Introduction
As-built documentation, as the name suggests, is a compilation of records that accurately represent a building as it was constructed. This documentation is comprised of drawings or 3D data sets and includes all the existing measurements of the completed project, such as the dimensions of facades, doors, windows, and the layouts of cables, pipes, etc. Moreover, as-built documentation is expected to encompass every alteration made during the construction phase, even those that were not pre-planned.
The essential need for as-built documentation arises from the inherent discrepancies that are often found between the initial intentions of a project and the final outcome. This is because construction projects are typically extensive and intricate, making it difficult to execute them exactly as initially planned. A variety of factors can cause these discrepancies, including scheduling conflicts, budget modifications, or unforeseen events that may impact the construction process in various ways.
Interestingly, despite advancements in building technology such as Virtual Design and Construction (VDC) and Building Information Modeling (BIM), it is still not always possible to achieve an exact match between the digital design and the physical building. This makes as-built documentation not just important, but indispensable. Additionally, there are other factors that contribute to the necessity of as-built documentation.
Who Really Requires As-Built Documentation?
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Facility Managers and Owners – Having comprehensive as-built documentation is vital for facility managers and building owners. This is because they need access to the complete history of the building for efficiently carrying out maintenance, as well as various operational activities, once the construction phase is over.
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General Contractors – For general contractors, the as-built documentation plays a crucial role in validating that the construction project has been executed in its entirety and in accordance with the required standards. The documentation, which includes the most recent records of the building’s condition, serves as robust evidence of their work.
- Service Providers and Future Contractors – Companies that may be engaged in providing services or conducting renovations to the building in the future also have a stake in as-built documentation. For instance, contractors involved in renovation projects need precise blueprints and measurements of the entire structure to accurately estimate and execute the required modifications.
In summary, as-built documentation is an essential tool for various stakeholders involved in the lifecycle of a building, aiding in maintenance, verification of construction quality, and future renovations.
The Importance of Precision in As-Built Documentation
As-built documentation demands an unparalleled level of precision to accurately represent the specific details of a building as it stands. To achieve this level of accuracy, the expertise of laser-scanning professionals and laser-scanning software is employed.
The incorporation of laser scanning is a relatively recent development in the creation of as-built documentation. Historically, as-built documentation largely depended on manual red-lining of existing 2D drawings. This manual method involved marking every deviation between the initial design and the finished structure, which was not only time-consuming but also error-prone due to human inaccuracies.
Laser scanning emerged as an innovative solution to these challenges. It not only facilitates the creation of 3D models of existing structures but also ensures an extremely high degree of accuracy, significantly reducing the likelihood of errors compared to manual marking. In the context of as-built verification, laser scanning is a game-changer, revolutionizing the way as-built documentation is created and enhancing the reliability of the data captured.
Evolution of As-Built Deliverables and the Shift in Paradigm
As-built documentation has undergone significant evolution over the years. Initially, 2D CAD (Computer-Aided Design) drawings were the primary form of as-built documentation. However, with the advent and proliferation of BIM (Building Information Modeling) methods in the construction industry, there has been a marked shift towards the use of centralized, comprehensive 3D models as opposed to relying on numerous individual drawings. This shift has been further propelled by government mandates in various countries that encourage or require the adoption of BIM, thus increasing the demand for precise 3D as-built documentation.
It is important to note that the transition to 3D as-built documentation, coupled with the integration of BIM, has led to some misconceptions. One major misunderstanding is the notion that BIM models and CAD drawings are essentially the same because both are in 3D. However, this is far from the truth.
BIM models are vastly more informative compared to traditional CAD drawings. A BIM model is not just a 3D representation; it is enriched with data about various elements of the building, such as installation dates, model numbers, and other specifications. This has driven the need for as-built documentation software to be capable of generating “as-is” models that are as detailed as standard BIM models.
