Constructibility is a widely supported concept throughout the construction industry. It is a technique that involves reviewing the entire project in the pre-construction phase. This helps to identify any challenges or errors before the building begins. So, contractors can correct errors and prevent delays – ensuring efficiency and accuracy in projects.
Some of the main challenges in construction projects occur in the documentation. But, harnessing constructible data makes groundbreaking building models, such as BIM, possible.
BIM consists of data-rich 3D representation. This includes geometric information, weight, unit pricing, and more. The content used is constructible because it contributes to the technical and geometric properties of data. This data translates into a 3D model.
Constructible Models
Constructible models are distinguished by their constructability/ buildability and being content-enabled and connected. They provide gateways for streamlined workflows. This enables processes such as modular construction, process optimization, and automation of job sites.
In the past, much of the design of constructions were completed during the construction. The use of modern design technology allows project managers and contractors to alter the design much earlier in the process. As such, they are able to develop models that are constructible and start construction sooner than traditionally modeled projects.
Data forms the foundation for developing and using effective models that are ready-for-construction and easily integrated into BIM processes. Historical data together with fabrication data and bills of quantities play a critical role in generating an efficient and constructible model.
What Makes A Constructible Model?
Level of Development (LODs) are used to form, share, and put constructible models into practice through the use of data. The concept of LODs was defined by the American Institute of Architects in 2009. Later, the Associated General Contractors of America expanded the concept.
LODs indicate the reliability and constructibility of the model. They also show the accuracy of the model’s associated data such as the attached and geometric properties. The various LODs that highlight the degree of a model’s constructibility include the following:
- LOD 100 (Conceptual design). This represents elements with generic symbols instead of using geometric representation.
- LOD 200 (Design development). The model shows the geometry of elements with generic placeholders.
- LOD 300 (Documentation). Data showing the geometric properties, location, orientation, measurements, and quantity of units.
- LOD 350 (Model coordination). For modeling and coordination, LOD 350 supports coordination with other building system interfaces. Typically, it represents this graphically.
- LOD 400 (Ready for construction). LOD 400 is a constructible model that includes all the necessary data that can be used for the accurate fabrication of elements.
- LOD 500 (As-built). The highest LOD represents a digital twin of the physical component i.e. an “as-built’ model.
To have a sufficient LOD, the data must be constructible. The requirements for good quality data include:
- Accurate and correct data
- Ease of use and maintenance
- Easy to source and navigate
- Routinely managed and updated
The Importance Of LOD In Constructibility
Models are highly dependent on the accuracy of the content they hold. One of the greatest problems with models in construction projects is the uncertainty of data or its poor management. This affects the confidence of project stakeholders and materializes in the deliverables.
In a situation where there is a lack of confidence, the extra caution across the project team drives excessive communication with the designers. This uses valuable time, energy, and money. As a result, it can lead to project timeline delays or significant losses in the profit margin.
But, if the project leads use a model without investigating its integrity, they will likely experience the same losses due to excessive rework or waste.
Designers and detailers aim to build successful constructible models. These need to have all the necessary, accurate information to build a project from conception to completion. The trust and reliability of a model increase as the LODs of the model components increase. The most trusted model components have the highest LOD possible.
A reliable model has countless benefits when applied to a project. Some of the most critical influences include:
- Reduced revisions and reworks by designers and detailers
- The contractor can implement the design without last-minute adjustments during construction
- The fabricator can easily feed compatible data into machines without errors
- It maintains project timelines and budgets by minimizing delays and errors
- The client avoids timeline delays and increased costs for the project deliverables
Final Thoughts
Data is key in the age where 3D models, such as BIM, are becoming commonplace. Each element of data drives constructible models to greater efficiency, accuracy, and profitability. As such, projects become more successful and time- and cost-efficient.
The present and future of construction depend highly on the use of constructible models. They are key to the efficient and accurate construction of projects. Thus, the early implementation of constructible models in projects is a valuable step to practical construction.
For more information on this technique, be sure to contact Chad Fisher Construction.