Denver’s Airport Expansion Pushing Toward BIM for Facility Management
Denver’s Hotel and Transit Center Program is an ambitious project that combines a commuter rail transit center and a 519-room Westin hotel to create a new gateway to the main terminal that incorporates sustainability goals.
The building information modeling (BIM) process employed for the design and construction of the Hotel and Transit Center Program at the Denver International Airport (DIA) is a unique and forward-thinking effort that kicks off an even more ambitious airport-wide BIM conversion that will greatly improve ongoing facility management and maintenance. DIA is the fifth-busiest airport in the United States, and the largest in terms of area (53 square miles), which means that there’s a lot to manage—and maintain—at this international airport.
According to Mark Hughes, BIM manager at AECOM for DIA, “53 million passengers pass through the airport on a yearly basis, and about half of those passengers are origination/destination passengers, which means they’re coming and going from the airport. That’s a lot of wear and tear on roads and infrastructure.”
Any airport project poses challenges given the need for added security, to report precise building location for the oversight of the Federal Aviation Administration (FAA), and to minimize inconvenience to travelers. DIA’s BIM model-based approach aids a faster construction pace with coordinated project timelines and impressive collaboration around a central model, but this project is just the start for the airport’s broader vision.
To achieve the facility-wide BIM effort, the airport first contracted with AECOM to scope and manage an overall airport BIM plan. The airport expansion with the Hotel and Transit center provided a great test project for a fully integrated BIM effort. This program-specific BIM management work is being spearheaded by HNTB. Both the airport and program-based BIM managers and design and construction teams work together to aggregate and integrate the model with other core systems.
DIA is nearing 20 years in age, which means the facility has increasing maintenance needs. Noting the benefits of BIM on the Hotel and Transit Center Program, DIA moved to implement BIM for use in the day-to-day asset management of the entire airport facility. When fully implemented, DIA hopes the BIM system will make maintenance of the airport infrastructure more efficient, which in turn saves time and money, and improves quality.
“For DIA, it was really about reducing redundancy and carrying the building model throughout the whole lifecycle of the project,” notes Eddy Krygiel, AIA, LEED AP, and formerly director of Design Technology, HNTB. “I know that sounds so cliché, because everyone says it, but they want to do it, and they’re actually doing it.”
DIA’s push toward BIM for maintenance is strategic for long-term benefits. This building effort is the first step in a conversion of the whole airport into using the BIM model as the primary source of data for facility management.
“When BIM first became available, the airport saw the benefits of connecting to the facility-management process,” says Dennis Rodriguez, AIA, project manager, Transportation and Aviation at AECOM, and the first member of the airport’s BIM implementation team. “The goal in mind was to establish a fully integrated facility-management workflow and avoid the dreaded failure-management pitfalls. This new process provided an opportunity for some housekeeping and content management.”
When the airport was built in the early 1990s (opening in 1995), the move from hand drawing to CAD was still fairly new. As a result, there are many drawings, but they were all on various disks, drives and file cabinets. A first step to the overall BIM project was bringing more than 9 million CAD files together in one place so they can be cataloged.
Unfortunately, because of the limitations of this prior technology, there’s no ability to identify which files are the most accurate. This points to a key benefit of a model-based approach where the model is updated continuously and becomes the central point of truth. Getting to the point of coordination, and integration with other systems, took a lot of staging, with 18 months of planning before any project documentation began.
“We knew it was going to be a very large project team, and we would need to do some planning to keep things organized,” adds Krygiel. “We tried to predict the obvious issues and create a number of workflows to help solve those problems before they arose. One of the biggest problems that you have on projects is that team members don’t model enough, or they model too much. Our goal was to create guidelines on what would be modeled and what wouldn’t, so the process was predictable for everyone.”
Getting to consensus wasn’t the easiest process as the team needed to talk to all the firms involved about collaboration on the BIM process. At first, many companies held back because they felt the process was too unique.
On the design side, 25 different firms created models and content, with some of those firms having multiple models, for more than 40 models total. On the construction side, there are 10 firms creating content across 25 different disciplines.
“I don’t think anyone, design or construction, was used to an owner that has this level of engagement,” notes Will Lineberry, design technology manager, HNTB. “The significant integration, and airport-wide scope, is much greater than most owners would tackle.”
Early in the process, there were weekly design review meetings where any problems were discussed and resolved. Later, the move was toward spatial coordination, where the model was analyzed for design or construction conflicts. Now the project has moved to construction-model coordination, where all the trades are modeling how it will be installed, down to hangers and flanges. The teams meet twice weekly to check for conflicts on upcoming work.
The construction fabrication model comes back into the Revit model, and gets justified and inspected to verify that everything is within tolerances spelled out in the BIM plan. If there’s a discrepancy, an RFI is generated, and the Revit model gets realigned so it always reflects what happens on the construction site.
At the end of the project, the client will have an as-constructed Revit and Navisworks model that will connect to DIA’s commissioning data. The building will be commissioned, and the commissioning data will go into a SQL database. The Revit model will be linked to the SQL database as well as the Maximo facility-management system.
“Designers really need to think as if they own it—they can’t just create a set of documents,” adds Hughes. “You have to have the mindset that you’ll need to come back to the model, and it will inform all that you do in the future. We’re in the process of originating the perpetual as-built.”
The all-digital approach was a challenge for some firms, as it meant a change in how they had been doing work up to this point.
“Our approach all along was that we needed to engage all disciplines (civil, infrastructure and vertical design, as well as construction groups for each of those), and they all have had very isolated views of how they do work,” notes Hughes. “The infrastructure guys really focused on that and had no perception of how to integrate with vertical design, and vice versa. There has traditionally been an isolated approach that each would get their job done independently, but BIM requires everyone to engage all disciplines all the way through.”
