Construction projects that involve modification, expansion, and renovations all face a common challenge: dealing with the existing environment in an efficient and precise manner during the design and construction phases. The challenges that the contractors and the professionals face on these types of projects often seem endless. The lack of existing drawings, unknown existing site conditions, and the inability to access and accurately measure the existing environment, can lead to incomplete and imprecise construction documentation. This can generate cost overruns and delays during project execution.
How can the design team help mitigate the above challenges and risks? What if we could recreate the existing environment accurately in 3D and use that as a base to design and coordinate the modifications and new elements?
We now have the tools and knowledge to do exactly the above. By using a combination of 3D laser scanning to capture the accurate 3D geometry of the existing environment and incorporating it into our Building Information Model (BIM) we are able to drastically increase the accuracy and completeness of our project documentation.
3D laser scanning captures a point cloud that is used to determine the geometry of the existing environment that is being measured. While traditional surveying can accurately determine the location of specific chosen key points, 3D laser scanning accurately determines the locations of a huge number of closely spaced points. A single point cloud file can contain millions of data points, that when viewed in 3D represents the complete geometry of the survey area.
A simple example can highlight the advantages:
A client in the food and beverage sector is installing new process equipment including conveyors and piping in an existing facility within a production area. New support structures are required to suspend the pipes and conveyors from the existing ceiling structure above, however there is a large amount of existing piping, electrical, and ventilation conduits that prevent easy access. Additionally, the work must be executed during a short shutdown window, so avoiding on site modifications is key. Using 3D scanning, we are able to capture the existing environment and accurately locate where it is possible to install new structural hangers attached to the structure above, without interfering with the existing suspended pipes and conduits. We can then produce construction documentation that includes exact dimensions that can be used for fabrication. This allows the support structures to be shop fabricated and then installed on site without interference issues, and without site modifications. The construction work is executed quickly within the shutdown window, without extras, and the quality of the work is excellent as field modifications were avoided.
The above example highlights an important common point and one that can be challenging for the professionals to communicate to the clients and end users: investing a little more time and resources during the project design phase saves a lot of time and money during the construction stage, which is by far the most critical step! Investing in the design is worth it.
For projects that involve existing conditions, the combination of 3D laser scanning to accurately capture the existing environment, and BIM for the coordination and production of our construction documents, helps minimize the challenges and risk associated with these projects. The advantages are clear:
SBSA is capable of providing the 3D laser in house; we do not have to hire other professionals, making it more affordable and easier to schedule. The small cost of this service is easily covered by the cost saving and during the construction phase by elimination of errors and delays.
Depending on the size of the project, it takes about 1 to 3 working days before we have a 3D point cloud file, with which can integrate into our 3D model. Once a scan is completed, it is rare that we need to return to the site to take additional measurements as all the required information can be found in seconds in the 3D model.
This is where we really see the power of 3D scanning. We have an accurate model of every corner of the building on hand which allows us to avoid any conflicts. This allows us to optimize the concept and design. In most cases, we are talking about a precision of 6mm. Virtually nothing can be measured or validated that accurately.
We continue to use this technology which is now available for projects of any size. The ease of progress of the construction stage for each project which has used 3D scanning is a testament to the tools’ usefulness and efficiency.
About the author:
Jean-Sébastien graduated as a Civil Engineering Technician from Collège Ahuntsic CEGEP in 1998. After working for a short period of time for a surveying company, he then started working for major firms in the industrial sector. Early in his career he started working in a 3D CAD environment. For more than 15 years in industries such as the pulp & paper, mining, petrochemical, natural gas and energy, on local projects or abroad, he was a key player within various engineering firms due to his strong knowledge in 3D, his quality as a very good interdisciplinary coordinator and for being a highly skilled tech. Jean-Sébastien joined SBSA in 2014 where he learned Revit and gained experience on residential/institutional projects.