As-Built Construction Assets: Key to Future Planning and Facilities Management

Preparing ‘as-built’ drawings and models is certainly one of the most crucial requirements of any design-build project. These final set of construction assets validates how the contractor built the structure including all the changes and modifications that were made in the process. The finalised drawings and models are passed on from the contractors to the building owners and property managers.

The set of as-built drawings and models, though underestimated and neglected, broadly serve a dual purpose. Firstly, the as-built drawings and models act as a guidebook to the AEC (architecture, engineering, and construction) firms that are contracted for renovation and refurbishment of an existing structure. So, the time, cost, and resources that would have been utilised during pre-renovation survey are saved. Secondly, they help owners and facilities managers to conveniently undertake maintenance and refurbishment activities besides helping them during emergency situations e.g. for rapid evacuation.

Whereas data-rich as-built 3D building information models have obvious benefits over 2D drawing sets, the decision to choose one over the other mainly involves factors, such as the scale of the project, owner’s preference, and the design-build teaming structure. The owners of relatively small building projects may prefer 2D as-built drawings of an existing building, prepared by a technician after collecting accurate data on site. On the contrary, large-scale design-build and renovation projects may require BIM-driven as-built 3D models.

Assuming that the project in question has not had a BIM model for the design process which is then updated during the as-built stage of the project, there are two typical ways of preparing as-built BIM models. Firstly, using the as-built drawings and other construction drawing sets as the starting point, 3D BIM models can be prepared using applications such as Autodesk Revit. The second method involves the Scan to BIM technique where   point cloud data of the structures. This point cloud data is then converted into an intelligent BIM model using tools such as Cloudworx and Scan to BIM applications such as Revit.

The as-built drawings and BIM models serve as a comprehensive reference tool for owners and property managers. They benefit from these as-built drawings and models in the following ways:-

·     The finalised as-built construction assets make future project planning, including renovations, extensions, and redevelopments, convenient and cost effective for the owners.

·     Since the as-built drawings and BIM models contain complete details related to dimensions, fabrication, erection, elevations, sizing, materials, location, and mechanical/electrical/plumbing utilities, the owners can use this data and conveniently manage facilities within budget.

·     The owners can use these as-built assets to resolve disputes regarding insurance claims. In case of a massive loss due to extreme disasters, the insurance company will require extensive documentation, including the as-built drawings and models to support your claims.

As the as-built drawings and models are prepared by combining the drawings/models of all the building services, the owners and property managers can schedule maintenance operations of the building’s MEP (M&E) systems in a timely manner.

Issues Affecting The Adoption of 3D BIM Modelling

Issues including cost and time overruns, material wastage, and process inefficiency have marred the architecture, engineering, and construction (AEC) industry worldwide. Whilst the reasons behind this may differ from project to project, lack of interdisciplinary coordination amongst the designers, the building services engineers, and the contractors is the most common of all. Considering these unfavourable project outcomes, there is a significant push from the governments, mainly in developed nations, to accelerate or mandate the adoption of 3D BIM modelling in varying levels for government-funded projects.

Whilst parametric modeling tools such as BIM technology is being increasingly used for government projects private construction projects are also seeing the benefits with many employing  forward-looking AEC firms that have already transitioned to using information-embedded Revit 3D models for design as well as construction stages. Although moving from traditional CAD-based design processes to modern BIM-enabled workflows is essential to eliminate design/coordination clashes and maximise project efficiency, there are some key inhibitions and apprehensions to what is a paradigm shift for the industry.

Firstly, many AEC firms have long been using the traditional 2D as well as non-BIM 3D CAD workflow for pre-construction 3D planning and are highly resistant to change their current conventional processes. More often than not, such firms are completely apprehensive of embracing new technology or are slow adopters of new technology and decide to change only if requested by clients or if they are part of a framework agreement requiring adoption of such technology.

 Another factor that pushes potential BIM implementers back is the steep learning curve of its tools and their real-life applications specific to disciplines, such as architecture, MEP engineering, and structural engineering. One common concern is training CAD technicians, who are familiar with drafting tools such as AutoCAD, and BIM and clash detection applications, such as Autodesk Revit and Navisworks.

The biggest impeding factor to BIM implementation is the perception amongst certain groups that current projects during the BIM transition period, will suffer. As BIM adoption is much more than just software training, it requires an overall change in the way a building project is conceptualised, designed, constructed, and maintained. Whilst the traditional design methods required CAD managers with a team of CAD technicians, the modern BIM-based projects require BIM managers who liaise with discipline-specific representatives to map out the level of details (LOD) or BIM Phases required by the client, worksharing protocols/processes, and assess the adherence to interoperability and information-exchange standards.

Furthermore, there is a widespread opinion amongst the AEC fraternity that whilst adopting a full-fledged 3D BIM modelling for the entire lifecycle of a building drives cost, time, and energy performance efficiencies, tremendous effort goes into preparing custom detailed content to client’s specifications. This group believes that whilst the generic libraries can be used for design and clash detection, accurately detailed models are needed to optimally use BIM for aspects, such as cost estimation, time scheduling, and quantity take-offs.

The requirement for BIM adoption also requires a level of interaction along the design and contracting teams that is not usual and has certainly been accelerated with the use of BIM practices.  Clearly defining BIM scope and requirements between the parties involved is already becoming a challenge, especially for the MEP sector where designers and trade contractors have traditionally handled conceptual design and detailed design individually.  The overlap in conceptual design and detailed design is becoming the type of challenge that MEP trades and MEP designers are getting used to resolving as part of BIM adoption.

Collectively these issues pose a challenge and sometimes cause the apprehension involved for BIM project take up, something that we observe will change with continued demand for intelligent building design.

Understanding of Building Information Modeling (BIM)

Building Information Modeling is an innovative and promising development witnessed by the architecture, engineering and construction industry (AEC).  With issues like over-budget and declining productivity pervading the AEC industry, Building Information Modeling instills a hope to minimize these issues to a large extent.
BIM in simple terms means creating a virtual 3D building before it is actually built with all the relevant data and proper geometry.  Thus viewing the digital representation of a building helps to avoid or correct any potential problem in the pre-construction stage.  The ‘information’ part in ‘Building Information Modeling’ is of utmost importance.  A BIM model digitally represents the real elements within the construction project along with its geometry, geographic information, spatial relations, quantities and properties of building components. This information can be extracted at any stage of the project.
BIM model is often confused with a 3D model. Not all 3D models are BIM models. Some 3D models created for visualization purpose that lacks intelligence and control for its position and sizes cannot be called as BIM models. BIM is lot more than 3D CAD modeling. It is a hub for rich information allowing access for product information, retrieving specifications for a part and many other details beyond geometric information.
BIM is a powerful tool that can simplify the construction process incredibly. A proper methodology needs to be adopted for proper implementation of BIM. By overcoming the challenges faced in adopting BIM, BIM can do wonders.