Another problem, beyond the need to educate different groups of the whole design process, concerned issues of ownership and liability. With a seamless flow of models, the disconnects between the design and finished building go away. Significant issues of building performance previously occurred in isolation, without validation from engineers nor simulating the impacts of mechanical changes.
Traditionally, documenting that change would happen in an RFI process, but often it would never get returned to engineers, and it wouldn’t get recorded back in a drawing. Most times, job-site changes don’t impact mechanical performance when they aren’t fully constructed as designed. Another issue, however, is when clashes in ductwork or piping occur, leading to a time-consuming and costly fix.
The owner understands that paying for changes during construction is the most expensive point in the process. Clashes balloon into a huge cost, so if they can be handled during design, it has cost benefits. When implementing BIM, there are cost savings in reduced work and change orders that are hard to quantify, as money that isn’t spent can’t be tallied.
Job-Site Model Access
With such a large job site, and a coordinated central model, making the model accessible to workers has always been a goal. Given the issues with unwieldy plan sets, contractors were willing to try electronic file sharing with iPads.
Without this digital device, there would have been a need to coordinate, store, share and secure thousands of paper plans onsite. Instead, there are daily updates on all iPads, and each of the trades can have a copy of the most-current model in-hand.
Workers can be looking at an iPad and a detailed model for tying rebar. This is done with Autodesk’s BIM 360 Glue, which allows them to easily visualize the 3-D model, pan around and see the plan in context to where they’re standing. With so many workers actively using the model onsite, it’s not uncommon to see 15 to 20 people holding an iPad. The feedback has been very positive for its ease of use and quick, up-to-date access.
The time saved and safety gains of not having workers walking across an active job site are further factors that are difficult to quantify in terms of dollar value.
“Just think of the guy checking rebar up on level five, and the amount of time it takes to walk down five flights of scaffolding, walk 1,500 feet over to the trailers, try to sort through plans to find the one with the detail he is looking for, think through it, and then make that return trip,” adds Hughes. “He has that model in his hand on an iPad, with the detail he needs, looking right at the install and seeing if it matches the model, and doing that within minutes. Simple analysis like that bears a lot of witness to the benefit of the technology integration in our everyday work.”
An additional benefit is that everyone involved in the process has access to the model, where they can see it and use it to visualize the building in a way that makes sense to them. Having that detail, they can understand the points of assembly and how their work fits into the overall process, identifying any problems well in advance.
“With all the graphical representations and notations, everyone doesn’t know what the notations mean in the model, but they won’t admit that in a meeting,” says Rodriguez. “But, if we link it to a model and a graphic representation where they can see it getting built, it’s communicating, and they can speak to it from the executive level all the way down to the guy with boots on the ground. They truly understand the schedule, and then we have time to plan and get input on how to correct any problems.”
Point of Truth
The airport uses CAD, BIM and GIS on a regular basis for a number of different operations. GIS is the “repository of truth” for deliverables to the FAA and to provide a less-granular view of the world. New information is provided by BIM platforms (Civil 3D or Revit) for authoring. In addition to being the authoring tool, BIM is used to integrate all building infrastructure, and Maximo is used for facility management. To maintain the synchronicity of these systems, there are bi-directional updates to all systems on a regular, scheduled basis.
“Up until the point of BIM becoming the primary authoring tool, maintenance was generating its own information in Maximo from construction documents that was 100 percent manually entered,” notes Rodriguez. “GIS was similar, because everything had to be manually entered from CAD tools, and the technician had to manually attribute the drawing. In both, the criticality of the data depends on how much the data-entry person knows or cares, and that’s how that system started falling apart.”
BIM information comes from the authors in design or construction processes. Designs are created by experts, with the model corresponding to the exact location through survey input. The models are detailed with attributes and specifications that can be pushed to Maximo and GIS, with no manual data entry at any of the integration points. And the model is just a starting point for some of the more-detailed facility-management tasks.
BIM has become the primary authoring tool for new and ongoing projects at DIA. The model will be used for maintaining the critical systems that run the airport: mechanical, electrical, plumbing and security. The process is about creating a detailed model that informs all ongoing actions, and not on creating visualizations.
Although this major expansion illustrated the full scope of a BIM project, from transition to operations, DIA also has been using this approach to capture information in other parts of the airport on smaller projects. It wouldn’t be cost effective to create a highly detailed as-built for the whole facility, but by expanding the model with each project, they will slowly fill in the gaps in the model. Where there are gaps, there’s an overall skeletal model for the entire facility that then accepts the greater detail as it becomes available.
An ongoing benefit of the model is the ability to perform detailed feasibility studies. A new element can quickly and easily be designed and scoped, based on a detailed model of what’s currently there. If the project is approved, then the early conceptual feasibility work helps to “jump start” the design. Having the model eliminates the need to survey and measure and capture what’s there. Avoiding lengthy and expensive consultant time on feasibility studies adds up to major savings through time.
This effort is truly at the forefront of BIM model adoption for this scale, scope and integration with operations. Although there are clear benefits, there are also many hurdles.
- HNTB refined the BIM process and is in charge of managing the BIM process.
- AECOM is working with DIA on the overall BIM for facility management.
- Parsons Transportation Group serves as program manager.
- Gensler is the architect of record for the hotel.
- Anderson Mason Dale is the architect of record for the Public Transit Center (PTC).
- Kiewit is providing all the earthwork, enabling and horizontal work.
- Mortensen Saunders, Hunt (Tri venture) manages the vertical work.
View this video from the project site: