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Outline the team’s experience with Building Information Modeling.
Structural Engineers Group, Inc. (SEG) is very experienced with the use of Building Information Modeling (BIM). We currently perform essentially all (greater than 99%) of our new project drawing production utilizing Autodesk Revit. Revit is the BIM platform of choice for the majority of our clients. In our discussion here, BIM and Revit will be used interchangeably. Although AutoCAD can still be utilized by SEG, it is only used on older, continuing projects with architects who still use CAD or on very small, quick delivery details on projects that are not BIM specific. All of our Engineers and BIM/CAD Technicians are very familiar with Revit, with the majority being quite proficient in its use in a structural BIM environment.
Lessons learned working on hundreds of BIM projects in Revit since 2007 are on-going. The more information on setup and procedures that can be coordinated among the different disciplines (Architect, Structural, MEP) the better the project documents progress and the better the final BIM product. We have found in working on major projects like the UF-368 Reitz Union Expansion and minor projects like UF – Watson House Repairs in St. Augustine, that one of the better ways to control the coordination of BIM Elements (individual pieces of the “Model”) is to develop a project specific BIM Implementation Plan Manual. We have been very fortunate to work with some Architects who are extremely adept at using Revit and we have been involved in the updating of the project BIM Implementation Plan and have used these lessons to update and improve our use of BIM.
Similar to project specific BIM Implementation Plans, SEG has developed its own “Revit Design Manual”. This Manual is a living document based on lessons learned from the projects on which we utilized BIM. More comprehensive than the way CAD drawing preparation was handled in the past, this BIM Manual allows for maintenance of tighter control of all aspects of production. After completion of each project, the SEG BIM Manual is updated to capture the best workflows and modeling practices. With each yearly Revit version update, the latest enhancements of the software are documented and incorporated into our workflows.
We started using Revit in 2007 with some minor projects but our introduction to Revit and the BIM environment truly began on a large, complicated project (not the preferred way to begin using Revit). An example of small project use of Revit is on the Design and Detailing of the Façade Addition to the Shands Hospital for Children. This project was performed as an addition to a building that was not originally produced in Revit but the area of renovation (original face of the building) could be isolated into its own BIM Model with the new details added to the BIM model.
Lessons learned, in addition to the need for a BIM Implementation Plan and a BIM Manual, include the items listed below. These lessons pertain generally to large projects but have also applied to the Minor Projects we have worked on:
- To model effectively, the user must be able to think and design in a three-dimensional environment and be able to combine this thinking with consideration of constructability.
- The accurate modeling of the BIM Elements to constructible geometry and precision is paramount.
- Models from Architects are not usually as precise as SEG requires, thus we build a separate structural BIM for each project.
- BIM elements must coordinate with more precise construction details illustrated in drafting views.
- The use of common base points and elevation datum is paramount in properly linking and/or overlaying BIMS.
- Use of worksets is important. They not only allow multiple users to simultaneously access the BIM file, but they are a powerful organizational tool for BIM Elements allowing visual control of the Elements in referenced views.
- The Design Team should agree and commit to a workset setup which in return will enhance coordination and presentation of the construction documents.
- The front end of the project, i.e. Design Development, currently requires much more effort on a BIM project than on a traditionally produced project. In some instance BIMs are built and then discarded. In some unusual cases this BIM rebuilding happens beyond the 50% construction documents submittal. Effective decision making in the programming of space requirements, life safety, and construction type needs to be implemented early in the project by the design team. Although rarely the case, we have seen this work very well when accomplished prior to the Design Development submittal.
- Construction document presentation must be developed prior to starting view layouts and modeling in the BIM environment. This needs to be agreed to by the Design Team prior to the submission of Design Development.
- To prepare the construction documents effectively, the user must be able to visualize how the plan, section, and elevation views can be strategically developed to capture and illustrate complex geometries in a fashion that can be easily interpreted by the construction team on 2-dimensional construction documents.
- All geometry and construction assembly should be captured in the BIM environment to the Level of Detail defined in the BIM Implementation Plan. This is very important for coordination. Modeling BIM Elements one way and defining construction another in drafting detail defeats the purpose of BIM.
- A firm should start on a small project as their first exposure to Revit – one with no real time constraints if possible.
- Users must work locally on their computer and save often to a central file on the project server.
- All of the above boils down to the need to plan ahead, coordinate the team members, be aware and be careful!