How It’s Done, and Why We Do it?
The following post is part one of a three-part series detailing how the Gilbane Virtual Design and Construction (VDC) team actively engages in risk mitigation throughout a project’s life. This post covers “Gap” Modeling. Part two will describe a BIM-supported procurement, and part three discusses Design-Assist Support Operators.
In the construction industry, risk mitigation is a critical component of project management. Ensuring that projects are completed safely, on time, within budget, and to the required quality standards involves issue identification and constructability analysis before issues become costly problems. Gilbane’s VDC team accomplishes this by leveraging building models in various ways. One approach to our risk mitigation strategy is “Gap” Modeling. This technique utilizes 3D modeling software and constructability knowledge to produce visual elements for the coordination model that are not captured in traditional design models or contract drawings and are, therefore, termed “scope gaps.”
To perform “Gap” Modeling, VDC uses a variety of 3D modeling software. These elements, or “gaps,” include various scope items and can include existing condition elements, scope installation or maintenance clearances, and discrepancies between contract drawings and design models. By creating a comprehensive visual representation of these scope gaps, project stakeholders can better visualize, coordinate, and plan their work, reducing the risk of issues arising during the installation process. While subcontractors or 3rd Party modelers can sometimes handle this, VDC often offers a project-wide approach that reduces friction from construction deliberations while protecting the interests of the entire construction project.
By revealing what is not on the contract drawings, teams can develop more comprehensive models that help projects more effectively.
Examples of Gap Modeling for a Construction Project
- Scope Clearances: Ensuring adequate space for all components to be installed and maintained without interference. For example, a foundation zone of influence is an element that a design team would rarely model but has a tremendous impact on the routing of underground utilities.
- Discrepancies Between Contract Drawing and Design Model: Identifying and resolving differences between the contract documents and the design model, such as the accurate sizes of concrete piers and foundation walls per the structural details.
- Existing Conditions Captured in Scans: Laser scans will capture the site’s current state and incorporate this data into the model. For example, an existing Fire Protection system will be modified.
- Early Fast Track Items: Modeling elements like sleeve locations, beam penetrations, and pre-cast concrete openings early in the project.
- Civil Scope: This includes civil engineering elements to ensure coordination between trades outside and inside the building footprint.
VDC Team Case Studies
- Fast-Track Scope Items: In the Northeast Metro Tech High School Project, the VDC team was responsible for extracting, analyzing, and informing early bid package subcontractors regarding penetration locations through pre-cast slabs, steel beams, and structural framing. Although this isn’t a modeling practice, VDC gathers information from the design model to perform educated guesses and provide sketches to the subcontractors to inform their early submittals. This allows our teams to deliver on a faster schedule.
- Concrete Pier Collars: In the Northeast Metro Tech High School project, we noticed that the concrete pier collars required an additional 3″ of concrete outside of the base plate. A superintendent caught this in the field, and the VDC team immediately modeled it to ensure the coordination model accurately reflected this condition.
- Existing Fire Protection: For interior projects like the Whoop HQ Relocation, our VDC team performed reality capture to aid coordination efforts through point clouds. The point cloud was then utilized as a background for VDC to model the existing FP system, ultimately providing a product that can be used in coordination for clash detection. This enabled all parties, including the FP subcontractor, to better use the model to coordinate their respective scopes.
- Civil Utilities: In the Gladstone Elementary School project, our VDC team oversaw the modeling of exterior utilities, which facilitated collaboration between interior and exterior trade contractors. Civil trades typically operate in CAD, which can lead to coordination challenges. By integrating these elements into the 3D model, the team ensured all inverts matched, preventing costly rework.
Gilbane’s VDC team provides the expertise necessary to account for these unknowns through an understanding of modeling tools and constructability, minimizing the impact of potential issues on the job site.
Improved stakeholder communication and enhanced project predictability are significant benefits of VDC “Gap” Modeling. Identifying and addressing gaps early reduces the likelihood of unexpected delays and cost overruns, leading to more successful project outcomes. Bridging the “gap” through effective modeling is not just a strategy for risk mitigation; it is a pathway to more efficient and predictable construction projects.
Comments
Cheryl Benn
Great article, Alex. Very informative on the benefits of Gilbane’s VDC team. Thank you.
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