A properly executed 3-D BIM model adds value to every aspect of a construction project, including improving safety, accelerating the schedule and reducing budget. However, it is not something that can be performed by a consultant alone and then passed off to a contractor to re-model for shop drawing development and installation.
The real efficiencies are only realized when both parties start communicating and sharing information and resources very early in the process in what is referred to as a unified workflow. Unified workflow is a single process in which each functional group of a construction project participates from the onset of design to the completion of construction.
For example, when a contractor has the ability to give input into design model items such as riser installation, equipment rigging, racking/modularization and rooftop equipment placement, they can all be evaluated and modeled to provide the safest and most efficient layout possible. Both the designer and contractor can usually strike an agreement that will allow for the most efficient installation, as well as meet the engineering requirements for the system.
These highly accurate design models also can be used to track and verify budget projections to ensure that the project is staying on track and that the unknown risks of coordination and construction are being properly mitigated well in advance.
Using a Unified Workflow for Successful 3-D BIM Models
There are three important areas to focus on when setting up a project that will utilize an efficient 3-D BIM model: people, process and technology.
The project team in a unified workflow is composed of four main leads: the project manager (PM), the project engineering lead (PEL), the project BIM lead (PBL), and the project constructability lead (PCL). Assigning these roles early and clearly laying out how each company will interact is critical to project success.
- The PM, like on many other projects, acts as the leader and main point of contact for the project. He is responsible for the design trade(s), subcontractor management, budget management and equipment procurement.
- The PEL leads the engineering team through the project’s design phase, selects and approves equipment to be procured for the job, and creates all of the construction documents. In a unified workflow, PELs are responsible for managing the modeling process and interfacing with the other design trades for coordination.
- The PBL manages all of the BIM technology from project concept to completion. This individual is responsible for reviewing the RFP for BIM requirements and facilitating the creation of the BIM execution plan based on project requirements. A BIM execution plan should be a roadmap that any architect, designer or contractor involved with the project and should be able to use in order to understand the required process and expected deliverables.
- The PCL acts as the liaison between the engineering group and the construction team. This person leads the constructability review process, and also manages the coordination and spooling processes once the design is at an acceptable level of completion to ensure that the integrity of the design intent is preserved during the coordination effort.
Properly incentivizing and motivating each member of the team is critical to the successful implementation of the unified workflow. It is important to recognize that the design group is typically contracted to produce a functioning design and a model that has some high level spatial coordination. The contractor adds its value by spatially coordinating and inserting content to make the model and resulting construction documentation useful to the field forces responsible for prefabricating and constructing the building.
Each company involved (from design through construction) must participate in a high-level scheduling process that sequences all of the required activities to complete the project. This includes sequencing the design submissions to match the construction schedule so the project can avoid instances where design changes significantly impact construction.
For example, in a design-build or design-assist style of project where construction will begin before the completion of design, items like the underground design, basement design and long-lead equipment submittals need to be finalized and issued for construction long before the rest of the building to ensure that those systems can be coordinated, procured and installed properly. For this to function properly, both the design and construction groups need to be contractually motivated to submit design packages in a fashion that protects the contractor from late design changes and allows the designers to budget and allocate their resources appropriately to complete the design in phases. If the schedules and contracts are set up properly from the beginning, the team will be enabled to properly complete constructability reviews, reduce drafting and modeling re-work, and input the proper levels of information into the model from the start as opposed to scrambling at the end of the process to input data.
Before any BIM 3-D modeling occurs, a plan must be put in place that dictates what technology will be implemented and how each team member will share information. The specifics of the software platforms, server locations or cloud applications are irrelevant as long as a decision is made early in the process that provides guidance for the team. This plan is called the BIM execution plan and should be created by the project BIM leaders to ensure proper integration of each software platform that will be utilized on the project. This plan needs to include all phases of the job from design to coordination to construction.
In short, using proper 3-D BIM modeling in a unified workflow allows the entire project team to plan efficiently, budget intelligently and allocate resources properly. When every trade coordinates the people, process and technology, all phases of the project are bound to be a success.