise in terrain close to the tracks. Using the 3D setup from the BIM model, we were able to analyze the interaction between sheet piles, anchor stretches and ground anchors in FEMdesign, and therefore saved a least 7-8 anchors alone on the long side of the construction pit. These anchors need to be drilled, fastened and cast, which is a costly process. This saving alone covered the cost of all the work of building the 3D model, and it is certainly not the only economic optimization the 3D model has brought.”

Digital twin optimizes the project

The project is a turnkey contract with CG Jensen as contractor, Arkitema are architectural consultants, Oluf Jørgensen consulting handle the engineering services, and Gefion Group is the client. As a turnkey contractor, CG Jensen is ´One point of entry´ on the project and handles this role via their construction division. The building's more than 500 homes are spread over 21 floors, so everything quickly becomes complex. “In order to design the foundation, we have received the building as an IFC file, which is easy to link into the 3D model, so we can continuously replace the model when we receive new versions of the project. It works smoothly once you have coordinated the zero points of the models, which is an important start of the collaboration. Even in 2020, there is never an agreement between the different parties' zero points in their 3D models,” Henrik Graversen wonders. By using BIM CG Jensen always have an updated and usable digital twin of the building, and potentially a continuous optimization of the building. “In a turnkey contract, you often work with a rolling design process. This means that nothing has been detailed when we go into the ground. With 3D and BIM, there are many opportunities for the contractor to optimize the construction in parallel with the consultants' projects getting more precise, which benefits the construction, the future residents, Rødovre City and the client,” emphasizes Henrik Graversen.

Great potential in BIM and 3D modeling

Henrik Graversen ooks forward to the future, but also acknowledges that there is a long way to go before you can build completely without paper drawings. "Many people have looked at drawings their entire work life. When we receive a new project, there are still some people that prefer 2D drawings on a printed drawing set – it seems a bit old school.” Not all external partners use BIM, so there is also great potential for improvement, which also applies to CG Jensen's own organization. “We are currently a small selected group working with BIM in CG Jensen. Several can handle 3D well, e.g. in Solibri Office, and there is just as quiet revival going on. I think the BIM transition will gain speed from now on… “ Henrik Graversen concludes.

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About Thomas Graabæk

Thomas Graabæk has been working 10 years as an architect, with a clear interest in the digital tools used for sketching and detailing, but also with 3D modeling and visualization. Since 2006 he has been working as a BIM Manager, and his main focus has been BIM in general and particularly OpenBIM, trying to bridge collaboration between disciplines and software platforms.
  • Denmark