Years ago, as a fresh graduate, I was involved in the construction of a residential building. Back then, if somebody had told me that in the near future, there would be a possibility of model-based construction site I would have killed him with laughter.
Fast forward and where am I? Involved in the set-up of such a project. Not only did our team develop concepts for that, but also the hospital took shape in the real world. So it is possible.
How? Let me explain!
Table of Contents
What is model-based construction?
Nowadays, BIM models are most commonly used in the offices. Designers create 3D models, but for construction site delivery, it is still a 2D documentation with lines, hatches and dimensions. In essence, they are pressing the 3D world they created, back into a flat surface.
The main difference between model-based construction and traditional projects is the grade for BIM models’ utility – we take them outside the office, to the site. Designers create fewer or no drawings, instead, they use saved time to add more details and data to the models themselves.
On such a building site, you can find BIM Stations and workers using tablets to view the construction documentation. High-speed internet, required to process gigabytes of design data, might come either from a wi-fi set-up or a 5G mobile device.
There is provided specific software for intuitively viewing the documentation. Since all data is available at the fingertip models provide more information and possibilities. Frequently, the software is connected to the issue managers or quality assurance checklists and allows for communication with a team.
In short, a model-based building site is a fully digitalized construction where software takes the place of drawings and offline processes are replaced by tools working in the cloud.
The difference between drawingless and paperless construction site
You might find both of these two terms circulating the internet.
A paperless construction site indicates that there are no paper drawings delivered on site (no printers, no paper documentation delivery from designers). Drawings are accepted and commonly used, but viewed on phones, tablets and laptops. In such projects, designers create both models and official 2D drawings.
Drawingless projects don’t produce blueprints for construction documentation. They serve only to comply with law requirements and all workers on-site rely solely on BIM models. Designers don’t create official drawings, yet sometimes sketches are necessary (assembly details, layers sections, etc.)
To avoid unnecessary mockery that a project has a drawing that’s why cannot be called “drawingless” it’s better to use the wording “model-based” 😉
Model-based construction - what do you need?
Appropriate models
Prior to making the models submitted for construction useful on-site, a great deal of conceptual work must be done. Should contractors rely solely on models as documentation, they have to be created according to contractors’ way of working and their needs.
Hereby designers have to model, calculate and export a full set of properties. They must follow a defined level and structure of information so that a worker on site knows which object corresponds to the physical equipment he is about to mount.
Processes and information flow
New thinking about construction documentation gives space to rethink the processes of its delivery, storage and revisions. The new solutions should be fully digital, based on models and a Common Data Environment. They have to tie together what the designers create with what the contractors need, and above all this has to be in sync with the schedule.
Numerous processes in various stages of a project affect different stakeholders. I’ll just drop some of them, from which we have already discussed a few in our blog:
- VDC
- Lean Construction
- Issue management
- Common Data Environment
- IFC exports
- 14-0 process
Technology
Obviously, it is impossible to achieve a model-based construction site without the right tools. Choosing the correct set of software can be a daunting task. On our blog, you will find some articles about how to make this decision and what is available in the market (for example here or here). But in the end, they have to fit your workflow. The most important rule is that no software works alone in today’s world. They have to talk to one another.
Construction site
Possibilities
Introducing models to the site gives many possibilities by redefining processes and refining digital workflows. Every stakeholder profits from having a common data environment and all services online, available at the construction site. What’s more, a lot of emphasis lies on timely design and giving contractors the possibility to be a part of that work. This, in turn, results in fewer last-minute changes.
Moreover, each stakeholder can reap the benefits in various ways. Let me point out some of them.
Designers
Their main gain is dropping drawings themselves. Designers can cut hours spent on creating 2D documentation and revision management. Of course, instead, they use this time to align a model to higher quality requirements.
Thanks to projects committing to digital tools, designers can automate numerous mundane tasks. From model deliveries, through quality assurance reports and even properties assigning.
All that contributes to a better deliverable, so in the end, the designers get paid more.
Contractors
Contractors get much better spatial information and better-coordinated building. Many projects proved many times, that thanks to a BIM design, the number of clashes on-site drops dramatically.
Moreover, contractors have all technical information within the model, connected to objects. In fact, it helps them to create order lists much faster and with a narrower risk margin. By developing the model further, there is also a massive potential for off-site prefabrication and full automation of the ordering process.
In the end, contractors can work more efficiently and save money.
Building Owners and Facility Managers
By the end of the construction, a Building Owner receives a better building with loads of correct data and a model that he can use years after completion. This opens the possibility for accurate and easier Facility Management by using the BIM model (more information about that).
Challenges
Dropping the drawings has certainly its drawbacks. The first that comes to mind is of course money. Purchasing and maintaining additional hardware and software costs. Dropping the drawings doesn’t give any direct savings. Although it gives indirect savings by reducing the reworks and increasing the quality of the delivery.
Additionally, paper construction documentation has its advantages and some of them have gone missing with the transition to 3D models. We’ve heard feedback that workers miss visible annotations and the bird’s eye overview that give floorplans. However, software vendors are cracking their heads to fix those inconveniences. And some have succeeded in reintroducing these options within a 3D model.
As the biggest challenge, I would place a learning curve. BIM adoption is rather slow even for designers and building owners, although these organisations are already familiar with digital tools and technologies. In addition, to achieve a model-based construction site, we must reach out to each construction worker, provide them with full training and help them adapt to the completely new working conditions. This takes time and unfortunately fails many times.
Summary
Model-based building shows opportunities to deal with the standard branch challenges. It redefines how we see and understand the construction site. New technologies, new processes, new workflows.
Yet this comes for a price – the technology is in the development phase, processes are in the making and testing, not to mention any standards. Moreover, there are only a few example projects to learn from.
If you become interested and want to know more, you will find a lot of practical knowledge in our case studies about two model-based projects.
