THERE’S NO PLACE LIKE HOME – BIM and the Multifamily Wood Project

Colt Highway Apartments, Farmington, CT

Less time and less waste. It’s the goal of any design team, right? Advancements in Building Information Modeling, or BIM, are allowing designers and constructors to take huge leaps in cutting construction waste, reducing field time, and trimming project budgets. However, basic BIM principles and other time and cost saving improvements are rarely utilized in wood multifamily construction. PES Structural Engineers is working to change the misconception that wood multifamily construction doesn’t warrant the use of BIM.  We’ve already realized huge benefits by utilizing and leveraging the process, and we are demonstrating that a BIM process does have a place within the multifamily project type.

Why BIM?

BIM is a general term describing either a model or the processes that allows a design team to go beyond the basic 2D construction documents and enhance communication with all project team members. A 3D model built with BIM principles is an invaluable tool. Designers and all project stakeholders are able to select a single element in the model and learn about its properties without having to flip through hundreds of pages of construction documents. The information is accurate, reliable and up to date.

Why aren’t BIM principles regularly used for wood multifamily construction projects?

Designers are faced with certain constraints that force them to convey design intent in schedules. While understandable, coordination with other systems is nearly impossible with this method of specification.  The coordination of wood buildings is usually staged from the field, largely because the tools and skill needed to change a wood element are considered to be much simpler than some other construction materials. While wood may be easier to modify than steel or concrete, time and cost are inherent side effects of field modifications. Even when 3D models are used during design, they are rarely accurate enough to be used for successful coordination. The lack of accuracy is mainly due to the constant battle against lower fees and shorter schedules.

How can this be improved?

Through the design and construction phases of a few similar projects, the BIM team at PES has recognized there are inherent issues with how these projects are typically completed. Realizing there are tools available to improve many common issues, the team began exploring resources and processes that go beyond typical design-intent models. The result is a construction service package.

The PES team uses Autodesk REVIT for the coordination of these projects, leveraging our advanced modeling capability as well as an additional rule-based framing software that sits on top of the REVIT platform. The virtual framing process starts with the complete structural/architectural coordination of contract drawings, ASIs and other supplemental information. Structural and architectural drawings, along with pertinent MEP (mechanical, electrical and plumbing) information are combined into one “intelligent” model. Coordinated documentation is released at key times during the pre-build and construction phases.

What issues were revealed?

When used on one project, several issues were discovered during the coordination phase. Discrepancies between the unit dimensions and overall layout dimensions were verified and coordinated ahead of time. Structural systems were introduced to the architectural model, ensuring a smooth fit prior to being constructed. These include wood, precast concrete, cast-in-place concrete and steel. Vertical coordination was also considered, including confirmation that load paths weren’t interrupted by any other systems. One often last-minute issue that arises during the coordination process is ADA and other permit compliance. While not reflected through a large drawing set, compliance issues can be very costly.

These problems might have remained hidden until on-site framing began, triggering a series of RFIs and costly change orders. It is far preferable to uncover the issues ahead of time, which is exactly what utilizing BIM accomplishes!

How do we move forward?

Relatively speaking, the BIM process is new in the construction industry and as with any new method, there are wrinkles that need to be ironed out. Certainly the earlier the coordination process can begin, the better for all parties involved. This helps with many aspects including acceptance of the process by the design team. Often times, identifying problems with the construction drawings can be seen as an attack on the quality of the construction documents by those who assemble the plans. It’s helpful for everyone to understand the intention is only to save time, money and waste in the field and in the design office. Another potential issue is the flow of information. Since the process will overlap with critical construction times, the supply of information can “dry up,” potentially creating issues for the entire build team.

This BIM or coordination process yields remarkable potential to reduce construction schedules, budgets and waste. It can add tremendous value to the project as whole. PES Structural Engineers is leading the charge in this new process. The PES BIM team is constantly challenging barriers and exploring new avenues to improve the process. To learn more about how BIM can save you and your clients time, money and field frustration, please contact Matt Sweeney.