Fortunately, BIM has addressed this need through a technology known as “scan-to-BIM.” This technology employs 3D laser scanning to create an accurate representation of an existing building and integrates this data with the existing BIM model. The result is an updated BIM model that serves not only as a comprehensive repository of information about the project but also functions as as-built documentation
In essence, the integration of BIM and advancements in 3D scanning have revolutionized as-built documentation, making it more detailed, accurate, and informative, thus providing invaluable resources for the various stakeholders involved in the life cycle of a building.
Generating Modern As-Built Documentation: A Step-by-Step Process
Creating contemporary as-built documentation involves multiple techniques for scanning the building in question. While the specifics of the process may vary depending on the technology and equipment used, the general framework can be broken down into four key steps:
Preliminary Site Survey: The initial step involves conducting a basic survey of the construction site, typically with minimal reliance on technology. The primary objective of this phase is to establish control points, which are critical reference points that ensure the different levels of the building align correctly. These control points create a unified georeference for the entire structure, which is crucial for the accuracy of the as-built documentation.
Control Points Scanning: In this phase, the first actual scanning of the control points takes place. This step generates a preliminary overview of the structure and sets a reference for all subsequent measurements. Having consistent control points is essential because it ensures that measurements taken at different times can be accurately aligned and compared, as they are referenced to the same locations.
Detailed Scanning with Cameras and Lasers: As the name suggests, this step involves comprehensive scanning of the construction site using cameras and lasers. This is the core of the scanning process, where high-resolution images and precise measurements are captured to create a detailed representation of the building.
Data Processing and Model Creation: The final step involves processing the vast amount of data collected through cameras and lasers. This data is compiled into a comprehensive model using specialized as-built documentation software. The software creates a point cloud model, which is then cleaned, processed, and compressed to form an accurate and detailed representation of the building. This model is made accessible to the relevant parties for review and use.
In summary, the creation of modern as-built documentation is a methodical process that combines traditional surveying techniques with advanced scanning technologies and data processing to generate highly accurate and detailed representations of buildings.
Benefits of As-Built Documentation
As-built documentation, particularly when created using modern technology, offers a range of benefits beyond just providing a digital 3D representation of the actual building. Here are the key advantages:
Verification of Compliance: Having both the planned model and the as-built model facilitates easy comparison between the two. This comparison is instrumental in verifying whether the construction adheres to various regulatory compliances. Additionally, it enables the documentation to be updated as necessary to reflect the actual state of the building.
Defect Management: When BIM validation software is integrated into the process, it enables effective management of IFC (Industry Foundation Classes) data for each exchange of information. This leads to the generation of comprehensive quality reports that attest to the integrity and competence of the model, thereby facilitating defect management.
Early Detection of Issues: The use of highly precise laser scanning in creating as-built models makes it possible to identify a range of issues and errors that may not be readily apparent to the human eye. This early detection is invaluable as it allows for issues to be addressed proactively, preventing long-term problems that would be more challenging and costly to rectify at a later stage.
Enhanced Quality Management: As a direct consequence of early detection of issues, the overall quality of the building is significantly improved. Problems are addressed at the initial stages, ensuring that the construction is of the highest standard and that it meets or exceeds the expectations outlined in the planning phase.
In conclusion, as-built documentation is not just a visual representation of a building; it is a powerful tool that facilitates compliance, defect management, early detection of issues, and quality management, thereby contributing to the successful completion and long-term sustainability of construction projects.
Conclusion
As-built documentation is a fundamental component of the construction process, serving as a digital blueprint of the completed structure, which can be utilized for various purposes such as maintenance, renovations, and more. The integration of Building Information Modeling (BIM) and laser measurement technology has revolutionized the creation of as-built documentation. This synergy not only streamlines and accelerates the measurement process but also significantly minimizes errors. Furthermore, it enables the embedding of a wealth of BIM data into each segment of the final model.
In essence, as-built documentation bridges the gap between the design and the reality of the construction, offering an accurate, data-rich, and detailed reflection of the finished building. This is invaluable for various stakeholders, from facility managers and contractors to service providers, as it facilitates informed decision-making, efficient management, and long-term sustainability of the structure. The advancements in technology and the adoption of BIM have made as-built documentation an even more powerful and indispensable tool in modern construction.
