“Design for Construction: The Federated Building Information Model (BIM) – This is the way”

Since the mid-1800s architecture and construction trades have been largely separate.? However, times are changing as owners increasingly demand relief from exorbitant construction costs and delayed timelines.? The industry has responded with better technology and a collaborative, data centric, BIM approach to project delivery.? Federated BIM has emerged as the user interface and “single source of truth” encompassing data from all the design and construction disciplines, in one model, to maximize the efficiency of downstream workflows including procurement, manufacturing, robotics, prefabrication, and field installation.? The following description of design phases below, followed by a Q&A section, outlines the real-life application of federated BIM.

Traditionally, projects are delivered through three successive design phases:

Phase I: Architect-managed construction documents, approved by Authority Having Jurisdiction (AHJ).

Phase II: Contractor-managed submittals (product data, shop drawings, samples, mockups, etc), prepared by the corresponding trade contractors, reviewed and coordinated by the General Contractor (GC), and approved by the Architect and relevant consultants (with deferred approval by AHJ, as applicable).

Phase III: Design additions and revisions initiated by the Superintendent, Field Foremen, and Inspector of Record (IOR).

Phases II & III often occur during construction, increasing the probability of delays, cost overruns, and quality issues. Submittals, RFIs, ASIs, COs, and Claims document the design additions and revisions in Phase II and III.

Q: Why isn't Phase II design performed during Phase I?

A:

1. Architects are often on a fast-track to submit construction drawings for AHJ approval, deferring submittal review to the construction period as part of their Construction Administration (CA) services.?
2. GCs are typically not onboarded until after AHJ submission, or their preconstruction services simply don't include submittals and coordination; these are part of their construction services.
3. Trade contractors, often needed to prepare submittals, are typically onboarded by the GC after AHJ approval.

Q: Why isn't Phase III performed concurrently with Phase II?

A:

Project managers, project engineers, detailers/modelers, and fabricators are generally responsible for Phase II design. Superintendents and foremen rarely contribute to submittal development as they are usually busy in the field-- where their greatest perceived value lies; this is “The Old Way”. ??

Q: Why is Phase III so problematic?

A:

Foremen delve into project details after on-site mobilization, raising questions about installation methods and trade coordination. Inspectors require missing details for inspection, and superintendents must coordinate among multiple trades. Labor resources may stall for days, weeks, or months while waiting for materials after new details are generated, submitted, and approved.

Q: How can Phases I, II, and III be combined BEFORE construction begins?

A:

Merging or running these phases concurrently allows for preconstruction coordination, prefabrication, enhanced preplanning, higher efficiency and quality, and lower cost. This approach leads to a complete and coordinated design BEFORE construction begins, greatly reducing RFIs, ASIs, COs, and claims during construction. Steps to achieve this include:

1. Define a collaborative design approach in your Request for Proposals (RFP) before selecting an Architect or GC.? Specify the required scope of services during design and construction phases, ensuring BIM development and updates throughout the project lifecycle.?
2. Onboard an Architect partner (and consultants) with strong VDC and construction experience who is open to collaborating with the trades during design.? Move much of the CA scope inside the Construction Documents (CD) and AHJ Approval phases.
3. Onboard a GC partner during Schematic Design (SD), ensuring they have strong design and VDC experience.? The GC must confirm that the design is on target with the Owners budget and must be familiar with design-phase key-trade buyout procedures.
4. Establish a "BIM Execution Plan", supporting a federated BIM, that includes every design discipline and key-trade. Develop the federated BIM to LOD 300 & 350 before construction begins and maintain it continuously until construction ends.
5. Use LEAN Last Planner System to map out the design phase and all the activities and commitments necessary to deliver a federated BIM that is ready for construction.
6. Onboard key trades before 50% Design Development (DD). Key trades vary by project but might include mechanical, electrical, plumbing, fire sprinkler, panelized walls/floors/soffits, steel, concrete, storefront/curtainwall, and conveying systems.? Use a best-value selection process with a fixed preconstruction cost for submittals/coordination and an “add alternate” for construction (Lump Sum).? This approach complies with the Public Contract Code for competitive bidding and meets the requirement to defer “construction” scope until after AHJ approval.? Design-build subcontractors, when applicable, would be onboarded even earlier utilizing a modified selection process.
7. Pair Field Foremen with detailers/modelers to ensure submittals reflect means, methods, materials, sequences, and details that support prefabrication and field installation.? This minimizes the occurrence of Phase III design.
8. Generate Construction Documents, submitted to AHJ, from a partial output of the federated BIM.
9. Obtain sign-off from all parties on the federated BIM to release early procurement of long-lead equipment and materials, while supporting manufacturing and prefabrication.
10. Implement a strict model-based "Layout & Control Plan" using fixed on-site control monuments for scanning, layout, verification, and inspection.

Q: What are the benefits of this approach?

A:

1. Improved Collaboration: A federated BIM serves as a single, authoritative resource, enabling cooperative collaboration among various parties and reducing mistakes and disruptions.
2. Enhanced Accuracy: The model offers a more precise depiction of building elements, allowing for early identification and resolution of potential problems, which is critical for precision fabrication and layout.
3. Cost Savings: By identifying conflicts/problems before construction begins and preventing expensive revisions during construction, the federated BIM reduces overall cost.? Additionally, labor and material costs are reduced through offsite manufacturing and prefabrication, along with savings from early procurement.
4. Time Savings: A federated BIM enables greater use of off-site manufacturing and pre-assembly, reducing on-site construction time and overall critical path.
5. Increased Sustainability and Durability: This approach contributes to sustainability by reducing material waste and minimizing the impact of human resources required during design, construction and over the life of the building.? The quality and durability of construction increases from the use of precision offsite machinery and assembly.
6. Intelligence and automation: the federated BIM is the path for integrating with robotics, AI, machine learning, and IoT into construction workflows.? Hold on to your hat—the way we design, build, and maintain our buildings is going to be awesome.

Q: Why do some firms and agencies struggle to adopt this approach?

A:

1.????? Misconceptions about timing: Many owners and architects believe that Phases II & III design can occur during construction without delays or added project cost. ?However, due to limited skilled labor resources and long material lead times, this is often not feasible. The process of compiling bids, subcontractor selection, GMP approval, subcontract issuance, and Phase II design submittals and coordination can take months to complete before materials can be released. ?This leaves little time for manufacturing and prefabrication, resulting in more work being done on-site at a higher cost.? They also believe that combining design phases will delay the design process and ultimately delay AHJ submission and approval.? This is also not true because the federated BIM accommodates streamlined communication and concurrent work among consultants and trades.? Many projects complete the design earlier than traditional because of this approach.

2.????? Limited expertise and perceived risk: Many parties have limited expertise in developing federated BIM and perceive significant risk. ?Architect firms (and their consultants) typically focus on producing 2D "Contract Documents" for owner approval and regulatory compliance, usually developing BIM to LOD 200-300 (with some that are not modeling at all). ?General contractors often don’t engage in early-stage BIM development and can't offer substantive input without their key trades. Architect firms (and their consultants) may refrain from active participation in late-stage BIM development as it's not part of their services or necessary for their main objective of AHJ approval. ?Their contracts often exclude determining the accuracy and completeness of dimensions, quantities, and installation or performance of equipment or systems.

3.????? Hard bid approach.? Many agencies still rely upon design-bid-build agreements that keep a wedge of separation between Phase I & II design.? The good news is that nearly every alternative delivery (DB, LLB, CM@R, PDB, PPP, etc.) can implement federated BIM and most agencies have shifted their programs toward alternative delivery agreements.

4.????? Handoff approach: A common approach is to "hand off" the model from the architect at LOD 300 during DD to the Contractor and trades for further development. The Contractor is then responsible for taking the "grossly coordinated" BIM and developing a “finely coordinated” BIM to LOD 300-400.? This can result in the architect dissociating from the federated BIM.

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Q: How do I maintain my timeline for AHJ approval and project completion with this approach?

A:

There is a reduction in both design and construction time utilizing this collaborative approach thanks to efficient platforms like Navisworks or Revizto.? Each design discipline collaborates inside the federated model with an abundance of data to achieve efficiency in their work.? One significant benefit is having the trades modeling continuously through the AHJ approval period so that the model is developed to LOD 350 prior to the start of the construction period.? This shaves months of the construction period without extending the design period.?

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Q: Does this increase the design/preconstruction cost?

A:

Yes, but there is a reduction in construction cost.? Understand that construction represents approximately 90% of the project cost and is the source of nearly 100% of delays, litigation and claims.? By moving a fraction of those dollars forward into the design phase you are achieving overall time and cost savings while also getting a better building and building experience.? Architect services need to include their coordination/engagement with the trades during phase II design period-- most intensely during the AHJ approval period.

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The approach of merging the three design phases through a federated model integrates traditional workflows of architects, engineers, GCs, and trade contractors. ?Establishing a clear scope of design services and selecting qualified design and construction partners is the foundation for success. ?This federated BIM approach promotes better resource utilization, reduces conflicts and lawsuits, and facilitates decision-making. ?As firms and agencies develop their understanding and expertise in this approach, the quality of the models, buildings and the overall building experience will continue to improve. ?As the industry continues to adopt this collaborative, BIM-centric approach, it will become clear that the old way is no longer feasible, paving the way for federated BIM to become mandatory.

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Fun Fact: The Hong Kong Government requires Building Information Modeling (BIM) to be used in the design and construction of all major (> HK$30 million) public capital works projects.