BIM Plan to Execute: Adding Tunnel/Road Capacity to Existing Thimble Shoal Tunnel
This article presents the initial planning, pre-execution, and execution stages of a BIM-driven project to create a new two-lane tunnel under Thimble Shoal Channel. When complete, the new tunnel will carry two lanes of traffic southbound and the existing tunnel will carry two lanes of traffic northbound.
The project design is quite a challenge, as it’s meant to connect to an existing highway and tunnel system in such a way so as not to disturb the flow of traffic during construction. Using Civil 3D, Revit, Navisworks, and additional Autodesk software, we were able maximize our use of the model data, not just for construction documents but also for analysis. Coordination of not just the design data, but also the various teams and interests on the project were integral to making it successful.
BIM Execution Planning
Key Project Challenges
a. Adding highway capacity to existing Thimble Shoal Tunnel.
b. Designing additional tunnel and road capacity, keeping in mind that construction can not interfere with existing tunnel operations.
c. Coordinating design and construction with multiple offices and consultants.
d. A tight schedule.
Key Technical Challenges
a. Needing to accommodate different skill sets and capabilities amongst project team members and consultants.
b. Starting the BIM execution planning and modeling, right after the pre-design stage.
c. Working with large geotechnical datasets for borehole analysis along tunnel length.
d. Coordinating design and construction with multiple offices and consultants
Where to Begin
We began the planning by looking at the scope of work and contract details to get an overall view of the total extent of the project. From there we worked with individual team members and managers to get an idea of the amount and type of structures that are being proposed or are existing, as well as the services needed to be provided to each.
I also like to get any existing renderings, project descriptions, site photos, and other types of identifying information from the proposal stage, as to help more conceptualize the entire project. Care must be taken to not use out of date material of course.
We then started to fill out our BIM execution plan template in as much detail as possible. We used an amended BIM execution plan template that was a combination of existing resources from Penn State, the Army Corp of Engineers, as well as prior Mott MacDonald projects. The plan included the following:
Contacts, Roles, and Responsibilities
Goals and Uses
Collaboration Procedures and Resources
Most of the project information as it was filled in on the BIM execution was gathered from the engineering services agreement. While important to fill in the information as much as possible, we decided to keep the amount of overall information to a minimum, as we did not want to duplicate information that was kept elsewhere, or run the risk of information not being up to date.
Key Points: Project Information
a. Use centralized source
b. Keep it concise
c. Think like the person reading it
d. Keep it precise
e. Avoid placeholder info
f. Avoid dated information that is sourced elsewhere
Contacts, Roles, and Responsibilities
We had contact list information from the very beginning of the project contained within the project execution plan, making filling in information about the engineers and managers easy. The challenge was to correctly identify the staff that would be doing production work and matching them up with an associated BIM role on the project, as we had multiple disciplines participating, some in different offices. This was where it was important for us to have designated local resources within each office, for example local office BIM/CAD managers, who could help us to identify the proper staff.
Over the course of the project the list of contacts also had to stay malleable, as we brought on additional consultants and internal project team members. The roles definitions we put in place were taken from internal definitions that Mott MacDonald had put in place for BIM projects. These roles and their definitions, once the kick off meeting took place, were properly explained to the management staff, and described within the BIM execution plan.
Key Points: Contacts, Roles, and Responsibilities
a. Use well-defined roles
b. Define role assignments as soon as possible
c. Some staff will serve in multiple roles
d. Explain the reason for the roles to management
Goals and Uses
The goals and uses were gleaned from team discussions and discovery of bid, pre-design materials available. With a project of this size, potential goals and uses were discussed as much as possible up front, but we did happen to come across new uses for the model as the project progressed.
Guiding the projects managers in the understanding of what BIM is from a functional standpoint, versus a higher level what they may have seen in presentations, gave them a better understanding of what the models could be potentially used for.
Key Points: Goals and Uses
a. Use well defined goals and uses
b. Check for existing corporate definitions
c. Look for additional areas of use
d. Work with engineers to explain the functional benefits of BIM
For us, defining the schedule for data exchange was kept as a moving target, because the project schedule tended to be in flux, due to its complex nature. For most of the project, we modeled to the level of detail required for contract drawings and some scheduling when feasible, with exceptions for space proofing in areas of concern or areas where visual analysis was important.
Key Points: Data Exchange
a. Be flexible with the upfront data exchange dates
b. Try to keep the level of detail in line with your BIM goals and uses
c. Identify key areas for additional detail