BIM on site

Environment, information and communication

Introduction

Implementing the BIM methodology in the construction phase is a major challenge, as neither the pace nor the way of working are the most suitable for developing a digital model. The project undergoes continuous changes and we have to make quick decisions to adapt to the reality of the execution. However, the use of BIM can bring us considerable benefits. Let’s look at three key aspects to take into account: environment, information and communication.

Environment: Changes in execution and deadlines

The deadlines for the execution of a project are always tight and, as we know, changes are going to occur during this phase. So, even inheriting a very accurate digital model from the executive project, this is a disadvantage when applying the BIM methodology on site. In order for the model to be functional on site, it must adapt to the pace of the work and not the other way around, and this means prioritizing. If we do not proceed in this way, we could be delaying the decision making process on site in order to finish the model, which should never happen.

Thus, the model must have the level of detail necessary to allow us to carry out a spatial coordination prior to the execution of the elements, hence anticipating delays and cost overruns.

If the time available is not sufficient to coordinate all elements, we should prioritize by taking into account the discipline that is likely to generate the most problems or those elements that have the greatest economic impact.

Example: The project for a building has been developed with lifts sized according to the specifications of a specific manufacturer. Once the contract has been awarded, the lifts are changed to another manufacturer, and these lifts do not have the same dimensions. In order to make this modification quickly in the models without affecting the execution of the floor slabs, it is sufficient to model a prism indicating the dimensions of the shafts that are finally necessary.

Information: models, drawings and other documents

Having a 3D model as well as BIM software allows us to produce and manage information in a very agile way. We highlight four main virtues:

Working drawings and sections

In the event that it is necessary to do a replanning on site or simply that the documentation of the executive project is not sufficient, BIM allows us to create working drawings and sections required easily. The fact that we can massively change properties of model elements or make annotations by means of tags that read parameters, make this process much faster than with “conventional” methods.

Quantity Take-Off

With a properly prepared model we can do quantity take-off of elements and line items and therefore we can make work certifications. We recommend that you take a look at our quantity take-off guide.

Progress of the work

Having a 3D model also makes it easier to control the progress of the work. This way we can monitor whether we are on schedule, which revisions should be prioritized or obtain “photographs” of the state of the work on different dates (useful, for instance, in cases of litigation).

• Example: The reinforced concrete structure of a project is being built. From the BIM model we can extract lengths, areas and volumes of slabs, beams and columns. We can show the measurements of any element in a schedule, and, if any of the lengths change, we update the model and automatically our schedule is up to date. If we add the information of the week in which it has been executed, we can also filter and extract the data for the periodic certifications.

Asset management

Construction companies are responsible for collecting, validating and delivering all asset information to the owner once the work is completed. If we are able to enter this data into the model, we will have all the information centralized and accessible for the possible subsequent management of the assets.

The difficult part of this task is getting the necessary information into the models, especially if the suppliers have no knowledge of BIM. But this is also solvable. For example, at Modelical we have developed a web application to facilitate this task for suppliers.
They can easily fill in all the required information on the assets they have installed on a site, and the construction company has all the information collected, ready for the handover of the project.

Communication: information exchanges

As important as having the models and documentation that we generate updated to the pace of the work is to be able to communicate it to the rest of the stakeholders involved. If any stakeholder works with obsolete information, it is very likely that we will have errors.

At BIM level it is important to work with federated models (models where models from all disciplines or stakeholders converge) that allow the rest of the teams to see the latest modifications as soon as they happen. For this it is necessary to choose a appropriate Common Data Environment (CDE). The CDE not only allows the management of the models, but also of other documents such as drawings, meeting minutes, photographs, technical data sheets, etc.

• Example: Prefabricated parts are to be installed on the façades and the company in charge is modelling the anchorages. They have studied the necessary modulation and have detected that the positions of these anchorages interfere with other elements. Each change is regularly uploaded to the CDE, allowing the teams concerned to view the updated 3D model and immediately review the documentation.

In any case, although we are seeing more and more tablet devices on construction sites, the reality is that in most cases we are still dependent on paper. It is quite normal for the technical manager or the site manager to be disconnected from the BIM part but, despite this, BIM can help us to ensure that the “papers” they work with are up to date and are not drawings or documents with an infinite number of accumulated changes written or drawn in pencil or pen with which the traceability of the information is called into question. But it is also true that the use of BIM continues to grow in the construction sector thanks to its benefits, so it is not unreasonable to think that in the not too distant future we will be able to do away with paper.

Conclusions

BIM management on site involves anticipating problems and solving them before they have major implications that can have repercussions on deadlines and costs. To do this, it is essential to develop a strategy that considers everything from how we are going to model and what uses we are going to make of this model to how we are going to communicate between teams.

As anticipated by our colleague Almudena in the post Project Management and BIM Management the former must incorporate the latter.